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, <i>Arundo donax</i>, 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.