It is currently vital to use more environmentally friendly cementitious composites, such as blended slag-limestone cements. However, many properties of slag-limestone cements are not yet fully research, especially in regards to the effect of limestone properties on properties of mortars and concrete. In the research, three types of slag cements were mixed with two types of limestone to obtain multi-component slag-limestone cements. Tests of rheological properties, heat of hydration, and compressive strength were conducted to ascertain the effect of limestone on the cement properties and to check the viability of this type of cement for engineering practice. It was found that the addition of up to 10% of limestone to slag cements did not have negative effects on tested properties; however, the exact influence of limestone was dependent on limestone particle size distribution. Increasing the amount of limestone in limestone-slag cements to 15% significantly decreased the compressive strength of the mortars and decreased hydration heat but had no significant effect on rheological properties. Currently, cement production is responsible for 5–8% of all anthropogenic CO2 emissions, and available data indicate that this percentage will increase in the next few years [2 emissions in clinker production are a result of a process of chemical breakdown of raw materials, mainly calcium carbonate CaCO3, during the clinker firing process and the high energy demand for this reaction to occur, as the temperature in the cement kiln reaches over 1450 °C [2, in which at least 0.6 t is a direct result of the reaction of calcium carbonate chemical breakdown [Sustainable development policy poses an ongoing challenge for the cement industry due to the harsh restrictions on COew years . High COWhile there is research conducted into alternative methods of clinker production, for example, by Ellis et al. , the mosLimestone is one of the main non-clinker components of cement in the countries that are members of Cembureau  due to iSlag-limestone cements have been the subject of research, which indicates that there might be a possibility of the synergistic effect of limestone and slag ,19,20. T3A to form carbonaluminates makes it possible for CaCO3 to act to a limited degree as a regulator of the setting time [Aside from the physical effects on the hydration process, calcium carbonate reacts with reactive aluminates from Portland cement clinker . This leing time ,25,26. Ting time ,28 and Bing time , also ining time .The current state of knowledge about lime-slag cements does not, however, allow for unequivocal determination of how the content of limestone and blast furnace slag affects the rheological properties of mortars and concretes. Courard and Michel  assessedInter-grinding the constituents;Designing the composition of cements from separately ground ingredients; andIntroducing limestones as a constituent of concrete (additive type I according to EN 206 ).There are three ways of obtaining slag-limestone cements:The first two methods are available only to cement plants, while the last method of obtaining slag-limestone cements is also often used in concrete plants and thus may prove to be more universal.Therefore, the presented research aims to test the basic properties of the slag-limestone cements obtained by mixing easily obtainable industrial Portland slag cements CEM II/A, B-S, and slag cement CEM III/A with ground limestone in amounts of 5, 10, and 15%. There were two types of limestone used to better see the influence of the limestone characteristic on the properties of slag-limestone cements. In the course of the research, conducted were rheological tests of yield stress and plastic viscosity after 5 and 60 min from the moment of mixing all the ingredients, compressive and flexural strength after 2, 7, 28, and 90 days of curing, and heat of hydration in the first 72 h of the reaction.The tests were performed mostly on mortars, with the exception of the heat of hydration test, which was performed on cement paste. The composition of all mortars used in the research was based on a standard mortar composition  and preparation, as described in EN 196-1 . The mixM-shear resistance moment, g-shear resistance, h-viscous flow resistance, N-rotational speed. In this equation, the flow limit τ0 corresponds to the shear resistance g, and the plastic viscosity ηpl-the viscous flow resistance h. The sample was put in the apparatus immediately after mixing. The single test lasted 5 min, and its exact course is shown in The rheological tests were performed in rheometer Viscomat NT  with fishbone probe, and simplified Bingham’s model was applied to calculate the values of rheological parameters:The compressive strength of mortars was tested after 2, 7, 28, and 90 days of curing. The preparation of samples and the testing process were performed according to the standard EN-196-1 . After mThe heat of hydration was measured by the isothermal calorimetry method in TAM air isothermal calorimeter  on cement paste for 72 h from the moment of adding water to cement. The measurement was conducted according to standard , at a teTo obtain the slag-limestone cements, three types of commercially available slag cements: CEM II/A-S 52.5N, CEM II/B-S 32.5R, and CEM III/A 42.5N, were mixed with two types of limestone, labeled T and B.The chemical and phase composition of the slag cements is presented in 3 is higher than 75%. XRD  of the limestones, presented in Two types of limestone were used: limestone B and limestone T. Their chemical composition is presented in 2/g (marked as “1”) and around 9000 cm2/g (marked as “2”). The actual specific surface area of all limestones is presented in Limestone T and B come from different quarries and different geological formations. Limestone B comes from Jurassic strata and limestone T from Triassic strata. Both limestones were ground in a ball mill to two specific surface areas, around 5000 cmThe proportions of the slag-limestone cements used for the research are presented in The results of rheological tests of multi-component slag-limestone cements obtained by homogenization of Portland slag cements with limestone T1 and B1 are presented in The addition of limestone B1 to cement caused an increase in the yield stress in mortar with cement CEM II/A-S 52.5N and, to a lesser extent, CEM III/A 42.5N. The yield stress of mortar with CEM II/B-S 42.5N with limestone B1 decreased slightly for 5% addition of limestone, but for the addition of 10–15% remained similar to the yield stress of reference mortar. The effect of the addition of limestone B1 on yield stress after 60 min of mixing is difficult to gauge due to the great variability of the obtained results. However, a general trend of increase in yield stress can be noticed for all types of cement.The results indicate that the yield stress is dependent on the type of limestone used. This effect could be connected with the particle size distribution of the limestone. Limestone B is characterized by a discontinuous distribution of grains and a high content of coarse grains, which can be detrimental to yield stress. Limestone T, being of a continuous particle size distribution and having less-coarse grains, did not influence the yield stress in a negative way, even decreasing it in the case of cement CEM II/B. It was previously established that in the given range of variability, the specific surface area of limestone does not influence yield stress in a significant way ,42.It should be noted that the type or amount of limestone did not affect the loss of workability in time to a significant degree, as the type of cement played a decisive factor. There was no indication that in the range of 5–15% of limestone content, there is a clear trend linking the amount of limestone to the change in yield stress. The yield stress of mortars with CEM II/A-S 52.5N increased by 31% in the first 60 min after mixing, while yield stress of mortars with CEM II/A-S 52.5N with limestone increased by 20% on average, with the lowest increase of 8% for the addition of 5% of limestone T1, and highest increase of 29% for addition of 10% of limestone T1. For mortars with cement CEM III/A 42.5N, there was no notable change in the loss of consistency, with the 17% increase in yield stress in 60 min from mixing of reference mortar and average yield stress increase for mortars with limestone being 18%. Only in the case of mortars with CEM II/B-S 42.5N, the addition of limestone T1 and B1 could cause an increase in yield stress after 60 min of mixing. For reference mortars, the yield stress increased by 18% during the first 60 min of mixing, while in the case of mortars with CEM II/B-S 42.5N and limestone, the average increase in yield stress was 29%.In the case of plastic viscosity, the results of which are presented in This, similarly to the results of yield stress measurements, can be attributed to the difference in the particle size distribution of limestone.The addition of limestone to cement has an effect on the increase in plastic viscosity during 60 min from adding water to cement. In the case of mortars with CEM II/A-S 52.5N, there was no increase in plastic viscosity during the first 60 min of hydration, both in the case of reference mortar and mortars with slag-limestone cements. However, for reference slag cements with high content of ground granulated blast furnace slag, the plastic viscosity increased in time: for CEM III/A 42.5N, the increase was 17%, and for CEM II/B-S 42.5N, the increase was 20%. This may be connected to the fact that the cements with high content of ground granulated blast furnace slag are characterized by lower density, meaning that the volume of binder in mortars is higher; this leads to an increased tendency to form a gel structure and intermolecular connections .However, the addition of limestone stops the increase in plastic viscosity, as an average increase in plastic viscosity for mortars with CEM III/A 42.5N and limestone is only 4%, and 0% in the case of CEM II/B-S 42.5N . This effect may be due to the fact that plastic viscosity increase is mostly dependent on the concentration of the clinker grains and their flocculation ,45. The The results indicate that in relation to rheological properties, there might be an underlying issue of compatibility between the cement and limestone. It can be seen that the mortars with CEM II/B-S 42.5N and limestone show signs of quicker workability loss; however, more tests are required to fully present the possible negative interaction between limestone and slag cement. The rheological properties of slag-limestone cements have not been well described in the available literature; however, obtained results show the same relation as tests of consistency conducted by Courard and Michel , who alsThe heat of hydration during the first 72 h of hydration of slag-limestone cements with limestones T1 and B1 is presented in The addition of limestone to cement reduces the heat of hydration after 72 h. The decrease does not depend on the type of limestone, as the difference between the heat of hydration of slag cements with limestone T1 and B1 is, in every case, less than 0.5%. The range of decrease in the heat of hydration after 72 h is not equal to the amount of clinker that was replaced by limestone. This effect indicates that the presence of limestone has a positive effect on the effectiveness of clinker and/or ground granulated slag hydration. As can be seen in Limestone is a mostly inert constituent of cement, with only up to 5% of limestone mass present in cement undergoing a reaction with alumina phases to form calcium carboalumiate ,47. WhilThe effect of limestone on the hydration of slag and clinker is also reflected in the course of the heat flow rate , where iIn the presence of limestone, a significant drop in maximum heat of hydration can be observed, which is linked with the decrease in clinker content. On the other hand, however, there can be observed a shortening of the induction phase. This effect can be attributed to the increased speed of alite reaction in cement in the presence of limestone. This is due to the previously mentioned filler effect and the nucleation seeding of limestone. This