Zr/Br-doped UIO-type core-shell MOF via organic functional grafting for elemental mercury removal

A Zr/Br-doped core-shell UIO-type MOF optimized for efficient mercury removal. • Synergistic interaction between Zr 4+ and Br − formed dual-functional “oxidation-fixation” active sites. In coal-fired power plants, mercury is released into the atmosphere along with flue gas during the combustion of coal, posing serious threats to both the environment and human health. In this work, a novel core-shell structured Zr/Br dual-doped metal-organic framework adsorbent UIO-type-Zr-Br was successfully synthesized using a multi-step templating strategy with precise control of structural modulation. Through a combined strategy of ZIF-67@ZIF-8 NPs nano-etching and Zr/Br doping, the optimal sample UIO-15 exhibited excellent mercury removal performance, achieving over 98.8% removal efficiency at 120 °C. The UIO-15 adsorbent also demonstrated strong resistance to coal combustion flue gas interference components such as SO 2 (600 ppm) and NO (600 ppm), maintaining nearly 80% efficiency. Furthermore, long-term dynamic tests showed that UIO-15 retained approximately 95% efficiency after 10 h of continuous operation. The Zr 4+ and centers maintained the oxidation state throughout the reaction, indicating the role as structural stabilizers rather than redox-active sites, while Br − participated in the oxidation of elemental mercury Hg 0 to form stable HgBr 2 , which was subsequently immobilized within the MOF framework; Mercury removal was effected by dual-functional oxidation-fixation centers formed via synergistic Zr 4+ -Br - interactions. These findings suggest that UIO-15 is a promising candidate for practical application in mercury removal systems for coal-fired power plants. Download: Download high-res image (363KB) Download: Download full-size image