Developing reactive CO₂ removal materials from thermally activated lizardite and marble waste: A pathway toward sustainable climate mitigation

To maximize the utilization of Mg-rich natural resources for CO ₂ removal (CDR), an integrated strategy has been proposed that focuses on synthesizing reactive CDR materials aimed at both climate change mitigation and environmental sustainability. This study demonstrates the use of lizardite-rich natural feedstock, an abundant and accessible resource, combined with industrial marble waste. Through thermal treatment at elevated temperatures, this mixture yields a reactive CDR material primarily composed of forsterite and lime. Carbonation experiments of the synthesized material show complete transformation of lime into calcite and substantial weathering of forsterite into hydrated and carbonated secondary minerals. Compared to the Ca₂SiO₄ + MgO system, the synthesized material exhibits higher eco-efficiency with comparable CO₂ sequestration, storing ~ 21% as CaCO₃ and ~ 6% as MgCO₃ in 30 days versus ~ 25% and ~ 5% over 7 weeks (Chen and Kanan 2025), while promoting sustainable industrial waste valorization. Additionally, forsterite is more suitable for ocean alkalinity enhancement applications, whereas Ca₂SiO₄ is better aligned with use in the cement industry. Taken together, we propose that our material has strong potential for large-scale deployment in ex-situ carbon mineralization, ocean alkalinity enhancement, soil amendment, industrial point-source capture, and in-situ geological carbonation. This potential depends on developing sustainable infrastructure to capture CO₂ emissions from material synthesis.