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RESEARCH PRODUCT

Evaluation of biosorbents for Cu removal from wastewater in the presence of EDTA

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BACKGROUND: This paper evaluates the use of several biosorbents for Cu removal from aqueous solutions in the absence and presence of ethylenediaminetetraacetic acid (EDTA). The objective was to determine the applicability of the sorption process after conventional physicochemical wastewater treatment, or as primary treatment, replacing the physicochemical process. RESULTS: Fixed-bed experiments were performed at Cu influent concentrations of 2 and 20 mg dm−3 and EDTA doses between 0 and 10 mg dm−3. At low Cu concentration without EDTA, Cu uptake capacity followed the order Posidonia oceanica > chitosan > chitin > Scharlau AC > Darco AC, with a maximum, at C/C0 = 0.2, of 23.2 mg g−1. In the presence of EDTA, Cu was detected in the effluent from the beginning of the operation, except for the activated carbons and chitosan at low EDTA doses. At higher EDTA doses, the activated carbons showed the best performance. Uptakes at Cu concentration of 20 mg dm−3 without EDTA were 51.6 (Posidonia oceanica) and 41.4 mg g−1 (chitosan) at C/C0 = 0.2. CONCLUSION: A sequence of one fixed bed with Posidonia oceanica followed by another with Scharlau AC should be an alternative to Cu precipitation, with Cu effluent concentration lower than 0.5 mg dm−3 for more than 350 pore volumes. Copyright © 2007 Society of Chemical Industry