Abstract
A polyvinylidene fluoride (PVDF) ultrafiltration (UF) membrane was modified by dispersing titanium oxide (TiO2) particles in a PVDF solution. PVDF flat-sheet membranes were prepared by a phase inversion method. This study investigates the potential low-fouling properties of these composite membranes during filtration, in darkness or under UV irradiation, of pure water and foulants representative of those found in membrane bioreactor processes: commercial bovine serum albumin (BSA) as a model protein and real soluble extracellular polymeric substances (EPS). The experimental results indicate that nanocomposite membrane has a structure with longer and larger macrovoid than neat PVDF membranes resulting in higher water flux performances. These higher flux performances were also due to an increase in surface hydrophilicity because of the presence of TiO2 particles. Moreover, such membranes are less prone to adsorption by BSA and present self-cleaning ability under static irradiation. During filtration of BSA and EPS without UV irradiation, nanocomposite membranes presented a little flux decline and reached stabilization more rapidly in comparison with PVDF membranes. Moreover, simultaneous UV irradiation during ultrafiltration has a benefit effect only on nanocomposite membranes for which initial flux was increased. Hydrophilic properties of nanocomposite membranes lead to better retention performances of BSA and EPS, which are still improved under UV irradiation. Finally, nanocomposite membranes under UV irradiation presented the best flux recovery ratio confirming their antifouling property.