Synthesis of Coal Fly Ash-Based Zeolites for Carbon Capture

DOI

10.2991/978-94-6463-797-7_15How to use a DOI?

Keywords

zeolite synthesis; carbon capture; fly ash utilization

Abstract

In the growing interest of creating novel technologies to combat the rise of CO₂ in the atmosphere, zeolites have emerged as a sustainable solution for carbon sequestration. Zeolites are aluminosilicate-based material that are highly porous, low cost, and highly stable. This research focuses on the production and utilization of hydrothermally-synthesized coal fly ash (CFA)-based zeolites. The CFA type utilised in this study is categorised as Class F, it had a total percentage of 𝑆𝑖𝑂₂, 𝐴𝑙₂𝑂₃, and 𝐹𝑒₂𝑂₃ as 86.23%. The CFA used in this study was 90-125µm. Loss on Ignition (LOI) for the CFA was also conducted and the median LOI for the samples was 3.95%. During pre-treatment using a permanent magnet, an average of 48.232% of magnetics were removed from the CFA. After synthesis of the zeolites, the samples were analysed and the results showed that the addition of NaOH gradually increased the concentration of sodium oxide (𝑁𝑎₂𝑂) in CFA from an average of 6.34% to an average of 7.23%. The results also revealed a significant reduction in 𝑆𝑖𝑂₂ and 𝐴𝑙₂𝑂₃ percentage by an average of 43.26% and 40.10% respectively, and the concentration of 𝑆𝑖𝑂₂ was always higher than that of 𝐴𝑙₂𝑂₃ in all the samples.

The compositions of 𝑆𝑖𝑂₂ and 𝐴𝑙₂𝑂₃ gradually increased with an increase in the four controlled variables but started to decrease at higher values of each variable. The zeolites were subjected to a carbon capture test and the highest carbon capture was at 4M NaOH, hydrothermal treatment time of 30 hours, hydrothermal treatment temperature of 120℃ and CFA: NaOH ratio of 1:12.5. It was also observed that there was a rapid increase of the adsorption capacity of 𝐶𝑂₂ from 10 minutes to 30 minutes followed by a progressively slow increase with the increase in contact time. The adsorption of 𝐶𝑂2 approached equilibrium within 30 min. The carbon capture test for CFA-based zeolites was then compared with that for the commercial zeolites and the carbon capture capacity of the commercial zeolites was approximately twice that of the CFA-based zeolites.

Copyright

© 2025 The Author(s)

Open Access

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TY  - CONF
AU  - N. Mambanje
AU  - L. Tshuma
AU  - L. B. Moyo
AU  - N. Tshuma
PY  - 2025
DA  - 2025/07/22
TI  - Synthesis of Coal Fly Ash-Based Zeolites for Carbon Capture
BT  - Proceedings of the 1st International Symposium on African Sustainable Energy Solutions (AfrSusEnS 2024)
PB  - Atlantis Press
SP  - 105
EP  - 114
SN  - 2352-5401
UR  - https://doi.org/10.2991/978-94-6463-797-7_15
DO  - 10.2991/978-94-6463-797-7_15
ID  - Mambanje2025
ER  -