Exfoliated hydrotalcite-modified polyethersulfone-based nanofiltration membranes for removal of lead from aqueous solutions

In recent years, the volume of wastewater produced worldwide has led to an increase in the study and use of different membranes and their properties. The progress of membrane technology in hand with nanotechnology has brought to the establishment of advanced membrane materials that are effective in the field of wastewater treatment and water reclamation. This study focuses on the effectiveness of exfoliated hydrotalcite (EHT) nanosheets in the membrane structure which has been evaluated by water flux and heavy metal rejection studies from aqueous solutions. Moreover, the shedding of HT in an organic polar solvent provides a new type of 2-D nanosheet with higher positive charge density. Hydrophilicity, porosity, surface and cross-section morphology, functional groups, and mechanical strength are determined to characterize the prepared membranes. The effect of adding a pore-forming agent to the dope solution is also investigated. Increased hydrophilicity of the modified membranes is confirmed by water contact angle measurement. Furthermore, EHT is found to be an efficient inorganic additive to get better membrane performance and can be employed as a promising candidate for the removal of Pb2+. The rejection % enhanced substantially (50.2% as compared with 29.5% for PES membrane) with increased loading of EHT up to 0.5 g.