摘要
在建立热脱附-气相色谱法分析气相中低浓度壬醛的基础上,研究了不同条件下真空紫外光对气相中低浓度壬醛的光化学降解。结果表明,壬醛的真空紫外光降解率基本不受初始浓度的影响,在所研究的浓度范围(0.13～1.74mg/m3)内符合一级动力学,其表观反应速率常数为2.3 min-1。相对湿度一开始增加时均使得不同浓度的壬醛的去除率降低,但低浓度壬醛的降解随后几乎不再受相对湿度变化的影响,而较高浓度壬醛的去除率则先随相对湿度增加而下降,随后则又上升。壬醛能在极干燥的氮气气氛中被真空紫外光降解,同时它在氮气气氛中的降解率随相对湿度的增加而增加,壬醛在极干燥的氮气、空气和氧气气氛中的降解率依次上升,说明真空紫外光直接光解、光解产生的羟基自由基、光解产生的氧原子或臭氧均能导致壬醛的有效降解,且这3种机制相互影响。
The ATD-GC（automatic thermal desorption-gas chromatography） method was established for qualitative and quantitative analysis of n-nonanal,which was used to study the photochemical degradation of low concentration n-nonanal in the gas phase induced by vacuum ultraviolet.It was showed that the degradation rate of n-nonanal was little influenced by its inlet concentration,and the reaction followed the first-order kinetics with the apparent first-order reaction rate constant of 2.3 min^-1 when the inlet concentration was in the range 0.13～1.74 mg/m^3.The removal rate of n-nonanal decreased with increasing relative humidity for both the high-and low-inlet concentration cases,but with further increases of relative humidity,they behaved differently： the removal rate of n-nonanal in the low-inlet-concentration case changed little while in the high-inlet-concentration case it decreased first and then increased again.n-nonanal could be photolyzed in dry pure nitrogen atmosphere and the degradation rate increased with the increasing humidity.The effects of different carrier gases were investigated and compared.The degradation rate of n-nonanal was in the following sequence： N2 air O2.It was suggested that in the process of vacuum ultraviolet-induced photochemical degradation the direct photolysis,photo-generated hydroxyl radicals and oxygen atom/ozone all contribute to the removal of n-nonanal and these three mechanisms interact with each other.
出处
《环境工程学报》
CAS
CSCD
北大核心
2010年第6期1368-1372,共5页
Chinese Journal of Environmental Engineering
基金
国家高技术研究发展计划(863)项目(2006AA06Z377)
国家重点实验室专项基金(08Y02ESPCT)
关键词
嗅味物质
壬醛
真空紫外光
光降解
室内空气
odorous substances
n-nonanal
vacuum ultraviolet
photochemical degradation
indoor air
