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Adsorption properties of Pb2+ on thermal-activated serpentine

ABSTRACT Adsorption properties of nature and thermal-activated serpentines to Pb2+ in aqueous solution were investigated. The results showed that Freundlich isotherm and pseudo-second-order kinetics model were suitable to describe the adsorption process of Pb2+ on serpentines. The thermodynamic parameters indicated that the adsorption process was endothermic and spontaneous. The serpentine activated at 700°C exhibited maximum adsorption capacity to Pb2+. Based on the XRD and XPS characterization, it could be found that the structure of serpentine did not change significantly during the adsorption process, and Pb2+ was adsorbed on the serpentine surface as the precipitation of Pb(OH)Cl and Pb(OH)2.