Poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels for pH-sensitive photocatalytic degradation of organic pollutants

Poly(vinyl alcohol)/poly(acrylic acid)/TiO₂/graphene oxide nanocomposite hydrogels were prepared using radical polymerization and condensation reaction for the photocatalytic treatment of waste water. Graphene oxide was used as an additive to improve the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO₂ nanocomposite hydrogels. Both TiO₂ and graphene oxide were immobilized in poly(vinyl alcohol)/poly(acrylic acid) hydrogel matrix for an easier recovery after the waste water treatment. The photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO₂/graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer. The improved removal of pollutants was due to the two-step mechanism based on the adsorption of pollutants by nanocomposite hydrogel and the effective decomposition of pollutants by TiO₂ and graphene oxide. The highest swelling of nanocomposite hydrogel was observed at pH 10 indicating that poly(vinyl alcohol)/poly(acrylic acid)/TiO₂/graphene oxide nanocomposite hydrogels were suitable as a promising system for the treatment of basic waste water.