Preparation, characterization and the effect of PANI coated TiO2 nanocomposites on the performance of polysulfone ultrafiltration membranes

Abstract

Polysulfone ultrafiltration (UF) membranes with PANI TiO2 (polyaniline titania) nanocomposites and PEG 1000 (Polyethylene Glycol 1000) as additives were prepared by the phase inversion method. PANI TiO2 nanocomposites were synthesized by coating TiO2 nanotubes with PANI via chemical oxidative polymerization. The synthesized PANI TiO2 nanocomposite was characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) analysis. PANI TiO2 nanocomposites with varying concentrations (0-1.5 wt%) were dispersed in the polysulfone membrane matrix with N-methyl-2-pyrrolidone (NMP) as solvent along with PEG 1000 as the pore former. The effect of addition of PANI TiO2 nanocomposites with different concentrations (0-1.5 wt%) on the membrane structure, performance, hydrophilicity and the antifouling nature of the membranes was analyzed. PANI TiO2 nanocomposite membranes showed better hydrophilicity, improved permeability, enhanced porosity, water uptake and good antifouling ability when compared with neat polysulfone membranes. The performance of the membranes improved with the increase in the addition of the PANI TiO2 nanocomposite. However, the membrane performance decreased slightly at 1.5 wt% addition of PANI TiO2 due to the agglomeration of PANI TiO2 at higher concentration. The well performed membranes were also subjected to heavy metal ion rejection. The membranes showed a rejection of 83.75% and 73.41% during the polymer enhanced ultrafiltration (PEUF) process and a rejection of 68% and 53.78% during the UF process for Pb2+ and Cd2+ respectively.