Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar

Biochars, produced via pyrolysis, are gaining attention in applications ranging from soil amendments to energy storage and environmental remediation. While lignocellulosic biochars from woody biomass are well studied, algal biochars remain comparatively overlooked despite offering diverse organic an...

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Main Authors: Brandon Lou, Mallory Parker, Eleftheria Roumeli
Format: Article
Language:English
Published: North Carolina State University 2025-04-01
Series:BioResources
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Online Access:https://ojs.bioresources.com/index.php/BRJ/article/view/24446
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author Brandon Lou
Mallory Parker
Eleftheria Roumeli
author_facet Brandon Lou
Mallory Parker
Eleftheria Roumeli
author_sort Brandon Lou
collection DOAJ
description Biochars, produced via pyrolysis, are gaining attention in applications ranging from soil amendments to energy storage and environmental remediation. While lignocellulosic biochars from woody biomass are well studied, algal biochars remain comparatively overlooked despite offering diverse organic and inorganic content that may broaden their applications. This study investigates how pyrolysis temperature and oxidative pretreatment affect the structure and properties of biochars derived from two macroalgae, Ulva expansa and Sargassum sp., under various pyrolysis conditions (500 to 900 °C). Using Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and nanoindentation, it was found that the C-O and C-N surface functional groups decreased in Ulva but the C=O and C-O-C groups increased in Sargassum upon pyrolysis. The reduced modulus ranged between 2.6 to 7.9 GPa and was governed by pyrolytic carbon content and inorganic composition. Of these two factors, the amount and type of pyrolytic carbon were determined by the heating conditions, with oxidation at 200 °C generally preserving more carbon than oxidation at 300 °C. Meanwhile, the final pyrolysis temperature dictated residual carbon content, salt formation, and carbonation. These findings highlight the potential for tailored pyrolysis to produce algal biochars with customizable structures and properties, enabling environmental and industrial applications such as carbon sequestration, filtration, and energy storage.
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spelling doaj-art-40d0f5ce41994f559c38929dcfe0add32025-08-20T03:52:07ZengNorth Carolina State UniversityBioResources1930-21262025-04-01202415241732733Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced BiocharBrandon Lou0https://orcid.org/0009-0001-0126-7781Mallory Parker1https://orcid.org/0000-0003-0526-6230Eleftheria Roumeli2https://orcid.org/0000-0002-2828-1428Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA, USA 98195-21120Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA, USA 98195-21120Department of Materials Science and Engineering, University of Washington, Box 352120, Seattle, WA, USA 98195-21120Biochars, produced via pyrolysis, are gaining attention in applications ranging from soil amendments to energy storage and environmental remediation. While lignocellulosic biochars from woody biomass are well studied, algal biochars remain comparatively overlooked despite offering diverse organic and inorganic content that may broaden their applications. This study investigates how pyrolysis temperature and oxidative pretreatment affect the structure and properties of biochars derived from two macroalgae, Ulva expansa and Sargassum sp., under various pyrolysis conditions (500 to 900 °C). Using Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscopy, and nanoindentation, it was found that the C-O and C-N surface functional groups decreased in Ulva but the C=O and C-O-C groups increased in Sargassum upon pyrolysis. The reduced modulus ranged between 2.6 to 7.9 GPa and was governed by pyrolytic carbon content and inorganic composition. Of these two factors, the amount and type of pyrolytic carbon were determined by the heating conditions, with oxidation at 200 °C generally preserving more carbon than oxidation at 300 °C. Meanwhile, the final pyrolysis temperature dictated residual carbon content, salt formation, and carbonation. These findings highlight the potential for tailored pyrolysis to produce algal biochars with customizable structures and properties, enabling environmental and industrial applications such as carbon sequestration, filtration, and energy storage.https://ojs.bioresources.com/index.php/BRJ/article/view/24446biocharbiomass pyrolysismacroalgaeoxidation
spellingShingle Brandon Lou
Mallory Parker
Eleftheria Roumeli
Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar
BioResources
biochar
biomass pyrolysis
macroalgae
oxidation
title Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar
title_full Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar
title_fullStr Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar
title_full_unstemmed Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar
title_short Effects of Pyrolysis Temperature of Macroalgal Biomass on the Structure and Mechanical Properties of Produced Biochar
title_sort effects of pyrolysis temperature of macroalgal biomass on the structure and mechanical properties of produced biochar
topic biochar
biomass pyrolysis
macroalgae
oxidation
url https://ojs.bioresources.com/index.php/BRJ/article/view/24446
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AT eleftheriaroumeli effectsofpyrolysistemperatureofmacroalgalbiomassonthestructureandmechanicalpropertiesofproducedbiochar