Toward fabrication of fouling resistant pervaporation membrane for desalination: Surface modification of TFC membrane via grafting of mPEG-NH2

A highly hydrophilic and fouling resistant membrane was developed via surface modification of a thin film composite membrane (TFC), prepared from polyacrylonitrile/polyvinyl alcohol (PAN/PVA), by polydopamine (PDA) coating and methoxy polyethylene glycol amine (mPEG-NH2) grafting (TFC/PDA-g-PEG). Various analyses were done on the membranes to investigate the quality and effectiveness of the modification. Based on the results, the pristine TFC membrane was positively charged (+7.71 mV), while the PDA coated TFC membrane (TFC/PDA) showed negative zeta potential (−1.65 mV), and TFC/PDA-g-PEG membrane had almost neutral surface charge (+0.15 mV). The water contact angle of the TFC membrane reduced from 74.1° to 46.2° after PDA coating. By grafting of mPEG-NH2 on TFC/PDA membrane, a further decrease in the water contact angle of the membrane was obtained (27.6°). The permeation flux of 75.7 kg/(m2.h) and salt rejection of 99.91 % were attained by TFC/PDA-g-PEG membrane in the treatment of 35 g/L salt solution at 65 °C. The antifouling behavior of virgin and modified TFC membranes against the foulant solution revealed that TFC/PDA-g-PEG membrane had an excellent resistance against fouling agents compared to TFC/PDA and unmodified membranes.