MnO_2对TiO_2光催化降解苯胺的影响

Influence of MnO_2 on TiO_2 photocatalytic degradation of aniline

采用动力学方法研究了MnO2颗粒物对TiO2光催化降解苯胺活性的影响,对比考察了光催化降解过程中苯胺溶液的UV吸收光谱的变化,并用HPLC方法鉴别了中间产物.结果表明,少量MnO2颗粒物就能使TiO2光催化降解苯胺的活性受到明显的抑制,不同结构的二氧化锰致毒效应由大到小的顺序为:δ-MnO2>α-MnO2>β-MnO2;降解不同时间后溶液的UV吸收光谱的变化也反映了MnO2颗粒物具有同样的致毒效应;MnO2颗粒物不改变TiO2光催化降解苯胺的途径,但对生成中间产物的基元步骤的抑制程度不同。

Influences of MnO2particles on the photocatalytic activity of TiO2 have been investigated using kinetical method through the photocatalytic degradation of aniline. The changes of UV spectra of aniline solution have been studied in the degradation process. The main products in the degradation process have been analyzed by HPLC. The experimental results showed thai the degradation rate of aniline by TiO2 photocatalysts was obviously decreased due to the presence of even a small amount of MnO2 particles. It was found that the poisoning effect varied with the crystal phases of MnO2 and the effect was in the order δ-MnO2 〉 α- MnO2 〉 β-MnO2. The same poisoning effect of MnO2 can also be displayed through the change of the UV absorption spectra of the solution after the degradation at different times. Although the degradation mechanism of aniline was not changed, the elementary reactions of forming different intermediate products were differently inhibited by the presence of MnO2.