可见光下聚乙烯醇负载EuPW光催化降解甲基橙的研究

Degradation of methyl orange by photocatalyst EuPW/PVA under visible light irradiation

以磷钨酸和稀土氧化物为原料合成了稀土杂多酸盐K8H3[Eu(PW11O39)2]·25H2O(简记EuPW,下同).将其负载在聚乙烯醇(PVA)上,制成复合膜光催化剂EuPW/PVA,用SEM、IR等对其进行了表征.以氙灯为灯源,选择具有代表性的有机污染物—甲基橙为目标降解对象,研究了EuPW与PVA的成膜比例、合成温度、催化剂用量、pH值、反应时间、底物浓度等因素对甲基橙降解效率的影响.结果表明:EuPW与PVA的比例为1∶1,处理温度为50℃,pH=2.0时催化降解效率最高,光照25min,甲基橙的降解率可达99.1%.同时,研究了EuPW/PVA光催化降解甲基橙的动力学方程,实验表明,EuPW/PVA对甲基橙的光催化降解反应符合一级动力学方程,该反应温度下的表观速率常数为0.197min-1.

In this paper, K3H3[Eu （PW11O39）2]·25H2O （EuPW） was synthesized by tungstophosphoric acid and europium oxide. It was then loaded on the polyvinyl polyvinyl alcohol （PVA）, characterized by SEM, IR. The photocatalytic degradation of methyl orange solution was investigated under Xenon lamp. In the experiment, several factors, such as the proportion of EuPW on PVA, the drying temperature, pH value, the initial concentration of methyl orange, were considered. It was found that the optimum conditions of photocatalytic degradation reaction were the initial concentration of methyl orange 10mg/L, the ratio of EuPW/PVA 1： 1, drying temperature 50℃, pH=2.0, irradiation time 25min, then the color removal could be up to 99.1%. The kinetic equation of photocatalytic reaction above mentioned accords to L-H mechanism, of which first order apparent rate constant is 0.197min^-1.