Brown macro-algae as natural cation exchangers for the treatment of zinc containing wastewaters generated in the galvanizing process

• Type: Article in International Scientific Journal
• Date: 2016

Authors

Tatiana A. Pozdniakova (Author) FEUP; Luciana P Mazur (Author) FEUP; Rui A. R. Boaventura (Author) FEUP; Vítor J. P. Vilar (Author) FEUP

Journal

Title: Journal of Cleaner Production

Vol. 119

Pages: 38-49

ISSN: 0959-6526

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 18 Citations

ISI Web of Science

Scopus - 0 Citations

INSPEC

Scientific classification

CORDIS: Technological sciences > Technology > Environmental technology

FOS: Engineering and technology > Environmental engineering

Associated Projects

LA 20 - PROJECTO ESTRATÉGICO - LA 20 - 2013-2014

ALGAEVALUE - Valorização de macroalgas marinhas na separação e recuperação de iões metálicos tóxicos presentes em água

LSRE-LCM - Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais

Other information

Authenticus ID: P-00K-89J

DOI: 10.1016/j.jclepro.2016.02.003

Abstract (EN): 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12