水热法合成的LaVO4/WO3复合纳米片的可见光光催化还原工业废水中Cr（Ⅵ）效果分析

Analysis of the effect of visible photocatalytic reduction of Cr（Ⅵ） in industrial wastewater by hydrothermal synthesis of LaVO4/WO3 composite nanoplate

针对工业废水中Cr(Ⅵ)毒性大,迁移性强的问题,采用水热法制备了不同复合比例的LaVO4/WO3复合纳米片光催化剂,通过XRD、SEM、XPS和DRS测试手段进行了表征。结果表明:LaVO4能进入WO3晶格之中,使其产生晶格缺陷;晶格缺陷可作为活性位点,促进光生载流子的分离,提高WO3的光催化活性。可见光下光催化还原工业废水中Cr(Ⅵ)测试表明:LaVO4/WO3复合纳米片的光催化还原效率比WO3更高,当LaVO4以质量比为3%负载WO3时,复合纳米片光催化还原性最高,可达92%,是纯WO3还原效率的8.3倍。分析结果表明,LaVO4能使WO3的氧空位得到扩散,提高界面光生电子的迁移速率,促进光生电子还原Cr(Ⅵ),提高复合纳米片的光催化还原性能。本研究为重金属工业废水,特别是难降解重金属污染物高效治理技术的研发提供了理论参考。

To solve the problem of high toxicity and strong migration of Cr(Ⅵ)in industrial wastewater,photocatalysts of LaVO4/WO3composite nanoplate with different composite ratios were prepared by the hydrothermal method and characterized by XRD,SEM,XPS and DRS techniques.The results showed that LaVO4could enter the lattice of WO3,causing lattice defects.Lattice defects can be used as active sites to promote the separation of photogenic carriers and improve the photocatalytic activity of WO3.The Cr(Ⅵ)test in industrial wastewater for photocatalytic reduction under visible light showed that the photocatalytic reduction efficiency of LaVO4/WO3composite nanoplate was higher than that of WO3.When LaVO4 loaded WO3with a mass ratio of 3%,the photocatalytic reduction efficiency of the composite nanoplate was the highest,up to 92%,which was 8.3 times that of pure WO3.LaVO4could diffuse the oxygen vacancy of WO3,improve the photogenerated electron migration rate at the interface,promote the photogenerated electron reduction Cr(Ⅵ),and improve the photocatalytic reduction of composite nanoplate.This study provides a theoretical reference for the research and development of efficient treatment technology of heavy metal industrial wastewater,especially refractory heavy metal pollutants.