effect is most pronounced in the case of CEM II/A-S 42.5N, which is connected to the fact that it has the highest content of Portland clinker.It should be noted that the presence of limestone also causes an increase in the second heat flow maximum. This effect is the result of an increase in the intensity of the reaction of ettringite formation in the presence of GGBFS . In the Similar effects were observed by Xuan et al.  and KuchThe results of the compressive strength test for slag-lime cements are presented in The addition of limestone in the amount of 5% of cement mass did not negatively affect the compressive strength of all slag-limestone cements. In some cases, there was an increase in compressive strength after 2 and 7 days, especially visible in the case of CEM II/B-S and CEM II/A-S. The increase was up to 6%. This effect can be linked to the physical effect of limestone on clinker hydration; small limestone grains can act as a nucleation seed, accelerating the clinker hydration ,54, whicThe addition of limestone to slag cement in an amount of 10–15% reduced the strength of cements both in the early (2 and 7 days) and later  periods. The decrease in average strength at 15% limestone content, i.e., the maximum amount tested for slag cements, is about 10%. The largest decrease in strength, even by 24%, is observed for CEM II B-S. The decrease is, naturally, linked to a lower content of the binder in the slag-limestone cements. In the case of the addition of over 10% of limestone, the effect of clinker dilution is more pronounced than the beneficial effect of limestone on the rate of hydration. However, it should be noted that, in general, the decrease in strength is less than the percentage of limestone. As it has already been noted, limestone is an almost inert component for which the effect on strength is virtually negligible. Slight decreases in strength are, therefore, a sign of the beneficial effect of limestone on the hydration of clinker and granulated blast furnace slag. However, it should be noted that for the tested slag-limestone cements, cements with a content of 5–10% limestone met the strength class requirements for slag cements from which they were prepared. It was not until the 15% limestone content that the cement strength class was decreased.The type of limestone had an effect on the early compressive strength of mortars with CEM II/A-S and CEM II/B-S. At the two- and seven-day mark, the differences between slag-limestone cements with limestone T and B were up to 50%; however, after 28 days of curing, there was no discernible difference in compressive strength of mortars. The same cannot be said for mortars with cement CEM III/A, in case of which mortars with limestone B were characterized by higher compressive strength in early stages; however, after 28 days, mortars with limestone T have similar or higher (up to 20%) compressive strength than mortars with limestone B.The specific surface area of limestone did not affect the compressive strength after 28 and 90 days. The difference between the compressive strength of mortars with different specific surfaces did not exceed 5% for both B limestone and T limestone; therefore, the effect could be considered negligible, as the standard deviation was, on average, around 3%. At earlier dates, however, differences of up to 30% in strength can be seen in the case of limestone B1 and B2. Interestingly, the cements with limestone with a lower specific surface area had exhibited consistently higher strength. This effect may be connected to the higher water demand of finer limestone fraction ,56. The The compressive strength to hydration heat ratio of the multi-component slag-limestone cements is shown in The compressive strength after 2 days is proportional to the hydration heat generated. This relationship is linear but not strict. This may be due to the fact that the analysis of multi-component cements includes three different cements with different strength gain rates and very different hydration heat, which may disturb the results. It should be noted that the relationship between the heat of hydration and compressive strength of mortars was a subject of research by Yoda et al. , as wellThe effect of limestone addition on the rheological properties of the mortar was dependent on the type of limestone. The addition of up to 15% of continuous-graded limestone to slag cements did not influence yield stress and plastic viscosity in a significant way, while the addition of gap-graded limestone caused an increase in yield stress and decrease in plastic viscosity. This may indicate that the different effects of both limestones on rheological properties may be dependent on the particle size distribution of limestone;Introduction of limestone to cement composition reduced the heat of hydration after 72 h. The decrease was dependent on the amount of limestone;The introduction of limestone to slag cement increased the heat generated by a gram of slag cement. This effect may be attributed to the nucleation effect of limestone. Fine grains of limestone act as nucleation seeds for clinker, increasing the hydration rate;No effect of the particle size distribution of limestone was observed in regards to hydration heat development;The substitution of slag cement with limestone in amount up to 10% of cement mass did not negatively affect the compressive strength of all cements; however, a decrease in compressive strength occurred for mortars with 15% of limestone in cement, especially in the case of blended cements based on CEM III/A 42,5N;The type of limestone had an effect on the early compressive strength of mortars, with the continuous-graded limestone to slag cements were characterized by higher strength than mortars with gap-graded limestone. This effect was not observed after 28 or 90 days.In the presented research, tests of rheological properties, the heat of hydration and compressive strength of mortars with blended slag-limestone cements were obtained by homogenizing commonly available slag cements with two types of limestone T and B in amounts of 5, 10, and 15% of cement mass. Conducted research leads to the following conclusions:Obtained results indicate the possibility of wider use of limestone in the composition of cement and/or concrete with granulated blast furnace slag due to the synergy effect resulting from different properties of these components. To definitively put those types of cements into practical use, more testing is, however, necessary, connected to the compatibility issues of slag and limestone, durability, and properties of concrete with slag-limestone cements.


This article describes a new technique for the preparation of hollow fiber (HF) membrane samples using an automatic manipulator unit. The manipulator uses a syringe needle to form a HF of a given geometry. The needle in automatic mode is sequentially immersed, first into the polymer solution and then into the coagulation bath. The possibility of using a manipulator to obtain HF samples was studied on the known polysulfone (PSf)/N-methylpyrrolidone (NMP)/pore-forming additive system. A series of HF membrane samples were made within 29 h from twelve 1 mL PSf casting solutions. This was 15 times faster than obtaining samples of HF membranes at the multifunctional research laboratory facility. From the point of view of the consumption of the components of the casting solution, the use of the manipulator was 30 times more economical, and the consumption of water for precipitation and washing was 8000 times less. The developed method made it possible to study samples of HF by scanning electron microscopy (SEM), ultrafiltration, and evaluate its mechanical properties without spinning the membranes. Using the new technique, the optimal composition of the casting solution for the wet spinning of HF PSf membranes was selected during two weeks. Thus, the manipulator makes it possible to significantly reduce the time of the new membrane preparation, reduce the volume of used polymer, and thus makes it promising to study expensive or new membrane materials. In general, the structure and material of the membrane must correspond to the separation process for which the membrane was created. In membrane separation, both flat and hollow fiber (HF) membranes are used. HF polymer membranes are most often prepared from natural and synthetic polymers by the solution method using the phase inversion process . The maiembranes , which sembranes ,5: the membranes .The initial solution, consisting of only one phase, breaks down into two: a solid polymer, which forms the matrix of the membrane, and a liquid, which forms pores in it. Due to contact with the non-solvent (coagulant), the upper surface quickly precipitates, forming a dense, selective layer. This layer slows down the penetration of the non-solvent agent into the polymer sublayer, which is deposited much more slowly and forms a more porous structure. The thermodynamic properties of the system and the kinetics of solvent and coagulant exchange have a strong influence on the morphology of the membrane, which in turn determines its transport and separation properties. Thus, for the manufacture of HF membranes with different transport and separation properties, it is important to select a polymer, a solvent, and a coagulant (non-solvent agent) for this ,6. HowevThere are a large number of scientific papers on the influence of the conditions of HF formation on their membrane properties. The results of more than 160 scientific publications including studies on 23 industrial polymers were collected in the review by Feng et al. . The 201Polysulfone (PSf) is one of the most common polymers for the manufacture of HF membranes for micro-, ultrafiltration, gas separation, and membrane contactors ,13,14. IAll of the above works describe the production of HF polymer membranes on laboratory installations of dry-wet casting, which is associated with the production of a large amount of fiber, 200 m or more. The main problem is that to study the effect of casting conditions on the membrane properties of HF membranes, such a large amount is not necessary. In addition, the production of large volumes for research purposes entails large losses of reagents , and the time from the beginning of solution preparation to the formation of the membrane can take up to three days.Another key factor in the preparation of polymer membranes using non-solvent induced phase separation is the determination of the membrane formation time, which is limited by the precipitation rate of the polymer solution. Usually, this is done by determining the diffusion coefficients of the coagulant in the “unlimited layer” of the polymer solution ,20. ThisTherefore, a method for determining the precipitation rate in a “limited layer” of a polymer solution was developed, which enables us to determine not only the precipitation time of a membrane with a given thickness, but also to predict the porous structure of the future membrane .Thus, the purpose of this work was to select the composition of the casting solution and the conditions for HF membranes formation with external precipitation using new express methods for studying the properties of the polymer solution and polymer membranes.