Removal of lead ions from water using PES-based nanocomposite membrane incorporated with polyaniline modified GO nanoparticles: Performance optimization by central composite design

In this paper, an in-L polymerization technique was employed to functionalize GO nanoparticles using polyaniline (PANI). In this regard, nanocomposite membranes were prepared by embedding PANI@GO nanoparticles into matrix of PES membrane, and characterized by measuring permeability, porosity, mean pore size and water contact angle as well as by the use of scanning using SEM and AFM. Moreover, response surface method, based on central composite design (CCD) experimental plan, was utilized to analyze, to model and to optimize the efficacy of membranes in removal of Pb2+ from water. In general, addition of nanoparticles into the membrane matrix decreased its permeability, porosity and hydrophilicity; however, lead removal increased noticeably. To add to that, it should be noted that decreasing the feed concentration and increasing the solution pH caused an increment in lead removal from water, and nanocomposite membrane fabricated by 0.25 wt.% of nanoparticles successfully removed almost all Pb2+ from water. In order to investigate the adsorption mechanism, the isotherm model and the kinetic of adsorption were experimented, and based on the outcomes, the Langmuir isotherm and pseudo-first order kinetic offered the most appropriate models for fitting the adsorption of Pb2+ ions onto the membrane. As a further point, results of reusability tests indicated the ability of membrane in removal of lead ions from water after several sequential adsorption-desorption tests.