Elemental mercury vapor adsorption of copper-coated porous carbonaceous materials

The removal of elemental mercury vapor on copper-coated porous carbonaceous materials (Cu/PC) was investigated. An electroless plating method was employed for Cu coating on PC surface and each sample was named as as-received, Cu-5–1.9, Cu-10–2.4, Cu-15–3.3, and Cu-25–5.8 according to the plating time and resulting metal content. The pore structures and total pore volumes of the Cu/PC were examined by N2/77 K adsorption isotherms. The microstructure and surface morphology of the Cu/PC were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The elemental mercury adsorption capacities of all Cu/PC were higher than those of the as-received porous carbonaceous materials despite the decrease in the specific surface area and total pore volume after the Cu coating. The mercury removal capacity was proportion to a Cu content up to Cu-15–3.3, and showed a decrease. On the other hand, the Cu2O/Cu ratio was lowest at Cu-25–5.8, even though the textural properties of Cu-15–3.3 and Cu-25–5.8 were similar. This suggests that the surface oxidation level of Cu particles and total Cu content can determine the mercury removal capacity of the PC due to the chemical affinity between the Cu particles and elemental mercury vapor.

Elemental mercury removal efficiency of the Cu/PC as a function of the plating time; (a) breakthrough time for the as-received sample, (b) breakthrough time for Cu-25–5.8, (c) breakthrough times for Cu-5–1.9 and Cu-10–2.4, (d) breakthrough time of Cu-15–3.3. Breakthrough means 90% filter performance for elemental mercury.Figure optionsDownload as PowerPoint slideHighlights
► The Hg removal of all Cu/PCs was higher than that of the as-received PC.
► The Hg removal efficiency increased with the Cu content on the PCs.
► The excessively Cu-coated PCs showed a low Hg removal due to the formation of Cu2O.
► There is a strong correlation between the Cu2O/Cu ratio and the Hg removal.