Efficient multicyclic sorption and desorption of lead ions on facilely prepared poly(m-phenylenediamine) particles with extremely strong chemoresistance

Nitric acid, hydrochloric acid and EDTA were carefully chosen as desorbent to systematically evaluate the adsorption/desorption performance of the Pb2+-adsorbing fine microparticles of poly (m-phenylenediamine). The sorption/desorption efficiency was maximized by optimizing desorption condition including the desorbent concentration, contact time, and desorption mode. The variation of the solution pH with Pb2+ desorption was recorded to speculate the desorption mechanism. The practical reusability of the microparticles was elaborated through the sorption-desorption cycle experiments in an optimum condition. It was found that the desorption was very rapid with an equilibrium time of several minutes. A strong dependence of the desorbability on the species and concentration of the desorbents was observed. When 20 mM EDTA was chosen as the desorbent, the highest desorptivity was up to 94.2% that was much higher than those using nitric and hydrochloric acids. A successive sorption-desorption study employing nitric acid indicated that the microparticles could be simply regenerated and reutilized for more than 5 cycles together with Pb2+ re-adsorption efficiency of about 50% and accumulative Pb2+ adsorption capacity of up to 720.4 mg L-1. Facilely prepared, extremely chemoresistant and cost-effective PmPD microparticles would be potentially used for multicyclic sorption of lead ions from aqueous solution. (c) 2007 Elsevier Inc. All rights reserved.