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Wang F, Chen A, Lan T, Chen X, Wang M, Hu X, Wang P, Cheng D, Zhang D. Synergistic catalytic removal of NO x and chlorinated organics through the cooperation of different active sites. J Hazard Mater 2024; 468:133722. [PMID: 38367433 DOI: 10.1016/j.jhazmat.2024.133722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/26/2024] [Accepted: 02/03/2024] [Indexed: 02/19/2024]
Abstract
The synergistic removal of NOx and chlorinated volatile organic compounds (CVOCs) has become the hot topic in the field of environmental catalysis. However, due to the trade-off effects between catalytic reduction of NOx and catalytic oxidation of CVOCs, it is indispensable to achieve well-matched redox property and acidity. Herein, synergistic catalytic removal of NOx and chlorobenzene (CB, as the model of CVOCs) has been originally demonstrated over a Co-doped SmMn2O5 mullite catalyst. Two kinds of Mn-Mn sites existed in Mn-O-Mn-Mn and Co-O-Mn-Mn sites were constructed, which owned gradient redox ability. It has been demonstrated that the cooperation of different active sites can achieve the balanced redox and acidic property of the SmMn2O5 catalyst. It is interesting that the d band center of Mn-Mn sites in two different sites was decreased by the introduction of Co, which inhibited the nitrate species deposition and significantly improved the N2 selectivity. The Co-O-Mn-Mn sites were beneficial to the oxidation of CB and it cooperates with Mn-O-Mn-Mn to promote the synergistic catalytic performance. This work paves the way for synergistic removal of NOx and CVOCs over cooperative active sites in catalysts.
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Affiliation(s)
- Fuli Wang
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Aling Chen
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Tianwei Lan
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Xin Chen
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Mengxue Wang
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Xiaonan Hu
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Penglu Wang
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China
| | - Danhong Cheng
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China.
| | - Dengsong Zhang
- School of Environmental and Chemical Engineering, State Key Laboratory of Advanced Special Steel, Innovation Institute of Carbon Neutrality, College of Sciences, Shanghai University, Shanghai 200444, China.
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Sharif HMA, Huang J, Khan K, Afzal S, Li C. Redox mediators boost NO x reduction via trade-off electron charges using a cube-shaped (cMn@rGO) catalyst; mechanism and electrochemical study. Chemosphere 2024; 346:140510. [PMID: 37918538 DOI: 10.1016/j.chemosphere.2023.140510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 10/07/2023] [Accepted: 10/20/2023] [Indexed: 11/04/2023]
Abstract
Gaseous pollutants like sulfur dioxide and nitrogen oxide(s) (SO2, NOx) have been increasing exponentially for the last two decades, which have had adverse effects on human health, aquatic life, and the environment. Recently, for air pollution taming, manganese/oxide (Mn/MnO) has become a very promising heterogeneous catalyst due to its environment-friendly, low-price, and remarkable catalytic abilities for toxic gases. In this work, cube-shaped Mn nanoparticles (cMn NPs) were decorated on the surface of reduced graphene oxide (rGO) by the solvothermal method. The resulting cMn@rGO composite was employed for electrochemical NOx reduction. However, the microscopic (TEM/HRTEM) and structural analysis were utilised to investigate the morphology and characteristics of the cMn@rGO composite. This electrochemical-based treatment for NOx reduction is employed by using electron shuttle or redox mediators. Here, four distinct redox mediators are used to address electrochemical obstacles, which effectively facilitate electron transportation and promoted NOx reduction on the electrode surface. These mediators not only significantly enhanced the NOx conversion into valuable products, i.e., N2 and N2O, but also made the process smooth with high performance. Among these mediators, neutral red (N.R) exhibited extraordinary potential in enhancing NOx reduction. The obtained results indicated that the remarkable catalytic performance (∼93%) of the cMn@rGO can be attributed to several factors, including the catalyst's three-dimensional architecture structure and abundant active sites. The designed catalyst (cMn@rGO) is not only cost-effective and sustainable but also exhibits excellent potential in effectively reducing NOx, which could be beneficial for large-scale NOx abatement.
