Enhancing compatibility and hydrophilicity of polysulfone/poly (ethylene-co-vinyl alcohol) copolymer blend ultrafiltration membranes using polyethylene glycol as hydrophilic additive and compatibilizer

Abstract

Hydrophilic poly (ethylene-co-vinyl alcohol) (EVOH) was blended with hydrophobic polysulfone (PSF) in the presence of polyethylene glycol (PEG) (20 kDa), which acted as a hydrophilic additive and compatibilizer, to fabricate ultrafiltration (UF) membranes with high porosity and antifouling properties. The polymer blend containing 10 wt% EVOH was selected for optimization using PEG (0 to 24 wt%). After a detailed study, it was concluded that 20 wt% of PEG content was optimal for mixing with PSF/EVOH to increase miscibility. The membranes were characterized using differential scanning calorimetry (DSC) analysis, contact angle, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The effectiveness of PEG as a compatibilizer was observed via no phase separation occurred when the solution was allowed to stand at room temperature for four weeks. It was further confirmed by the appearance of a single Tm peak in DSC. In addition, molecular dynamic simulations illustrated that the PSF/EVOH 90/10 wt% blend had a radial distribution of g(r) = 3.29 Å, and g(r) = 2.69 Å in the presence of PEG, indicating better miscibility in the presence of PEG. Pure water permeance of blend membrane (85/15 wt%) reached 316 L.m-2h−1 bar−1, 54% greater than the pristine membrane. Simultaneously, bovine serum albumin (BSA) rejection of up to 97% and permeance recovery ratio of 87% were observed for the PSF/EVOH 90/10 wt% blend membrane, showing improved hydrophilicity and antifouling properties. These findings identify a potential modifier for fabricating low fouling UF membranes for wastewater treatment by blending with EVOH and PEG.