Exploring Activated Carbons for Sustainable Biogas Upgrading: A Comprehensive Review

Global energy supply remains, to this day, mainly dominated by fossil fuels, aggravating climate change. To increase and diversify the share of renewable energy sources, there is an urgent need to expand the use of biofuels that could help in decarbonizing the energy mix. Biomethane, obtained by upgrading biogas, simultaneously allows the local production of clean energy, waste valorization, and greenhouse gas emissions mitigation. Among various upgrading technologies, the use of activated carbons in adsorption-based separation systems has attracted significant attention due to their versatility, cost-effectiveness, and sustainability potential. The present review offers a comprehensive analysis of the factors that influence the efficiency of activated carbons on carbon dioxide adsorption and separation for biogas upgrading. The influence of activation methods, activation conditions, and precursors on the biogas adsorption performance of activated carbons is revised. Additionally, the role of adsorbent textural and chemical properties on gas adsorption behavior is highlighted. By synthesizing current knowledge and perspectives, this work provides guidance for future research that could help in developing more efficient, cost-effective, and sustainable adsorbents for biogas upgrading.