Ag/TiO2光催化还原硝酸氮  

Photocatalytic Reduction of Nitrate by Ag/TiO2 Catalyst

作　　者：柳丽芬[1] 董晓艳[1] 杨凤林[1] Jimmy C Yu 

机构地区：[1]大连理工大学环境与生命学院,大连116023 [2]香港中文大学化学系,中国香港沙田

出　　处：《无机化学学报》2008年第2期211-217,共7页Chinese Journal of Inorganic Chemistry

基　　金：国家自然科学基金资助项目(No.20477006)

摘　　要：利用化学还原法制备不同Ag掺杂量TiO2纳米催化剂,采用TEM、XRD、XRF和UV-Vis对催化剂进行表征。考察了催化剂在紫外光(254nm)和可见光照射下还原初始浓度100mgN·L-1水相硝酸氮的活性和效果。重点考察了紫外光照射下Ag掺杂量、不同空穴捕获剂(甲酸、甲醇、乙酸、乙醇、草酸、草酸钠等)及甲酸浓度对硝酸氮还原的影响;对硝酸氮转化率和总氮去除率、形成亚硝酸氮、氨氮浓度及氮气选择性的影响。甲酸浓度为0.030mol·L-1、Ag掺杂量为1.0wt%时催化剂效果最佳。此时,硝酸氮、总氮的转化率分别为98.43%、78.13%;亚硝酸氮浓度为零,转化的硝酸氮中只有20.76%转化为氨氮,氮气选择性为79.24%。可见光下进行光催化还原反应时,硝酸氮转化率仅37.98%,但氮气的选择性较高。Ag/TiO2 catalysts were prepared by a simple chemical reduction method and characterized by TEM, XRD, XRF and UV-Vis and further tested for photo-catalytic nitrate reduction under germicidal UV （254 nm） and visible light irradiation. The effects of Ag content, hole scavengers （such as formic acid, acetic acid, ethanol and oxalic acid, sodium oxalate）, concentration of formic acid on N removal were investigated. Best catalytic activity for photocatalytic reduction of nitrate （100 mgN·L^-1） with the presence of formic acid was obtained when the content of Ag was 1.0wt%, the concentration of formic acid was 0.030 mol·L^-1. Best nitrate conversion after 2 h UV irradiation, reached 98.43% and N2-N selectivity was 79.24%, no nitrite was detected, and 20.76% converted nitrate existed in NH4-N form. A higher selectivity for N2 （92%） was obtained by using visible light illumination （300 W）, although the nitrate conversion was only 37.9%.

关 键 词：银掺杂 TIO2 还原 硝酸根 

分 类 号：O614.122[理学—无机化学] O614.411[理学—化学]