Ag/g-C3N4可见光催化技术降解水中磺胺嘧啶的研究

Study on degradation of sulfadiazine in water by visible-light catalytic technology of Ag/g-C3N4

将Ag/g-C3N4(银/石墨相氮化碳)可见光催化技术应用于废水中磺胺嘧啶的去除,考察Ag/g-C3N4对磺胺嘧啶的降解效果、水质因素对降解效果的影响、降解机理、中间产物及其应用于实际水体时磺胺嘧啶的降解情况.结果表明:1)质量分数为5%的Ag/g-C3N4在可见光照射下能将磺胺嘧啶有效降解,去除率高达98.3%,且降解过程符合拟一级动力学模型;2)溶液的pH值和碱度对Ag/g-C3N4降解磺胺嘧啶的效果影响不大,但溶液中腐殖酸的存在对磺胺嘧啶的降解起抑制作用;3)在磺胺嘧啶的降解过程中,·O 2-和光生空穴是主要的活性物种;4)降解过程主要产生4种中间产物,分别为2-氨基嘧啶、对氨基苯磺酸、羟基化磺胺嘧啶和硝基化磺胺嘧啶;5)以松花江水和生活污水的二级出水为水质背景时,Ag/g-C3N4对磺胺嘧啶的去除率分别为95.4%和77.5%.

Visible-light catalysis technology of Ag/g-C3N4(silver/graphite carbon nitride)was applied to the removal of sulfadiazine in wastewater.The degradation effect of Ag/g-C3N4 on sulfadiazine and water quality factors,degradation mechanism,intermediate products and its degradation effect on sulfadiazine in actual water were investigated.The results showed that Ag/g-C3N4 with a mass fraction of 5%could effectively degrade sulfadiazine under visible-light irradiation,with a removal rate of up to 98.3%,and the degradation process conformed to the pseudo-first-order kinetic model;the pH and alkalinity of the solution Ag/g-C3N4 had little effect on the degradation of sulfadiazine,but the presence of humic acid in the solution inhibited the degradation of sulfadiazine;during the degradation of sulfadiazine,·O 2-and photogenerated holes were the main activities species;the degradation process mainly produced 4 kinds of intermediate products,which were 2-aminopyrimidine,p-aminobenzenesulfonic acid,hydroxylated sulfadiazine,and nitrated sulfadiazine.When the Songhua River water and the secondary effluent of domestic sewage were used as the water quality background,the removal rates of Ag/g-C3N4 for sulfadiazine were 95.4%and 77.5%,respectively.