Dahiru Usman H, Saleem Faisal, Zhang Kui, Harvey Adam
Department of Chemical Engineering, School of Engineering, Newcastle University Newcastle upon Tyne NE1 7RU UK
Raw Materials Research and Development Council, Federal Ministry of Science and Technology Abuja Nigeria.
RSC Adv. 2022 Apr 7;12(18):10997-11007. doi: 10.1039/d2ra01097f.
In this work, a non-thermal plasma dielectric barrier discharge (DBD) was used to remove methanol from ambient air. The effects of carrier gases (N, dry and humidified air), power (2-10 W), inlet concentration (260-350 ppm), and residence time (1.2-3.3 s) were investigated to evaluate the performance of the plasma DBD reactor in terms of removal efficiency, product selectivity and reduction of unwanted by-products at ambient temperature and atmospheric pressure. It was found that the conversion of methanol increased with power and residence time regardless of the carrier gas used. However, the removal efficiency decreased with the increasing concentration of CHOH. Almost complete removal of methanol (96.7%) was achieved at 10 W and a residence time of 3.3 s in dry air. The removal efficiency of methanol followed a sequence of dry air > humidified air > N carrier gas. This was due to the action of the O radical in dry air, which dominates the decomposition process of the plasma system. The introduction of water vapour into the DBD system decreased the removal efficiency but had a number of significant advantages: increased CO selectivity and yield of H it significantly reduced the formation of O, CO and higher hydrocarbons. These influences are probably due to the presence of potent OH radicals, and the conversion pathways for the various effects are proposed. It is important to note that no solid residue was formed in the DBD reactor in any carrier gas. Overall, this research indicates that methanol can be almost completely removed with the correct operating parameters (96.7% removal; 10 W; 3.3 s) and shows that humidification of the gas stream is beneficial.
在本研究中，采用非热等离子体介质阻挡放电（DBD）从环境空气中去除甲醇。研究了载气（氮气、干燥空气和加湿空气）、功率（2 - 10瓦）、进气浓度（260 - 350 ppm）和停留时间（1.2 - 3.3秒）对等离子体DBD反应器在常温常压下的去除效率、产物选择性和减少有害副产物方面性能的影响。结果发现，无论使用何种载气，甲醇的转化率均随功率和停留时间的增加而提高。然而，去除效率随甲醇浓度的增加而降低。在干燥空气中，功率为10瓦、停留时间为3.3秒时，甲醇几乎能完全去除（96.7%）。甲醇的去除效率顺序为：干燥空气＞加湿空气＞氮气载气。这是由于干燥空气中的O自由基起作用，它主导了等离子体系统的分解过程。向DBD系统中引入水蒸气会降低去除效率，但有许多显著优点：提高了CO的选择性和H的产率，显著减少了O、CO和高级烃的生成。这些影响可能是由于强OH自由基的存在，并提出了各种效应的转化途径。需要注意的是，在任何载气条件下，DBD反应器中均未形成固体残留物。总体而言，本研究表明，在正确的操作参数下（去除率96.7%；10瓦；3.3秒）甲醇几乎可以完全去除，并且表明气流加湿是有益的。
