Synthesis of Attapulgite Clay@Fe₂O₃ Composite via Ionic Liquid and Its Application in the Oxidation of Elemental Mercury

Abstract

Attapulgite clay@Fe₂O₃ (ATP@Fe₂O₃) composite was prepared by a one-pot calcination process via the ionic liquid (IL), [bmim]PF₆, using two cheap, ecofriendly materials (i.e., Fe(NO₃)₃•9H₂O and ATP, which is a magnesium aluminum silicate that is abundant in nature). The resulting composite was characterized by different techniques. IR spectra indicated that the ATP clay has been successfully modified by the functional Fe₂O₃species. X-ray diffraction analysis demonstrated that the natural ATP still existed in ATP@Fe₂O₃ composite and plays the role as a template. The specific surface areas determined by the BET method from N₂ sorption isotherms decreased with the entrance of Fe₂O₃. The activity for oxidation of elemental mercury (Hg₀) in flue gases was investigated, which exhibited the highest efficiency value of 91% at 220 ℃. The results showed that this composite was qualified for controlling and removing Hg0 in flue gases as a low-cost, sustainable, effective catalyst.