影像科学与光化学 ›› 1998, Vol. 16 ›› Issue (3): 237-244.DOI: 10.7517/j.issn.1674-0475.1998.03.237

• 研究论文 • 上一篇    下一篇

Cr(Ⅵ)-氯代苯酚共存污染体系中的光反应与光催化反应研究

付宏祥, 吕功煊, 李树本   

  1. 中国科学院兰州化学物理研究所羰基合成与选择氧化国家重点实验室, OSSO, 兰州 730000
  • 收稿日期:1997-11-16 修回日期:1998-03-09 出版日期:1998-08-20 发布日期:1998-08-20
  • 通讯作者: 李树本

STUDY ON PHOTO INDUCED AND PHOTOCATALYTIC REACTIONS IN Cr (Ⅵ) CHLOROPHENOL CO EXISTED POLLUTION SYSTEMS

FU Hongxiang, LU Gongxuan, LI Shuben   

  1. State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, P. R. China
  • Received:1997-11-16 Revised:1998-03-09 Online:1998-08-20 Published:1998-08-20

摘要: Cr(Ⅵ)-4CP(4-氯苯酚)共存污染体系中Cr(Ⅵ)离子的紫外光致还原主要是由于Cr(Ⅵ)与4CP光解产物之间的氧化还原反应而引起的。Cr(Ⅵ)离子还原受光强和体系酸度影响较大,还原速率呈零级反应。随体系pH值增大,Cr(Ⅵ)离子还原速率下降。中性条件下,光反应结束后有沉淀产物生成,这对于采用光化学方法消除环境污染提供了很有意义的结果。4CP存在对Cr(Ⅵ)离子在TiO2表面的暗态吸附没有影响。Cr(Ⅵ)-4CP-TiO2体系中Cr(Ⅵ)离子的紫外光致还原主要包括了两种反应:Cr(Ⅵ)与4CP之间的均相反应以及Cr(Ⅵ)离子在TiO2表面的光催化还原反应。一定波长紫外光下,排除Cr(Ⅵ)-4CP-TiO2体系中的均相反应,使得4CP对Cr(Ⅵ)离子光催化还原反应的促进作用得以证实。

关键词: 氯苯酚, 光致还原, 光催化, 酸度

Abstract: UV induced Cr (Ⅵ) reduction in Cr (Ⅵ) 4CP co existed pollution system mainly results from the redox reaction between Cr (Ⅵ) ion and photolysis products of 4CP.The light intensity and system acidity affect Cr (Ⅵ) reduction dramatically.The pollutants can be easily removed and decontaminated because some precipitate of products is formed after the photo induced reaction in neutral medium.This is an important result for the application of photo chemistry to the decontamination in complex component pollution mixtures.The presence of 4CP has no interference on Cr (Ⅵ) dark adsorption on TiO2. Under UV irradiation, the reaction in Cr (Ⅵ) 4CP TiO2 system is much complicated and two different reactions contribute to the overall Cr (Ⅵ) reduction:photo induced homogeneous reaction between Cr (Ⅵ) and 4CP,and photocatalytic reduction of Cr (Ⅵ) ion by TiO2 as an efficient semiconductor photocatalyst,which is promoted by another photocatalytic half reaction:4CP degradation.Cr (Ⅵ) reduction in Cr (Ⅵ) 4CP and Cr (Ⅵ) 4CP TiO2 systems under UV irradiation are both zero order reactions.In the condition of excluding other homogeneous reactions,the promotion effect of 4CP on photocatalytic reduction of Cr (Ⅵ) ion is distinguished and proved.

Key words: chlorophenol, photo induced reduction, photocatalysis, acidity