1
|
Chen Z, Zhao C, Wei N, Yun J, Chu R, Zheng H, Feng X, Tong Z, Chen Z. New insights and reaction mechanisms in the design of catalysts for the synergistic removal of NO x and VOCs from coke oven flue gas: Dual regulation of oxidative properties and acidic sites. JOURNAL OF HAZARDOUS MATERIALS 2024; 477:135052. [PMID: 39067287 DOI: 10.1016/j.jhazmat.2024.135052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 06/16/2024] [Accepted: 06/26/2024] [Indexed: 07/30/2024]
Abstract
The acid and redox sites of the MnCo catalysts are simultaneously fine-tuned by the addition of V. A dual-function catalyst, designated as V0.5Mn5Co5, has been constructed for the synergistic removal of NOx and volatile organic compounds under coke-oven flue gas conditions, which exhibits > 95 % NOx conversion and > 80 % N2 selectivity at 180-300 °C. Meanwhile, it removes 70 % of ethylene at 240 °C. Besides it has excellent sulfur and water resistance. The characterization results indicate that this acid-redox dual sites modulation strategy appropriately weakens the oxidation capacity of the catalysts while increasing the surface acidity of the catalysts. The catalyst mainly performs SCR reaction through the E-R mechanism, and N2O is generated through the transition dehydrogenation of NH3 and NSCR reaction. Ethylene is first adsorbed on the catalyst surface then oxidized to form carbonate species, and finally decomposed to CO2. Ethylene oxidation follows the MvK mechanism. There is a competitive adsorption between NH3 and C2H4, and a mutual inhibition between the SCR reaction and the ethylene oxidation reaction. V0.5Mn5Co5 exhibits excellent synergistic removal of NOx and VOCs in coke oven flue gas compared with commercial VWTi catalysts, which indicates great promise for industrial application.
Collapse
Affiliation(s)
- Zimo Chen
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Cheng Zhao
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Ninghan Wei
- Department of Chemistry, School of Chemistry and Chemical Engineering, Northwestern Polytechnical University, Xi'an, China
| | - Junge Yun
- College of Environment and Resources, Xiangtan University, Xiangtan, China
| | - Rencheng Chu
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Han Zheng
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China
| | - Xin Feng
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Zhangfa Tong
- Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology, School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
| | - Zhihang Chen
- Guangdong Key Lab of Water & Air Pollution Control, Guangdong Province Engineering Laboratory for Air Pollution Control, South China Institute of Environmental Sciences, Ministry of Ecology and Environment, Guangzhou 510655, China; College of Environment and Resources, Xiangtan University, Xiangtan, China.
| |
Collapse
|
2
|
An C, Hong W, Jiang X, Sun Y, Li X, Shen F, Zhu T. Catalytic Ozonation of Low Concentration Toluene over MnFeO x-USY Catalyst: Effects of Interactions between Catalytic Components and Introduction of Gas Phase NO x. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39088742 DOI: 10.1021/acs.est.4c02050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/03/2024]
Abstract
A series of Mn and Fe metal oxide catalysts loaded onto USY, as well as single metal oxides, were prepared and characterized. The effects of interactions between the catalytic components and the introduction of gas phase NO on the catalytic ozonation of toluene were investigated. Characterization showed that there existed strong interactions between MnOx, FeOx, and USY, which enhanced the content of oxygen vacancies and acid sites of the catalysts and thus boosted the generation of reactive oxygen species and the adsorption of toluene. The MnFeOx-USY catalyst with MnOx and FeOx dimetallic oxides exhibited the most excellent performance of catalytic ozonation of toluene. On the other hand, the presence of NOx in reaction gas mixtures significantly promoted both toluene conversion and mineralization, which was attributed to the formation of nitrate species on the catalysts surface and thus the increase of both acid sites and toluene oxidation sites. Meanwhile, the reaction mechanism between O3 and C7H8 was modified in which the strong interactions between MnOx, FeOx, and USY accelerated the reaction progress based on the L-H route. In addition, the formation of the surface nitrate species not only promoted reaction progress following the L-H route but also resulted in the occurrence of the reaction via the E-R route.
