A Magnetically Recoverable Fe₃O₄-NH₂-Pd Sorbent for Capture of Mercury from Coal Derived Fuel Gas

A sort of magnetical material named Fe₃O₄-NH₂-Pd was prepared by loading varying amounts of immobilizing Pd on the surface of the magnetic Fe₃O₄-NH₂ microspheres. This magnetical material was used firstly for capturing Hg° from coal derived fuel gas based on its recoverability. The experimental results showed that the loading Pd on the amine-functionalized magnetite nanoparticles can greatly improve the efficiency of removing Hg° at a high temperature range between 200 and 300 °C. The magnetic Fe₃O₄-NH₂-Pd sorbent with 5% Pd loaded exhibited significantly high activity and stability in capturing Hg°, affording over 93% capture efficiency at 200 °C for more than 8 hrs. Compared to the Fe₃O₄-NH₂ sorbent that converted the Hg° as HgS, this Fe₃O₄-NH₂-Pd sorbent can remove the Hg° by forming Pd-Hg amalgam and HgS. In addition, the experimental tests indicated that the as-synthesized Fe₃O₄-NH₂-Pd sorbent still showed stable magnetic properties after two regeneration cycles in removing Hg°, which provided the opportunity for preparing a recyclable sorbent which can be easily separated and recovered for Hg° removal.