Study of the involved sorption mechanisms of Cr(VI) and Cr(III) species onto dried Salvinia auriculata biomass.
Removal of Cr(VI) species by dried biomass of the aquatic macrophyte Salvinia auriculata was studied in order to understand the involved sorption mechanisms. Kinetic tests were carried out under the conditions such as concentration range of Cr(VI) from 50 to 250 mg L-1 and a temperature of 30 °C. Modification of the biosorbent by the presence of Cr(VI) species was assessed by analysis of its porosity, density and infrared molecular absorption spectrum. A series of experimental approaches involving directed chemical modifications on the biosorbent surface was performed. The main functional groups involved in the sorption mechanisms were identified. The gas sorption analyser was applied and proved that a strong chemical effect of Cr(VI) species on the surface took place, resulting in a leaching organic matter with an obvious and significant increase in the porosity parameters. The intra-particle diffusion model revealed different mass transfer zones into the adsorbent during Cr(VI) removal. New combined Langmuir and Dubinin-Radushkevich isotherm was the best to fit the equilibrium data of Cr(VI) species removal. Finally, Cr(VI) removal was mainly mediated by a redox process where Cr(III) species were formed.
['Módenes|Aparecido Nivaldo|AN|', 'de Oliveira|Ana Paula|AP|', 'Espinoza-Quiñones|Fernando R|FR|', 'Trigueros|Daniela Estelita Goes|DEG|', 'Kroumov|Alexander Dimitrov|AD|', 'Bergamasco|Rosângela|R|']
D000327:Adsorption D000465:Algorithms D018533:Biomass D002857:Chromium D004058:Diffusion D029624:Ferns D005740:Gases D006863:Hydrogen-Ion Concentration D007700:Kinetics D008962:Models, Theoretical D010084:Oxidation-Reduction D016062:Porosity D013055:Spectrophotometry, Infrared D017550:Spectroscopy, Fourier Transform Infrared D014874:Water Pollutants, Chemical
Biosorbent characterisation Cr(VI) species uptake Intra-particle diffusion approach Physical-sorption mechanisms