Title: Cadmium(II) adsorption by activated carbon: batch studies and reversibility

Authors: Wagner A. Carvalho, Cristiane I.C.B. Zanin, Cristiane Zanutelo, Flavia C.A. Figueiredo, Antonio R. Cestari, Eunice F.S. Vieira

Addresses: Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Catequese, 242, CEP 09090-400, Santo Andre – SP, Brazil. ' Faculty of Chemical Engineering, Universidade Estadual de Campinas, C.P. 6066, CEP 13083-970, Campinas – SP, Brazil. ' Faculty of Chemical Engineering, Universidade Estadual de Campinas, C.P. 6066, CEP 13083-970, Campinas – SP, Brazil. ' Faculty of Chemical Engineering, Universidade Estadual de Campinas, C.P. 6066, CEP 13083-970, Campinas – SP, Brazil. ' Laboratory of Materials and Calorimetry, Department of Chemistry/CCET, Universidade Federal de Sergipe, CEP 49100-000, Sao Cristovao – SE, Brazil. ' Laboratory of Materials and Calorimetry, Department of Chemistry/CCET, Universidade Federal de Sergipe, CEP 49100-000, Sao Cristovao – SE, Brazil

Abstract: Adsorption of cadmium(II) by Brazilian activated carbons, in their original and nitric acid activated forms, was evaluated. The equilibrium was reached within the first 15 min of contact between carbon and metal solution, and obeys a pseudo-second order Lagergren model. The maximum adsorption capacity is higher than 64 mg/g for the oxidised sample. Negative ΔG⁰ values indicate the spontaneity of the adsorption process. Thermodynamic results emphasise that chemisorption plays an important role in the adsorption by oxidised carbon. Moreover, this sample can be efficiently recycled by treatment with HCl, allowing total recover of adsorbed cadmium(II) during four adsorption/desorption cycles.

Keywords: cadmium(II) adsorption; activated carbons; heavy metals; cadmium removal; effluent pollution; desorption; recycling; Brazil; thermodynamics; chemisorption.

DOI: 10.1504/IJETM.2010.031532

International Journal of Environmental Technology and Management, 2010 Vol.12 No.2/3/4, pp.257 - 276

Published online: 10 Feb 2010 *

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