Collapse
Affiliation(s)
- Chenguang An
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Wei Hong
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Xinxin Jiang
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| | - Ye Sun
- School of Energy and Power Engineering, Beihang University, Beijing 100191, China
| | - Xiang Li
- School of Energy and Power Engineering, Beihang University, Beijing 100191, China
| | - Fangxia Shen
- School of Energy and Power Engineering, Beihang University, Beijing 100191, China
| | - Tianle Zhu
- School of Materials Science and Engineering, Beihang University, Beijing 100191, China
| |
Collapse
|
3
|
Peng Z, Liu H, Zhang C, Zhai Y, Hu W, Tan Y, Li X, Zhou Z, Gong X. Potential Strategy to Control the Organic Components of Condensable Particulate Matter: A Critical Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:7691-7709. [PMID: 38664958 DOI: 10.1021/acs.est.3c10615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
More and more attention has been paid to condensable particulate matter (CPM) since its emissions have surpassed that of filterable particulate matter (FPM) with the large-scale application of ultralow-emission reform. CPM is a gaseous material in the flue stack but instantly turns into particles after leaving the stack. It is composed of inorganic and organic components. Organic components are an important part of CPM, and they are an irritant, teratogenic, and carcinogenic, which triggers photochemical smog, urban haze, and acid deposition. CPM organic components can aggravate air pollution and climate change; therefore, consideration should be given to them. Based on existing methods for removing atmospheric organic pollutants and combined with the characteristics of CPM organic components, we provide a critical overview from the aspects of (i) fundamental cognition of CPM, (ii) common methods to control CPM organic components, and (iii) catalytic oxidation of CPM organic components. As one of the most encouraging methods, catalytic oxidation is discussed in detail, especially in combination with selective catalytic reduction (SCR) technology, to meet the growing demands for multipollutant control (MPC). We believe that this review is inspiring for a fuller understanding and deeper exploration of promising approaches to control CPM organic components.
Collapse
Affiliation(s)
- Zhengkang Peng
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hanxiao Liu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
- Zhejiang Feida Environmental Science & Technology Co., Ltd., Zhuji 311800, China
- Zhejiang Environmental Protection Group Eco-Environmental Research Institute, Hangzhou 310030, China
| | - Chuxuan Zhang
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yunfei Zhai
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wei Hu
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yuyao Tan
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaomin Li
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zijian Zhou
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xun Gong
- State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
4
|
Zhao H, Meng P, Gao S, Wang Y, Sun P, Wu Z. Recent advances in simultaneous removal of NOx and VOCs over bifunctional catalysts via SCR and oxidation reaction. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167553. [PMID: 37802335 DOI: 10.1016/j.scitotenv.2023.167553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/26/2023] [Accepted: 09/30/2023] [Indexed: 10/08/2023]
Abstract
NOx and volatile organic compounds (VOCs) are two major pollutants commonly found in industrial flue gas emissions. They play a significant role as precursors in the formation of ozone and fine particulate matter (PM2.5). The simultaneous removal of NOx and VOCs is crucial in addressing ozone and PM2.5 pollution. In terms of investment costs and space requirements, the development of bifunctional catalysts for the simultaneous selective catalytic reduction (SCR) of NOx and catalytic oxidation of VOCs emerges as a viable technology that has garnered considerable attention. This review provides a summary of recent advances in catalysts for the simultaneous removal of NOx and VOCs. It discusses the reaction mechanisms and interactions involved in NH3-SCR and VOCs catalytic oxidation, the effects of catalyst acidity and redox properties. The insufficiency of bifunctional catalysts was pointed out, including issues related to catalytic activity, product selectivity, catalyst deactivation, and environmental concerns. Subsequently, potential solutions are presented to enhance catalyst performance, such as optimizing the redox properties and acidity, enhancing resistance to poisoning, substituting environment friendly metals and introducing hydrocarbon selective catalytic reduction (HC-SCR) reaction. Finally, some suggestions are given for future research directions in catalyst development are prospected.
Collapse
Affiliation(s)
- Huaiyuan Zhao
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Zhejiang Tianlan Environmental Protection Technology Co., Ltd., Hangzhou 311202, China; Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Pu Meng
- Zhejiang Tianlan Environmental Protection Technology Co., Ltd., Hangzhou 311202, China; Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Shan Gao
- Zhejiang Tianlan Environmental Protection Technology Co., Ltd., Hangzhou 311202, China; Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, 866 Yuhangtang Road, Hangzhou 310058, China.
