Ag_6P_2W_(18)O_(62)/TiO_2/膨胀石墨复合光催化剂的制备及甲基橙的降解

Preperation of Ag_6P_2W_(18)O_(62)/TiO_2/expended graphite composite photocatalyst and degradation of methyl orange

以钛酸四丁酯为钛源、膨胀石墨(EG)为载体,通过溶胶凝胶-浸渍法制备了Ag_6P_2W_(18)O_(62)/TiO_2/EG复合光催化剂。采用SEM,EDS,XRD,FTIR,UV-vis等技术对其进行表征,研究了该催化剂在紫外光及可见光下对甲基橙的降解性能。表征结果显示:Ag_6P_2W_(18)O_(62)被成功负载到TiO_2上且保持Dawson结构;经Ag_6P_2W_(18)O_(62)表面修饰后的复合光催化剂可见光吸收性能增强;EG提供的丰富孔道有利于有机污染物吸附去除。实验结果表明:在甲基橙质量浓度为20 mg/L、催化剂加入量为1.0 g/L、反应温度为25℃的条件下,n(Ag)∶n(Ti)=1∶16时的复合光催化剂(ATE-2)的紫外光、可见光催化活性最佳;紫外光下反应70 min时甲基橙去除率为96.5%,可见光下反应40 h时甲基橙去除率为83.5%;ATE-2使用5次后,反应70 min时,其甲基橙去除率仍为92.5%。

Using tetrabutyl titanate as titanium source and expended graphite（EG）as carrier,the Ag6P2W18O62/TiO2/EG composite photocatalyst was prepared by sol-gel and impregnation method and characterized by SEM,EDS,XRD,FTIR,and UV-vis. The degradation abilities of the photocatalyst to methyl orange under ultraviolet and visible light irradiation were studied. The characterization results show that：Ag6P2W18O62 is successfully loaded onto TiO2 with Dawson structure;The visible light absorption on the Ag6P2W18O62-modified composite photo-catalyst is enhanced;The rich channel structure of EG is good for adsorption of organic pollutants. The experiment results show that：under the conditions of methyl orange mass concentration 20 mg/L,photocatalyst dosage 1.0 g/L and reaction temperature 25 ℃,the catalytic activities of the composite photocatalyst with n（Ag）∶n（Ti）=1∶16（ATE-2）under ultraviolet and visible light irradiation are the best;The removal rates of methyl orange after reacted under ultraviolet irradiation for 70 min and under visible light irradiation for 40 min are 96.5% and 83.5%,respectively;After 70 min of reaction,the removal rate of methyl orange on the 5-time reused ATE-2 is still 92.5%.