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Affiliation(s)
- Hafiz Muhammad Adeel Sharif
- State Key Laboratory of Electronic Thin Film and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, China; Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan, 523808, China
| | - Jintong Huang
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan, 523808, China
| | - Kifayatullah Khan
- Department of Environmental and Conservation Sciences, University of Swat, 19130, Pakistan
| | - Shahzad Afzal
- Department of Environmental engineering China Jiliang university Hangzhou, Zhejiang, 310018, China
| | - Changping Li
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan, 523808, China.
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Wang T, Wang Y, Zhang Z, Liang C, Shan M, Sun Y. A regional cooperative reduction game model for air pollution control in North China. J Environ Manage 2023; 346:118949. [PMID: 37717391 DOI: 10.1016/j.jenvman.2023.118949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/12/2023] [Accepted: 09/06/2023] [Indexed: 09/19/2023]
Abstract
Due to variations in economic scale, economic structure, and technological advancement across different Chinese provinces and cities, the cost of air pollution reduction differs significantly. Therefore, the total reduction cost can be decreased by capitalizing on these regional discrepancies in reduction cost to carry out cooperative emission reduction. In this paper, taking NOx reduction in North China as an example, a regional cooperative reduction game (CRG) model was constructed to minimize the total cost of emission reduction while achieving future emission reduction targets. The fair allocation of benefits from cooperation plays a crucial role in motivating regions to participate into the cooperation. A comprehensive mechanism of benefits allocation was proposed to achieve fair transferred compensation. The mechanism combines the consumption responsibility principle based on input-output theory and the Shapley value method based on game theory. Compared to the cost before the optimized collaboration, the CRG model will save 20.36% and 13.71% of the total reduction cost in North China, respectively, under the target of 17.68% NOx reduction by 2025 and 66.44% NOx reduction by 2035 relative to 2020. This method can be employed in other regions to achieve targets for air pollution reduction at minimum cost, and to motivate inter-regional cooperation with this practical and fair way of transferred compensation.
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Affiliation(s)
- Tingyu Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Yuan Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China.
| | - Zengkai Zhang
- State Key Laboratory of Marine Environmental Science, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, 361102, China.
| | - Chen Liang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Mei Shan
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
| | - Yun Sun
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300350, China
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Chen Y, Tian L, Liu T, Liu Z, Huang Z, Yang H, Tian L, Huang Q, Li W, Gao Y, Zhang Z. Speciation and transformation of nitrogen for sewage sludge hydrothermal carbonization-influence of temperature and carbonization time. Waste Manag 2023; 162:8-17. [PMID: 36917884 DOI: 10.1016/j.wasman.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 02/20/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Hydrothermal carbonization (HTC) is an effective means of energizing high-water-content biomass that can be used to convert sewage sludge (SS) into hydrochar and reduce nitrogen content. To further reduce the emission of NOx during the combustion of hydrochar and seek proper disposal method of liquid product, the mechanism of nitrogen conversion was studied in the range of 180-320 °C and 30-90 min. At 180-220 °C, 42.15-52.91% of the nitrogen in SS was transferred to liquid by hydrolysis of proteins and inorganic salts. At 240-280 °C, the nitrogen in hydrochar was mainly in the form of heterocyclic -N (quaternary-N, pyrrole-N, and pyridine-N). The concentration of NH4+-N increased from 6.82 mg/L (180 °C) to 26.58 mg/L (280 °C) due to the enhancement of the deamination reaction. At 300-320 °C, pyrrole-N (from 15.92% to 9.38%) and pyridine-N (from 5.52% to 3.73%) in the hydrochar were converted to the more stable quaternary-N (from 0.31% to 4.28%). Meanwhile, the NH4+-N and amino-N in the liquid decomposed into NH3. Prolonging the carbonization time promoted the hydrolysis of proteins, the conversion of heterocyclic -N, and the production of NH3. Under optimal reaction conditions (280 °C and 60 min), the nitrogen in the SS is converted to stable forms and the energy balance meets the requirements of circular-economy. The results show that temperature determines the nitrogen form and the carbonization time affects the nitrogen distribution. So HTC has the potential to reduce NOx emissions from SS energy utilization processes.
