双重改性TiO_2光催化剂的制备及性能研究

Synthesis of Dual Modification of TiO_2 Photocatalyst and Its Performance

采用空心和SnO_2包覆制备了双重改性的TiO_2光催化剂,并利用FTIR和TEM对其进行表征,对比改性前后对Pb^(2+)、Ag^+去除率。FTIR图谱分析可知,煅烧的样品中已不存在聚苯乙烯模板;TEM图象显示制备的催化剂具有空心结构,且其表面均匀包覆一层物质。以Pb^(2+)、Ag^+模拟重金属废水的去除率考察光催化剂的活性,初始pH值为6,初始质量浓度为120 mg·L^(-1),改性TiO_2投加量为0.2%时,去除率最高。Langmuir和Freundlich等温模型均能较好地描述光催化剂的吸附过程,说明此催化剂吸附Pb^(2+)、Ag^+是单分子层和非均质表面兼有的一个过程。

Dual modification ofTiO2 photocatalyst with core-shell structure and SnO2 coating was prepared in our paper. Xhe prepared catalyst was characterized by Transmission electron microscope （TEM） and Fourier transform infrared spectroscopy （FTIR）. The removal rate of Pb2., Ag＊ was compared before and after modification. FTIR showed that the polystyrene template did not exist in the burnt samples. TEM indicated that the prepared photocatalyst had a core-shell structure, and its surface was uniformly coated by a layer of material. ~he photocatalytic activity was evaluated based on the removal rate of heavy metals such as Pb2＋, Ag＊. The removal rate of heavy metals was highest under the conditions as follows： the catalyst dosage was 0.2%, the initial solution concentration of heavy metals was 120 mg·L-1, the initial pH value was 6. Both Langmuir and Freundlich models could well illustrated the adsorption process of photocatalyst were established to further study the absorption activity before the photocatalytic decolorization, and the adsorption of Pb2＊, Ag＊ on the photocatalyst acted on both monomolecular layer and the heterogeneous surface.