Biomass waste as an alternative source of carbon and silicon-based absorbents for CO₂ capturing application

The production of low-cost solid adsorbents for carbon dioxide (CO₂) capture has gained massive consideration. Biomass wastes are preferred as precursors for synthesis of CO₂ solid adsorbents, due to their high CO₂ adsorption efficiency, and ease of scalable low-cost production. This review particularly focuses on waste biomass-derived adsorbents with their CO₂ adsorption performances. Specifically, studies related to carbon (biochar and activated carbon) and silicon (silicates and geopolymers)-based adsorbents were summarized. The impact of experimental parameters including nature of biomass, synthesis route, carbonization temperature and type of activation methods on the CO₂ adsorption capacities of biomass-derived pure carbon and silicon-based adsorbents were evaluated. The development of various enhancement strategies on biomass-derived adsorbents for CO₂ capture and their responsible factors that impact adsorbent's CO₂ capture proficiency were also reviewed. The possible CO₂ adsorption mechanisms on the adsorbent's surface were highlighted. The challenges and research gaps identified in this research area have also been emphasized, which will help as further research prospects.