Circular Carbon Capture: Comparative Life Cycle and Techno-Economic Assessment of Waste-Derived Activated Carbons

Addressing climate change and waste management demands integrative strategies that reduce emissions and valorize waste streams. This study presents a comprehensive life cycle assessment (LCA) and techno-economic assessment (TEA) of activated carbon (AC) production from six waste-derived feedstocks, including sawdust, jujun grass, Arundo donax, municipal solid waste, coconut shell, and palm kernel shell, for postcombustion CO2 capture. We integrate experimental CO2 adsorption data with detailed thermodynamic modeling to evaluate the energy demand, environmental impact, and cost performance of each production route. Chemically activated ACs exhibit higher CO2 uptake but incur greater material and energy costs, primarily due to potassium hydroxide. Sensitivity analysis identifies variable costs as the primary drivers of the minimum selling price. When deployed in a vacuum pressure swing adsorption (VPSA) system, all ACs offset their production-phase CO2 emissions within 1-4 days. Substituting grid electricity with renewable energy reduces life cycle emissions by up to 72%. Scenario analysis reveals considerable mitigation potential if deployed at scale in high-waste-generating countries. This work establishes the first integrated framework combining experimental performance data, process modeling, and sustainability assessment across multiple feedstocks, highlighting waste-derived activated carbon as a scalable and circular solution for carbon capture.