| | - Yuejun Wang
- Zhejiang Tianlan Environmental Protection Technology Co., Ltd., Hangzhou 311202, China; Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, 866 Yuhangtang Road, Hangzhou 310058, China
| | - Pengfei Sun
- Department of Chemistry, Key Laboratory of Surface & Interface Science of Polymer Materials of Zhejiang Province, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | - Zhongbiao Wu
- Department of Environmental Engineering, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Engineering Research Center of Industrial Boiler & Furnace Flue Gas Pollution Control, 866 Yuhangtang Road, Hangzhou 310058, China
| |
Collapse
|
5
|
Gao C, Wei W, Bai S, Li H. Application of CeTiOx-MOFs catalysts for synergistic removal of toluene and NOx. CATAL COMMUN 2023. [DOI: 10.1016/j.catcom.2023.106621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
|
6
|
Lyu Y, Xu J, Cao Q, Zhou Z, Hu W, Liu X. Highly efficient removal of toluene over Cu-V oxides modified γ-Al 2O 3 in the presence of SO 2. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129041. [PMID: 35588656 DOI: 10.1016/j.jhazmat.2022.129041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/24/2022] [Accepted: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Developing efficient catalysts with good resistance to complex flue gas is essential for VOCs removal in coal-fired flue gas. In this study, by exploring the effect of transition metal oxide additive, metal loading and bimetallic synergy on toluene oxidation in coal-fired flue gas, 10Cu-3V/γ-Al2O3 is identified as the optimal catalyst. It achieves 90% of CO2 generation at 350 ℃, which is decreased by ca. 46 ℃ compared with 13Cu/γ-Al2O3. And it also exhibits good resistance to H2O and good stability. ICP-OES, N2 adsorption-desorption isotherms, XRD, TEM, XPS, EPR and H2-TPR analyses were applied to characterize the catalyst composition and physicochemical properties. Doping V into 13Cu/γ-Al2O3 not only leads to better dispersity of CuO and homogeneous elements distribution that benefits to produce more active centers, but also constitutes the redox cycle of V5+ + Cu+ ↔ V4+ + Cu2+ which induces more surface chemical oxygen (Osur). Moreover, since SO2 is the main inhibiting factor in toluene oxidation, the SO2 poisoning mechanism was illustrated by XPS, TG and in situ DRIFT analyses in depth.
Collapse
Affiliation(s)
- Yue Lyu
- School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jingying Xu
- School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
| | - Qingquan Cao
- School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zijian Zhou
- School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wei Hu
- School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Xiaowei Liu
- School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
| |
Collapse
|
7
|
Liu H, Chen J, Wang Y, Yin R, Yang W, Wang G, Si W, Peng Y, Li J. Interaction Mechanism for Simultaneous Elimination of Nitrogen Oxides and Toluene over the Bifunctional CeO 2-TiO 2 Mixed Oxide Catalyst. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:4467-4476. [PMID: 35254804 DOI: 10.1021/acs.est.1c08424] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Simultaneous catalytic elimination of nitrogen oxides (NOx, x = 1 and 2) and volatile organic compounds (VOCs) is of great importance for environmental preservation in China. In this work, the interactions of simultaneous removal of NOx and methylbenzene (PhCH3) were investigated on a CeO2-TiO2 mixed oxide catalyst, which demonstrated excellent bifunctional removal efficiencies for the two pollutants. The results indicated that NOx positively promotes PhCH3 oxidation, while NH3 negatively inhibits through competitive adsorption with PhCH3. The underlying mechanism is that a pseudo PhCH3-SCR reaction happened in this process is parallel to NH3-SCR. Combined with in situ diffuse reflectance infrared Fourier transform spectroscopy and quasi in situ X-ray photoelectron spectroscopy, the interaction mechanism between NOx and PhCH3 is proposed. Specifically, NOx is adsorbed on the catalyst surface to produce nitrate species, which reacts with the carboxylate generated during PhCH3 oxidation to form organic nitrogen intermediates that create N2 and CO2 in the following reactions. In the reaction process, the superoxide (O2-) generated by O2 activation on the catalyst surface is an important species for the propelling of oxidation reaction. This work could provide guidelines for the design of state-of-the-art catalysts for simultaneous catalytic removal of NOx and VOCs.
Collapse
Affiliation(s)
- Hao Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Jianjun Chen
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Ya Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Rongqiang Yin
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Wenhao Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Guimin Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Wenzhe Si
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Yue Peng
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| | - Junhua Li
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, P. R. China
| |
Collapse
|
8
|
Recent Advances in MnOx/CeO2-Based Ternary Composites for Selective Catalytic Reduction of NOx by NH3: A Review. Catalysts 2021. [DOI: 10.3390/catal11121519] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Recently, manganese oxides (MnOx)/cerium(IV) oxide (CeO2) composites have attracted widespread attention for the selective catalytic reduction (SCR) of nitrogen oxides (NOx) with ammonia (NH3), which exhibit outstanding catalytic performance owing to unique features, such as a large oxygen storage capacity, excellent low-temperature activity, and strong mechanical strength. The intimate contact between the components can effectively accelerate the charge transfer to enhance the electron–hole separation efficiency. Nevertheless, MnOx/CeO2 still reveals some deficiencies in the practical application process because of poor thermal stability, and a low reduction efficiency. Constructing MnOx/CeO2 with other semiconductors is the most effective strategy to further improve catalytic performance. In this article, we discuss progress in the field of MnOx/CeO2-based ternary composites with an emphasis on the SCR of NOx by NH3. Recent progress in their fabrication and application, including suitable examples from the relevant literature, are analyzed and summarized. In addition, the interaction mechanisms between MnOx/CeO2 catalysts and NOx pollutants are comprehensively dissected. Finally, the review provides basic insights into prospects and challenges for the advancement of MnOx/CeO2-based ternary catalysts.
Collapse
|