DMSA-incorporated silsesquioxane-based hybrid polymer for selective adsorption of Pb(II) from wastewater

It is a challenging task to remove Pb(II) ions efficiently from wastewater containing high concentrations of hardness ions. In this study, a novel hybrid polymer (DVP) for selective adsorption of Pb(II) ions was successfully prepared via photopolymerization of vinyl-POSS and dimercaptosuccinic acid (DMSA). The chemical structure and composition of DVP were characterized by FTIR, XPS, SEM, TEM, XRD and TGA techniques. DVP exhibited high efficiency in removing Pb(II) from aqueous solutions with a maximum adsorption capacity of 349.5 mg g −1 at pH 4, exceeding lots of adsorbents reported in the literature. The adsorption performance of Pb(II) by DVP was found to fit the Freundlich isotherm well and its kinetics followed the Elovich model. Moreover, DVP showed selective adsorption of Pb(II) in the presence of high concentrations of Ca(II) and Mg(II) ions and could reduce Pb(II) in real lake water to 25 ppb at a DVP dose of 1 g L −1 . Moreover, the adsorption process of DVP was endothermic in nature. The adsorption mechanism demonstrated that Pb(II) ions can be chelated with the thioether and carboxyl groups of DVP simultaneously, which was confirmed by spectroscopic analysis and DFT calculations. Good reusability in continuous fixed-bed column experiments suggested that DVP was an ideal candidate for the selective removal of Pb(II) ions from contaminated aquatic systems.