Concentration influence of different additives on performance of asymmetric polyethersulfone (PES) ultrafiltration flat sheet membranes

Abstract

This paper reports the effects of additive concentration in the casting solution on performance of asymmetric PES ultrafiltration flat sheet membranes. The membranes were prepared by phase inversion process from the casting solution containing polyethersulfone (PES) as polymer, N, N-dimethylformamide (DMF) as solvent and polyethylene glycol (PEG) of various molecular weights. The concentration of additives were varied from 5 to 25 wt% in the casting solutions. The membranes were characterized in terms of the pure water permeation, solute separation and flux. The results indicated that increased concentration of PEG 400 and PEG 600 in casting solution increased pure water permeation. It is observed that when higher concentration of PEG 200 was added in the casting solution, pure water permeation decreased significantly. As concentration of PEG 400 and PEG 600 in casting solution is increased, solute separation gradually decreases and flux increased. However, when PEG 200 concentration is increased in the casting solution, the solute separation increased significantly while flux decreased. The morphology of the membranes changed with different concentration of additive added. Experimental results revealed that different molecular weights and concentration of additives greatly influenced the performance of PES ultrafiltration flat sheet membranes.