Efficient removal of lead ions from aqueous solution by graphene oxide modified polyethersulfone adsorptive mixed matrix membrane

In this study, we report the combined effect of graphene oxide (GO) and polyvinylpyrrolidone (PVP) for the heavy metal removal efficiency of polyethersulfone (PES) membranes. PVP with four different amounts of GO was infused in the membrane matrix by the physical blending method. Characterizations such as porosity, contact angle, water flux and Fourier transform infrared spectroscopy were conducted for all prepared membranes. Viscid behavior of polymer dope solution was examined to understand the phase separation phenomena better. PVP enhanced the GO distribution within the membrane surface to some extent via hydrogen bond. The addition of nanoparticles enhanced the membrane physicochemical properties with water permeation, Pb2+ rejection and adsorption capacity. Permeate flux of modified membrane (m4) was found to be 150.21 L/m2h and it is 8.03 times higher than unmodified membrane (m0). Besides, all fabricated membranes were evaluated for Pb2+ rejection from synthetic wastewater and rejection % of m4 (80.6%) had increased twofold than m0 (38.9%). Membrane cleaning was performed using different methods and the best results were achieved with a concentration of 0.05 wt% sodium hypochlorite under pH 7 and further reused for the filtration test. Moreover, adsorption isotherm was tested using Freundlich and Langmuir models and the Langmuir model offered the best fitting.