Competitive adsorption behavior and mechanism for Pb2+ selective removal from aqueous solution on phosphoric acid modified sugarcane bagasse fixed-bed column

Abstract

Competitive adsorption behavior and mechanism for Pb2+ selective removal from aqueous solution on phosphoric acid modified sugarcane bagasse (PA-SCB) were investigated in Pb/Cu, Pb/Zn, Pb/Cd and Pb/Ca binary system under dynamic condition. Results verified by EDX analysis showed that Pb2+ with the highest adsorption affinity substituted the adsorbed co-ions during the adsorption process, and amount of Cu2+, Zn2+, Cd2+ and Ca2+ desorbed was 5.5, 6.3, 13.7 and 6.2 mg g−1, respectively. Desorption and release of the adsorbed co-ions into the solution resulted in an obvious overshoot peak in their breakthrough curves, which could be predicted well by Chromatographic Gaussian equation. Selective adsorption of Pb2+ was further verified in Pb/Cu/Zn/Cd/Ca/Mg system, and amount of Pb2+ adsorbed on the column was respective 24.5-, 13.6-, 12.8-, 91.1- and 159.5- times of Cu2+, Zn2+, Cd2+, Ca2+ and Mg2+. Wastewater treatment experiment showed that the amount of Pb2+ adsorbed on the column was 73.7 mg g−1, while that of Cu2+, Cd2+, Zn2+, Ca2+ and Mg2+ was 4.4, 0.4, 0.3, 0.2 and 0.03 mg g−1, demonstrating that Pb2+ could be absorbed efficiently from the complex system. The as prepared column had great potential in Pb2+ selective removal form practical waste water.