Multi-component sorption of Pb2+, Cu2+ and Ni2+ on PEI modified chitosan-based hybrid membranes

Novel poly(ethylene imine) (PEI) modified chitosan-based hybrid membranes (PMCHMs) were created via a soft chemistry method, in which unmodified chitosan (CS) firstly reacted with PEI to produce a CS-PEI precursor. Later, such CS-PEI precursor was blended with silicone to create the membrane solution of PMCHMs. Finally, PMCHMs could be obtained via phase-inversion process. Multi-component sorption of Pb2+, Cu2+ and Ni2+ on PMCHMs in metal mixed solutions, such as, Pb2+&Cu2+ and Pb2+&Ni2+ binary, Pb2+, Cu2+ and Ni2+ ternary, as well as Pb2+, Cu2+, Ni2+, Cd 2+ and Cr3+ quintuple mixed solutions, was inspected. The calculation of effective diffusion coefficients, distribution coefficients and selectivity coefficients showed that Pb2+ sorption on PMCHMs had excellent selectivity in these mixed multi-metal solutions. While, the calculation of activation energy proved that Pb2+, Cu2+ and Ni2+ sorption on PMCHMs was a physic-sorption process Also, mechanism insight reveals that Pb2+ sorption on PMCHMs could be depicted via Lagergren pseudo-2nd-order kinetic model and Langmuir or Freundlich isotherm equation. Exclusively, intra-particle diffusion process was discussed in detail. Desorption testing verified that HCl is a good desorbent for metals sorption on PMCHMs and the cycle time of membranes can arrive at 6 times. These results demonstrate that PMCHMs can be used to preferentially eradicate Pb2+ from metal mixture solutions, showing prospective applications in the treatment of metal mixture wastewater from waste vehicle power-battery and other various metal-bearing polluted water.