Evaluation of Processing Parameters in the Hydrothermal Carbonisation of African Fan Palm Nut

This study explores the conversion of African fan palm nut an underutilized agricultural waste into valuable hydrochar using hydrothermal carbonization (HTC). The main aim was to optimize the HTC process conditions and assess the physicochemical characteristics of the produced hydrochar for potential use as an adsorbent. HTC experiments were carried out in a temperature-controlled batch reactor under inert conditions. Process optimization was performed using Response Surface Methodology (RSM) with a Central Composite Design (CCD), considering reaction temperature (180–220°C), residence time (30–90 min), and biomass-to-water ratio (1:8–1:12). The optimal conditions were determined to be 220°C, a residence time of 70.22 min, and a biomass-to-water ratio of 1:10.06. At these conditions, hydrochar and bio-oil yields of 24.72% and 28.60%, respectively, were achieved, alongside a maximum specific surface area of 729.56 m² g⁻¹. The resulting hydrochar exhibited desirable properties, including high carbon content (80.00%), low ash content (0.78%), and well-developed surface characteristics, confirming its suitability for adsorption-based applications. Overall, the results highlight African fan palm nut as a promising and sustainable feedstock for hydrochar production via HTC. This study supports the valorization of biomass waste and contributes to the development of environmentally sustainable materials in line with the Sustainable Development Goals (SDGs). Further studies should focus on application-specific performance, process scalability, and comprehensive environmental sustainability assessments.