Desalination of dye solution utilizing PVA/PVDF hollow fiber composite membrane modified with TiO2 nanoparticles

Abstract

Novel poly(vinyl alcohol) (PVA)/poly(vinylidene fluoride) (PVDF) hollow fiber composite membranes modified with nano-TiO2 were prepared by a dip-coating method and they are suitable to be utilized in dye desalination and wastewater treatment. Glutaraldehyde (GA) was used as a cross-linker for the composite polymer membrane in order to enhance the chemical, thermal as well as mechanical stabilities. The surface morphologies and chemical structures of modified membranes were observed by scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS) and FTIR spectroscopy. Zeta potential of the membrane surface was used to analyze the membrane separation performance. Separation efficiency of dye and salts through novel PVA/PVDF composite membrane was dramatically influenced by dye concentration, salts concentration, pH and temperature of feed solution. Fouling and thermal stability of the membrane were also evaluated with CR, NaCl, and Na2SO4 as model compounds. The separation datas showed that the 1g/L nano-TiO2 modified membrane presented highest performance in terms of the rejections to CR, MO, and MB being 94±2.57%, 52.1±2.45%, and 92±2.20%, respectively. And all the PVA composite membranes had no rejection to salts (NaCl, Na2SO4). Compared with PVA composite membrane, the PVA composite membrane modified with nano-TiO2 has higher separation efficiency, antifouling and thermal stability.