A novel chitosan/clay/magnetite composite for adsorption of Cu(II) and As(V)

A composite adsorbent was prepared by entrapping cross-linked chitosan and nano-magnetite (NMT) on heulandite (HE) surface to remove Cu(II) and As(V) in aqueous solution. The optimized mass ratio among chitosan, HE, and NMT was determined to be 1:1:2. Kinetics studies indicated the removal of both ions followed pseudo-second order kinetics, suggesting specific interaction with surface functional groups was the major route of the removal process. The composite gave the maximum equilibrium uptakes of Cu(II) and As(V) of 17.2 and 5.9 mg g(-1) in initial concentration ranges of 16-656 and 17-336 mg L-1 respectively. The thermodynamic data showed that both adsorption processes were thermodynamically favorable, spontaneous, and endothermic nature. The adsorption capacity for Cu(II) increased continuously with an increase in initial solution pH (3-9), but adsorption of As(V) showed an opposite trend. The overall results demonstrated the potential utility of the composite for Cu(II) and As(V) removal from aqueous solutions. (C) 2012 Elsevier B.V. All rights reserved.