Fabrication of low-fouling reverse osmosis membranes by grafting poly(2-methoxyethyl acrylate) via surface-initiated atom transfer radical polymerization method

Abstract

The surfaces of polyamide-based low-pressure reverse osmosis (RO) membranes were modified with poly(2-methoxyethyl acrylate) (PMEA) via surface-initiated atom transfer radical polymerization for the first time to achieve low-fouling characteristics. The successful grafting of PMEA was demonstrated by attenuated total reflectance Fourier-transform infrared spectroscopy and zeta potential measurements. The grafting amount could be tuned from 0.020 to 0.23 mg cm⁻² by changing the grafting time. The modified membranes maintained their salt rejection performances with slight reductions of pure water permeability especially when the grafting amount was smaller than 0.05 mg cm⁻². This result indicated that the grafted PMEA had almost no effect on salt rejection but slightly increased the permeation resistance. Compared with unmodified membranes, the modified membranes were found to exhibit low fouling against a variety of organic substances, such as lysozyme, guar gum and tetraethylene glycol monooctyl ether. The results indicate that surface modification of a low-pressure RO membrane with PMEA is a feasible method to obtain a membrane with low-fouling characteristics.