真空紫外光解α-蒎烯的去除特性和产物分析

采用真空紫外(vacuum ultraviolet,VUV)光解α-蒎烯模拟废气,系统研究了工艺参数、反应介质、活性自由基团对去除率的影响,并对光解产物初步进行分析。结果表明,随着进气流量和进气浓度的增加,去除率相应减少;停留时间为15s,去除负荷达到最大值,为39.003mg.m-3.s-1;进气浓度对反应动力学有较大影响,低浓度转变为高浓度时,一级反应动力学转变为二级反应动力学;反应介质对一级动力学常数影响较大,湿度为35%～45%的标准空气作为反应介质时,一级动力学常数达到最大值,为0.0520s-1;光解体系中存在羟基自由基和臭氧两类主要的强氧化性物质,且羟基自由基最先和α-蒎烯反应,但臭氧氧化占据量的优势;光解产物主要是水溶性较好的小分子醛酮类化合物和羧酸类化合物。

Removal characteristics and intermediates analysis of α-pinene photodegradation by vacuum ultraviolet

α-pinene from simulating waste gas was degraded by vacuum ultraviolet in a spiral photo-reactor at various process parameters, media and active radicals, and the effects of them on the removal efficiency were studied systematically.The results showed that the efficiency gradually decreased with increasing flow rate and inlet concentration, and was of the maximum value 39.003 mg·m^-3·s^-1 at 15 s of residence time.It was also found that the removal efficiency followed first order kinetics at low concentration whose rate constant was affected more by the reaction medium and reached the maximum 0.0520 s^-1 at air with 35%—45% relative humidity, and second order kinetics at high concentration.In the system of photo-degradation there existed two kinds of strong oxidizer, hydroxyl radical and ozone, that were detected indirectly or directly.Although hydroxyl radicals reacted with α-pinene first, ozone played significant role for the removal of α-pinene.The photo-degradation products were mainly low weight molecule organic aldehydes, ketones and acids, which were of better water-solubility.