Methacrylic Acid (MAA)‐Chemical Grafted Polyethersulfone Nanofiltration Membrane for Forward Osmosis Application

Abstract This study successfully modifies NF2 PES membrane via chemical grafting with methacrylic acid (MAA) at predetermined monomer concentrations, reaction times, and initiator concentrations by means of producing forward osmosis (FO) membrane. The membranes are utilized in the FO system, and performance is discussed in terms of water and solute flux. The surface characteristics of the modified membrane are analyzed in terms of water contact angle, functional groups, and degree of grafting (DG), meanwhile, morphological studies are analyzed via AFM and FESEM characterization. Based on the FO test performance, it can be concluded that increasing monomer concentration results in an increase in the permeate fluxes until a certain value is reached; only then does the permeate flux start to decrease. However, the effect of monomer concentrations is not significant on the permeate flux when shorter reactions are applied. This is probably due to the limitation of reaction time, which only allows certain values at a time for co‐polymerization to be completed, hence affecting the permeate flux. Increasing reaction time offers more reactions to occur, leading to more surface grafting activity. However, prolonging the reaction time does not always improve the surface grafting, especially when higher monomer concentration and initiator concentration are involved.