TiO2 entrapped nano-composite PVDF/SPES membranes: Preparation, characterization, antifouling and antibacterial properties

In the current study, poly (vinylidene fluoride) (PVDF)/sulfonated polyethersulfone (SPES) blend membrane was modified using TiO2 nano-particles. Firstly, sulfonation of polyethersulfone (PES) was carried out, then PVDF/SPES blend membranes were prepared with and without TiO2 nano-particles in the casting solution using phase inversion induced by immersion precipitation technique. Polyvinylpirrolidone (PVP) with the concentration of 4 wt.% was added in the casting solution as pore former. The morphological studies were investigated using SEM, AFM, XRD, FTIR and contact angle goniometry. They showed that the average sizes of membrane pores in surface and sub-layer were reduced with addition of TiO2 nano particles in the casting solution. The presence of TiO2 nano-particles in the membrane structure was confirmed by XRD, FTIR and EDX analyses. The contact angle measurements demonstrated that the hydrophilicity of modified membranes was enhanced by addition of TiO2 in the casting solution. The experimental results demonstrated that the initial flux of TiO2 entrapped PVDF/SPES membranes was lower than the initial flux of neat PVDF/SPES membrane. The antifouling properties of membranes were improved by changing the membrane surface from hydrophobic to hydrophilic after TiO2 addition in the casting solution. Finally, neat and 4% TiO2 modified PVDF/SPES membranes were tested to possess the dramatic photo-bactericidal effect on Escherichia coli (E. coli). (C) 2011 Elsevier B.V. All rights reserved.