组合光源反应条件下Ag/TiO_2催化还原水中硝酸盐

Catalytic Reduction of Nitrate by Ag/TiO_2 Catalyst under the Combination of Ultra Violet

用化学还原法制备Ag/TiO_2催化剂,采用扫描电子显微镜对催化剂进行表征。研究了不同光源照射下Ag掺杂量、空穴清除剂、甲酸浓度、催化剂用量以及煅烧温度对硝酸根还原的影响。重点考察了365nm、308nm及254nm三种波长的紫外灯组合光源照射下硝酸根的还原反应。结果发现,Ag掺杂量为2wt.%、甲酸浓度为30mmol/L、催化剂用量为1g/L时,采用365nm、308nm和254nm三种波长的紫外灯组合光源,硝酸根的还原效果最好。此时,硝酸盐氮的去除率为21.2%,亚硝酸盐氮浓度为零,转化的硝酸盐氮中氨氮的转化率只占12.56%,氮气的选择性为87.44%。

Ag/TiO2 catalysts were prepared by a chemical reduction method and characterized by SEM.Effects of the Ag content,the hole scavengers,the amount of formic acid,the dosage of titanium dioxide and the calcination temperature of TiO_2 have been investigated,and The reduction of nitrate in the combination of 365 nm,308nm and 254 nm with three wavelength ultraviolet light was studied.The results showed that nitrate can be removed efficiently under the combination of Ultra-Violet（365nm,308 nm,254nm）.Best catalytic activity for photocatalytic reduction of nitrate with the presence of formic acid was obtained when the content of Ag was 2wt.%,the concentration of formic acid was 30mmol/L,the dosage of TiO_2 was 1g/L.The nitrate conversion was 21.2%,no nitrite was detected,only 12.56% converted nitrate existed in ammonia form,nitrogen selectivity was 87.44%.