TiO2 coated on PVDF membrane for dye wastewater treatment by a photocatalytic membrane

This work investigated the membrane modification to increase hydrophilicity aiming for application in a photocatalytic membrane. The modified poly(vinylidene fluoride) (PVDF) flat sheet membrane was coated with titanium dioxide (TiO2). The chemical and physical changes of membranes were characterized by contact angle, scanning electron microscopy and porosity. The results found that TiO2 successfully modified the PVDF membrane by decreasing the contact angle from 127.1 degrees to 114.3 degrees on increasing the TiO2 concentration from 0.1 to 1.0 g/L. The contact angles were decreased with the increase of coating time. The water permeation after PVDF membrane modification decreased compared with the original membrane, whereas water fluxes increased with the increase of TiO2 concentration. TiO2 particles were observed on the membrane surface while the porosity of the membrane coated with TiO2 decreased. The optimum condition of membrane coating was obtained at 1.0 g/L of TiO2 and 60 min of coating time. The decolorization of RB 19 by photolysis and photolysis followed by filtration was less than 10%; in contrast, the decolorization of RB 19 by photocatalytic oxidation was as good as a photocatalytic membrane for 60 min. The TiO2 photocatalytic membrane is a feasible technology for RB 19 decolorization in wastewater.