® S 6010 granules . N-methylpyrrolidone (NMP)  99% extra pure was used as solvents. Pore-forming agents were introduced into the solution:-polyvinylpyrrolidone (PVP) K 30 with a molecular weight of 40,000 g/mol produced by Sigma Aldrich Co. LLC, St. Louis, MO, USA, presented as a white powder; and-polyethylene glycol (PEG400) in the form of a yellowish liquid with a molecular weight of 400 g/mol and a dynamic viscosity of 120 MPa s produced by Acros Organics, Waltham, MA, USA.In this work, polymer casting solutions and membranes were prepared from a commercial polymer-polysulfone (PSf) in BASF UltrasonA model dye Blue Dextran with a molecular weight of 69,000 g/mol produced by Sigma Aldrich Co. LLC, St. Louis, MO, USA was used to evaluate the separation properties of the produced samples of HF membranes.Group I: PSf-NMP;Group II: PSf-NMP—5 wt% PVP; andGroup III: PSf-NMP—5 wt% PEG400.Twelve casting polymer solutions of various compositions with a volume of 10 mL were prepared . SolutioIn each group, PSf concentration varied from 15 to 24 wt%.The components of the solution were mixed in a glass bottle at a temperature of 80 °C, then degassed and filtered for 24 h. A magnetic stirrer IKA C-MAG HS 10 was used for stirring.A Brookfield DV III-Ultra rotary viscometer produced by Brookfield Engineering,  was used to measure the viscosity of the polymer solutions. Measurements for each of the solutions were carried out at a temperature of 25 °C. Three viscosity measurements were carried out for each polymer solution.d) of 300–400 µm was formed, open to the atmosphere on one side. The channel was then filled with a PSf solution. The sample with a polymer solution was fixed on a slide. Using a Pasteur pipette, a coagulant (water) was added into the polymer solution from the side open to the atmosphere, and the process of phase separation of the PSf solution was observed using a microscope and recorded on a video camera.To study the kinetics of the precipitation of PSf polymer solutions, the “limited” layer technique was used . This end, µm) to the time of its precipitation .The kinetics of polymer precipitation was evaluated using the precipitation rate of a polymer solution in a layer of a given thickness. This was calculated as the ratio of the total thickness of the polymer layer  and z (movement of the carrying needle perpendicular to the polymer platform) and of the polymer platform with bottles in axis y  as well as the contact time of the carrier needle with the casting solution and the coagulant. To obtain each short-sample of the HF PSf membrane, an algorithm for the movement of the carrier needle and platform with bottles was created, consisting of the following commands:Using a carrier needle, a wet method of forming HF membranes was carried out. The speed of the carrier needle movement along the x, y, z axes was selected relative to the viscosity of the casting solution. Distilled water was used as a coagulant. The contact time of the needle (carrier of the polymer solution) with the coagulant corresponded to the time of precipitation of this solution in the “limited” layer. After precipitation, the samples were washed alternately in two bottles with water. During one cycle of operation of the manipulator, 12 short-samples of HF membranes were formed. The maximum fiber length was 75 mm.Scanning electron microscopy (SEM) was used to characterize the structure and morphology of the membranes. SEM was carried out on a Thermo Fisher Phenom XL G2 Desktop SEM, Waltham, MA, USA. Cross-sections of the membranes were obtained in liquid nitrogen after preliminary impregnation of the specimens in isopropanol. A thin (5–10 nm) gold layer was deposited on the prepared samples in a vacuum chamber (~0.01 mbar) using a desktop magnetron sputter “Cressington 108 auto Sputter Coater”, . The accelerating voltage during image acquisition was 15 keV. Further image analysis and determination of the selective layer thickness was carried out using the Gwyddion software .Mechanical characteristics were studied using a TT-1100 bursting machine  at room temperature (22–24 °C). The traverse travel speed was 3.8 cm/min. The samples possessed a length of 70 mm. The initial distance between the clamps was 50–60 mm. Young modulus was determined by the slope of the initial stress-strain dependence close to the rectilinear section at strain values not exceeding 5%. The stresses were calculated on the initial cross-section of the sample.The study of the permeability of the prepared short-samples was carried out in an installation as shown in P is the permeability (L/m2 h bar); V is the volume of the taken sample (l); t is the sampling time (h); S is the surface area of the selective layer of the short-sample of the hollow fiber (m2); and Δp is the overpressure (bar).The permeability was calculated using the formula:R is the rejection (%); pC is the concentration of the solute in the permeate (mg/L); and fC is the concentration of the solute in the feed stream (mg/L).The calculation of the rejection rate was conducted with the formula:To measure the rejection, an aqueous solution of Blue Dextran (MM = 69 kg/mol) with a concentration of 100 mg/kg was prepared and used.In order to predict the properties of future hollow fiber PSf membranes and to select the casting conditions, the first stage of the work was carried out to study the properties of all prepared casting solutions. Their dynamic viscosity was measured .As PSf concentration increased from 15 wt% to 24 wt%, dynamic viscosity increased monotonically . For PSfIn addition to the dynamic viscosity, the precipitation rates for all prepared casting solutions were investigated. The precipitation rate was studied using the “limited” layer method, which most accurately simulates the process of forming the wall of a HF when it is prepared .CPSf = 15–18 wt%) and high-concentration (CPSf = 20–24 wt%). Analyzing the obtained values of the deposition rates for all solutions, it can be concluded that for PSf-NMP solutions on going from 15 to 18 wt% and from 20 to 24 wt%, the deposition rate decreased by 28%, for PSf-NMP-PVP solutions by 25%, and for PSf-NMP-PEG400 solutions by 15%. However, when going from low-concentration to high-concentration solutions, there was a sharp decrease in the deposition rate by about 60% in all groups. This effect is possibly associated with an increase in the viscosity of solutions during PSf concentration, which exhibits an exponential character  . In grouAs shown in In order to explain the data obtained from the precipitation rate and time, the Hansen solubility parameters were analyzed for the pore-forming agents, NMP solvent, and water coagulant .δp) and for the formation of hydrogen bonds (δh) were comparable for PVP  and NMP . Therefore, the dissolution of PVP in the coagulant (water) took longer than the dissolution of PEG400, which was why the precipitation process itself took longer in the group of polymer solutions with PVP.The SEM method showed that in the absence of a pore-forming agent, large spongy pores were formed (PSF-20 and PSf-24 membranes). Introduction of 5 wt% PEG400 in solutions with the same concentration led to a decrease in the diameter of the spongy pores. At the same time, at a PSf concentration of 24 wt%, a denser near-surface selective layer with a thickness of about 30 µm was formed in the membrane. Addition of 5 wt% PVP in PSf-NMP solutions led to the preparation of a membrane with the densest support layer.To date, the use of a carrier needle does not enable one to control the wall thickness of the resulting HF membrane. The lack of alignment in the HFs is presumably related to some deviation of the carrier needle from an angle of 90°. At the same time, this is an advantage from the point of view of studying the evolution of the porous structure of the membrane along its wall thickness. Thus, for example, in PSF-20 and PSf-PVP-24 membranes, when the wall thickness increased from 200 to 350 µm and from 220 to 400 µm, respectively, macrovoids began to form in the support sponge layer. In PSF-PEG-18 and PSf-PEG-20 membranes prepared from group II solutions, finger-shaped pores formed along the entire wall at a thickness of about 50 µm. However, with an increase in the wall thickness in these membranes, the layer with finger-shaped pores was replaced by a dense support layer with spongy pores. In addition, the wall thickness increased with an increase in the viscosity of the solution [The influence of the composition of the casting solution for the preparation of short-samples of hollow fiber PSf membranes using the manipulator was studied from the point of view of the mechanical properties .All short-samples of hollow fiber PSf membranes were examined in terms of permeability  and the 2 h bar; from group II from 178.7 to 35 L/m2 h bar; and from group III from 475.6 to 0.1 L/m2 h bar. At the same time, introduction of 5 wt% PEG400 significantly increased the permeability of PSF-PEG400-15 and PSf-PEG400-18 membranes compared to the PSF-15 and PSf-18 membranes. The latter were made from similar solutions, but without the addition of a pore-forming agent. When PSf concentration increased to 20 wt%, there was a sharp drop in the water permeability in group III solutions to 28.6 L/m2 h bar in the PSf-PEG400-20 membrane. With a further increase in PSf concentration to 24 wt%, the formation of a near-surface dense layer with a thickness of about 30 µm  of PSf-PEG400-15 was 87.8%. The reduced R and high P for this membrane relative to the others seem to be due to the high ratio between PSf and PEG400, equal to 25%, which led to a less dense structure with finger-shaped pores.All short-samples of HF PSf membranes, except for PSf-PEG400-15, had a high rejection of 99.9%. The rejection  made it possible to calculate and compare the material and time costs for the manufacture of samples of HF PSf membranes on the manipulator and at the laboratory facility. The calculation of the cost of the components of the mixture for both methods of production is presented in Analysis of the consumption and cost of the mixture components required for the preparation of 12 molding solutions demonstrate that the use of a manipulator to obtain research samples of HF membranes was 30 times economically more profitable than the laboratory facility. At the same time, the calculation did not take into account the consumption of distilled water and the energy consumption for its production for 12 solutions: the precipitation and washing bath of the laboratory facility of 2880 L vs. precipitation and washing bath manipulator of 360 mL.The calculation of the time costs showed that the manipulator reduced the time to obtain research samples of HF membranes from 12 spinning solutions by almost 15 times.In order to analyze the influence of the composition of the casting solution on the morphology, mechanical, transport, and separation properties of the HF membranes, a new unique manipulator based on a 3D printer was designed. The manipulator used a syringe needle to form a HF of a given geometry. The needle in automatic mode was sequentially immersed first into the polymer solution and then into the coagulation bath. Special software was developed for the manipulator, which enabled us to obtain the speed of the carrier needle along the x, y, z axes and the platform with containers for various purposes  as well as the residence time of the carrier needle within the casting solution and the coagulant. During one cycle of operation of the manipulator, 12 short-samples of HF membranes formed from solutions of various compositions.The possibility of using a manipulator to obtain HF samples was studied on the known PSf/NMP/pore-forming additive system. A series of HF membrane samples were made within 29 h from twelve 1 mL PSf casting solutions. This was 15 times faster than obtaining samples of HF membranes at the multifunctional research laboratory facility. From the point of view of the consumption of the components of the casting solution, the use of the manipulator was 30 times more economical, and the consumption of water for precipitation and washing was 8000 times less2 h bar with the rejection of the Blue Dextran model dye (MM = 69 kg/mol) of 99.9% over the entire range of PSf concentrations in the casting solution. Moreover, these membranes demonstrated higher strength  compared to the other samples. Taking into account the combination of morphology, mechanical, transport, and separation properties of short samples of HF membranes, casting solutions of 20 and 24 wt% PSF in NMP with the addition of 5 wt% PVP pore former are the most suitable compositions.Having analyzed short-samples of HF PSf membranes, it was found that the best transport and separation characteristics were demonstrated by the membranes prepared from solutions with the addition of 5 wt% PVP with a PSf content of 15 to 24 wt%. The permeability of the membranes varied from 178.7 to 35 L/mThus, the new manipulator makes it possible to significantly reduce the time of the technological process of polymer membrane preparation and the volume of used polymer, which makes it promising to study expensive or previously unknown new membrane materials.


