Modifications of polyethersulfone membrane by doping sulfated-TiO2 nanoparticles for improving anti-fouling property in wastewater treatment

Polyethersulfone (PES) composite membranes mixed with sulfated-TiO2 nanoparticles were fabricated using a non-solvent induced phase inversion method. Sulfating had little effect on particle size and crystal phase of TiO2 nanoparticles. However, the roles of each nanoparticle as doping materials to reduce membrane fouling for the PES membrane were apparent. The PES membrane embedded with sulfated-TiO2 nanoparticles showed higher pure water permeability and larger membrane pore size while lowering fouling rate than the PES membrane embedded with bare TiO2 nanoparticles (without sulfating) for bovine serum albumin solution as a feed. Water uptake capacity and hydrophilicity of the PES membrane was improved significantly by introducing the sulfated-TiO2 nanoparticles into the membrane. As a dosage of sulfated TiO2 nanoparticles was above 0.8 wt%, however, membrane porosity was reduced due to aggregation of the nanoparticles causing membrane pore blockage. The sulfatedTiO2 nanoparticles improved membrane hydrophilicity while reducing fouling rate under strong acidity caused by incorporation of sulfate groups with PES polymer chains.