Please use this identifier to cite or link to this item: https://hdl.handle.net/10216/106048
Author(s): Fernanda B. de Souza
Heloisa de Lima Brandão
Fabíola Vignola Hackbarth
Antônio Augusto Ulson de Souza
Rui A. R. Boaventura
Selene M. A. Guelli Ulson de Souza
Vítor J. P. Vilar
Title: Marine macro-alga Sargassum cymosum as electron donor for hexavalent chromium reduction to trivalent state in aqueous solutions
Issue Date: 2016
Abstract: In this study, the brown macro-alga Sargassum cymosum was used as an electron donor for the reduction of hexavalent chromium to its trivalent form, through the oxidation of the biomass, and as a natural cation exchanger for the subsequent trivalent chromium sequestration from aqueous solutions. The reaction kinetics for hexavalent chromium reduction in aqueous solutions was evaluated as a function of the pH and initial concentrations of Cr(VI) and biomass. Hexavalent chromium reduction was found to be highly dependent on the pH of the solution, since protons are involved in the reduction mechanism. The concentration of organic compounds per unit of biomass able to reduce the hexavalent chromium was 3.0. mmol/g, i.e., 1. g of biomass was able to reduce 3. mmol of Cr(VI). FTIR and potentiometric titration techniques showed that trivalent chromium removal was mainly associated with weak acidic carboxylic groups present at the surface of the biomass. The oxidation of the biomass during Cr(VI) reduction generated new binding sites responsible for trivalent chromium removal. A kinetic model based on a pseudo-first-order reaction successfully fitted the hexavalent chromium concentration profiles. Trivalent chromium concentration was predicted based on a mass balance of the total chromium in solution, considering the instantaneous binding of trivalent chromium to the negatively charged functional groups present at the surface of the biomass. (c) 2015 Elsevier B.V.
Subject: Tecnologia ambiental, Engenharia do ambiente
Environmental technology, Environmental engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia do ambiente
Engineering and technology::Environmental engineering
URI: https://hdl.handle.net/10216/106048
Related Information: info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/UID/EQU/50020/2013- POCI-01-0145-FEDER-006984/Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais/LSRE-LCM
info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projectos de I&DT em Todos os Domínios Científicos/PTDC/AAG-TEC/2685/2012|FCOMP-01-0124-FEDER-027877/Valorização de macroalgas marinhas na separação e recuperação de iões metálicos tóxicos presentes em água/ALGAEVALUE
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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