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Rational synthesis of microporous carbons for enhanced post-combustion CO2 capture via non-hydroxide activation of air carbonised biomass

Altwala, Afnan; Mokaya, Robert

Rational synthesis of microporous carbons for enhanced post-combustion CO2 capture via non-hydroxide activation of air carbonised biomass Thumbnail


Authors

Afnan Altwala

Robert Mokaya



Abstract

This work explores the use of a less corrosive activating agent, potassium oxalate (PO), in combination with difficult to activate carbonaceous matter for the preparation of activated carbons. The design of the study allowed a fuller understanding of the workings of PO compared to hydroxide (KOH) activation, and also optimised the preparation of highly microporous carbons with exceptional CO2 storage capacity under low pressure (≤1 bar) conditions at ambient temperature. The PO activated carbons have a surface area of up to 1760 m2 g−1 and are highly microporous with virtually all of the surface area arising from micropores. The porosity of the PO activated carbons can be readily tailored towards having pores of size 6-8 Å, which are highly suited for CO2 storage at low pressure (i.e., post-combustion capture). At 25 °C, the PO activated carbons can store up to 1.8 and 5.0 mmol g−1 of CO2 at 0.15 bar and 1 bar, respectively. On the other hand, KOH activated carbons reach a higher surface area of up to 2700 m2 g−1, and store up to 1.0 and 4.0 mmol g−1 of CO2. This work demonstrates that PO may be used as a mild, less corrosive and less toxic activating agent for the rational and targeted synthesis of biomass-derived activated carbons with tailored porosity. The targeted synthesis may be aided by careful selection of the biomass starting material as guided by the O/C ratio of the biomass.

Journal Article Type Article
Acceptance Date Jul 5, 2022
Online Publication Date Jul 12, 2022
Publication Date Jul 12, 2022
Deposit Date Aug 16, 2022
Publicly Available Date Aug 16, 2022
Journal RSC Advances
Electronic ISSN 2046-2069
Publisher Royal Society of Chemistry (RSC)
Peer Reviewed Peer Reviewed
Volume 12
Issue 31
Pages 20080-20087
DOI https://doi.org/10.1039/d2ra02661a
Keywords General Chemical Engineering; General Chemistry
Public URL https://nottingham-repository.worktribe.com/output/8955898
Publisher URL https://pubs.rsc.org/en/content/articlelanding/2022/RA/D2RA02661A

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