Rethinking hydrothermal carbonization: development of lignin-focused biorefinery for generation of high-value hydrochar and lignin spheres
Author(s)
Date Issued
January 2026
Type
article
Volume
28
Issue
18
Start Page
7659
End Page
7691
ISSN
1463-9262
1463-9270
Journal
Abstract
This tutorial review aims to provide a comprehensive overview of hydrothermal carbonization (HTC) as a
unified platform for biomass valorisation including the most recent developments and future challenges.
After the introduction, section 2 distils HTC fundamentals – operating regimes, acid-catalysed pathways
(hydrolysis, dehydration, aromatization), and the distribution of solids, liquids and gases under subcritical
water conditions. Section 3 examines hydrochar, highlighting how variations in feedstock, temperature,
and residence time govern surface functionality, porosity and thermal stability, and enable applications in
soil amendment, CO2 capture, heavy-metal adsorption, and solid-acid catalysis. Section 4 surveys HTCderived
carbon spheres, demonstrating that control over dopants, activation protocols, and reaction parameters
yields particles with tailored meso-/microporosity, surface chemistry, and electrochemical performance
for supercapacitors and water purification. Section 5 introduces lignin-focused strategies that
recover structurally preserved lignin directly from hydrochar and convert it into micro-/nanospheres with
high carbon content, intact β-O-4 linkages, and tuneable functionality for catalytic and materials applications.
Lastly, section 6 is dedicated to the environmental assessment of solvents and chemical reagents
used in post-HTC functionalization and activation. Collectively, these developments establish HTC as a
versatile, zero-waste biorefinery approach – producing hydrochar, engineered carbon nanostructures,
and high-value lignin under green chemistry principles and scalable process conditions.
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2026-pierpaoli-ACS.pdf
Size
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Format
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Checksum (MD5)
e440923a059e68700236c5d191f34a32
Project(s)
0000025 RomeTechnopole – CUP B83C22002820006, PNRR