(250g) The Binding Of Flue Gas Pollutants On Pd, Au, Ag, Cu And Their Alloys

With the reduction of natural gas and petroleum sources and subsequent increases in their costs, energy from coal is becoming increasingly popular. However, coal is not a clean technology, so with this demand comes a subsequent demand to make this energy source more environmentally-friendly. Trace elements, such as mercury, arsenic, and selenium, are highly volatile and are known to escape into the atmosphere from coal combustion flue gas.

Many sorbent materials such as activated carbon, metal oxides, metal sulfides and pure metals can remove mercury under different conditions. Among these sorbent materials activated carbon is one of the most-studied sorbents. In spite of the high mercury removal capacity of activated carbon, it has been reported that activated carbon prevents concrete from meeting the freeze-thaw requirements in the recycling step involving the addition of particulate matter for concrete manufacturing. It would be more efficient to find a concrete-friendly sorbent material while simultaneously maintaining a high mercury removal capacity.

Density Functional Theory calculations have been performed to predict the binding mechanism of flue gas pollutants such as SO2, Hg0, HgCl2, HgO and SeO2 on pure Pd (001), Au (001), Ag(001), Cu(001) and their binary alloys. The vast majority of the mercury released from coal combustion is elemental (Hg0) and its binding on PdAu (111), PdAg (111) and PdCu (111) has been investigated. It has been found that the Pd surface is more reactive than the Au, Ag and Cu surfaces to the pollutants of coal combustion flue gas. Calculations for Hg0 binding on binary alloys have shown that small additions of Au, Ag and Cu to Pd increase the binding energy by improving the surface reactivity of the alloy.