Aqueous miscible organic-layered double hydroxides with improved CO 2 adsorption capacity
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Aqueous miscible organic‑layered double hydroxides with improved CO2 adsorption capacity Xuancan Zhu1,3 · Chunping Chen2 · Yixiang Shi1 · Dermot O’Hare2 · Ningsheng Cai1 Received: 31 August 2019 / Revised: 17 January 2020 / Accepted: 25 January 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Potassium-promoted layered double hydroxide (LDH)-derived materials are suitable elevated temperature C O2 adsorbents for pre-combustion C O2 capture. A challenge for the commercialization of LDHs as efficient C O2 adsorbents is their low capacities (ca. 0.5–0.6 mmol/g@400 °C) due to their hydrogen-bonded stacked structure. In this study, the aqueous miscible organic solvent treatment (AMOST) was used to exfoliate M g3Al–CO3 LDH into nanosheets with a flower-like morphol2 ogy, resulting in high surface areas of 287 and 212 m /g for CC1 (washed with ethanol) and CC2 (washed with acetone), respectively. The exfoliated LDH structure exposed more interlayered C O2 active sites and promoters for alkali metal modification. Six impregnation solvents, water, acetone, ethanediol, ethanol, DMAC, and methanol were screened to optimize the CO2 uptake of 20 wt% K 2CO3-promoted CC1. K 2CO3/CC1(ed) using ethanediol as the impregnation solvent reached a CO2 working capacity of 1.46 mmol/g at 400 °C in the first cycle and 1.23 mmol/g after 10 cycles, twice the capacity of the commercial K2CO3/MG70. Material characterization indicated that the unexpectedly high performance of K2CO3/CC1(ed) could be attributed to the uniform K+ dispersion on the surface of K2CO3/CC1(ed) rather than bulk phase formation and the release of the residual solvent during calcination that could generate more paths for CO2 diffusion. Keywords Aqueous miscible organic solvent treatment · Layered double hydroxides · Pre-combustion CO2 capture · CO2 working capacity · Surface modification
1 Introduction
Xuancan Zhu and Chunping Chen have contributed equally to this work. * Yixiang Shi [email protected] * Dermot O’Hare [email protected] 1
Key Laboratory for Thermal Science and Power Engineer of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 10084, China
2
Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
3
Institute of Refrigeration and Cryogenics, Key Laboratory of Power Mechanical Engineering, Shanghai Jiao Tong University, MOE China, 800 Dongchuan Road, Shanghai 200240, China
Evidence suggests that global warming is related to increasing CO2 concentration in the atmosphere, which has already exceeded 400 ppm and is projected to increase by 2 ppm/ year (Liu et al. 2019). Carbon capture and storage (CCS) is an important technology for potentially reducing anthropogenic CO2 emissions from the combustion of fossil fuels (Bui et al. 2018). Currently, most commercial CCS projects are based on post-combustion CO2 capture using liquid amine absorption. However, despite problems incl
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