Abstract: The catalytic effect of typical heteropolyacids (HPA) on ozonation was investigated by ozonation of polyvinyl alcohol (PVA) which was not easily biodegradable. First, silicotungstic acid (HSiW) with catalytic effect on ozonation PVA was screened out among three typical heteropoly acids, and the effects of reaction time, ozone mass concentration, pH value of the system, catalyst dosage and reaction temperature on removal rate of PVA were investigated. Then, the optimal conditions for removing PVA were determined by orthogonal experiments. The results show that the pH value of the system has the greatest influence on the removal rate of PVA, and the effect of catalyst dosage is small. The optimal conditions for the removal of PVA by the silicotungstic acid catalytic ozonation system are: ρ(O₃)=25 mg/L, reaction temperature of 30 ℃, pH=83, catalyst dosage of 250 mg/L. Under this condition, the degradation experiment was carried out for 5 m
in, and the removal rate of PVA can reach 983%, the addition of silicotungstic acid does not change the basic pathway for ozonation to degrade PVA, the silicotungstic acid can promote ozone decomposition to generate more HO·, and can also catalyze the direct reaction between ozone and PVA.

Key words: heteropolyacid, polyvinyl alcohol, simulated wastewater, catalysis, ozonation