Demineralization-assisted porous carbon production from palm oil shell: Enhancing pore accessibility under low-severity conditions for sustainable applications.

Porous carbon derived from biomass has been widely explored due to its high surface area and adsorption capability. However, its production is typically dominated by aggressive chemical pore-forming processes that prioritize maximum porosity at the expense of process complexity, chemical consumption, and environmental sustainability. In this context, this study challenges the conventional pore-forming-centric approach by demonstrating that HCl treatment functions primarily as a selective demineralization and pore-unblocking agent, shifting the governing mechanism from pore generation to pore accessibility. Palm oil shell was converted into porous carbon through carbonization (300-500 °C, 2-4 h) followed by HCl treatment. The results show that increasing temperature enhances carbon content, structural stability, and energy properties, while demineralization significantly improves pore accessibility and surface exposure. The resulting material exhibits a moderate surface area (up to 139 m2/g), indicating that functional performance can be achieved without intensive chemical process. A process-structure-property framework is proposed to link carbonization conditions, structural evolution, and material performance. The findings highlight the dominant role of lignin-derived carbon frameworks in defining pore architecture, while mineral removal governs accessibility. These results suggest that the development of biomass-derived porous carbon does not necessarily rely on aggressive chemical treatment, and instead can be achieved through accessibility-driven design under low-severity conditions, enabling more scalable, resource-efficient, and sustainable carbon materials within a circular economy context.