Integrating life cycle assessment and life cycle costing using TOPSIS to select sustainable biomass-based -carbonaceous adsorbents for CO2 capture

The release of carbon dioxide (CO2) through human activities causes the global warming issue. CO2 can be captured using a variety of carbonaceous adsorbents, such as activated carbon (AC), amine-modified activated carbon (ACNH), and graphene (G). However, the sustainability of these adsorbents needs to be investigated. The goal of this research is to find the most sustainable option from environmental, economic, and technical perspectives. The scope is from cradle to grave, by considering three end-of-life management options: incineration (I), reactivation (R), and landfilling (L). The Life Cycle Assessment (LCA), Life Cycle Cost (LCC) analysis, and CO2 adsorption capacity, were integrated into this study. The Simapro software was applied to the LCA analysis. Our result shows that AC, ACNH400, ACNH800, and G had CO2 adsorption capacities of 2.98, 1.10, 3.22, and 7.19 mmol/g, respectively. Meanwhile, the manufacturing processes of AC, ACNH400, ACNH800, and G contributed to 30-73%, 37-68%, 21-39%, and 80-97% of each environmental impact category, which were mostly related to energy consumption. Marine aquatic ecotoxicity (MAE) exhibited the largest environmental consequences (74-86%) across all adsorbents, followed by freshwater aquatic ecotoxicity (FWAE). Graphene, ACNH400, ACNH800, and AC had average energy consumption of 22500, 2200, 3400, and 800 MJ/kg, respectively. TOPSIS was used to select the optimal option from a variety of perspectives. The AC is the most sustainable option for capturing CO2. Accordingly, the rank of the options was followed as: AC-L > AC-R > AC-I > ACNH400-R > ACNH800-L > ACNH800-R > ACNH400-L > ACNH800-I > ACNH400-I > G-L > G-I > G-R. Variations in electricity and HCl resulted in considerable changes in the LCA and LCC outputs, according to sensitivity analysis.