Copper–manganese mixed oxides: CO2- selectivity, stable, and cyclic performance for chemical looping combustion of methane
IR@CSIR-NEERI
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Title |
Copper–manganese mixed oxides: CO2- selectivity, stable, and cyclic performance for chemical looping combustion of methane |
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Creator |
Mungse, Pallavi
Saravanan, Govindachetty Tomoki, Uchiyama Nishibori, Maiko Teraoka, Yasutake Rayalu, Sadhana Labhsetwar, Nitin |
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Subject |
Materials Science
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Description |
Chemical looping combustion (CLC) is a key technology for oxy-fuel combustion with inherent separation of CO2 from a flue gas, in which oxygen is derived from a solid oxygen carrier. Multi-cycle CLC performance and the product selectivity towards CO2 formation were achieved using mixed oxide of Cu and Mn (CuMn2O4) (Fd%3m, a = b = c = 0.83 nm) as an oxygen carrier. CuMn2O4 was prepared by the co-precipitation method followed by annealing at 900 1C using copper(II) nitrate trihydrate and manganese(II) nitrate tetrahydrate as metal precursors. CuMn2O4 showed oxygen-desorption as well as reducibility at elevated temperatures under CLC conditions. The lattice of CuMn2O4 was altered significantly at higher temperature, however, it was reinstated virtually upon cooling in the presence of air. CuMn2O4 was reduced to CuMnO2, Mn3O4, and Cu2O phases at the intermediate stages, which were further reduced to metallic Cu and MnO upon the removal of reactive oxygen from their lattice. CuMn2O4 showed a remarkable activity towards methane combustion reaction at 750 1C. The reduced phase of CuMn2O4 containing Cu and MnO was readily reinstated when treated with air or oxygen at 750 1C, confirming efficient regeneration of the oxygen carrier. Neither methane combustion efficiency nor oxygen carrying capacity was altered with the increase of CLC cycles at any tested time. The average oxygen carrying capacity of CuMn2O4 was estimated to be 114 mg g�1, which was not altered significantly with the repeated CLC cycles. Pure CO2 but no CO, which is one of the possible toxic by-products, was formed solely upon methane combustion reaction of CuMn2O4. CuMn2O4 shows potential as a practical CLC material both in terms of multi-cycle performance and product selectivity towards CO2 formation. RSC 2014 Article PeerReviewed application/pdf http://neeri.csircentral.net/1080/1/mungse2014.pdf http://pubs.rsc.org/en/journals/journalissues/cp#!recentarticles&adv Mungse, Pallavi and Saravanan, Govindachetty and Tomoki, Uchiyama and Nishibori, Maiko and Teraoka, Yasutake and Rayalu, Sadhana and Labhsetwar, Nitin (2014) Copper–manganese mixed oxides: CO2- selectivity, stable, and cyclic performance for chemical looping combustion of methane. PCCP, 16. pp. 19634-19642. ISSN 1463-9076 http://neeri.csircentral.net/1080/ oai:neeri.csircentral.net:1082 2018-01-11T09:05:06Z 7374617475733D707562 7375626A656374733D5355423534 74797065733D61727469636C65 Nitric oxide absorption by hydrogen peroxide in airlift reactor: a study using response surface methodology Bhanarkar, A D Gupta, R K Biniwale, Rajesh Tamhane, S M Materials Science Absorption of nitric oxide from nitric oxide /air mixture in hydrogen peroxide solution has been studied on bench scale internal loop airlift reactor. The objective of this investigation was to study the performance of nitric oxide absorption in hydrogen peroxide solution in the airlift reactor and to explore/determine the optimum conditions using response surface methodology. A Box– Behnken model has been employed as an experimental design. The effect of three independent variables—namely nitric oxide gas velocity, 0.02–0.11 m/s; nitric oxide gas concentration, 300–3,000 ppm and hydrogen peroxide concentration, 0.25–2.5 %—has been studied on the absorption of nitric oxide in aqueous hydrogen peroxide in the semi-batch mode of experiments. The optimal conditions for parameters were found to be nitric oxide gas velocity, 0.02 m/s; nitric oxide gas concentration, 2,246 ppm and hydrogen peroxide concentration, 2.1 %. Under these conditions, the experimental nitric oxide absorption efficiency was observed to be *65 %. The proposed model equation using response surface methodology has shown good agreement with the experimental data, with a correlation coefficient (R2) of 0.983. The results showed that optimised conditions could be used for the efficient absorption of nitric oxide in the flue gas emanating from industries. Springer 2014 Article PeerReviewed application/pdf http://neeri.csircentral.net/1082/1/Int%20J%20Environ%20Sci%20Technol%202014%20RSM%20Nitric%20Oxide.pdf https://link.springer.com/journal/13762 Bhanarkar, A D and Gupta, R K and Biniwale, Rajesh and Tamhane, S M (2014) Nitric oxide absorption by hydrogen peroxide in airlift reactor: a study using response surface methodology. International Journal of Environmental Science and Technology, 11 (6). pp. 1537-1548. ISSN 1735-1472 (Print) 1735-2630 (Online) http://neeri.csircentral.net/1082/ oai:neeri.csircentral.net:1083 2018-01-11T09:09:03Z 7374617475733D707562 7375626A656374733D5355423534 74797065733D61727469636C65 Synthesis and visible light photocatalytic activity of nanocrystalline PrFeO3 perovskite for hydrogen generation in ethanol–water system Tijare, S N Bakardjieva, S Subrt, J Joshi, M V Rayalu, Sadhana Hishita, S Labhsetwar, Nitin Materials Science Nanocrystalline PrFeO3 perovskite type orthoferrite was synthesized at 700â—¦C by using three different synthesis methods, namely sol–gel, template and combustion method. The synthesized materials were characterized by XRD, BET-SA, SEM, HRTEM, XPS, FTIR and UV-DRS techniques to understand their physico-chemical properties. Characterization data reveal the formation of nanocrystalline PrFeO3 perovskite composition with improved physical properties, possibly due to lower synthesis temperature used. PrFeO3 synthesized by sol–gel method consists of crystallite size of about 20 nm with absorption maxima at 595 nm wavelength in visible light range. This photocatalyst shows hydrogen generation of about 2847 μmol.gâ^’1.hâ^’1, under visible light irradiation in ethanol–water system. The photocatalyst was further investigated for various operational parameters such as photocatalyst dose variation, illumination intensity, time, etc. in a view to optimize the hydrogen generation as well as to understand mechanistic aspects. This material appears to follow a semiconductor type mechanism for ethanol-assisted visible light photocatalyic water-splitting and can also be an interesting candidate to develop hetero-junction type photocatalysts. |
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Publisher |
Indian Academy of Sciences
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Date |
2014
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Type |
Article
PeerReviewed |
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Format |
application/pdf
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Identifier |
http://neeri.csircentral.net/1083/1/tijare2014.pdf
Tijare, S N and Bakardjieva, S and Subrt, J and Joshi, M V and Rayalu, Sadhana and Hishita, S and Labhsetwar, Nitin (2014) Synthesis and visible light photocatalytic activity of nanocrystalline PrFeO3 perovskite for hydrogen generation in ethanol–water system. Journal of Chemical Sciences, 126 (2). pp. 517-525. ISSN 0974-3626 |
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Relation |
http://www.ias.ac.in/Journals/Journal_of_Chemical_Sciences/
http://neeri.csircentral.net/1083/ |
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