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Affiliation(s)
- Yu Chen
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; College of Civil Engineering and Architecture, Liaoning University of Technology, Jinzhou 121001, China
| | - Lifeng Tian
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technology Institution Physical and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Tingting Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
| | - Zewei Liu
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Zechun Huang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Haoyue Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Lu Tian
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Qifei Huang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Weishi Li
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; State Environmental Protection Key Laboratory of Hazardous Waste Identification and Risk Control, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Yanjiao Gao
- College of Civil Engineering and Architecture, Liaoning University of Technology, Jinzhou 121001, China
| | - Zhao Zhang
- College of Civil Engineering and Architecture, Liaoning University of Technology, Jinzhou 121001, China
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Sharif HMA, Asif MB, Wang Y, Hou YN, Yang B, Xiao X, Li C. Spontaneous intra-electron transfer within rGO@Fe 2O 3-MnO catalyst promotes long-term NO x reduction at ambient conditions. J Hazard Mater 2023; 441:129951. [PMID: 36115094 DOI: 10.1016/j.jhazmat.2022.129951] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/29/2022] [Accepted: 09/06/2022] [Indexed: 06/15/2023]
Abstract
Iron (Fe)-based catalysts are widely used for taming nitrogen oxides (NOx) containing flue gas, but the regeneration and long-term reusability remains a concern. The reusability can be acquired by external additives, and resultantly can not only increase the cost but can also add to process complexity as well as secondary pollutants. Herein, a self-sustainable material is designed to regenerate the catalyst for long-term reusability without adding to process complexity. The catalyst is based on reduced graphene-oxide impregnated by Fe2O3-MnO (rGO@Fe2O3-MnO; G-F-M) for spontaneous intra electron (e-)-transfer from Mn to Fe. The developed catalyst; G-M-F exhibited 93.7% NOx reduction, which suggests its high catalytic activity. The morphological and structure characterizations confirmed the Fe/Mn loading, contributing to e--transfer between Mn and Fe due to its conductivity. The synthesized G-F-M showed higher NOx reduction about 2.5 folds, than rGO@Fe2O3 (G-FeO) and rGO@MnOx (G-MnOx). The performance of G-M-F without and with an electrochemical system was also compared, and the difference was only 5%, which is an evidence of the spontaneous e- transfer between the Mn and Fe-NOx complex. The designed catalyst can be used for a long time without external assistance, and its efficiency was not affected significantly (<3.7%) in the presence of high oxygen contents (8%). The as-prepared G-M-F catalyst has great potential for executing a dual role NOx removal and self-regeneration of catalyst (SRC), promoting a sustainable remediation approach for large-scale applications.
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Affiliation(s)
- Hafiz Muhammad Adeel Sharif
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, PR China; School of Electronic Science and Engineering, State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, PR China
| | - Muhammad Bilal Asif
- Advanced Membranes and Porous Materials Center (AMPMC), Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Yuwei Wang
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, PR China
| | - Ya-Nan Hou
- Tianjin Key Laboratory of Aquatic Science and Technology, School of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, PR China
| | - Bo Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen 518060, PR China
| | - Xu Xiao
- School of Electronic Science and Engineering, State Key Laboratory of Electronic Thin Film and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054, PR China
| | - Changping Li
- Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, PR China.
