无水条件下气相三氯乙烯的光催化降解研究

Study on the semiconductor photocatalytic degradation of gaseous trichloroethylene without water

以二氧化钛为光催化剂，主波长２５４ｎｍ紫外线杀菌灯为光源，研究了气相三氯乙烯（ＴＣＥ）在无水条件下的光催化降解反应。结果发现，ＴＣＥ的光催化降解产物为ＨＣｌ、ＣＯ２及Ｃｌ２，并得出ＴＣＥ在无水条件下光催化反应的计量式为Ｃ２ＨＣｌ３＋２Ｏ２ｈｖＴｉＯ２→ＨＣｌ＋２ＣＯ２＋Ｃｌ２，该计量式与有水条件下光催化反应降解ＴＣＥ的计量式不同。结果还发现，ＴＣＥ初始反应速率与光强的０．１６次方呈正比，光催化降解速率方程符合Ｌａｎｇｍｕｉｒ－Ｈｉｎｓｈｅｌｗｏｏｄ公式〔１〕。

The photocatalytic degradation has attracted more and more attention. It should be noted that water vapor was incorporated in the feed gases in most of such studies. The photocatalytic degradation of trichloroethylene (TCE) in the gas phase without water was studied using anatase titanium dioxide powder and 254 nm UV lamp. It was proved that the products were HCl、CO_2 and Cl_2,and that the reaction stoichiometry was described as C_2HCl_3 + 2O_2 hvTiO_2HCl + 2CO_2 + Cl_2,which is different from that of under humid conditions. The equation of photocatalytic degradation agreed with Langmuir-Hinshelwood rate form and the degradation rate was direct proportional to the power of 0.16 of light intensity.