Preparation ultrafine l-Methionine (C,N,S triple doped)-TiO2-ZnO nanoparticles and their photocatalytic performance for fouling alleviation in PES nanocomposite membrane

Abstract

TiO2, and ultrafine l-Methionine (C,N,S triple doped)-TiO2-ZnO nanoparticles (NPs) were synthesized and blended in polyethersulfone (PES) matrix with various loadings (0.1, 0.5, and 1 wt %). The prepared nanoparticles (NPs) were characterized by XRD, FT-IR, FE-SEM, PL, and DRS analyses. The effect of embedded NPs on the morphology and hydrophilic properties of the fabricated membranes was also analyzed by AFM, SEM and contact angle measurement. The results showed that the membrane structure (morphology and porosity) and its hydrophilic properties are changed with addition of the NPs in the PES casting solution. Results showed that the membrane hydrophilicity and permeation flux improved by embedding the NPs in the PES mix matrix. The influence of embedded NPs on the membrane performance and antifouling properties was also studied in a dead end and cross flow systems. The nanofiltration performance was investigated by rejection of Direct Red 16 (DR16). The results indicated that 0.5 wt % of the NPs had the highest pure water flux (PWF), flux recover ratio (FRR), and rejection efficiency compared to the other concentrations of NPs. Finally, the photocatalytic properties of the M3 (optimum blended membrane) and unfilled PES was investigated in a cross flow system for filtration of biologically treated palm oil mill effluent (POME) under continuous visible light irradiation. The value of permeation flux for unfilled PES membrane showed a significant decline while it was not obviously changed for M3 during filtration biologically treated POME under continuous visible light irradiation. The results revealed that the M3 membrane presented the best antibiofouling characteristics due to high hydrophilic properties and low surface roughness and strong photocatalytic activity.