Potassium and zeolitic structure modified ultra-microporous adsorbent materials from a renewable feedstock with favourable surface chemistry for CO2 capture

LIU, Xin and Sun, Yuan and Liu, Jingjing and Sun, Chenggong and Liu, Hao and Xue, Qian and Smith, Emily F. and Snape, Colin E. (2017) Potassium and zeolitic structure modified ultra-microporous adsorbent materials from a renewable feedstock with favourable surface chemistry for CO2 capture. ACS Applied Materials & Interfaces . ISSN 1944-8244

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Abstract

Novel hierarchically structured microporous bio-carbons with exceptionally high capacities for CO2 capture have been synthesized from the abundant agricultural waste of rice husk (RH), using a facile methodology that effectively integrated carbonisation, activation and potassium intercalation into a one-step process. Textural characterisation demonstrates that the synthesized bio-carbons exhibit exceedingly high ultra-microporosity accounting for up to 95% of total porosity mainly as a result of the naturally occurring silicon compounds within the RH molecular framework structures. With a modest surface area of up to 1035 m2/g and a total pore volume of 0.43 cm3/g, the best performing RH carbon has showed exceptionally high and fully reversible CO2 uptake capacity of 2.0 mmol/g at 25 oC and a CO2 partial pressure of 0.15 bar, which represents one of the highest uptakes ever reported for both carbon and MOF materials usually prepared from using cost-prohibitive precursor materials with cumbersome methodologies. It has been found that up to 50% of the total CO2 uptake is attributable to the unique surface chemistry of the RH carbons, which appears to be dominated by the enhanced formation of extra-framework potassium cations owing to the exceedingly high levels of ultra-microporosity and the presence of zeolitic structures incorporated within the carbon matrices. Characterisations by EDX element mapping, XPS and the heat of adsorption measurements confirm the existence of a range of zeolitic structures, which essentially transforms the RH carbons into a kind of zeolite-carbon nanocomposite materials with strong surface affinity to CO2.

Item Type: Article
Additional Information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials & Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/acsami.7b06665
Keywords: CO2 capture, carbon materials, rice husk, surface chemistry, ultra-microporosity
Schools/Departments: University of Nottingham, UK > Faculty of Engineering > Department of Chemical and Environmental Engineering
Identification Number: 10.1021/acsami.7b06665
Depositing User: Sun, Cheng-gong
Date Deposited: 12 Jul 2017 13:39
Last Modified: 12 Jul 2017 13:41
URI: http://eprints.nottingham.ac.uk/id/eprint/44111

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