pH-responsive P(AA-b-SBMA)-grafted magnetic GO high-performance ultrafiltration membrane with improved antifouling tendency and cleaning efficiency

Nanocomposite ultrafiltration polysulfone membrane with pH-responsive surface was designed and synthesized using poly (AA-b-SBMA)-grafted magnetic graphene oxide (MGP) nanofiller. The obtained membranes revealed advanced antifouling, high cleaning-efficiency, and high rejection when compared to pristine PSf membranes. The novel MGP nanofiller was synthesized by copolymerization of acrylic acid and sulfobetaine monomers on the grafted magnetic graphene oxide surface by RAFT polymerization. The non-solvent-induced phase separation was used to prepare polysulfone nanocomposite ultrafiltration membranes with pH-responsive surfaces optimized by the MGP content of 0.05 to 0.3 wt% in the dope solution. The MGP content embedded within the polysulfone matrix greatly influences the water flux. The optimal 144 LMH flux of water, achieved by 0.1 wt% MGP, was almost 80 % higher compared with the pure polysulfone. The optimal MGP-modified nanocomposite membrane showed high antifouling tendency and 72 % flux recovery value. Also, when pH changed from 3 to 8, the pH-responsive membrane revealed the best water flux recovery for bovine serum albumin adsorption-desorption. Comprehensive characterization of MGP nanofiller, the modified polysulfone, and pristine membranes confirmed that the surface hydrophilicity, cross-section morphology, surface roughness, and compositions of the modified ultrafiltration membranes could be modified considerably by the incorporation of MGP nanofiller.