Removal of polyvinyl alcohol from aqueous solutions using P-25 TiO2 and ZnO photocataysts: A comparative study

This investigation evaluates the effectiveness of P-25 TiO2 and ZnO in removing polyvinyl alcohol (PVA) from aqueous solutions. The effects of pH, photocatalyst dosage, initial PVA concentration, and UV wavelength on the removal efficiency of PVA were studied. Under acidic conditions, the removal efficiency of PVA using P-25 TiO2 exceeded that under alkaline conditions. However, the removal efficiency of PVA using ZnO under alkaline conditions exceeded that under acidic conditions. Additionally, the removal efficiency of PVA increased with photocatalyst dosage, but declined as the initial PVA concentration increased. The UV wavelength slightly affected the removal efficiency of PVA using P-25 TiO2, but dramatically affected that using ZnO. At UV-254 nm, pH 9, a photocatalyst dosage of 0.12 g/L, and an initial PVA concentration of 20 mg/L, the removal efficiencies of PVA using P-25 TiO2 and ZnO were 54% and 74%, respectively. Therefore, at UV-254 nm and pH 9, ZnO was more effective than P-25 TiO2. (C) 2013 Elsevier B.V. All rights reserved.