Alkaline pretreatment of walnut shells increases pore surface hydrophilicity of derived biochars
Journal article
Barr, M. R., Forster, L., D’Agostino, C. and Volpe, R. (2022). Alkaline pretreatment of walnut shells increases pore surface hydrophilicity of derived biochars. Applied Surface Science. 571, p. 151253. https://doi.org/10.1016/j.apsusc.2021.151253
Authors | Barr, M. R., Forster, L., D’Agostino, C. and Volpe, R. |
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Abstract | The surface chemistry and morphology of biochars produced by pyrolysis of walnut shells affects their utility for adsorption applications. Yet, little is known about surface interactions in the pores of these materials, mostly due to the challenging nature of accessing information at this length scale in a non-destructive manner. Here, for the first time, the relative adsorption strengths of solvents comprising different functional groups to internal (pore) surfaces of walnut shells and derived biochars were investigated using low-field nuclear magnetic resonance (NMR) relaxation time measurements to non-destructively probe interactions of fluids with pore surfaces. Carbon bonding state compositions of these materials with respect to distance from the particle surface were determined using X-ray photoelectron spectroscopy coupled with ion beam etching. Alkaline pretreatment was found to increase the hydrophilicity of both walnut shells and derived biochars. It was found to increase surface interactions with hydroxyl groups, and to decrease those with methyl groups. Results were contextualised by thermogravimetric analysis, scanning electron microscopy, and previous in-situ X-ray imaging results. Taken together, results showed that alkaline pretreatment may be used to modulate responses to pyrolysis temperature of several factors that affect adsorption properties including surface hydrophilicity, particle size, porosity, pore accessibility, and surface texture. |
Keywords | Biomass; Electron microscopy; NMR spectroscopy;Photoelectron spectroscopy; Surface chemistry |
Year | 2022 |
Journal | Applied Surface Science |
Journal citation | 571, p. 151253 |
Publisher | Elsevier |
ISSN | 1873-5584 |
Digital Object Identifier (DOI) | https://doi.org/10.1016/j.apsusc.2021.151253 |
Web address (URL) | https://www.sciencedirect.com/science/article/pii/S0169433221023060 |
Publication dates | |
01 Jan 2022 | |
Online | 13 Sep 2021 |
Publication process dates | |
Accepted | 08 Sep 2021 |
Deposited | 18 Aug 2023 |
Accepted author manuscript | License File Access Level Open |
https://openresearch.lsbu.ac.uk/item/94v66
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Accepted author manuscript
APSUSC-D-21-08758 Revised manuscript.docx | ||
License: CC BY 4.0 | ||
File access level: Open |
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