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Sharif HMA, Ali M, Mahmood A, Asif MB, Din MAU, Sillanpää M, Mahmood A, Yang B. Separation of Fe from wastewater and its use for NO x reduction; a sustainable approach for environmental remediation. Chemosphere 2022; 303:135103. [PMID: 35623439 DOI: 10.1016/j.chemosphere.2022.135103] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/13/2022] [Accepted: 05/22/2022] [Indexed: 06/15/2023]
Abstract
The nitrogen and sulphur oxide (NOx and SO2) emissions are causing a serious threat to the existence of life on earth, requiring their effective removal for a sustainable future. Among various approaches, catalytic or electrochemical reduction of air pollutants (NOx) has gained much attention due to its high efficiency and the possibility of converting these gases into valuable products. However, the required catalysts are generally synthesized from lab-grade chemicals, which may not be a sustainable approach. Herein, a sustainable approach is presented to synthesize an efficient iron-based catalyst directly from industrial/lake wastewater (WW) for NOx-reduction. According to the theoretical calculations and experimental results, Fe-ions could be readily recovered from wastewater because it has the best adsorption efficiency among all other co-existing metals (Ni2+, Cd2+, Co2+, Cu2+, and Cr6+). The subsequent experimental investigations confirmed the preferential Fe adsorption from different WW streams to develop Fe3O4@EDTA-Fe composite, whereby Fe3O4 could be used due to its high recycling ability, and ethylenediaminetetraacetic acid (EDTA) acted as a chelating agent to adsorb Fe-metal from effluents. The Fe3O4@EDTA-Fe exhibited high efficiency (≥87%) for NOx reduction even in the presence of high-degree oxygen contents (10-12%). Moreover, Fe3O4-EDTA-Fe showed excellent long-term stability for 24 h and maintained more than 80% NOx reduction. The fabricated catalyst has a great potential for executing a dual role simultaneously for Fe-recovery and NOx removal, promoting the circular economy concept and providing a potentially sustainable remediation approach for large-scale applications.
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Affiliation(s)
| | - Moazzam Ali
- Centre of Excellence in Solid State Physics, University of the Punjab, Lahore, Pakistan
| | - Ayyaz Mahmood
- College of Physics and Optical Engineering, Shenzhen University, Shenzhen, 518060, PR China
| | - Muhammad Bilal Asif
- Advanced Membranes and Porous Materials Center (AMPMC), Physical Sciences and Engineering (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | | | - Mika Sillanpää
- Department of Biological and Chemical Engineering, Aarhus University, Nørrebrogade 44, 8000, Aarhus C, Denmark; Department of Chemical Engineering, School of Mining, Metallurgy and Chemical Engineering, University of Johannesburg, Doornfontein, 2028, South Africa
| | - Asif Mahmood
- School of Chemical and Biomolecular Engineering, The University of Sydney, Australia.
| | - Bo Yang
- College of Chemistry and Environmental Engineering, Shenzhen University, Shenzhen, 518060, PR China.
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Xie R, Ma L, Sun K, Zhou G, Qu Z, Yan N. Catalytic performance and mechanistic evaluation of sulfated CeO 2 cubes for selective catalytic reduction of NO x with ammonia. J Hazard Mater 2021; 420:126545. [PMID: 34274807 DOI: 10.1016/j.jhazmat.2021.126545] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 06/09/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Sulfated CeO2 cubes were prepared by the impregnation of CeO2 cubes by ammonium sulfates, and further evaluated in selective catalytic reduction of NOx with ammonia (NH3-SCR). Catalytic activity tests indicated that NOx reduction conversions and N2 selectivity of sulfated CeO2 cubes could be significantly improved compared to pure CeO2 cubes. The synthesized sulfated CeO2 cubes were further characterized by atom-resolved high angle annular dark-field (HAADF) imaging, Fourier-transform infrared spectroscopy (FTIR) by pyridine adsorption, and temperature-programmed reduction by H2 (H2-TPR). The characterization results showed that sulfates were primarily dispersed through the corners, edges, and surfaces of CeO2 cubes, and did not significantly affect the crystal structures of CeO2 cubes. Sulfation treatment could create and strengthen Brønsted acid sites originated from the protons on surface sulfates, further facilitating ammonia adsorption and activation. The kinetic data indicated that the apparent reaction order of NO, O2, and NH3 was 0.95 to 1.01, -0.01 to 0.00, and -0.18 to -0.15, respectively. It could speculate that gaseous phase NO involving in NO catalytic oxidation was the rate-determining step over sulfated CeO2 cubes for NH3-SCR reaction. The presence of NH3 slightly inhibited the SCR reaction rate due to the competitive adsorption blocking NO oxidation sites.
