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采用连续流配气系统,利用氮掺杂TiO2,在UV(4 W,254 nm)光照下光催化降解(PCO)室内甲苯和苯甲醛污染物,运用质子转移反应质谱仪实时检测气相中间产物,应用健康风险评估模型分析甲苯、苯甲醛光催化降解过程的健康效应.结果表明,甲苯和苯甲醛转化率和矿化率较高,但如乙醛和甲醛等低级醛类(VAs)中间产物形成潜在的健康风险,常规的转化率和矿化率指标不能全面表征苯系物的光催化过程的健康风险.乙醛极易在气相积累,是影响健康风险变化的关键;甲醛的摩尔分数稳定在较低水平,但其影响不可忽视.甲苯和苯甲醛降解过程的健康风险指数增大因子(η)随VAs积累而增大,最大值分别为8 499.68和21.43,VAs的贡献率为99.3%和98.3%;光催化降解稳定后η分别为236.09和2.30,VAs的贡献率为97.9%和97.8%;η平均值(30 min)分别为932.86和8.52,VAs的贡献率为98.5%和98.0%.由此提出了以低级醛类健康风险指数增大因子贡献值(ηVAs)表征苯系物光催化安全降解过程的特征评价指标.
Toluene and benzaldehyde pollutants were photocatalytically degraded (PCO) using nitrogen-doped TiO2 and UV (4 W, 254 nm) light respectively. The gas-phase intermediate products were detected by proton transfer reaction mass spectrometry The healthy risk assessment model was applied to analyze the health effects of toluene and benzaldehyde on photocatalytic degradation. The results showed that toluene and benzaldehyde had high conversion and mineralization rate, but intermediate products of lower aldehydes (VAs) such as acetaldehyde and formaldehyde formed Potential health risks, conventional conversion rates, and mineralization indices do not fully characterize the health risks of the photo-catalysis of benzene-based compounds. Acetaldehyde, which easily accumulates in the gas phase, is the key to health-risk changes; the molar fraction of formaldehyde is stable at (Η) increased with VAs accumulation, the maximum values were 8 499.68 and 21.43, respectively, and the contribution rate of VAs was 99.3% and 98.3% respectively; η were 236.09 and 2.30 respectively after the stabilization of photocatalytic degradation, and the contribution rates of VAs were 97.9% and 97.8%; the average values of η were 932.86 and 8.52 respectively (30 min), and the contribution rates of VAs were 98.5% and 98.0%. It is proposed to lower aldehyde health The value of risk index increase factor (ηVAs) to characterize the characteristics of benzene degradation process of biodegradation process evaluation index.