Development of the tetrathioterephthalate filler incorporated PES nanofiltration membrane with efficient heavy metal ions rejection and superior antifouling properties

Abstract

The novel antifouling nanofiltration membranes were developed for efficient heavy metal ions rejection from water. These membranes were fabricated by the introduction of the tetrathioterephthalate (TTTP) filler into Polyethersulfone (PES) matrix via the phase inversion. Surface roughness, pore radius distribution, average pore radius, surface charge, overall porosity, and water contact angle were also characterized. FTIR and XPS analysis were performed to confirm the presence of TTTP filler in the TTTP embedded PES (T-PES) membranes. As confirmed by FESEM images, more finger-like voids with higher connectivity were formed in the presence of TTTP fillers in the membrane matrix. Compared with the PES membrane, the T-PES membranes exhibited higher hydrophilicity, porosity, and mean pore radius. Besides, these membranes exhibited higher pure water permeation flux and superior antifouling properties. For 0.1 wt.% TTTP embedded PES membrane the FRR value stayed at a high level during five repeated filtration cycles. This improvement was mainly ascribed to the hydrophilic quiddity of TTTP fillers resulting from its functionalities like C = S and C–S bonds. Furthermore, these membranes showed high rejection towards heavy metal ions (Zn2+, 99.2%; Cu2+, 98.5%; Pb2+, 97.4%). Moreover, the metal ion removal experiments in the presence of foreign ions of Fe3+, Mg2+, and Na+ indicated acceptable results.