Efficient removal of gaseous elemental mercury by Fe-UiO-66@BC composite adsorbent: performance evaluation and mechanistic elucidation

To achieve the efficient removal of gaseous elemental mercury in coal-fired flue gas, the study successfully prepared the isostructural bimetallic MOFs-based biochar composite by introducing the transition metal Fe into the UiO-66 by solvothermal method and using in-situ growth method for structural design. In addition, the effect of doping the secondary metal Fe and biochar on the Hg 0 removal performance and the corresponding quantitative correlation mechanism was established. The results showed that the overall mercury removal performance of the samples after Fe modification was improved. The optimal Fe loading ratio was 10 %, which corresponded to the adsorption capacity of 127.65 μg·g −1 . The biochar promoted the electron transmission and transfer of the overall reaction system by exerting the carrier effect. The 10 %Fe-UiO-66@20 %BC composite showed the best Hg 0 removal performance, with the corresponding adsorption capacity of 150.74 μg·g −1 . Fe 3+ , lattice oxygen, and chemisorbed oxygen jointly participated in the oxidation process of Hg 0 and finally oxidized Hg 0 to HgO.