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https://hdl.handle.net/10216/106067
Author(s): | Tatiana A. Pozdniakova Luciana P Mazur Rui A. R. Boaventura Vítor J. P. Vilar |
Title: | Brown macro-algae as natural cation exchangers for the treatment of zinc containing wastewaters generated in the galvanizing process |
Issue Date: | 2016 |
Abstract: | In this study, brown macro-algae harvested from the north coast of Portugal, Laminaria hyperborea, Fucus spiralis, Pelvetia caniculata and Ascophyllum nodosum, were used as natural cation exchangers for the treatment of zinc-containing rinse waters generated in the galvanizing process. The zinc wastewater is characterized by a high conductivity (1.5 mS/cm), a low organic content and a zinc concentration of 10 mg/L, being approximately 80% and 20% in the form of Zn2+ and ZnSO4(aq), respectively. Although the ion-exchange capacity of the four macro-algae is similar (2.2-2.4 mEq/g), mainly associated with the presence of weak acidic carboxylic and strong acidic sulfonic groups, L. hyperborea showed a higher selectivity for zinc ions. The uptake capacity for zinc ions is highly affected by the galvanic wastewater matrix, when compared with the performance using a pure zinc solution. Zinc uptake equilibrium, on all the natural cation exchangers, was well described by a linear relationship. Cation exchange kinetic was adequately represented by a mass transfer model, considering a linear driving force model for intraparticle diffusion. Na-loaded alga showed a higher affinity for zinc ions when compared with Ca-loaded alga and raw alga. HCl, HNO3, H2SO4 and CaCl2 eluents were tested for zinc displacement from exhausted algae. HNO3 reached an elution efficiency of 100% in less time than the other eluents tested. After the acid elution, the resin was converted to Na or Ca form (Na- or Ca-H-loaded biomass), using NaCI and CaCl2 solutions. Although the regenerated alga in the form of sodium showed a higher affinity for zinc ions, its physical deterioration after Na loading may affect its application in a full-scale treatment. |
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/10216/106067 |
Related Information: | info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e a Tecnologia/Projetos Estratégicos/PEst-C/EQB/LA0020/2013/PROJECTO ESTRATÉGICO - LA 20 - 2013-2014/LA 20 info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e a 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 info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e a 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 |
Document Type: | Artigo em Revista Científica Internacional |
Rights: | restrictedAccess |
Appears in Collections: | FEUP - Artigo em Revista Científica Internacional |
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