Antifouling BaTiO3/PVDF piezoelectric membrane for ultrafiltration of oily bilge water

Abstract

Barium titanate/polyvinylidene fluoride (BaTiO3/PVDF) piezoelectric membrane was successfully prepared and generated in-situ vibrations to reduce membrane fouling by applying alternating current (AC) signal for oily bilge water ultrafiltration. The effect of in-situ vibration on membrane fouling was investigated through changing in the excitation alternating voltage and its frequency, pH, crossflow rate. The results indicated that the piezoelectric membrane by applying AC signal remarkably alleviated the membrane fouling for bilge water ultrafiltration. The membrane fouling decreased with increasing the AC signal voltage. The final steady-state permeate flux from the piezoelectric membrane for bilge water ultrafiltration increased with the AC signal voltage, raising it by up to 63.4% at AC signal voltage of 20 V compared to that of the membrane without applying AC voltage. The high permeate flux was obtained at the resonant frequency of 220 kHz. During the 50-h ultrafiltration of bilge water with the piezoelectric membrane excited at 220 kHz and 15 V, the permeate flux from the membrane was stable. The oil concentration in outflow from the piezoelectric membrane was below 14 ppm, which met the discharged level required by IMO convention. The total organic carbon removal rate in bilge water was over 94%. HIGHLIGHTS BaTiO3/PVDF piezoelectric membrane for bilge water ultrafiltration reduced membrane fouling by applying alternating current signal.; The permeate flux from BaTiO3/PVDF piezoelectric membrane was stable during 50-h ultrafiltration of bilge water.; The oil content in outflow from BaTiO3/PVDF piezoelectric membrane for bilge water ultrafiltration was below 14 ppm, which can meet the level required by IMO convention.;

Keywords

• batio3/pvdf
• bilge water treatment
• in-situ vibration
• membrane fouling
• piezoelectric membranes