COL1A1, COL2A1, COL9A2, COL9A3, COL11A1 and COL11A2. In addition, the role of genes COL1A2, COL9A1 and others is being actively studied. (4) Conclusions: In our review, we summarized and systematized the available information on the role of genetic factors in IVD collagen fibers turnover and also focused on the functions of different types of collagen present in the IVD. Understanding the etiology of impaired collagen formation can allow doctors to prescribe pathogenetically-based treatment, achieving the most effective results.(1) Background: The purpose of this review is to analyze domestic and foreign studies on the role of collagen-encoding genes polymorphism in the development of intervertebral discs (IVDs) degeneration in humans. (2) Methods: We have carried out a search for full-text articles published in e-Library, PubMed, Oxford Press, Clinical Case, Springer, Elsevier and Google Scholar databases. The search was carried out using keywords and their combinations. The search depth was 5 years (2016–2021). In addition, this review includes articles of historical interest. Despite an extensive search, it is possible that we might have missed some studies published in recent years. (3) Results: According to the data of genome-wide and associative genetic studies, the following candidate genes that play a role in the biology of IVDs and the genetic basis of the processes of collagen degeneration of the annulus fibrosus and nucleus pulposus of IVDs in humans are of the greatest interest to researchers:  Intervertebral disc degeneration (IVDD)  is a comThe etiology of IVDD as a multifactorial disease includes a genetic predisposition and exposure to environmental factors . Over thThe genetic aspects of turnover  of collagen fibers and their role in health and disease are under active study. The largest number of works is devoted to collagen of bone tissue and internal organs. The number of studies concerning genetic predictors of collagen formation in the IVDs has increased in recent years, but there is a need to systematize the existing data.The purpose of this review is to analyze domestic and foreign studies on the role of collagen-encoding genes polymorphism in the development of intervertebral discs (IVDs) degeneration in humans.We have carried out a search for Russian-language and English-language full-text articles published in e-Library, PubMed, Oxford Press, Clinical Case, Springer, Elsevier and Google Scholar databases. The search was carried out using keywords and their combinations, including intervertebral disc, degeneration, candidate genes, genetics, genetic predisposition, back pain, collagen and intervertebral disc disease.The search depth was 5 years (2016–2021). In addition, this review includes articles of historical interest. Despite an extensive search, it is possible that we might have missed some studies published in recent years.COL1A1, COL1A2, COL2A1, COL9A1, COL9A2, COL9A3, COL11A1 and COL11A2.We analyzed 324 publications, of which 38 met the objectives of this review, including 20 associative genetic studies of SNVs of candidate genes predisposing to IVDD development: One of the most important functions of the IVDs, protection from mechanical damage, is realized due to the mechanism of reversible deformation of the structure and is possible to a large extent due to collagen fibers. There are ethnic features of the structure of collagen fibers and the cellular composition of the IVDs, but with age, the IVDs becomes thinner, more rigid, less tense and less elastic. Changes also occur in the structure of collagen fibers. Specifically, with age, collagen fibers become more disorganized; the diameter of collagen fibers decreases in people up to 45 years old, while in people after 45 years old, the collagen fiber becomes coarser and more rigid .Collagens play a key role in the regulation of cell migration and differentiation; it has a signaling function since proteins of the cell surface bind to it . CollageCollagens are present in all anatomical structures of the spine, including: IVDs; intervertebral joints; ligaments, tendons and muscles; membranes -protective layers that surround and nourish the spinal cord; and blood vessels ,17.In humans, like in other vertebrates, 28 types of the collagen are currently identified , encoded by at least 45 different genes . The comCOL1A1, COL1A2, COL2A1, COL9A1, COL9A2, COL9A3, COL11A1 and COL11A2  and the impact of environmental factors. Internal factors include the state of the hormonal background; the genetic code of the structural elements of the IVD, inherent at birth; epigenetic regulation of the activity of genes encoding key proteins and enzymes of collagen formation. Thus, the role of collagens in the mechanical and elastic functions of IVDs is great, which explains the growing interest of researchers and clinicians in studying the predictive role of single nucleotide variants (SNVs) of genes, encoding collagen types I, II, IX and XI in the development of IVDD:  COL11A2 . COL1A1, COL1A2, COL2A1, COL9A1, COL9A2, COL9A3, COL11A1 and COL11A2 genes . Ty. TyCOL11COL11A1 gene and IVDD. The frequency of the 4603T allele was significantly higher in the patients with IVDD than in the healthy controls ..79].COL1A1 gene with an increased risk of IVDD [COL1A1 gene has been studied, but its association with IVDD in the Iranian population has not been reliably proven [COL1A2 gene in the development of IVDD is questionable, which explains the need for additional studies in various racial and ethnic groups of patients.Many recent studies show the clinical significance of the association of the rs1800012 polymorphism of the  of IVDD ,29,30,31y proven . At the COL2A1 gene are predictors of the development of IVDD in adult patients [In 2016 and 2017, two similar associative genetic studies were carried out, the first of which showed that the SNVs rs2276454 and rs2070739 of the patients . The secpatients .COL9A1, COL9A2 and COL9A3) in the development of pathological processes in IVD is also being actively studied at the present time. At the same time, increased attention of researchers has been paid to the genes COL9A2 and COL9A3. The rare Trp2 allele (rs137853213) of the COL9A2 gene has been well studied. As a result, it was shown that the inheritance of the Trp2 allele is associated with IVDD in the families of all patients [The role of SNVs of the genes encoding type IX collagen chains  of the COL11A2 gene were associated with certain abnormalities of the IVD surface and signal intensity from it according to MRI data. In the same study, the SNV of the genes COL1A1 (rs2075555) and COL9A1 (rs696990) also provided reliable evidence of an association with the presence of pathological signals from IVD according to MRI of the spine [Another large study, conducted with the participation of Finnish men, showed that two SNVs (rs1463035 and rs1337185) of the COL11A2 gene, but also that another SNV of this gene (rs986522) significantly increases the risk of lumbar IVDD in women [A study by Yang X. et al. in 2018, in the Chinese Han population, not only indicated an association with degeneration of the lumbar IVD in the rs2071025 SNV of the in women .Some limitations of our study should be noted . First, The authors undoubtedly see the need to plan and conduct large, randomized studies on the pathology under consideration with the inclusion of representatives of different ethnic and racial groups, different age groups of both sexes (men and women).With more than 20 unique SNVs of candidate genes associated with IVDD, the molecular changes in the associated collagens or pathology of the IVDs are not yet fully understood. In the coming years, research targeted toward fully understanding the protein changes of extracellular matrix of IVDs due to the already identified SNVs is crucial. If we can fully understand the molecular changes involved in IVDD, then creating targeted therapeutics based on genetic profiling becomes a possibility. With improved understanding of the genetic variants associated with IVDD and rapid genomic analysis available through next-generation genotype sequencing and DNA tests, the possibility of providing effective personalized medicine can become a reality in the future ,81,82.COL1A1, COL2A1, COL9A2, COL9A3, COL11A1 and COL11A2. In addition, the role of genes COL1A2, COL9A1 and others is being actively studied. This is important for the development of modern methods of drug and non-drug strategies for the prevention and treatment of IVD pathology.According to genome-wide and associative genetic studies, the following candidate genes that play a role in IVD biology in humans and the genetic basis of collagen degeneration of the annulus fibrosus and nucleus pulposus are of the greatest interest to researchers: A large number of SNVs of the candidate genes are being actively studied as genetic predictors (biomarkers) of dysfunction and collagen degradation as one of the mechanisms of IVDD in adults. On the one hand, this indicates the relevance of the problem from a scientific and clinical point of view. On the other hand, this indicates that, at present, there are more questions than answers about the genetics of the interdisciplinary spine pathology under consideration.


Table 1 of the main manuscript, and Table S2 of the supplementary material, the authors described the results of exploratory factor analyses. In both tables, the CATI item labelled “I would describe myself as a very sensory-sensitive person” is mislabelled and should read “I am over-sensitive to bright lighting”.In The correct text for this item was used in the supplementary material relating to the distributable version of the CATI, and in the CATI materials on the CATI website.the abstract, the sample sizes of studies 1, 2 and 3 were incorrect and referred to the number of non-autistic participants recruited in each study instead of the overall sample size. These were originally listed as 1119, 1068, and 195, respectively. The correct sample sizes are Study 1 = 1166, Study 2 = 1119, and Study 3 = 202.In These sample sizes were correct in the main article body and in the additional file of the article.Following publication of the original article , the autThese errors do not impact the conclusions of the article. The original article and Additional File Additional file 1. Supplementary tables and figures.Supplementary tables and figures