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Affiliation(s)
- Renyi Xie
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lei Ma
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
| | - Kai Sun
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA
| | - Gang Zhou
- School of Science, Hubei University of Technology, Wuhan 430068, China
| | - Zan Qu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Naiqiang Yan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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Zinatloo-Ajabshir S, Ghasemian N, Mousavi-Kamazani M, Salavati-Niasari M. Effect of zirconia on improving NOx reduction efficiency of Nd 2Zr 2O 7 nanostructure fabricated by a new, facile and green sonochemical approach. Ultrason Sonochem 2021; 71:105376. [PMID: 33142222 PMCID: PMC7786589 DOI: 10.1016/j.ultsonch.2020.105376] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 06/11/2023]
Abstract
Here, we offer an easy and eco-friendly sonochemical pathway to fabricate Nd2Zr2O7 nanostructures and nanocomposites with the help of Morus nigra extract as a new kind of capping agent. For the first time, the performance of Nd2Zr2O7-based ceramic nanostructure materials has been compared upon NOx abatement. Diverse kinds of techniques have been employed to specify purity and check the attributes of the fabricated Nd2Zr2O7-based nanostructurs by Morus nigra extract. Outcomes revealed the successful fabrication of Nd2Zr2O7 nanostructures and nanocomposites applying Morus nigra extract through sonochemical pathway. All nanostructured samples have been fabricated through ultrasonic probe with power of 60 W (18 KHz). Further, the fabricated Nd2Zr2O7-based ceramic nanostructure materials can be applied as potential nanocatalysts with appropriate performance for propane-SCR-NOx, since the conversion of NOx to N2 for the best sample (Nd2Zr2O7-ZrO2 nanocomposite) was 70%. In addition, in case of Nd2Zr2O7-ZrO2 nanocomposite, the outlet quantity of CO as an unfavorable and unavoidable product was lower than the rest.
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Affiliation(s)
| | - Naser Ghasemian
- Department of Chemical Engineering, University of Bonab, P.O. Box. 5551761167, Bonab, Iran
| | | | - Masoud Salavati-Niasari
- Institute of Nano Science and Nano Technology, University of Kashan, Kashan, P. O. Box. 87317-51167, Iran
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Baleta J, Martinjak M, Vujanović M, Pachler K, Wang J, Duić N. Numerical analysis of ammonia homogenization for selective catalytic reduction application. J Environ Manage 2017; 203:1047-1061. [PMID: 28576263 DOI: 10.1016/j.jenvman.2017.04.103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/01/2017] [Accepted: 04/09/2017] [Indexed: 06/07/2023]
Abstract
Selective catalytic reduction based on urea water solution as ammonia precursor is a promising method for the NOx abatement form exhaust gasses of mobile diesel engine units. It consists of injecting the urea-water solution in the hot flue gas stream and reaction of its products with the NOx over the catalyst surface. During this process flue gas enthalpy is used for the urea-water droplet heating and for the evaporation of water content. After water evaporates, thermolysis of urea occurs, during which ammonia, a known NOx reductant, and isocyanic acid are generated. The uniformity of the ammonia before the catalyst as well as ammonia slip to the environment are important counteracting design requirements, optimization of which is crucial for development of efficient deNOx systems. The aim of this paper is to show capabilities of the developed mathematical framework implemented in the commercial CFD code AVL FIRE®, to simulate physical processes of all relevant phenomena occurring during the SCR process including chemical reactions taking part in the catalyst. First, mathematical models for description of SCR process are presented and afterwards, models are used on the 3D geometry of a real SCR reactor in order to predict ammonia generation, NOx reduction and resulting ammonia slip. Influence of the injection direction and droplet sizes was also investigated on the same geometry. The performed study indicates importance of droplet sizes on the SCR process and shows that counterflow injection is beneficial, especially in terms of minimizing harmful ammonia slip to environment.
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Affiliation(s)
- Jakov Baleta
- Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10 002, Zagreb, Croatia.
| | - Matija Martinjak
- TE-TO Sisak, HEP Proizvodnja d.o.o., Industrijska cesta 10, 44010, Sisak, Croatia.
| | - Milan Vujanović
- Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10 002, Zagreb, Croatia.
| | - Klaus Pachler
- AVL List GmbH, Alte Poststraße 152, 8020, Graz, Austria.
| | - Jin Wang
- School of Energy and Environmental Engineering, Hebei University of Technology, Xiping Road No. 5340, Beichen District, Tianjin, 300401, China.
| | - Neven Duić
- Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10 002, Zagreb, Croatia.
