Pore surface hydrophilicity of activated carbons derived from different biomass precursors: Evaluation for energy and environmental applications via the hydrophobic paraffin encapsulation and the hydrophilic H₂S adsorption-removal processes

• Bio-based Activated Carbon (AC) Surface Chemistry. • Surface Chemistry Dependence from Biomass Source. • Pore Surface Hydrophilicity-Lipophilicity Effect on Adsorption Processes. • H2S Removal Process Dependence from Activated Carbon Pore Surface Chemistry. • Phase Changing Materials Loading Dependence from AC Pore Surface Chemistry. Nowadays, interest in the circular-economy has established biomass valorisation as a sustainable approach to develop activated carbons (ACs) for energy and environmental applications. Until a few years ago, biomass-derived ACs were regarded as hydrophobic with high adsorption capacity towards organic molecules. Recent studies indicated that this AC’s hydrophobic nature is not mandatory, and this nature depends on several parameters such as the kind of activator. In this study we present the synthesis of a hydrophobic AC host matrix derived from spent coffee via a simple pyrolysis and chemical activation process, and the characterization of it. This material was compared with a commercial hydrophilic AC which was derived from pine-needles biomass. To prove that the biomass origin significantly affects the hydrophilic or not nature of the produced activated carbon, the capacity of all materials in one hydrophilic (H 2 S adsorption-removal) and one hydrophobic (paraffin loading) process was investigated. Our findings highlight that ACs produced by different biomass sources and via different processes exhibit different properties. Hydrophilic or lipophilic nature is one of the key factors for such materials effectiveness in different processes. This study offers new insights on surface chemistry and polarity modification of biomass derived activated carbons and paves the way for practical applications by exploiting these properties. Furthermore, it offers results for biomass-derived ACs’ capacity in Phase Changing Materials (PCMs) encapsulation and H 2 S adsorption-removal processes.