Cancer is a genetic disease caused by mutations in DNA and epigenetic alterations that control gene expression. The majority of epidermoid carcinomas develop within the fields of epithelial genetic alterations. The mechanisms underlying tumorigenesis of epidermoid carcinoma are as yet unknown; therefore, precise identification of the risk factors is needed. Aim: The main aim of this study is to analyse and identify the emergence of the mutations described in the literature of the p53 gene with regard to the emergence of cancer in a sample of dysplastic and cancerous lesions in oral cavity mucosa in the population of the south of Spain, in order to determine the presence of said mutations and the percentage of them in our population. A cross-sectional study was carried out, with a sample size of 22 patients with potentially malignant oral lesions ancillary to biopsy. All were patients, of both sexes, over 18 years of age from the Virgen del Rocío University Hospital with potentially malignant lesions in oral mucosa ancillary to biopsy . An anatomopathological study was performed on all the samples and the lesions were divided into three types: low-grade dysplasia, high-grade dysplasia and squamous cell carcinoma. In respect of the genome study process, a complete search or scan for mutations in exons 5, 6, 8 and 9 of the p 53 gene was carried out, given that in the IARC database we observed that the 5 and 6 as well as the 8 and 9 exon sizes can be scanned completely in this way, since they have amplificon sizes of 476 and 445 base pairs respectively. In the scan for the complete exons 5, 6, 8 and 9 only a single result of interest was found to be described. In patient NBI 57 a change was observed in the TAT triplet by ATT of EXON 6, the change being of the T nucleotide by the A and in both directions both in Forward and Reverse. The exact location in the NCBI is GR Ch 37 p13 on chromosome 17, EXON 6 of the P53 gene and the change is in the C.613 T>A nucleotide; NM_000546.On reviewing this genetic variant in different scientific databases, such as ENSEMBL among others, in at least 6 different biocomputing tools it is described as a pathogen, therefore we can conclude that it is a pathogenic mutation for this case in particular. The rest of the mutations described in the literature on exons 5, 6, 8 and 9 of the p53 gene have not been found in our sample. Key words:Oral cancer, p53, Mutations, Exon. Oropharyngeal cancers are amongst the ten most frequent neoplastic tumours in the world, with an estimated incidence of approximately 275,000 cases of isolated oral cancer per year ,2. Oral Patients with oral cancer are typically men aged over 40 with a history of frequent exposure to risk factors such as smoking, alcohol, malnutrition, lack of oral hygiene, etc.; however, there is a cohort of younger patients with lower accumulated exposure to alcohol and smoking who, with increasing frequency, are presenting with oropharyngeal cancer. These latter cases are associated with the human papillomavirus ,4.Despite major progress in the treatment of oral cancer in the last 30 years, the 5-year survival rate remains around 50% and can drop to 15% in cases which present as advanced stage cancers with cervical metastases . ConsequThese changes in mucosa may appear as white, red or combined staining, and are called leukoplakias, erythroplasias or erythroleukoplakias respectively. There are other less frequent lesions, but also potentially malignant such as oral lichen planus and lichenoid lesions, chronic candidal hypertrophy and proliferative verrucous leukoplakia . All in Although only a small proportion of potentially malignant lesions will ultimately become malignant, it is believed that the key to improving a patient’s prognosis is through early detection and management of these lesions.To achieve better survival results in the handling of squamous cell oral carcinoma intervention needs to take place in the initial stages. Early detection and diagnosis of patients with risk factors and potentially malignant oral lesions must be undertaken. A selection must be made among patients with dysplastic lesions in the environment of multi-disciplinary primary care and specialist care .Cancer is a genetic disease caused by mutations in DNA and epigenetic alterations that control gene expression. The majority of epidermoid carcinomas develop within the fields of epithelial genetic alterations. The mechanisms underlying tumorigenesis of epidermoid carcinoma are as yet unknown; therefore, precise identification of the risk factors is needed .Currently genetic markers are being sought to evaluate the risk of malignant transformation . The perMutations of p53 have also been observed in a variety of dysplastic epithelial lesions in several tissues, including the oral cavity. This leads us to think that mutations of the p53 gene may be an early event in the squamous epithelium during the progression to cancer .The p53 gene is located in the short arm of chromosome 17p13.1 which contains 11 exons and is a suppressor gene in carcinogenesis because under normal conditions it acts as a negative regulator of cell proliferation increasing the amount of p53 nuclear protein; interrupting the cell cycle by inducing p21 protein which blocks the replication of DNA and ultimately inducing cell apoptosis .Mutation of the p53 tumour suppressor gene is one of the most frequent genome changes in human cancers. Immunohistochemical demonstration of p53 protein cannot be assumed to be an absolute marker for p53 gene mutations, besides its expression is seen in half of oral cavity carcinomas at advanced stages . More thThe presence of mutations in TP53 seems to be an interesting biomarker for the screening of potentially malignant oral mucosa and apparently predicts malignant progression ,22.Furthermore, some TP53 mutations may be easily detected by immunohistochemistry of p53 protein, such that immunohistochemical testing could be a really simple alternative to mutation testing.Conversely, mutations of p53 gene increases the risk of the emergence of other synchronic neoplasias. Given that, at least that we know of, the detailed study of the mutations of the P53 gene in squamous cell cancer and in potentially malignant lesions has not be undertaken up to now in Spain, this study was carried out to identify the mutation in different exons in the gene in patients with the previously described lesions.Consequently, the main aim of this study is to analyse and identify the emergence of the mutations described in the literature of the p53 gene with regard to the emergence of cancer in a sample of dysplastic and carcinomatous lesions of oral cavity mucosa in the south of Spain population, with a view to determining the presence of said mutations and the percentage of these in our population.Retrospective case study and controls and approved by the corresponding Ethics Committee . The study is descriptive and observational where the only invasive procedure on patients is the collection of a small amount of blood and a dental examination. The patient (or the person responsible for them) gives their consent based on the direct benefits for the research patient.A cross-sectional study was carried out, with a sample size of 22 patients with potentially malignant oral lesions ancillary to biopsy.The study population is made up of patients of both sexes from “Virgen del Rocío” University Hospital, Seville, who attended the Oral and Maxillofacial Surgery Unit for the assessment of potentially malignant oral lesions. Patients met each and every one of the inclusion criteria and none of the exclusion criteria. Surgery was performed over a period of 18 months. All patients were likewise subjected to an operation protocol. They were duly informed about the nature of the study and gave their express consent.Among the pre-inclusion criteria were: patients of both sexes over 18 years of age who attend the Virgen del Rocío University Hospital with potentially malignant oral lesions in oral mucosa ancillary to biopsy  and agreed to take part in the study by signing an informed consent form. As an inclusion criterion and once biopsies had been taken of the lesions, the results were found to be dysplasias or carcinomas.Among the exclusion criteria were patients with vascular malformations, general poor state of health preventing examination of the patient and sampling, those under-age and patients with intellectual disability unable to understand and sign the informed consent form.Once the inclusion and exclusion criteria had been met the operation protocol and information gathering was carried out. A conventional oral examination was performed based on the inspection and palpation of the lesion. If the clinician considered that a biopsy of the lesion could be taken, the patient was invited to take part in the study. The clinician would record the biopsy site deemed most suiTable.Left (reverse) exon 5-6 P53 / 20mer / 0,0250 UMO / Desalted PurificationTGTTCACTTGTGCCCTGACT(5`-3`) SIGM A Aldrich .Right (forward) exon 5-6 P53 / 20mer / 0,0250 UMO / Desalted PurificationTTAACCCCTCCTCCCAGAGA (5`-3`) SIGM A Aldrich .Patient characteristics: Some 22 patients were recruited between November 2017 and May 2019 (18 months) diagnosed with lesions in oral mucosa a priori potentially malignant, 9 women and 13 men, with ages grouped in under 60 years, 10 patients and over 60 years, 12. We divided patient lesions based on location in the oral cavity including those appearing in retromolar trigone, 1; buccal mucosa, 4; ventrolateral tongue, 7; labial mucosa ,1; floor of the mouth, 3; dorsal tongue, 2; attached gingival,1; and palate, 3 patients.Concerning patient habits we computed alcohol consumption ; smoking  oral hygiene and brushing of teeth .Aspects of patients such as history of prior oral carcinoma were analysed (19 had none and 3 patients had), having received radiotherapy (no patients had received it) and systemic diseases .Recorded characteristics of oral mucosa lesions were type of lesion ; size of lesion ; if there had been underlying induration or not (in 5 patients it had existed); and whether spontaneous pain had occurred ; days of progression grouped in less than 850 days, with 18 patients, and more than 850 days, 4; and finally the pathological anatomy results were classified according to .In respect of the gene study, no patient in our population in the south of Spain was found with point mutation described in exon 5 of the P53 gene as a transition from T base to C base in codon 270 (c.T 270 C).This made us consider continuing to search for the other point mutations described in the reference article  in exonsThe analysis was performed on sequences in both directions to dismiss false positives, as has been described in the Materials and Methods section, employing Codon Code Alignery software .In the scanning of complete exons 5, 6, 8 and 9 just one interesting result worth describing was found. In patient NBI 57 a change was observed in the TAT triplet by ATT of EXON 6, the change being of the T nucleotide by the A and in both directions both in Forward and Reverse. In this patient, the pathological anatomy report was of low-grade dysplasia. It was a man whose lesion was located in the floor of the mouth, a drinker, 46 years of age, smoking less than one packet of cigarettes a day. The lesion had a leukoplastic appearance, less than one centimetre in size, with a 60-day course and not indurate. He had no history of carcinoma or prior radiotherapy, but he did present systemic diseases. The exact location in the NCBI is GR Ch 37 p13 on chromosome 17, EXON6 of the P53 gene and the change is in the C.613 T>A nucleotide; NM_000546. On reviewing this genetic variant in different scientific databases, such as ENSEMBL among others, in at least 6 different biocomputing tools it is described as a pathogen, therefore we can conclude that it is a pathogenic mutation for this case in particular.In the genetic reference article  point muSeveral cytogenetic studies have described genetic abnormalities in oral epidermoid carcinoma,  such as The patient sample in our study is limited, there are only 22 patients, but they represent the whole spectrum of malignant and potentially malignant lesions in oral mucosa, indicating in the case of the potentially malignant ones the degree of pathologic dysplasia.To ensure in such a small cohort that we do not dismiss any other interesting change, we considered whether it would be possible, instead of searching for point mutations, to review the sequences of complete exons, in this way we would have more chances of finding a mutation in our population.We observed that the size of exons 5 and 6 are 476 base pairs and in the case of the 8 and 9 exons there are 445 base pairs. Both, therefore, are easy to tackle by means of adequate oligonucleotide design, amplification with PCR and sequencing analysis as we have described earlier.After carrying out the gene study we can conclude that, in our cohort of patients in the south of Spain, one case of low-grade dysplasia was found in the pathology anatomy report which presented genetic change in exon 6, from a T to an A, in nucleotide 613 and identified with the coordinate value rs 1057520008.Hence, we also conclude that, on reviewing this genetic variant in different scientific databases, such as ENSEMBL among others, in at least six different biocomputing tools it is described as pathogenic, consequently, we can conclude that it is a pathogenic mutation for this specific case.The rest of the mutations described in the literature on exons 5, 6, 8 and 9 of the p53 gene have not been found in our sample.


