金属离子掺杂二氧化钛及水体光催化脱氮研究

采用溶胶-凝胶法制备了掺杂Ce³⁺、La³⁺、Ag⁺、Fe³⁺的TiO₂光催化剂,以考察其薄膜和粉体形式对水中无机氮的光催化去除效果和活性.用所制备的催化剂对含氨氮-亚硝酸氮的混合液进行了光催化脱氮研究.本文利用UV-Vis吸收光谱、XRD和TEM对催化剂进行了表征.同时,对影响TiO₂光催化效率的因素:如掺杂金属离子的种类、浓度、涂膜层数、反应液中有无Fe²⁺、不锈钢和玻璃载体、反应器的构型等进行了探讨,并对今后的研究进行展望.经过2 h紫外光照射反应,实验最佳脱氮效果:金属离子掺杂TiO₂薄膜型催化剂总氮去除率在30%左右,金属离子掺杂粉末型催化剂光催化最高总氮去除率可达41.7%.

Study on Photocatalytic Activity of TiO2 Photocatalysts Doped with Metal Ions in Nitrogen Removal

Titanium dioxide photo-catalysts doped/co-doped with Ce3+,La3+/Ag+/Fe3+ by using the sol-gel method were prepared and tested to evaluate their photo-catalytic activities on nitrogen removal from solution which contained ammonium and nitrite.The catalysts were characterized using UV-Vis,XRD and TEM.Also investigated were the influencing factors such as different kinds and concentration of doped metal ion,dipping times(thickness of catalyst films),addition of Fe2+ to the solution,different substrate(glass or stainless steel net),different designs of reactor and different light sources(UV or solar light) on photocatalytic N removal efficiency.After 2 hours UV irradiation,simultaneous removal of ammonium and nitrite could be achieved.The removal efficiency for TN was about 30% when TiO2 film was used.A higher removal rate of 41.7% could be achieved by using TiO2 powders.