Novel translucent hollow fiber polyvinylidene fluoride photocatalytic membrane for highly efficient oil-produced wastewater treatment: The role of translucency on degradation efficiency

A novel method, Thermally Modified Non-Solvent Induced Phase Separation (T-NIPS) has been developed to fabricate translucent hollow fiber (THF) photocatalytic membrane for membrane's photodegradation efficiency enhancement. The process involves two-step temperature treatment that attacks crystalline property of polyvinylidene fluoride (PVDF). Graphitic carbon nitride in a modified morphological structure (hollow nanofiber) was used as photocatalyst to investigate the effect of translucency on membrane's photo-degradation efficiency. UV-Vis analysis coupled with FTIR highlighted different crystalline phase appearance and membrane's translucency. The membranes showed high translu-cency, ranging from 60.0% to 93.9%, with THF-PVDF/PVP-GCN (2.0) exhibiting the highest. The filtration experiment showed that membrane with GCN photocatalyst had high PWF (1200 L/m2h) and rejection (90%) OPW compared to neat THF-PVDFs. In suspended mode, GCN demonstrated an impressive photodegradation efficiency of 99.98%. When im-mobilized in opaque PVDF membrane, the photodegradation has decreased substantially to 49.40%. However, when immobilized in a translucent PVDF membrane, the photo-degradation efficiency of HN-GCN significantly improved compared to the opaque PVDF membrane, reaching 95%. Translucent membrane was subjected to five cycle regeneration test and showed 90% recovery even after the fifth cycle. The 10% reduction in the recovery was investigated using FESEM analysis revealed that there is a cake layer formation on the membrane surface. Therefore, this study proved that translucency of membrane has significant effect on immobilized photocatalyst's photocatalytic efficiency.(c) 2023 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.