The novel magnetic adsorbent derived from MIL-100 (Fe) loading with bimetallic Cu and Mn oxides for efficient Hg0 removal from flue gas

A novel magnetic adsorbent derived from MIL-100(Fe) loading with bimetallic Cu and Mn oxides, namely CuMnOx/MIL-100(Fe), was easily synthesized and used to remove elemental mercury (Hg0) from flue gas. Different mass loadings of CuMnOx (3%, 6%, and 9%) were impregnated on MIL-100(Fe) and calcinated at 200–500 °C to form CuMnOx/MIL-100(Fe), which was used to inspect Hg0 removal efficiencies at different reaction temperatures (40–200 °C). The Hg0 removal performance was studied through a variety of characterizations, including XRD, BET, SEM-EDS, TGA, XPS, VSM, H2-TPR, and Hg-TPD. 6%CuMnOx/MIL-100(Fe) calcined at 500 °C had a superior Hg0 removal efficiency of 92.4% and capacity of 1.16 mg/g at 120 °C, indicating that high-temperature calcination and bimetal loading were capable of improving the catalytic activity of MIL-100(Fe) and thereby improving the removal efficiency of Hg0 at a relatively low operating temperature of 120 °C. Under different flue conditions, the increase in O2 and NO concentrations can obviously promote the removal efficiency of Hg0, while SO2 and H2O had an opposite trend. The Hg0 removal efficiency remained above 90% after 8 cycles, which exhibits potential for industrial application. Furthermore, the Hg0 removal mechanism was attributed to the reaction with chemisorbed oxygen or lattice oxygen to form HgO on CuMnOx/MIL-100(Fe), which follows the Langmuir-Hinshelwood and Mars-Maessen mechanism.