Feedstock nitrogen content mediates maximum possible Pb sorption capacity of biochars

Ogbuagu, C., Robinson, S. ORCID: https://orcid.org/0000-0003-1045-4412 and Sizmur, T. ORCID: https://orcid.org/0000-0001-9835-7195 (2023) Feedstock nitrogen content mediates maximum possible Pb sorption capacity of biochars. Environmental Science: Process and Impacts, 25 (12). pp. 1853-2190. ISSN 2050-7895 doi: 10.1039/D3EM00246B

Abstract/Summary

The use of biochar for the adsorption of contaminants from soil and water has received considerable interest due to biochar’s high surface area, negative charge, and resistance to degradation. However, a knowledge gap still exists concerning the optimum selection of feedstocks and pyrolysis temperatures to maximise sorption capacity for metals. In this study, biochars were produced from 4 different feedstock materials (hay, wheat straw, coco coir, and pine bark) at 10 pyrolysis temperatures ranging from 300°C to 750°C, at 50°C intervals. Batch sorption experiments were conducted to determine the maximum Pb sorption capacity for each biochar using the Langmuir model. The sorption isotherms fit the Langmuir model well (generally R2 > 0.7). The Langmuir maximum sorption capacity increased with an increase in pyrolysis temperature, according to a sigmoidal relationship. A sigmoidal model was fit to the data to derive the theoretical maximum possible sorption capacity obtainable from a feedstock. We observed a positive correlation between the nitrogen content of the feedstock and the theoretical maximum possible sorption capacity obtainable from the feedstock. This relationship highlights the importance of nitrogen content in feedstock to create biochars with a high Pb sorption capacity. It is possible cation-π interactions with heterocyclic N structures are the primary mechanism for the sorption of Pb to these biochar, and this warrants further investigation.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/113754
Identification Number/DOI	10.1039/D3EM00246B
Refereed	Yes
Divisions	Science > School of Archaeology, Geography and Environmental Science > Earth Systems Science Science > School of Archaeology, Geography and Environmental Science > Department of Geography and Environmental Science Interdisciplinary centres and themes > Soil Research Centre Interdisciplinary centres and themes > Chemical Analysis Facility (CAF) > Optical Spectroscopy (CAF)
Publisher	Royal Society of Chemistry
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