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

Abstract

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 sulfated-TiO₂ nanoparticles improved membrane hydrophilicity while reducing fouling rate under strong acidity caused by incorporation of sulfate groups with PES polymer chains.