Study on the preparation of the hierarchical porous CX-TiO2 composites and their selective degradation of PHE solubilized in soil washing eluent.
A series of CX-TiO2(Carbon Xerogel- TiO2) composites with a hierarchical porous structure were obtained through the sol-gel method followed by drying and carbonization, and have been applied to treating solubilizing wastewater containing a high concentration of phenanthrene (PHE). The characterizations demonstrated that the CX-TiO2 exhibits a hierarchical porous structure, with particles of carbon and P25 being uniformly in the matrix. Removal efficiency of CX-TiO2 on PHE in soil washing eluent (SWE) were evaluated under ultraviolet (UV) irradiation or dark condition, and P25 was employed as the reference. The results revealed that CX-TiO2(0.2) had the best removal effect on PHE, with the efficiency as high as 97.8% under UV illumination within 15 h. It demonstrated that in the process of PHE removal by CX-TiO2 whether it was under UV illumination or not, the adsorption plays a dominant role in the early stage. The kinetic behavior of PHE adsorption was fitted using the pseudo-first-order and pseudo-second-order, and Langmuir model and Freundlich models were applied to describe the PHE adsorption isotherms. The results indicating that it was a chemical adsorption process, which was influenced by the interaction between PHE and CX-TiO2, and PHE is adsorbed on the interface of CX-TiO2(0.2) in a single layer form, instead of agglomerating in the admicelle. A possible mechanism of removal of solubilized PHE in SWE was speculated, in which both hierarchical porous structure and appropriate micropores size of CX-TiO2 were indispensable to the selective adsorption and degradation of PHE. Recycling performance certificated that the selective removal efficiency of PHE could still reach 82.09% after five recycles. Thus the excellent performance testified that the CX-TiO2 have great potential in treating SWE containing solubilized PAHs.
['Wang|Aijing|A|', 'Peng|Xiao|X|', 'Shi|Ning|N|', 'Lu|Xiaohui|X|', 'Yang|Chunlei|C|', 'He|Ping|P|', 'Wu|Yan|Y|']
D000327:Adsorption D002384:Catalysis D007700:Kinetics D010616:Phenanthrenes D016062:Porosity D012989:Soil Pollutants D014025:Titanium D014466:Ultraviolet Rays D062065:Waste Water
Soil washing Hierarchical porous structure Selective adsorption Carbon xerogels composites Photocatalytic degradation