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Issue 27, 2018
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Kinetic analysis for cyclic CO2 capture using lithium orthosilicate sorbents derived from different silicon precursors

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Abstract

A series of Li4SiO4 was synthesized using LiNO3 and six different silicon precursors. The precipitated-silica-derived Li4SiO4 presented the highest CO2 capacity in a 10 h sorption test, and ZSM-5-derived Li4SiO4 demonstrated the most rapid CO2 sorption. The CO2 sorption kinetics predominantly followed the nucleation mode and could be accurately described by the Avrami-Erofeev model. The Avrami-Erofeev model provided an in-depth analysis of correlation between sorption performance and material properties. Both the nucleation speed and nucleation dimensionality affected the overall sorption kinetics. The kinetics and pore-size distribution suggest that the sorption kinetics was dependent on the quantity of ∼4 nm-pores which favors nucleation dimensionality. For the cyclic tests, the precipitated-silica-derived sample presented the poorest performance with the capacity decreasing from 31.33 wt% at the 1st cycle to only 11.52 wt% at the 30th cycle. However, the sample made from fumed silica displayed an opposite trend with the capacity increasing from 19.90 wt% at the 1st cycle to 34.23 wt% at the 30th cycle. The radically distinct behaviour of samples during cycles was on account of the alternation of sorption kinetics. The decrease in ∼4 nm-pores after cycles was responsible for the decrease of nucleation dimensionality for the precipitated-silica-derived sample. The rearrangement during cycles could enrich the pores of ∼4 nm for the fumed silica-derived sample, which improved the nucleation growth, thus enhancing the kinetics with cycles.

Graphical abstract: Kinetic analysis for cyclic CO2 capture using lithium orthosilicate sorbents derived from different silicon precursors

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Publication details

The article was received on 23 Apr 2018, accepted on 10 Jun 2018 and first published on 11 Jun 2018


Article type: Paper
DOI: 10.1039/C8DT01617H
Citation: Dalton Trans., 2018,47, 9038-9050
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    Kinetic analysis for cyclic CO2 capture using lithium orthosilicate sorbents derived from different silicon precursors

    M. Zhao, H. Fan, F. Yan, Y. Song, X. He, M. Z. Memon, S. K. Bhatia and G. Ji, Dalton Trans., 2018, 47, 9038
    DOI: 10.1039/C8DT01617H

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