The paper first presents a set of experimental data on the measurements of the metallic cation fluxes through a perfluorinated sulfonic acid cation-exchange membrane. Not only WPA, but also synthetic phosphoric acid solutions with mixed metallic cations (MPA) and with a single metallic cation (SPA) were studied. This confrontation confirms (1) that the order of metallic cations fluxes is Mg2+ > Al3+ > Fe3+; (2) that, compared with MPA, the purification effect of WPA causes only negligible change; (3) that, by comparing the DD processes with SPA and MPA solutions, the reason for the low transmembrane fluxes of Fe3+ and Al3+ could be explained by the large ionic charge and large hydrated ion radius. Furthermore, by analyzing the ion composition of membranes equilibrated in SPA solutions, we conclude that the forms of cations in the membrane are most likely Fe3+, Al3+, and Mg2+.This work reports the application of an electromembrane process, Donnan dialysis (DD), for the purification of so-called wet-process phosphoric acid (WPA). Nitric acid is used as the stripping solution to remove metallic cations (mostly Fe Ion-exchange membranes (IEMs) are an important class of dense polymeric membranes that bear fixed charges and mobile counterions in the polymer matrix, in the presence of polar solvents . These membranes can selectively allow the passage of oppositely charged ions (counterions), while obstructing similarly charged ions (coions) ,2. CommoAs a membrane-based equilibrium process, DD is employed as a useful separation technology for chemical analysis, water treatment ,4, and dUntil now, the purification of WPA in industry relied mainly on solvent extraction or chemical precipitation. The solvent extraction method has advantages like a relatively high extraction ratio of phosphoric acid, good selectivity, easy phase separation, good flow properties of streams, and it is cheap and easy to realize. Both academia and industry have done a lot of work on extractant screening and purification performance evaluation. However, the extraction method uses a large amount of organic extractants , each with only one type of cation as the corresponding component in WPA (SPA), were employed to study the removal ratios of different metallic cations in the DD process. The existing form of cations in the membranes was also studied by comparing the molar ratios of metallic cations and phosphorus in the membrane.The WPA solution came from a phosphate ore processing plant located in Inner Mongolia in China. The characteristic contents of each component in this WPA are shown in 3PO4 mass fraction of 85% was used in the preparation of synthetic phosphoric acid solutions. The NaCl, MgO, and Al2(SO4)3 used were from Chengdu Kelong Chemical Co., Ltd. Fe2(SO4)3 was purchased from Chengdu Jinshan Chemical Reagent Co., Ltd. (China). All chemicals were of analytical pure grade. MPA was prepared according to the contents of target components listed in A commercial phosphoric acid solution with a HA perfluorinated sulfonic acid cation-exchange membrane (CEM) was used in this study. An inductively coupled plasma optical emission spectrometer  and X-ray fluorescence spectroscopy  were used to detect the contents of metallic cations in solutions. Fluorine and phosphorus contents in solutions were detected with an ion meter  and UV spectrophotometer , respectively. A scanning electron microscope  was used to observe the morphology of the membrane.3+ (Mg2+ and Al3+) is the target impurity cation and the driving ion is H+ in this case. The membrane area, the concentration of stripping (nitric acid solution), and the starting solution volumes of both the stripping solution and the WPA feed are 1.77 cm2, 5 mol L−1, and 9 mL, respectively. The phosphoric acid and nitric acid solutions were well mixed in Chambers I and II via magnetic stirrers, respectively. Intensive agitation was assured to diminish the resistance of the liquid films on both sides of the membrane surfaces. The perfluorinated sulfonic acid CEM was clamped between the two chambers of the cell. In this circumstance, the metallic cations in the phosphoric acid solution could be driven against their concentration gradients, as Moya described [The experiment of using the DD process for WPA purification is schematically shown in escribed , and did0,I and Ct,II are the concentrations of cations at time zero in Chamber I and at time t in Chamber II, respectively; VI and VII are the volumes of electrolyte solutions in Chambers I and II, respectively.Among them, C−1 NaCl solution for 48 h to allow sodium ions to replace the metal ions in the CEM. Lastly, the phosphorus content and the metal ion content in the desorbing solutions were measured by UV spectrophotometer and ICP-OES, respectively. For Fe3+-SPA, Al3+-SPA, and Mg2+-SPA, the membrane areas used in the absorption experiments were 83, 85, and 83 cm2, respectively.A certain amount of the CEM was pretreated and then soaked in SPA for 48 h to ensure complete ion exchange between the membrane and the synthetic solutions; then the CEM was washed with deionized water to remove the absorbed free salts and acids. Afterwards, the CEM was soaked in 50 mL of 1 mol L2+ > Al3+ > Fe3+. The removal ratio of Mg2+ is much greater than those of the other two metal ions. After 9 h, the removal ratio of Mg2+ reached 48.23%. At the same time, the removal ratios were only 14.64% and 3.35% for Al3+ and Fe3+, respectively; the accuracy in determining the ratios presented is 6%. This experimental result is in line with expectations. In DD, the exchange of ions is a chemical reaction, and ions react with the sulfonic acid groups on and in the CEM to replace protons or other metal ions that had previously been there. The number of such groups in the membrane is certain. The greater number of charges carried by the ions, the more fixed groups are involved, and the mass transfer ratio of the moving ion is correspondingly smaller. This is the main reason for the biggest mass transfer ratio, seen in Mg2+, which has a lower charge. Meanwhile, the hydrated radius of ions is also an important factor for explaining the mass transfer ratio. Although the CEM is treated as a homogeneous membrane at a macroscopic scale, it contains some “pores” filled with water for ions to pass through. The larger the hydrated radius of ions is, the more difficult it is for them to pass through the membrane. The charge numbers of Fe3+ and Al3+ are the same, but the hydrated radius of Fe3+ is larger than that of Al3+ [3+ in the DD process will be smaller than Al3+.+, Na+, and some Ca2+ ions) in WPA. Although most Al3+ will form stable AlF63− with F−, the remaining Al3+ will form AlF2+ or AlF2+ with F− [3+.In order to investigate the mutual influence of impurity cations in phosphoric acid on metal removal in the DD process, MPA was used. The removal ratio data are shown in  with F− , which l2+, Al3+, and Fe3+-SPA, the average mass transfer rates in the first 30 min were 0.0261, 0.0062, and 0.0026 mol m−2 min−1. The removal ratio of Mg2+ can be improved by 13% compared with that in the MPA, but the removal ratio of 3+ ions in the membrane. The removal ratio of In this case, the feed is SPA and the other experimental conditions are kept unchanged. The experimental data of the removal ratios of three metallic cations are summarized, and the results are shown in 2+ > Al3+ > Fe3+.According to the comparison of the absolute removal amount of metallic cations in different experiments, as summarized in A, DA, qA, and ZA being the flux, self-diffusion coefficient, concentration in the membrane, and charge of Ion A, respectively.The basic formula for the quantitative treatment of ion transfer across the CEM, i.e., the Nernst–Planck equation, requires knowledge of the existing form of the metallic cations in the membrane. Equation (2) below describes the target ion flux in the DD process, with JObviously, the charge of the ion has a large effect on the mass transfer rate in the mass transfer process in the membrane. In order to determine in which forms these metallic cations exist in the CEM, absorption experiments have been done, and the data are shown in 3+, Al3+, and Mg2+, respectively.According to the molar ratio of a metal ion and the corresponding phosphorus content in the same membrane specimen, it can be concluded that most of the iron, aluminum, and magnesium ions in the CEM are present in the form of Fe2+, Al3+, and Fe3+) from wet-process phosphoric acid (WPA) solutions. The possibility of employing the Donnan dialysis to purify WPA is verified. Based on the ion composition of membranes equilibrated with synthetic phosphoric acid solutions each with a single metallic cation, it is concluded that the existing forms of the metallic cations in the CEM are Mg2+, Al3+, and Fe3+. This work would be of considerable relevance for the application of the electromembrane processes toward the purification of WPA.In this work, a Donnan dialysis process with a perfluorinated sulfonic acid cation-exchange membrane (CEM) as the separator, and nitric acid as the stripping solution, is proposed to remove metallic cations (Mg


In this work, sugarcane bagasse fiber, a waste product of agroindustry, was added to mortar mixes at different proportions looking to seal porosities so as to improve the resistance of concrete to carbonation and to improve its mechanical properties. To evaluate the behavior of bagasse fibers in the alkaline media typical of mortars, bagasse fibers were subjected to solutions with alkaline pH values, and their chemical structure and morphological behavior was evaluated using FTIR (Fourier transform infrared spectroscopy) and SEM (Scanning Electron Microscopy). Using mortar cylinders in an accelerated carbonation chamber to obtain results in short lapses, the compressive strength and the carbonation were evaluated. The FTIR analysis results indicate that pH values of 11 and 12 causes a delignification, while at pH 9 and 10, a swelling of the molecule occurs because of the addition of hydroxyl ions, behavior that is confirmed with SEM images. A clear effect of the fiber addition on the performance of concrete was observed as the carbonation front of 35 mm for the sample without fibers was reduced to 2 mm for the sample with 2% fiber addition, resulting in an increase of 5 MPa in compressive strength. These results indicate that in the range of mortar pH, chemical changes occured over the sugarcane surface that could cause the growth of fibers and could partially seal the porosity in the mortars, thus enhancing its performance. However, it is not an inert material, as the pore solution formed inside it can react with the carbon dioxide  and chemical changes in sugar cane bagasse fibers subjected to pH values typical of mortars, and to explore how these changes can affect the properties, in terms of compressive strength and carbonation resistance, of mortar samples made with the addition of cane bagasse fibers at different percentages, giving added value to this waste. This is an initial study on the addition of sugar cane fiber in order to reduce the rate of carbonation. Although the results are for a short time (90 days), is a quality test to assist with recommendations for medium- and long-term use.A bagasse sample was taken at La Joya sugar mill located in Sihochac, Municipality of Champotón, Campeche, Mexico. Three sacks of fiber were mixed to obtain a representative distribution of the material. Subsequently, by applying the method of quartering, a 2 kg sample was obtained to prepare the test specimens, which were subjected to two washes with water from the municipal intake, and one wash with purified water to remove possible traces of sugar.Dry samples of approximately 1 g of sugarcane bagasse were weighed and exposed to solutions with pH values of 12, 11, 10, 9, and 7 as controls. Solutions were prepared with reagent grade NaOH and distilled water. After periods of 15 and 30 days of exposure, the samples were separated from the solutions by filtration.