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Yang Y, Zhou J, Xie C, Tian W, Xue M, Han T, Chen K, Zhang Y, Liu Y, Huang Y, Sun H, Liu C, Li SM. A New Methodology for High Spatiotemporal Resolution Measurements of Air Volatile Organic Compounds: From Sampling to Data Deconvolution. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:12488-12497. [PMID: 38958408 DOI: 10.1021/acs.est.4c05669] [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: 07/04/2024]
Abstract
Monitoring of volatile organic compounds (VOCs) in air is crucial for understanding their atmospheric impacts and advancing their emission reduction plans. This study presents an innovative integrated methodology suitable for achieving semireal-time high spatiotemporal resolution three-dimensional measurements of VOCs from ground to hundreds of meters above ground. The methodology integrates an active AirCore sampler, custom-designed for deployment from unmanned aerial vehicles (UAV), a proton-transfer-reaction mass spectrometry (PTR-MS) for sample analysis, and a data deconvolution algorithm for improved time resolution for measurements of multiple VOCs in air. The application of the deconvolution technique significantly improves the signal strength of data from PTR-MS analysis of AirCore samples and enhances their temporal resolution by 4 to 8 times to 4-11 s. A case study demonstrates that the methodology can achieve sample collection and analysis of VOCs within 45 min, resulting in >120-360 spatially resolved data points for each VOC measured and achieving a horizontal resolution of 20-55 m at a UAV flight speed of 5 m/s and a vertical resolution of 5 m. This methodology presents new possibilities for acquiring 3-dimensional spatial distributions of VOC concentrations, effectively tackling the longstanding challenge of characterizing three-dimensional VOC distributions in the lowest portion of the atmospheric boundary layer.
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Affiliation(s)
- Yanrong Yang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Jietao Zhou
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Conghui Xie
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
- Laboratory of Gas Instrument Testing, Center for Environmental Metrology, National Institute of Metrology, Beijing 100029, China
| | - Wang Tian
- PipeChina Institute of Science and Technology, PipeChina, Tianjin 300457, China
| | - Ming Xue
- State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety and Environmental Technology, Beijing 102206, China
| | - Tianran Han
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Keyu Chen
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yuheng Zhang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yayong Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Yufei Huang
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Haijiong Sun
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Chang Liu
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Shao-Meng Li
- State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
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Mondal SK, Aina P, Rownaghi AA, Rezaei F. Cooperative and Bifunctional Adsorbent-Catalyst Materials for In-situ VOCs Capture-Conversion. Chempluschem 2024; 89:e202300419. [PMID: 38116915 DOI: 10.1002/cplu.202300419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 12/21/2023]
Abstract
Volatile organic compounds (VOCs) are gases that are emitted into the air from products or processes and are major components of air pollution that significantly deteriorate air quality and seriously affect human health. Different types of metals, metal oxides, mixed-metal oxides, polymers, activated carbons, zeolites, metal-organic frameworks (MOFs) and mixed-matrixed materials have been developed and used as adsorbent or catalyst for diversified VOCs detection, removal, and destruction. In this comprehensive review, we first discuss the general classification of VOCs removal materials and processes and outline the historical development of bifunctional and cooperative adsorbent-catalyst materials for the removal of VOCs from air. Subsequently, particular attention is devoted to design of strategies for cooperative adsorbent-catalyst materials, along with detailed discussions on the latest advances on these bifunctional materials, reaction mechanisms, long-term stability, and regeneration for VOCs removal processes. Finally, challenges and future opportunities for the environmental implementation of these bifunctional materials are identified and outlined with the intent of providing insightful guidance on the design and fabrication of more efficient materials and systems for VOCs removal in the future.
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Affiliation(s)
- Sukanta K Mondal
- Linda and Bipin Doshi Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, MO 65409-1230, United States
| | - Peter Aina
- Linda and Bipin Doshi Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, MO 65409-1230, United States
- Department of Chemical, Environmental and Materials Engineering, University of Miami, Miami, FL 33124, United States
| | - Ali A Rownaghi
- National Energy Technology Laboratory, United States Department of Energy, Pittsburgh, PA 15236, United States
| | - Fateme Rezaei
- Linda and Bipin Doshi Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, MO 65409-1230, United States
- Department of Chemical, Environmental and Materials Engineering, University of Miami, Miami, FL 33124, United States
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Liu Z, Xu B, Jiang YJ, Zhou Y, Sun X, Wang Y, Zhu W. Photocatalytic Conversion of Methane: Current State of the Art, Challenges, and Future Perspectives. ACS ENVIRONMENTAL AU 2023; 3:252-276. [PMID: 37743954 PMCID: PMC10515711 DOI: 10.1021/acsenvironau.3c00002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 05/24/2023] [Accepted: 06/02/2023] [Indexed: 09/26/2023]
Abstract
With 28-34 times the greenhouse effect of CO2 over a 100-year period, methane is regarded as the second largest contributor to global warming. Reducing methane emissions is a necessary measure to limit global warming to below 1.5 °C. Photocatalytic conversion of methane is a promising approach to alleviate the atmospheric methane concentrations due to its low energy consumption and environmentally friendly characteristics. Meanwhile, this conversion process can produce valuable chemicals and liquid fuels such as CH3OH, CH3CH2OH, C2H6, and C2H4, cutting down the dependence of chemical production on crude oil. However, the development of photocatalysts with a high methane conversion efficiency and product selectivity remains challenging. In this review, we overview recent advances in semiconductor-based photocatalysts for methane conversion and present catalyst design strategies, including morphology control, heteroatom doping, facet engineering, and cocatalysts modification. To gain a comprehensive understanding of photocatalytic methane conversion, the conversion pathways and mechanisms in these systems are analyzed in detail. Moreover, the role of electron scavengers in methane conversion performance is briefly discussed. Subsequently, we summarize the anthropogenic methane emission scenarios on earth and discuss the application potential of photocatalytic methane conversion. Finally, challenges and future directions for photocatalytic methane conversion are presented.
