A facile method for polyamide membrane modification by poly(sulfobetaine methacrylate) to improve fouling resistance

Membrane fouling is a long-standing problem in many industrial and fundamental applications. In this work, a zwitterionic poly(sulfobetaine methacrylate) (pSBMA) is grafted on the surface of an aromatic polyamide membrane to improve membrane fouling using surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting pSBMA-coated polyamide membrane exhibits excellent surface resistance to protein adsorption and high water permeability. As compared to untreated membrane, the adsorption amount of irreversible proteins on the pSBMA-coated membrane is significantly reduced by ∼97% and water flux is also greatly improved by ∼65%, while rejection rate remains unchanged as large fouling molecules (humic acid, bovine serum albumin) in the solution are filtrated. More importantly, the pSBMA-coated polyamide membrane consistently retains a much higher water flux and improves the rejection rate of NaCl at high operating pressure. These results demonstrate that new pSBMA-coated membrane with easy synthesis can serve as potential promising membranes for membrane industry. •A membrane modification method to resist protein adsorption is developed.•The water permeability of such membranes is higher than of the untreated membrane.•The lower salt rejection rate is suppressed by high working pressure.•This new method could be applied in most interfacial polymerization method.