{"title":"Effect of chlorobenzene on the performance of NH3-SCR over Mn6Co4Ox catalyst","authors":"Dongrui Kang, Peng Zhao, Qiqi Shi, Mingtao Yang, Ao Huang, Honghong Lyu, Boxiong Shen","doi":"10.1016/j.seppur.2024.129901","DOIUrl":null,"url":null,"abstract":"The simultaneous removal of nitrogen oxides (NO<sub>x</sub>) and volatile organic compounds (VOCs) in NH<sub>3</sub>-SCR units can simplify the flue gas treatment process and has great potential for economic and environmental benefits. Mn-based catalysts have shown excellent performance in NO<sub>x</sub>/chlorobenzene (CB) synergistic removal, however, the mechanism of CB influence on NH<sub>3</sub>-SCR is not clear till now. In this paper, the impact of CB on the performance of NH<sub>3</sub>-SCR over Mn<sub>6</sub>Co<sub>4</sub>O<sub>x</sub> catalysts is investigated in detail. The findings demonstrate that while the presence of CB clearly inhibits the adsorption of NH<sub>3</sub> and NO, the Cl-produced during CB breakdown can actually promote the adsorption of them. In addition, the emission of N<sub>2</sub>O and NO<sub>2</sub> in the NH<sub>3</sub>-SCR reaction with CB participation was significantly reduced, and the N<sub>2</sub> selectivity was significantly improved at the same time. The impact of CB on the NH<sub>3</sub>-SCR reaction pathway under 250 ℃ was explored using in situ DRIFT further. It showed that the NH<sub>3</sub>-SCR reaction on the Mn<sub>6</sub>Co<sub>4</sub>O<sub>x</sub> catalyst was found to follow both the Eley − Rideal (E-R) and Langmuir − Hinshelwood (L-H) mechanisms. The presence of CB in the reaction accelerated the rate of the nitrate reaction, hindered the synthesis of M−NO<sub>2</sub> nitro compounds, and enhanced the generation of the intermediate product-NH<sub>2</sub> for the improvement of the NH<sub>3</sub>-SCR reaction. Conversely, the slow deactivation of the Mn<sub>6</sub>Co<sub>4</sub>O<sub>x</sub> catalysts could be attributed to the by-products of CB decomposition and the unfavorable accumulation of MnCl<sub>x</sub> or CoCl<sub>x</sub> on the catalyst surface, which inhibited the NH<sub>3</sub>-SCR reaction.","PeriodicalId":427,"journal":{"name":"Separation and Purification Technology","volume":null,"pages":null},"PeriodicalIF":8.1000,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Separation and Purification Technology","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1016/j.seppur.2024.129901","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The simultaneous removal of nitrogen oxides (NOx) and volatile organic compounds (VOCs) in NH3-SCR units can simplify the flue gas treatment process and has great potential for economic and environmental benefits. Mn-based catalysts have shown excellent performance in NOx/chlorobenzene (CB) synergistic removal, however, the mechanism of CB influence on NH3-SCR is not clear till now. In this paper, the impact of CB on the performance of NH3-SCR over Mn6Co4Ox catalysts is investigated in detail. The findings demonstrate that while the presence of CB clearly inhibits the adsorption of NH3 and NO, the Cl-produced during CB breakdown can actually promote the adsorption of them. In addition, the emission of N2O and NO2 in the NH3-SCR reaction with CB participation was significantly reduced, and the N2 selectivity was significantly improved at the same time. The impact of CB on the NH3-SCR reaction pathway under 250 ℃ was explored using in situ DRIFT further. It showed that the NH3-SCR reaction on the Mn6Co4Ox catalyst was found to follow both the Eley − Rideal (E-R) and Langmuir − Hinshelwood (L-H) mechanisms. The presence of CB in the reaction accelerated the rate of the nitrate reaction, hindered the synthesis of M−NO2 nitro compounds, and enhanced the generation of the intermediate product-NH2 for the improvement of the NH3-SCR reaction. Conversely, the slow deactivation of the Mn6Co4Ox catalysts could be attributed to the by-products of CB decomposition and the unfavorable accumulation of MnClx or CoClx on the catalyst surface, which inhibited the NH3-SCR reaction.
期刊介绍:
Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.