−1, with an average of 100 scans at a resolution of 4 cm−1.To know the chemical composition of the materials before and after the exposure periods, Fourier transform infrared spectroscopy (FTIR) tests were carried out using the attenuated total reflectance (ATR) technique in a spectral interval of 4000 to 400 cmThe above was done to get the approximate effect of the pH variation on the chemical stability of bagasse, with the knowledge that freshly cast concrete reaches a pH of 12 to 12.5 and, when carbonated, the pH can reach values close to 9.Scanning electron microscopy images were obtained for the samples subjected to the degradation described in the previous section. The materials were chosen in stages and at strategic pH values in order to monitor their degradation. A Hitachi Flexsem 1000 scanning electron microscope  at 20 kV and 60 Pa was used for this purpose.Conventional cylindrical mortar samples with a 15 cm diameter and 30 cm height were prepared for the compressive strength tests. A 1:2:3 ratio of water/cement/fine aggregate was used, and the water/cement ratio was 0.5. A quantity of 35 mL of fluidizing additive (lignosulfonate), namely, DISPERCON AL-100 trademark PROCONSA , was used for each liter of water (0.0175 water/cement). Dry sugarcane bagasse was added to the mortar mixture in proportions of 0.5, 1.0, and 2.0% weight of cement.Composite Portland cement (CPC) according to NMX-C-414-ONNCCE-2017 , Maya co2 solution, according to the NMX-C−159-ONNCCE-2016 [Cylinders with a 15 cm diameter and 30 cm height were cured by immersion in a saturated Ca(OH)CCE-2016 . Sample 2 concentration. The carbonation front was measured at 90 days of exposure, as indicated in the NMX-C-515-ONNCCE-2016 standard, by using a phenolphthalein acid/base indicator [For the carbonation tests, cylindrical samples with a 7.5 cm diameter and 15 cm height were made, with the same bagasse addition rates as those used for the compression resistance . They were placed in an accelerated carbonation chamber with the function of maintaining the experimental conditions at 25 ± 2 °C temperature; 65 ± 5% relative humidity, and 3% COndicator .The standard ASTM C 642 2006  procedur−1 corresponds to the stretching vibrations of the OH bonds; at 1730 cm−1, the peak corresponding to the stretching vibration of the C=O bond is found because of the ester and acetyl groups from either hemicellulose or to the ester type linkages of the carboxylic groups of the ferulic and p-coumaric acids contained in the lignin and/or hemicelluloses. The absorption peaks close to 1602 cm−1 and 1505 cm−1 correspond to the symmetric stretching vibration in the plane of the C=C bonds of the aromatic rings found in the lignin structures. There is a small peak between 1430 cm−1 and 1420 cm−1 is associated with the scissoring of the CH2 bonds present in cellulose. At 1375 cm−1 and 1320 cm−1 the absorptions of CH bending and OH bending in-plane are found. At a wavenlength of 1245 cm−1, the out-of-plane stretching vibration of the CO bond of the aryl groups present in the lignin is also found; while the peak at 1054 cm−1 corresponds to the asymmetric stretching vibration of the C-O-C bond, both characteristic of the glycosidic structures present in all of the components of sugarcane bagasse. Finally, at 902 cm−1, it presents a peak that is associated with the absorption of the β-glycosidic bonds between glucose units in cellulose [In ellulose ,39,40.−1, which indicates that, at these pH values, the OH groups were inserted into the molecular structures, specifically into the structures of the hemicellulose and lignin [In the spectra of degraded fibers at different pH values after 15 days a, the spd lignin .−1, 1602 cm−1, 1505 cm−1, and 1245 cm−1, were lost. The first was characteristic of the ester-type bonds that bind hemicellulose and lignin with cellulose fibers [−1 and a higher absorption for the peak at 1430 cm−1, which was also specific to cellulose.In the spectra of samples subjected to pH values of 11 and 12, there were clearly observable changes with respect to all of the previous samples, as the peaks at 1730 cme fibers , while a−1, which is characteristic of cellulose; however, the peak at 902 cm−1 remained unchanged.Degradation at 30 days produced results very similar to those at 15 days. The spectra of samples subjected to pH 7, 9, and 10 remained practically unchanged, while the spectra of samples subjected to pH 11 and 12 lost their peak at 1430 cm2 can be related to the crystallization of lime in the fiber pores [These results prove that at high pH values (11 and 12), the samples lose the characteristic lignin peaks, which correspond to delignification, while at pH values of 9 and 10, hydroxyl ions are added to the structure of the components of the bagasse fiber, which causes swelling of the molecules, hydrolysis of the ester bonds, and the breaking of the inter-molecular hydrogen bonds between hemicellulose and cellulose, causing hemicelluloses to be solubilized in water, separating from the cellulose fibers . These rer pores .The SEM images of the blank and degredation samples were taken at representative pH values and times in order to observe the degradation of samples under such conditions. It is known that cane bagasse fibers are mainly composed of fibers of crystalline polymer cellulose (C on images). The other main components are hemicellulose (HC on images), which is an amorphous polymer, and lignin (L on images), which functions as a cementitious matrix between cellulose and hemicellulose . All of 2  concentration from 1% v/w to 2 v/w%, and the mechanism is said to be saponification of intermolecular ester bonds cross-linked with hemicelluloses and lignin [The FTIR results show the depolymerization of lignin, which were modified to form derivatives with the characteristics mentioned above. Some authors of investigations into sugarcane bagasse treatments in alkaline media have found variations of components after reactions. Wunna et al. analyzed the decomposition of sugarcane bagasse in an alkaline pH, and found decomposition of lignin and hemicellulose . Maryanad lignin . In this work, at 2% of the bagasse, resistance after 90 days decreased, possibly due to the decomposition of fibers when exposed to an alkaline environment. However, this sample still had a better compressive strength, exceeding the control sample by 5 MPa at 90 days.The densities of the composite mortar increased with increasing the fiber length and volume. The compressive strengths of the composite mortar increased at 2% fiber volume with lengths of 10 and 20 mm . This efAt concentrations of 0.5, 1, and 2%, the tendency was to maintain a higher value than the control. Huerta and Martínez  mention Wegdan  reports 2 and the precipitation of ettringite (3CaO-Al2O3-3CaSO4-31H2O). As the pH decrease continues, close to 12, the phase 4CaO-Al2O3−13H2O is dissolved. Subsequently, in an interval of 11.6 to 10 pH, the gypsum (CaSO4-2H2O) and gibbsite (Al(OH)3) precipitate at the expense of the dissolution of ettringite. Finally, when close to pH 8, the CSH gel dissolves, and amorphous silica (SiO2) is formed [Monteagudo proposed that when the pH decreases in a cement paste, the sequence of reactions that follow comprise the dissolution of the portlandite Ca(OH)s formed . This seIn a fresh mortar with a pH greater than 12, the matrix maintained the stability of the hydrated calcium silicates and therefore the chemical properties, while the fibers broke down into smaller units. A decrease in pH promoted reactions that generated new compounds in the matrix, while in the cane bagasse fibers, the decrease in pH only caused them to acquire a greater volume. Contrary effects were noted in a very alkaline pH, where the matrix remained in good condition, but the fiber was affected; by lowering the pH, the matrix reacted, and the fiber presented morphological but not chemical changes.The performance tests indicated that the addition of sugarcane bagasse fiber improved the properties of the mortars. According to the results, the fiber deteriorated with the pH of the freshly cast mortar, but it is proposed that its decomposition generated smaller derivatives that increased its volume in the pore solution and sealed the porosities. As this was a process that was carried out throughout the mortar paste, it was assumed that the advance of the carbonation process from the surface was reduced.Subjecting the bagasse fibers to alkaline pHs, such as the one that occurs during the mortar carbonation process, has a series of effects on the fibers according to the specific pH value to which it is exposed. When the pH is highly alkaline (pH 11 and 12), the fibers undergo delignification to form smaller chemical units, which is corroborated by the loss of the characteristic lignin peaks in the FTIR spectra of the samples subjected to these values of pH. In weak alkaline environments (pH 9 and 10), what happens is that the hydroxyl ions are added to the structure of the bagasse fiber components, causing the solubilization and separation of the hemicellulose from the cellulose.Both phenomena can cause structural changes to the bagasse fibers, as was observed by the SEM analysis. In a neutral pH, the non-fibrous materials appear to be disordered and swollen because of the gain of hydroxyl ions. However, at pH 12 after 30 days of exposure, microfibrils of cellulose can be observed, because the lignin and hemicellulose layers that cover them are hydrolyzed and solubilized under these exposure conditions, which leads to the defibrillation of the fibrils, leaving the cellulose microfibrils more exposed to progressive degradation.2 and thus the carbonation of mortar from 35 mm of the control sample to 2 mm for the 2% bagasse fiber addition sample.With the dispersion of fibers in the cementitious matrix, the mortars acquire a greater compressive strength. The effect of increasing the compressive strength when augmenting the fiber concentration is remarkable, up to 50% after adding 2% bagasse. In turn, that compressive strength increases over time. However, at 2% bagasse, the resistance after 90 days decreases, possibly because of the decomposition of fibers when exposed to an alkaline environment, but it still has a better compressive strength. The sugarcane bagasse fiber concentration reduces the penetration of COBoth the better compressive strength and the reduction in the carbonation front for samples with cane bagasse added can be explained with the fibers behavior results of the FTIR and SEM analyses of fibers submitted to alkaline pH values of mortars, as it is observed that the fibers suffer a breakdown and an increment in their volume, causing a pore sealing effect in the mortar pastes. Because of this, the addition of cane bagasse fiber contributes to an enhancement in the durability properties of the manufactured mortars.


