Copper oxide incorporated polyvinylidene fluoride dual layer hollow fiber photocatalytic membrane for bisphenol a removal

Abstract

Bisphenol A (BPA) is grouped under endocrine disrupting compound (EDC), which accumulating in most Southeast Asia rivers from 8 ng/L to 36.9 ng/L. It is a common plasticizer have been in plastic bottles, water pipes, and toys and enters our household water after being exposed to heat, acid, or base. Continuous exposure to BPA may lead to myocardial infraction, cardiac hypertrophy, preterm birth, and neuro-behavioral disturbances. This study developed a novel photocatalytic membrane to remove BPA from water body efficiently. The photocatalysis process was chosen to be a hybrid with membrane in this work as it is safe and has no secondary by-product. Copper (I) oxide (Cu2O), also known as cuprous oxide, is a type of semiconductor which is nontoxic and able to work under visible light with its low band gap of 2.2 eV. In this study, Cu2O was incorporated into polyvinylidene fluoride (PVDF) based dual-layer hollow fiber membrane at different Cu2O to PVDF ratios, namely 0.25, 0.50, and 0.75. The outer dope layer flowrate was also varied at 3, 6, and 9 ml/min. The membranes were analyzed for scanning electron microscope, contact angle, porosity, tensile strength test, atomic force microscopy, X-ray diffraction, dispersive energy X-ray, Fourier-transform infrared spectroscopy, and water flux measurement. Based on the finding, a higher outer dope flowrate increased the outer layer finger like structure and thickness. 6 ml/min outer dope flowrate had the highest porosity (63.13% ± 5.09), and water flux (4919.02 ± 42.52 L/m2h). Meanwhile, the increase in photocatalyst loading had increased the Cu2O agglomeration in the outer layer membrane, copper mapping in the outer layer membrane, and surface roughness. The DLHF membrane with a Cu2O/PVDF ratio of 0.5 possessed the highest water flux (13890.99 ± 164.96 L/m2h) and the lowest contact angle (58.90° ± 1.72). Thus, the selected membranes were observed for their performance to degrade BPA with 10, 20, and 30 mg/L concentrations under visible light irradiation for 360 minutes. The treated water sample was analysed for the leaching test. The best membrane configuration as photocatalytic membrane is 0.50 Cu2O/PVDF ratio with 6 ml/min outer dope flowrate with the ability to remove 75 % of 10 mg/L BPA, 69.23 % of 20 mg/L BPA and 68.42 % of 30 mg/L BPA in 360 minutes under visible light irradiation. In conclusion, Cu2O/PVDF DLHF membrane is able to remove BPA under visible light irradiation.