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Affiliation(s)
- Zhuo Liu
- State
Key Laboratory of Pollution Control and Resource Reuse, Frontiers
Science Center for Critical Earth Material Cycling, School of the
Environment and State Key Laboratory of Analytical Chemistry for Life Science, School
of Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Biyang Xu
- State
Key Laboratory of Pollution Control and Resource Reuse, Frontiers
Science Center for Critical Earth Material Cycling, School of the
Environment and State Key Laboratory of Analytical Chemistry for Life Science, School
of Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Yu-Jing Jiang
- State
Key Laboratory of Pollution Control and Resource Reuse, Frontiers
Science Center for Critical Earth Material Cycling, School of the
Environment and State Key Laboratory of Analytical Chemistry for Life Science, School
of Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Yang Zhou
- Key
Laboratory for Organic Electronics & Information Displays (KLOEID),
Institute of Advanced Materials (IAM), Nanjing
University of Posts & Telecommunications (NJUPT), Nanjing 210046, China
| | - Xiaolian Sun
- State
Key Laboratory of Natural Medicines, Key Laboratory of Drug Quality
Control and Pharmacovigilance, Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, China
| | - Yuanyuan Wang
- State
Key Laboratory of Pollution Control and Resource Reuse, Frontiers
Science Center for Critical Earth Material Cycling, School of the
Environment and State Key Laboratory of Analytical Chemistry for Life Science, School
of Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
| | - Wenlei Zhu
- State
Key Laboratory of Pollution Control and Resource Reuse, Frontiers
Science Center for Critical Earth Material Cycling, School of the
Environment and State Key Laboratory of Analytical Chemistry for Life Science, School
of Chemistry and Chemical Engineering, Nanjing
University, Nanjing 210023, China
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Wang Y, Tang J, Xie D, Li F, Xue M, Zhao B, Yu X, Wen X. Temporal variation and grade categorization of methane emission from LNG fueling stations. Sci Rep 2022; 12:18428. [PMID: 36319852 PMCID: PMC9626451 DOI: 10.1038/s41598-022-23334-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 10/29/2022] [Indexed: 11/23/2022] Open
Abstract
Natural gas is increasingly seen as the fossil fuel of choice for China as it transitions to renewable sources. The significant development of China's LNG vehicle application and fueling stations and the urgency of climate changes make it particularly important to quantify methane emission from LNG stations, where the data are extremely rare. We carried out a pilot study on direct measurement and quantitative analysis of methane emission from five LNG fueling stations located in Shandong, China following the standard stationary EPA OTM 33A method. The measured methane emission of these five stations vary from 0.01 to 8.76 kg/h. The loss rates vary from 0.004 to 0.257%. We demonstrated that the emission from LNG stations consist of continuous and intermittent contents. The intermittent emission shows a strong temporal variation. If a station is only monitored for 20 min, it may either under-estimate or over-estimate the total emission. Both the distribution of emission events and total emission rates among different stations are highly skewed. We found that these LNG fueling station emission can be categorized into 3 grades, as low, medium and high, corresponding to emission rates below 0.1 kg/h; between 0.1 and 1 kg/h and above 1 kg/h, which can be characterized by the measured average methane concentration enhancement.
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Affiliation(s)
- Yifan Wang
- grid.497420.c0000 0004 1798 1132College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, China
| | - Jianfeng Tang
- grid.497420.c0000 0004 1798 1132College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, China
| | | | - Fei Li
- grid.497420.c0000 0004 1798 1132College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, China
| | - Ming Xue
- grid.453058.f0000 0004 1755 1650State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety and Environmental Technology, Beijing, China
| | - Bo Zhao
- Qingdao ENN Energy Corporation Limited, Qingdao, China
| | - Xiao Yu
- grid.497420.c0000 0004 1798 1132College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, China
| | - Xiaojin Wen
- grid.497420.c0000 0004 1798 1132College of Pipeline and Civil Engineering, China University of Petroleum (East China), Qingdao, China
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On the Viability of Video Imaging in Leak Rate Quantification: A Theoretical Error Analysis. SENSORS 2021; 21:s21175683. [PMID: 34502574 PMCID: PMC8434307 DOI: 10.3390/s21175683] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 11/25/2022]
Abstract
Optical gas imaging through multispectral cameras is a promising technique for mitigation of methane emissions through localization and quantification of emissions sources. While more advanced cameras developed in recent years have led to lower uncertainties in measuring gas concentrations, a systematic analysis of the uncertainties associated with leak rate estimation have been overlooked. We present a systematic categorization of the involved uncertainties with a focus on a theoretical analysis of projection uncertainties that are inherent to this technique. The projection uncertainties are then quantified using Large Eddy Simulation experiments of a point source release into the atmosphere. Our results show that while projection uncertainties are typically about 5% of the emission rate, low acquisition times and observation of the gas plume at small distances from the emission source (<10 m) can amount to errors of about 20%. Further, we found that acquisition times on the order of tens of seconds are sufficient to significantly reduce (>50%) the projection uncertainties. These findings suggest robust procedures on how to reduce projection uncertainties, however, a balance between other sources of uncertainty due to operational conditions and the employed instrumentation are required to outline more practical guidelines.
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