Carbon Sequestration Potential of Coconut Shell Biochar Produced by Slow Pyrolysis

Authors: *Ejimadu, M.C., Okuo, J.M. And Okieimen, F.E.

DOI Info: http://doi.org/10.5281/zenodo.18060952

ABSTRACT

Coconut shell biochar samples were subjected to slow pyrolysis at various temperatures: 350 - 700 ^oC, and characterized in terms of physicochemical properties: yield, pH, cation exchange capacity, elemental composition (C, H, N, S, and O), and biochar stability using the KMnO4 oxidation method. The biochar yield decreased markedly (by about 47.17%) with an increase in pyrolysis temperature from 350 – 700 ^oC, while the values of pH and cation exchange capacity increased with an increase in pyrolysis temperature. The carbon content (mol %) of the biochar samples increased from 4.50 for the unpyrolysed coconut shell to 5.72 mol (%) for the biochar sample obtained at 700 ^oC. The O, N, and O contents decreased with an increase in pyrolysis temperature. The H:C and O:C ratios, indices obtained, and values that are indicative of the carbon sequestration potential of coconut shell-derived biochar, decreased with an increase in pyrolysis temperature. The accelerated chemical oxidative test with KMnO4 gave values for biochar stability that increased with an increase in pyrolysis temperature, consistent with the suggestion that coconut shell biochar prepared by slow pyrolysis at high temperatures (> 600) has potential in carbon sequestration applications.

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