Department of Chemistry, University of Copenhagen , Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark.
Environ Sci Technol. 2014;48(15):8768-76. doi: 10.1021/es5012687. Epub 2014 Jul 10.
In this article, gas-phase advanced oxidation, a new method for pollution control building on the photo-oxidation and particle formation chemistry occurring in the atmosphere, is introduced and characterized. The process uses ozone and UV-C light to produce in situ radicals to oxidize pollution, generating particles that are removed by a filter; ozone is removed using a MnO2 honeycomb catalyst. This combination of in situ processes removes a wide range of pollutants with a comparatively low specific energy input. Two proof-of-concept devices were built to test and optimize the process. The laboratory prototype was built of standard ventilation duct and could treat up to 850 m(3)/h. A portable continuous-flow prototype built in an aluminum flight case was able to treat 46 m(3)/h. Removal efficiencies of >95% were observed for propane, cyclohexane, benzene, isoprene, aerosol particle mass, and ozone for concentrations in the range of 0.4-6 ppm and exposure times up to 0.5 min. The laboratory prototype generated a OH(•) concentration derived from propane reaction of (2.5 ± 0.3) × 10(10) cm(-3) at a specific energy input of 3 kJ/m(3), and the portable device generated (4.6 ± 0.4) × 10(9) cm(-3) at 10 kJ/m(3). Based on these results, in situ gas-phase advanced oxidation is a viable control strategy for most volatile organic compounds, specifically those with a OH(•) reaction rate higher than ca. 5 × 10(-13) cm(3)/s. Gas-phase advanced oxidation is able to remove compounds that react with OH and to control ozone and total particulate mass. Secondary pollution including formaldehyde and ultrafine particles might be generated, depending on the composition of the primary pollution.
本文介绍了一种基于大气光氧化和颗粒形成化学的新型污染控制方法——气相高级氧化。该工艺使用臭氧和 UV-C 光产生原位自由基来氧化污染物，生成的颗粒通过过滤器去除；臭氧则使用 MnO2 蜂窝催化剂去除。这种原位过程的组合可以用相对较低的比能输入去除广泛的污染物。建造了两个概念验证设备来测试和优化该工艺。实验室原型由标准通风管道制成，最大处理能力为 850 m(3)/h。在一个铝制飞行箱中建造的便携式连续流原型可以处理 46 m(3)/h。在 0.4-6 ppm 的浓度范围内和 0.5 分钟的暴露时间内，观察到丙烷、环己烷、苯、异戊二烯、气溶胶颗粒质量和臭氧的去除效率>95%。实验室原型在 3 kJ/m(3)的比能输入下，从丙烷反应中产生的 OH(•)浓度为(2.5 ± 0.3) × 10(10) cm(-3)，便携式设备在 10 kJ/m(3)下产生(4.6 ± 0.4) × 10(9) cm(-3)。基于这些结果，原位气相高级氧化是大多数挥发性有机化合物（特别是那些 OH(•)反应速率高于约 5 × 10(-13) cm(3)/s 的化合物）的可行控制策略。气相高级氧化能够去除与 OH 反应的化合物，并控制臭氧和总颗粒物质量。根据初始污染的成分，可能会产生包括甲醛和超细颗粒在内的二次污染。
