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Non-thermal plasma Methane capture Carbon dioxide capture Metal organic framework Methanol synthesis Atmospheric remediation 1. Introduction The stabilization of CO2 and CH4 concentrations in the air to control global warming is accelerating. There are continued efforts to develop and optimize different technologies for capture and sequestration of these greenhouse gases from industrial emission sites. From these gases, CH4 is the most dominant anthropogenic greenhouse gas (after CO2). Methane can react with nitrogen oxides leading to tropospheric ozone pollution and posses a higher global warming potential (GWP) than CO2. It is 84 times more potent than CO2 over the first 20 years after release and ~28 times more potent after a century. Methane concentrations could be restored to preindustrial levels by removing ~3.2 of the 5.3 Gt of CH4 currently in the atmosphere [1]. Rather than capturing and storing the methane, CH4 could be oxidized to CO2, through the ther- modynamically favorable reaction: CH4 + 2O2 → CO2 + 2H2O; ΔHrx = –803 kJ mol–1. With the possible production of valuable condensates such as form- aldehyde and methanol when employing different reaction conditions (i. e., gas ratio, oxidant type, temperature) and rational selected catalysts. The large activation barrier associated with splitting methane’s C– H * Corresponding author. E-mail address: Maria.CarreonGarciduenas@sdsmt.edu (M.L. Carreon). https://doi.org/10.1016/j.jcou.2021.101642 The direct capture of CO2 and CH4 from the atmosphere to stabilize the concentrations in the air to control global warming is accelerating. There are continued efforts to develop and optimize different technologies for capture and sequestration of these greenhouse gases from industrial emission sites. In this work we employed MOF-177 as an efficient CO2 and CH4 adsorbent at standard temperature and pressure conditions. We demonstrated the possibility of desorbing the gases under study when employing gentle plasma pulses of He. Moreover, we per- formed the synthesis of methanol from CH4 using O2 and CO2 as oxidants respectively in the presence of MOF- 177. We observed the highest conversion for the CH4 + O2 system when employing the MOF-177 at (5:1) (CH4: O2) flow ratio of 23.5 % and methanol selectivity of 17.65 %. While the best performance for the CH4 + CO2 system at the same conditions i.e., (5:1) (CH4: O2) flow ratio was 18.4 % for the methane conversion and 11.68 % for the selectivity towards methanol. We expect this preliminary understanding of the adsorption-reaction system under non-thermal plasma environment can lead to future atmospheric remediation technologies.
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Managing dissolved methane gas in anaerobic effluents using microbial resource management-based strategies
This study reports the findings of three independent microbial resource management-based strategies to manage dissolved methane (D-CH4) gas in anaerobic effluents. In the first approach, an aerobic methanotroph Methylococcus capsulatus was immobilized. A maximum of 1.75 kg COD m−3 d−1 at a hydraulic retention time of 0.5 h was recorded in the attached growth aerobic methane oxidizing reactor. In the second strategy, denitrifying methane oxidizing organisms (DAMO) were first enriched in a lab-scale batch reactor which enabled a maximum methane oxidation rate of 0.31 kg COD m−3 d−1. In the last strategy, a mixed community of aerobic ammonia oxidizers was immobilized on sponge carriers and used to convert the D-CH4 gas into useful biofuel methanol at a rate of 0.73 kg COD m−3 d−1 equivalent of COD with a methanol production of 31.5 g COD m−3 d−1. On a COD basis, the amount of methanol generated could denitrify nearly 7 mg L−1 of NO3-N.
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- Award ID(s):
- 1657725
- PAR ID:
- 10144123
- Date Published:
- Journal Name:
- Bioresource technology
- ISSN:
- 1873-2976
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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