Experimental evidences for a new model in the description of the adsorption-coupled reduction of Cr(VI) by protonated banana skin
2013
López García, Marta | Lodeiro, Pablo | Herrero, Roberto | Barriada, José Luis | Rey-Castro, Carlos | David, Calin | Sastre de Vicente, Manuel E.
This work reports experimental evidences, not previously considered, to evaluate the Cr(VI) removal by protonated banana skin biomass. Variations in the number of hydroxyl groups, quantified by potentiometric titrations, and CO2 evolution during experiments, were attributed mainly to the oxidation of hydroxylic entities present in the studied material. The results indicate that these groups together with the carboxylic moieties are the main functionalities involved on the adsorption-coupled reduction process. The column experiment carried out provides a new approach to obtain the maximum reduction capacity of the material (3.72 mmol g 1). Moreover, we hereby propose a model that reports the first evidence for the instant bound of Cr(III) species to the material used, formed after the reduction of Cr(VI) present in solution. The removal process was quantified carrying out experiments under various pHs, biomass doses and Cr(VI) concentrations, and the mechanism underlying chromium removal was identified.
Show more [+] Less [-]This work was funded by the projects CTM2012-37272 (Ministerio de Economía y Competitividad of Spain) and PGDIT06TAM0 0401CT (Xunta de Galicia). P. Lodeiro gratefully acknowledges financial support through Ángeles Alvariño project AA 10.02.56B.444.0 and the grant for research stay 10.02.561B.480.0 (Xunta de Galicia) both co-funded by 80% with European Social Funds.
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