La~(3+)和Fe~(3+)共掺杂TiO_2/浮石的制备及光催化矿化二级出水的效果

采用溶胶-凝胶法和浸涂法制备了以浮石为载体、La~(3+)和Fe~(3+)为共掺杂离子的TiO_2光催化剂,并用其光催化矿化城市污水处理厂二级出水.La~(3+)、Fe~(3+)改性TiO_2/浮石催化剂用X射线衍射、电镜扫描进行了表征和分析,探讨了La~(3+)、Fe~(3+)掺杂量对TiO_2光催化性能的影响,以及浮石粒径、涂膜层数、催化剂投加量对TiO_2/浮石光催化矿化二级出水效果的影响.结果显示,所制备的TiO_2以混晶形式存在,锐钛矿的含量为78.1%,平均粒径为36nm;TiO_2薄膜在浮石上负载良好,当La~(3+)、Fe~(3+)掺杂量分别为0.5%和0.05%、浮石粒径为20-40目、涂膜层数为4层、催化剂投加量为15 g·L~(-1),光催化反应时间为200min时,二级出水中TOC的去除率为51.6%,La~(3+)、Fe~(3+)改性TiO_2/浮石光催化是一种有效的污水深度处理方法.

Preparation of La~(3+)/Fe~(3+) co-doped TiO_2 pumice and photocatalytic mineralization of secondary effluents

A research on photocatalytic mineralization of secondary effluents by La~(3+)/Fe~(3+) co-doped TiO_2 pumice was studied. La~(3+)/Fe~(3+) co-doped TiO_2 pumice were prepared by sol-gel and dip-coating method, and the catalysts were characterized and analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Influencing factors such as ration of La~(3+) and Fe~(3+), particle size of pumice, number of TiO_2 films and dosage of catalysts, were investigated. The results showed that semiconductive compound TiO_2 appeared as a complex form with anatase and futile, and the proportion of anatase in TiO_2 was 78.1%. When the ration of La~(3+) and Fe~(3+) were 0.5% and 0.05%, the particle size of pumice were from 20 to 40 meshes, the number of TiO_2 films were 4 and the dosage of catalysts were 15 g·L~(-1), the reduction rate of TOC is 51.6%. La~(3+)/Fe~(3+) co-doped TiO_2 pumice was an effective catalyst using in advanced treatment of secondary effluents with a good mineralization performance.