Study on the Regeneration-Cycle Mechanism of Cu-BTC@MWS Composites Following Mercury Adsorption.

Abstract

Coal-fired power plants, as the largest source of human-made mercury emissions, often lack specialized mercury emission control devices. Therefore, developing cost-effective adsorbents and studying their regeneration properties are highly important for mercury removal from flue gas. In this study, the regeneration efficiency and stability of a composite material made from polymetallic Fe/Cu-doped modified biochar combined with the MOF material Cu-BTC were investigated. Based on the analysis of microscopic characteristics, the molecular structure of the regenerated composites was modeled, and the adsorption and regeneration process of Hg⁰ on their surface was simulated using density functional theory. This helped uncover the underlying mechanisms of mercury removal and regeneration. The results indicate that the optimal regeneration temperature and atmosphere were 350 °C and 5% O₂, resulting in the formation of a derived carbon material. The regeneration efficiency reached 92% of that of the original mercury adsorption capacity, and over 80% efficiency was maintained after 10 regeneration cycles. The regenerated samples adsorbed Hg⁰ through the combined action of surface metal oxides, the metal element Cu, and oxygen-containing functional groups.