Effect of functionalized silica nanoparticles on sulfonated polyethersulfone ion exchange membrane for removal of lead and cadmium ions from aqueous solutions

Abstract

Polyethersulfone (PES) was successfully sulfonated by sulfuric acid and used for membrane synthesis. Silica nanoparticles were functionalized by amine and thiol groups and then introduced in a sulfonated polyethersulfone membrane (SPES) matrix. The effect of silica and functionalized silica particles on ion exchange of lead ion (Pb2+) and cadmium ion (Cd2+) was studied. X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX) analysis were used to confirm the successful functionalization of silica particles and the effective incorporation of silica and the functionalized silica particles in the membranes matrix. The dialysis process during 8 h,using the SPES-SiO2-(CH2)3-NH2 membrane, leads to a significant elimination rate of Pb2+and Cd2+ ions estimated at 43.2% and 31.6%, respectively. whereas a selective separation of Pb2+ from feed (Pb2+/Cd2+) solution was observed at 2 h of dialysis. On the other hand, the SPES-SiO2-(CH2)3-SH membrane adsorbs more Cd2+ than Pb2+ ions, which represents another outcome for Pb2+/ Cd2+ separation.