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Author(s): Bárbara R. C. Vieira
Ariana M. A. Pintor
Rui A. R. Boaventura
Cidália M. S. Botelho
Sílvia C. R. Santos
Title: Arsenic removal from water using iron-coated seaweeds
Issue Date: 2017
Abstract: Arsenic is a semi-metal element that can enter in water bodies and drinking water supplies from natural deposits and from mining, industrial and agricultural practices. The aim of the present work was to propose an alternative process for removing As from water, based on adsorption on a brown seaweed (Sargassum muticum), after a simple and inexpensive treatment: coating with iron-oxy (hydroxides). Adsorption equilibrium and kinetics were studied and modeled in terms of As oxidation state (III and V), pH and initial adsorbate concentration. Maximum adsorption capacities of 4.2 mg/g and 7.3 mg/g were obtained at pH 7 and 20 degrees C for arsenite and arsenate, respectively. When arsenite was used as adsorbate, experimental evidences pointed to the occurrence of redox reactions involving As(III) oxidation to As(V) and Fe(III) reduction to Fe(ll), with As(V) uptake by the adsorbent. The proposed adsorption mechanism was then based on the assumption that arsenate was the adsorbed arsenic species. The most relevant drawback found in the present work was the considerable leaching of iron to the solution. Arsenite removal from a mining-influenced water by adsorption plus precipitation was studied and compared to a traditional process of coagulation/flocculation. Both kinds of treatment provided practically 100% of arsenite removal from the contaminated water, leading at best in 12.9 mu g/L As after the adsorption and precipitation assays and 14.2 mu g/L after the coagulation/flocculation process.
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/Comissão de Coordenação e Desenvolvimento Regional do Norte/P2020|Norte2020-Projetos Integrados ICDT/NORTE-01-0145-FEDER-000006/Advanced Industrial Processes and Materials for a Sustainable North Region of Portugal2020/AIProcMat@N2020
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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