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10
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Kuwahara T, Nakaguchi H, Kuroki T, Okubo M. Continuous reduction of cyclic adsorbed and desorbed NO(x) in diesel emission using nonthermal plasma. J Hazard Mater 2016; 308:216-224. [PMID: 26844402 DOI: 10.1016/j.jhazmat.2016.01.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/17/2015] [Accepted: 01/13/2016] [Indexed: 06/05/2023]
Abstract
Considering the recent stringent regulations governing diesel NO(x) emission, an aftertreatment system for the reduction of NO(x) in the exhaust gas has been proposed and studied. The proposed system is a hybrid method combining nonthermal plasma and NOx adsorbent. The system does not require precious metal catalysts or harmful chemicals such as urea and ammonia. In the present system, NO(x) in diesel emission is treated by adsorption and desorption by adsorbent as well as nonthermal plasma reduction. In addition, the remaining NO(x) in the adsorbent is desorbed again in the supplied air by residual heat. The desorbed NO(x) in air recirculates into the intake of the engine, and this process, i.e., exhaust gas components' recirculation (EGCR) achieves NO(x) reduction. Alternate utilization of two adsorption chambers in the system can achieve high-efficiency NO(x) removal continuously. An experiment with a stationary diesel engine for electric power generation demonstrates an energy efficiency of 154 g(NO2)/kWh for NO(x) removal and continuous NO(x) reduction of 70.3%. Considering the regulation against diesel emission in Japan, i.e., the new regulation to be imposed on vehicles of 3.5-7.5 ton since 2016, the present aftertreatment system fulfills the requirement with only 1.0% of engine power.
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Affiliation(s)
- Takuya Kuwahara
- Department of Products Engineering and Environmental Management, Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro-machi, Minamisaitama, Saitama 345-8501, Japan
| | - Harunobu Nakaguchi
- Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531, Japan
| | - Tomoyuki Kuroki
- Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531, Japan
| | - Masaaki Okubo
- Department of Mechanical Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai 599-8531, Japan.
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Fan W, Zhu T, Sun Y, Lv D. Effects of gas compositions on NOx reduction by selective non-catalytic reduction with ammonia in a simulated cement precalciner atmosphere. Chemosphere 2014; 113:182-187. [PMID: 25065808 DOI: 10.1016/j.chemosphere.2014.05.034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Revised: 05/06/2014] [Accepted: 05/07/2014] [Indexed: 06/03/2023]
Abstract
The effects of gas compositions on NOx reduction and NH3 slip by selective non-catalytic reduction (SNCR) with NH3 were investigated in a simulated cement precalciner atmosphere. The results show that the presence of H2O improves NOx reduction and widens the reduction temperature window significantly. O2 is indispensable for reducing NOx. The optimum reduction temperature decreases and the temperature window widens to a lower temperature with the increase of O2 content. In addition, the increase of O2 content also results in a decrease of the maximum NOx reduction efficiency. The effect of SO2 on NOx reduction is negligible in the simulated precalciner atmosphere. To increase CO concentration makes NO reduction take place at relatively low temperatures. However, NH3 will tend to be oxidized into NO instead of reducing NO after entering the stream containing O2 at high temperatures if it is initially blended with a high concentration of CO in an oxygen-free environment. The increase of H2O, O2, SO2 or CO concentration is helpful to reduce NH3 slip in the temperature region below 900°C. These effects are resulted from the fact that the generation and consumption of O and OH radicals which are crucial to NO reduction and formation can be influenced by the four gas compositions. In industrial operation of SNCR for cement precalciner, these effects should be taken into account to increase NOx reduction efficiency and avoid NH3 slip.
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Affiliation(s)
- Weiyi Fan
- School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Tianle Zhu
- School of Chemistry and Environment, Beihang University, Beijing 100191, China.
| | - Yifei Sun
- School of Chemistry and Environment, Beihang University, Beijing 100191, China
| | - Dong Lv
- School of Chemistry and Environment, Beihang University, Beijing 100191, China
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