Since 2013, the generation of scrap tire waste in the U.S. has risen by over 32%, while the utilization of waste tire-derived materials has dropped by more than 25%, resulting in a 123% increase in the land disposal of scrap tires. These trends underscore the urgent need for new markets, innovative processing methods, and recycling solutions. Using an approach from an industrial ecology perspective, this study aims to convert scrap tires into adsorbent materials through carbonization and activation processes, with the goal of purifying landfill gas (LFG). LFG, produced by the unavoidable anaerobic decomposition of organic waste in landfills, contains methane (CH4; 50-60 vol.%) and carbon dioxide (CO2; 40-50 vol.%), along with smaller amounts of hydrogen sulfide (H2S), water vapor, and siloxanes. Purifying LFG into renewable natural gas (RNG) for use in natural gas grids or in electricity generation provides a renewable energy source while mitigating greenhouse gas and odor emissions. To investigate the feasibility of using amine-modified activated carbon (aminocarbon) derived from scrap tires for LFG treatment, waste tires were characterized to assess their composition and identify potentially necessary pre-treatment steps. Carbonization was performed in an oxygen-deficient environment using both microwave heating for energy efficiency and a muffle furnace for additional process comparison, followed by activation of the resulting carbon. Textural and structural properties of the synthesized activated carbon (AC) samples were evaluated via N2 physisorption and one selected AC samples was modified with tetraethylenepentamine (TEPA) and TEPA modified with the following epoxides: 1,2-epoxybutane (EB), 1,2-epoxyoctane (EO), 1,2-epoxydodecane (ED), and 1,2-epoxyhexadecane (EH). The CO2 adsorption capacities of the aminocarbons were tested under dry conditions (30 vol.% CO2, balance N2), and one promising sample was further analyzed under humid condition as well as in terms of thermal stability. Additionally, the H2S adsorption capabilities of the final candidate was assessed. Preliminary results demonstrate that tire-derived activated carbons exhibit potential for removing multiple impurities from LFG.
