Effect of modified PVDF hollow fiber submerged ultrafiltration membrane for refinery wastewater treatment

Submerged ultrafiltration process was studied for treatment of refinery wastewater using PVDF hollow fiber membranes. The membranes were prepared via the phase inversion method by dispersing LiCl·H 2O and TiO 2 in the dope to study the effects of surface properties on membrane performance. The comparison of the performance and morphology was conducted on prepared PVDF composite membranes with various LiCl·H 2O and TiO 2 contents. The hollow fiber membranes were characterized by field emission scanning electron microscope (FESEM) and energy dispersive x-ray (EDX), average pore size and effective porosity measurements, contact angle measurement, permeability and rejection test. Maximum results were observed for membrane hydrophilicity, membrane porosity and average pore size when the TiO 2 concentration was 1.95%. It was also found that interactions between the membrane surface and suspended solid constituents strongly influenced the membrane fouling. The maximum flux and rejection of refinery wastewater were 82.5 L/m 2 h and 98.8%, respectively, when the PVDF composite membrane with TiO 2 content of 1.95% is used at pH = 6.9. ► TiO 2 in PVDF UF promotes higher hydrophilicity, small pore size and high porosity. ► Higher TiO 2 concentration leads to an aggregate phenomenon and pore blockage. ► Higher membrane hydrophilicity and small pore size significantly enhanced flux. ► Higher flux is achieved at higher pH values.