Preliminary studies on iron oxide nanoparticles as potential catalysts for oxidation of elemental mercury vapour

Mercury emissions have recently been stated as the most important global chemical issue facing the world today. The major source of elemental mercury vapour emissions are the flue gases that emanate from coal powered power plants. Currently, the most widely used method for removing mercury from these flue gases is by activated carbon adsorption. This process can require 10,000 to 50,000 kilograms of carbon per kilogram of mercury adsorbed and can cost in excess of $50,000 for every kilogram of mercury removed. It also produces a considerable amount of contaminated waste. One alternative process that has received interest in recent years for removing Hg0 from stack gases involves catalytically oxidising Hg0 to Hg2+ and capturing the Hg2+ by wet scrubbing. Iron oxides have received particular attention for use in this process due to reported high activities combined with the low cost of this material. In this study the characteristics of synthesised and commercially available hematite and magnetite nanoparticles have been investigated using X-ray diffraction, transmission electron microscopy and surface area analysis. Some significant differences, which could potentially influence catalytic activity, were observed between the synthesised and commercial nanoparticles of the same iron oxides.