School of Space and Environment, Beihang University, Beijing, 100191, PR China.
Research Institution of Chemical Defense, Beijing, 102205, PR China.
Chemosphere. 2021 Jan;263:127893. doi: 10.1016/j.chemosphere.2020.127893. Epub 2020 Aug 17.
Toluene and styrene were two typical aromatic VOCs which were commonly used and coexistence in the exhaust gases from industrial manufacturing. Their simultaneous removal performances under non-thermal plasma (NTP) and NTP-catalysis were carried out and compared by a single stage coaxial dielectric barrier discharge (DBD) reactor. The effects of VOCs mixture, humidity, materials filling in the discharge zoon on the removal efficiency, CO selectivity, byproducts types and their emission levels were deeply investigated to explore the degradation mechanism and coexistence effect. Experimental results showed that the toluene removal was significantly inhibited when treated together with styrene under plasma treatment. But that of styrene was hardly affected at the same conditions. It was found that benzaldehyde as the primary organic byproducts from styrene consumed the oxidizing particles (O and OH), limiting the conversion of toluene. The introduction of Cu-doped MnO materials significantly improved the VOCs removal performance with nearly 100% conversion to CO at a discharge power less than 30 W, as well as O generation from more than 1.2 mg L by NTP to 1.6 × 10 mg L by NTP-catalysis. With the help of in situ FT-IR, it was believed that catalysts not only accelerated the adsorption and degradation of pollutants but also utilized ozone to involve this process. At last, a plausible explanation on binary coexistence effect under different conditions had been suggested and discussed.
甲苯和苯乙烯是两种典型的芳香族挥发性有机化合物，常用于工业制造过程中的废气中。采用单级同轴介质阻挡放电（DBD）反应器，对非热等离子体（NTP）和 NTP 催化下同时去除这两种挥发性有机化合物的性能进行了实验和比较。深入研究了 VOCs 混合物、湿度、放电区填充材料对去除效率、CO 选择性、副产物类型及其排放水平的影响，以探讨降解机制和共存效应。实验结果表明，在等离子体处理下，甲苯的去除率显著下降，而苯乙烯的去除率几乎不受影响。研究发现，苯乙烯的主要有机副产物苯甲醛消耗了氧化颗粒（O 和·OH），限制了甲苯的转化。引入 Cu 掺杂 MnO 材料可显著提高 VOCs 的去除性能，在放电功率小于 30 W 时，CO 的转化率接近 100%，而 NTP 产生的 O 生成量从 1.2 mg·L 增加到 NTP 催化下的 1.6×10 mg·L。通过原位傅里叶变换红外光谱（FT-IR）分析，可知催化剂不仅加速了污染物的吸附和降解，还利用臭氧参与了这一过程。最后，对不同条件下二元共存效应提出了合理的解释并进行了讨论。
