Engineering biomass-derived CO2 capture materials via hydrothermal processes

Abstract

Hydrothermal carbonization (HTC) has emerged as a promising technology for converting biomass into high-performance carbon materials, offering potential sustainable solutions for CO₂ capture. HTC operates under moderate conditions to produce hydrochar with enhanced porosity and surface functionality ideally suited for CO₂ sequestration. Recently developed nitrogen-doped and alkali metal-activated hydrochars have improved adsorption capacities, and CO₂ capture capacities up to 320 ​mg/g, surpassing some traditional materials like zeolites. However, despite its potential to contribute significantly to global efforts seeking to mitigate carbon emissions, HTC faces challenges such as energy consumption and product variability. In this review we explore the fundamental mechanisms of HTC, emphasizing the transformation of wet biomass into porous, carbon-rich materials suitable for adsorption applications. We also discuss the technoeconomic viability of HTC as a scalable and sustainable technology and highlight future research needs aimed at optimizing reaction conditions, synergizing catalysts and solvents, reducing costs, and improving reactor designs that can help pave HTC's role in a low-carbon future.