AT-POME colour removal through photocatalytic submerged filtration using antifouling PVDF-TNT nanocomposite membrane

This study explores the potential of novel hybrid polyvinylidene fluoride/titanate nanotube (PVDF-TNT) photocatalytic membranes for the colour removal of aerobically treated palm oil mill effluent (AT-POME) in a submerged membrane photo reactor (SMPR). Different loadings (0–1.0 wt%) of TNT photocatalysts were physically mixed into PVDF dope solution prior to the membrane fabrication through dry/wet phase inversion process. The membranes modules were subsequently fitted into a 15 L SMPR tank, with a UV light source placed at the center of the SMPR. The performance analysis indicated that PVDF-TNT0.5 showed the best colour removal of 67.3%. The synergistic effects rendered by both membrane filtration and photocatalysis have remarkably improved the colour removal efficiency compared to filtration alone that barely exhibited colour removal of 34.2%. The operating conditions of the SMPR, such as initial concentration and pH of the feed AT-POME were also investigated. The photocatalytic activity has greatly reduced the fouling susceptibility of PVDF-TNT membranes, where flux loss of only 5.7% was observed after 5 cycles of usage. With its promising performance in terms of colour removal, flux and low membrane fouling susceptibility, this hybrid SMPR holds great potential to be directly applied in the current POME treatment system to improve the effluent quality and reduce freshwater consumption for palm oil extraction process.