PO2) and temperatures were applied to investigate the analytical performances of the sensing film for gaseous O2 monitoring. Results show that the response time of all the sensing films was extremely fast. The sensitivities and dynamic ranges of the sensing films with the blended polymer matrix were separately decreased and increased as the EC/PMMA ratio decreased, and the S-V curve of the sensing films blended with equal content of EC and PMMA exhibited good linearity under different temperatures, showing a promising prospect in practical application.In this work, eight different types of optical oxygen sensing films were prepared by impregnating indicator and matrix solution on the surface of a polypropylene microporous filter membrane. The polymer matrix of the sensing films was ethyl cellulose (EC), polymethyl methacrylate (PMMA), and their blends with different mixing ratios. Scanning electron microscopy (SEM), laser confocal microscopy, and fluorescence spectrometer were used to investigate the morphologies and optical properties of the sensing films. Phase delay measurements under different oxygen partial pressures ( Precise and fast sensing of the oxygen concentration in different environments, such as in blood, respiration gas, and water, has attracted particular attention in various fields, including environmental detection, medical monitoring, and industrial gas monitoring ,2. To th2 and SnO2) can greatly improve the detecting performance of gaseous sensors [Generally, a typical optical oxygen sensor (OS) incorporates an optical signal detection device (OSD) and a sensing film. As the functional part, sensing film is mainly composed of fluorescent indicators and a matrix. Transition metal complexes, especially metalloporphyrin, such as Pt (II) complexes ,12, are  sensors ,21,22. N sensors . Under t sensors . In cont sensors .Since the indicator is often mixed with the polymer matrix, a film that hosts the mixture of indicator and polymer also acts as the sensing film substrate. The structure of the film can dramatically affect the response time of the oxygen sensor. Compared with flat structures, the large specific surface area of the porous structure can improve  the collIn short, the difference in the intrinsic permeability of polymers towards oxygen hinders the fabrication of oxygen sensors that can adapt to both low-concentration and hyperbaric oxygen environments. Moreover, tuning the sensitivity by altering the polymer types also demands great intervention for a specific sensor system, since the matrix of the sensing film can only be used in a specific environment. Koren et al.  achievedIn the present work, a series of sensing films are produced by embedding the Pt (II) octaethylporphine (PtOEP) into a polymer matrix with different blending ratios of EC and PMMA on a polypropylene microporous membrane. The optical properties and surface morphologies of the sensing films with different blending ratios were investigated by a fluorescent spectrometer, scanning electron microscopy (SEM), and laser confocal microscopy. Phase delay methods were employed to test the sensitivities and response time of the sensing films with different blending ratios of EC and PMMA. Consequently, the performance parameters of different polymer-sensing films were measured. Our finding shows that the blending of different types of polymers can significantly tune the sensitivity and dynamic ranges of the sensing film, thus providing a new path for the preparation of the sensing films that adopt both low-concentration and hyperbaric oxygen environments. The sensing films prepared in this work display a wide dynamic range and sufficient sensitivities, showing a promising application potential in the field as respirators, hyperbaric oxygen chambers, air quality detectors, and hazardous gas alarms.τ0 is the lifetime of indicators in the environment without oxygen, τ is the lifetime under a different oxygen partial pressure, KSV is the Stern-Volmer quenching constant, and PO2 is the oxygen partial pressure. Ideally, the Stern-Volmer plot (SVP) is linear, and KSV is equal to the slope of SVPs, which visually represents the sensitivity of the sensing system.Normally, it is assumed that the indicators are uniformly distributed in the polymer matrix and the microenvironment around each luminary remains the same. Then, the bimolecular collision process between oxygen and indicators can be described by the Stern-Volmer equation ,33:(1)τ0However, since the media for the quenching processes is not always homogeneous, the standard quenching model based on ideal SVPs often fails to perfectly accommodate the practical conditions ,35. It iθ0 is the delay phase obtained in the absence of oxygen and θ is the delay phase under different oxygen partial pressure.Although the oxygen partial pressure can be acquired by fluorescence intensity measurements, several limitations, such as background light source interference and laser light source intensity drift, will interfere with the accuracy of the relative results . An altew ~120,000 by GPC) were commercially available from Macklin Biochemical Co., Ltd. . The polypropylene microporous membrane was provided by Yibo Filter Equipment Factory . Chloroform was purchased from Aladdin Ltd. . All chemicals and reagents were stored and used as required.Pt (II) octaethylporphine  was purchased from Sigma-Aldrich . Polymers including ethyl cellulose  and polymethyl methacrylate  were chosen for the polymer matrix of the sensing films. Afterward, the microporous filtration membrane was impregnated into the fluorescent solution for 1–2 s and then dried at room temperature to evaporate the solvent (CHCl3) in a dark environment for 1 h. In the following sections, the sensing films with different polymer matrices were labeled according to the blending ratio, i.e., SF-EC referred to the sensing film with EC as matrix and SF-E1P3 represented the film with the EC/PMMA ratio of 1:3.Prior to the preparation of the sensing films, the microporous filtration membrane was rinsed via deionized water and ethanol in sequence to eliminate the contaminants, then dried in a vacuum drying chamber for 1 h. Then, 4 mg of PtOEP was mixed with 80 mg of polymer powder in 4 mL CHClThe absorption spectra of the experimental sensing films were measured in an UV-3600 UV-VIS-NIR spectrophotometer. The emission spectrum was measured in a FLS980 fluorescence spectrometer with an excitation wavelength of 535 nm. The surface of the sensing films was first sprayed with a thin layer of platinum to become conductive and then observed by field emission scanning electron microscopy (FE-SEM) of the type Gemini 500. The autofluorescence of the sensing film was photographed by the Nikon Eclipse Ti2-E Laser Confocal Microscope.θr) and fluorescence (θf) could be acquired, as could the delay phase between them , followed by inflating 100 kPa of nitrogen. The tank was then pumped twice to ensure an oxygen-free environment, and the lag phase of the sensing film in the anaerobic phase was recorded. Then, the delay phase of the experimental sensing film was obtained by inflating different concentrations of oxygen that ranged from 10% to 100%, which corresponded to the oxygen partial pressure of 10–100 kPa under normal atmospheric pressure. Oxygen partial pressures above 100 kPa were achieved by inflating oxygen with 100% concentration above normal atmospheric pressure. All data are averages of phase angles within 60 s.Since all the prepared sensing films were the same color, here, we only present the macro image of the sensing film with pure EC in The microstructure of the experimental sensing films was obtained by SEM see , and theBased on the above observation, the adsorption method in this work can efficiently obtain sensing films with strong structural stability, and therefore, the polymer and indicator mixture on the microporous filter membrane fiber is stable enough to fall off.The absorption and emission spectra of the sensing films with different polymer matrices under ambient conditions (~25 °C and ~101 kPa) are further illustrated in 90up and T90down) of the sensing films with different polymer matrices is further tabulated in 90up values of the sensing films are generally higher than T90down. Therefore, the T90down here is the criteria for evaluating the response performance of the experimental sensing films. From 90down for all the samples are 3 s and 4 s; as the sampling frequency is 1 Hz, the response time of the sensing films with different polymer matrices can be treated as the same. In addition, the T90up values of SF-E1P3 and SF-PMMA samples are slightly lower than those of other samples. This could be attributed to the fact that the viscosity of the PMMA solution is higher than the EC solution, leading to a more even coverage of mixture (indicator and polymer) around the fiber, and the mixture film on the fiber surface with a certain PMMA content (75 wt.%–100 wt.%) is relatively thinner . The reason could be ascribed to the different quenching degrees of indicator molecules in heterogeneous microenvironments. However, the SVPs of the sensing films with a blending polymer matrix still exhibit good linearity when the oxygen partial pressure is beyond 10 kPa, suggesting that they are promising for application over a broad range of oxygen concentrations.ure PMMA . It is wθ0/tan θ for the sensing film with pure EC is higher than other samples at different temperatures, and the delay phase of the sensing films with the blending polymer matrix is increased with the decrease of the EC/PMMA ratio.The temperature affects the fluorescence intensity of the indicator and thus the sensitivity of the sensing film ,39,40; hSince the collision quenching effect is determined by the diffusion of oxygen molecules, and the viscosity change of the polymer matrices with temperature is determined by their remelting point, the temperature sensitivity cross effect of the sensing film cannot be avoided, and it is necessary to deduce the temperature compensation function for each sensing film in practical application . In thisY-axis with the rise of temperature. One possible explanation is the hybrid quenching process of the sensing films, which includes both static quenching and dynamic quenching and can be defined using the following equation [kd is the dynamic quenching constant and ks is the static quenching constant, namely the constant for the formation of the oxygen-indicator complex. In order to facilitate the calculation, we rewrite Equation (3) in a quadratic polynomial:A and B are the quadratic and linear coefficients related to temperature, respectively, and C is a constant.Except for sample SF-E1P1, the quenching curves of sensing films are biased towards the equation ,42:(3)tA values of SF-EC and SF-E3P1 are nearly one order of magnitude higher than that of other samples. It is worth noting that the A values of SF-E1P1 are in the range of 8.22 × 10−6 − 1.81 × 10−5, showing good linearity for its S-V curve. We thus linearly fitted the S-V plot of the SF-E1P1 sample, and the results in 2 > 0.99), indicating that the sensing films with a polymer matrix containing equal weight contents of EC and PMMA are more readily calibrated for practical use. In addition, A and B values for all the experimental sensing films can be defined as the quadratic functions of temperature 3Cl2, and Ru(dpp)3(ClO4)2 in the polymer matrix, are prone to be stable when the environmental oxygen content reaches a high value [It has been widely reported that the fluorescence change of nearly all the indicators, such as PtOEP, Ru, the tan θ0/tan θ value should be 1. That is, the SVP of the sensing films should intersect the  point on the graph. In the present work, the intercepts of SVPs of SFs with pure EC and PMMA matrices and the matrix of EC/PMMA with a ratio of 1/3 under different temperatures are close to 1. However, the intercepts of the SVP for the sensing films with a blending polymer matrix of different EC/PMMA ratios with 3/1 and 1/1 show a deviation from 1. The underlying mechanisms are unfortunately not clear yet. It is worth noting that Lee et al. [2) is higher than 15%, while the intercepts for the sensing films’ SVPs in the (O2) range from 0 to 15% are close to 1. Due to the limitation of our instruments, the SVPs for the present sensing films in the PO2 range from 0–10 kPa cannot be achieved. It therefore can be inferred that because the slopes of SVPs for the present sensing films with blended polymer matrices might be changed when PO2 is less than 10 kPa and the intercepts of their SVPs are not equal to 1 when PO2 is larger than 10 kPa.According to Stern-Volmer equation (Equation (1)), in the absence of oxygen (i.e., e et al.  fabricatIn this study, a simple and low-cost approach for tuning the sensitivity and dynamic range of optical oxygen sensing film is achieved by the physical blending of EC and PMMA with different mixing ratios as sensing film matrices. The use of a polypropylene microporous filtration membrane as the support allows the uniform distribution of indicators on the sensing film surface. This structure endows the sensing films with a fast dynamic response time, which is less than 1 s.−1 and smallest dynamic range of 0–70 kPa, while the sensing film with the PMMA matrix with the lowest oxygen permeability exhibits the lowest sensitivity of 0.017 kPa−1 and widest dynamic range of 0–180 kPa. The sensitivities and dynamic ranges of the sensing films with the blended polymer matrix are decreased and increased as the EC/PMMA ratio decreased, respectively, achieving a good balance that is favorable for the application over a broad range of oxygen concentrations.The sensitivities and dynamic ranges of the sensing films are mainly determined by the oxygen permeability of the polymer matrix. The sensing film with pure EC, which possesses the highest oxygen permeability, exhibits the highest sensitivity of 0.298 kPaIn addition, the S-V curves of the sensing film with equal EC and PMMA contents show good linearity at different temperatures, which is more readily calibrated for temperature varying environments.