紫外-微臭氧工艺中O_3的产生及其在有机物降解中的作用

Generation and contribution to degradation of organic pollutants of ozone in UV-microO_3

研究以低压汞灯作为光源的高级氧化工艺中石英玻璃套管内O3的产生情况,考察紫外-微臭氧工艺(UV-microO3)对氯苯、苯胺和甲基叔丁基醚的去除能力,分析O3在降解有机物中的作用。研究结果表明:套管内空气接受185 nm紫外辐射能够产生一定质量浓度的O3,当空气以3.0 L/min的流量通过套管时产生O3质量浓度为0.778 mg/L,降低进气湿度和压强均有利于O3的产生;低质量浓度O3的投加能够显著提高UV对有机物的去除效果,不同工艺对氯苯、苯胺和甲基叔丁基醚的去除能力由大到小为:UV-microO3,UV/曝气,UV;投加羟基自由基(·OH)清除剂——叔丁醇对UV-microO3去除有机物产生抑制作用;UV-microO3去除有机物过程中O3分子的直接氧化作用可忽略,而O3受到紫外激发产生的·OH发挥了重要作用。在氯苯、苯胺和甲基叔丁基醚的去除中,·OH的贡献率分别为:48.29%,65.31%和69.05%,ACUCHEM程序模拟结果验证了该结论。

The generation of ozone between the quartz glass tube and low pressure mercury lamp in advanced oxidation process was investigated, and the degradations of chlorobenzene, aniline and methyl tert-butyl ether （MTBE） by UV-microO3 were compared while the effect of ozone was analyzed. The results show that ozone is generated when air is exposed to the UV irradiation at 185 nm. When the air flow rate is 3.0 L/rain, 0.778 mg/L of ozone is generated, and the decrease of humidity and pressure of inlet air is favorable to the generation of ozone. The removal of organic pollution is enhanced by the introduction of ozone in low-concentration, and the removal ability decreases in the following order： UV-microO3, UV/aeration, UV. The removal of organic pollutants is inhibited by Tert-butyl alcohol （TBA） in UV-microO3. The direct oxidation of organic pollutants by ozone can be ignored but .OH generates as a production of photolysis of ozone plays an important role in the degradation of organic pllutants. The contributions of ·OH to the removal of chlorobenzene, aniline and MTBE are 48.29%, 65.31% and 67.50%, respectively, which is verified by the theoretical values of ACUCHEM program.