Role of polyethylene glycol with different solvents for tailor-made polysulfone membranes

A detailed study on effects of additive (polyethylene glycol, PEG) in polysulfone (PSF) membrane was undertaken. The effects of molecular weight of PEG, its concentration, the nature of solvents, and thickness of casting solution were investigated. The cast membranes were characterized in terms of scanning electron microscopy for study of surface morphology, distilled water permeability, molecular weight cut-off (MWCO), contact angle, porosity, tensile strength. It was observed that more porous membranes were obtained using N-methyl-2-pyrrolidone (NMP) as solvent compared to N, N-dimethylformamide (DMF). Controlling the concentration of PEG in the casting solution, one can get membrane of MWCO in the range of 10,000 to 70,000 while DMF was used as solvent. Hydrophilicity of the membranes increased with concentration and molecular weight of PEG. The average pore radius of the cast membranes was evaluated by two standard methods and the calculations led to reproducible results. Finally, the efficacy of the cast membranes for all the dosages of the PEG 400/PSF/DMF system was tested for filtration of turbid water of maximum turbidity 600 NTU. The feed and permeate were characterized using various properties, such as pH, conductivity, etc. It was observed that the cast membranes were effective for treatment of turbid water.