弱紫外光光催化降解2,4-二氯苯氧基乙酸、对氯酚和草酸同时产氢  

Photocatalytic Degradation of 2,4-Dichlorophenoxyacetic Acid,4-Chlorophenol,and Oxalic Acid with Simultaneous Hydrogen Production under weak UV Light Illumination

作　　者：张向华[1] 刘鸿[2] 李文钊[1] 徐恒泳[1] 

机构地区：[1]中国科学院大连化学物理研究所,辽宁大连116023 [2]中山大学化学与化学工程学院,广东广州510275

出　　处：《催化学报》2008年第3期281-286,共6页

基　　金：国家自然科学基金(20207008)

摘　　要：考察了弱紫外光光催化氧化降解2,4-二氯苯氧基乙酸(2,4-D)、4-氯酚(4-CP)和草酸(OA)三种模型有机污染物及其同时产氢现象.结果表明:在光催化剂1.0%Pt/TiO2(1.0 g/L)作用下,用弱紫外光分别光照含有2,4-D,4-CP和OA的三种水溶液(均为1.0 mmol/L,160 ml)悬浮体系2 h,产生了38.43,0.05及111.35μmol的氢气和73.80,4.49及175.99μmol的二氧化碳,同时污染物2,4-D和4-CP去除率分别为83.83%和36.19%.可见,低碳的有机污染物OA和芳香性有机污染物2,4-D都表现出显著的光催化降解同时产氢性能,是好的光催化产氢的电子给体,而4-CP给电子性能较差.改用强紫外光照射(其强度比弱紫外高150倍),5 min内2,4-D和4-CP的去除率达到90%以上.光照2,4-D,4-CP和OA 2 h后相应的产氢量分别为113.02,38.98和191.30μmol;二氧化碳的产量分别为195.60,31.41和306.96μmol.根据污染物组成和含量,可以设计强紫外光和弱紫外光联合使用的光催化降解有机污染物同时产氢工艺,以便高效节能地实现污染物的去除以及光能和污染物的化学能向氢气化学能的转化.Photocatalytic degradation of three organic pollutants, 2,4- dichlorophenoxyacetic acid （2,4-D）, 4- chlorophenol （4-CP）, and oxalic acid （OA）, with simultaneous hydrogen evolution was investigated with weak UV light illumination. The photocatalytic reactions were carried out in 160 ml solutions of the pollutants （1.0 retool/L） using 1.0%Pt/TiO2（1.0 g/L） as the catalyst. After 2 h illumination, 38.43, 0.05, and 111.35 μmol of hydrogen and 73.80, 4.49, and 175.99μmol of carbon dioxide were produced. Simultaneously, 83.83% of 2,4-D, 36.19% of 4-CP, and 98.81% of OA were removed. These results showed that OA and 2,4-D were good electron donors for the photocatalytic hydrogen evolution. On the other hand, under the illumination of a strong UV light source with light intensity 150 times that the weak UV light, more than 90% of 2,4-D and 4-CP were removed within 5 rain. The amounts of hydrogen produced were 113.02, 38,98, and 191.30 μmol for 2,4-D, 4-CP, and OA solutions, respectively, and 195.60, 31.41, and 306.96 μmol of carbon dioxide was also produced. Therefore an appropriate combination of the processes of weak UV light and strong UV light can perform ultimate mineralization of organic pollutants with high hydrogen production and collective carbon dioxide of easy disposal. In this way the pollutants can be removed, and the light energy and chemical energy of the organic pollutants can be transferred to chemical energy in the form of hydrogen.

关 键 词：光催化 紫外光 二氧化钛 铂 有机污染物 降解 同时产氢 

分 类 号：O643.3[理学—物理化学] TQ116.2[理学—化学]