Mercury Removal with Sulfur-Impregnated Activated Carbon
Mercury is the most insidious contaminant in industrial gas streams: colorless, odorless, and too volatile for standard activated carbon to hold effectively. The solution is to pre-load the carbon’s pores with sulfur. When mercury vapor meets sulfur, it converts to stable mercury sulfide and binds permanently to the carbon surface.
Simple chemistry, critical engineering
The reaction runs on its own: Hg + S → HgS. Mercury sulfide (known in nature as the mineral cinnabar) neither dissolves in water nor evaporates; captured mercury is never re-released. Yet making this simple chemistry work in the field depends on three engineering parameters:
- Sulfur loading ratio: typically 10–15 percent by weight; loading determines capacity
- Contact time: gas velocity must be low enough for mercury to reach the pores
- Temperature window: high temperature drives off the sulfur; the typical range is 5–60°C
Where is it used?
| Application | Note |
|---|---|
| Natural gas processing | Protects aluminum equipment in LNG plants from mercury corrosion |
| Flue gas | Emission compliance at waste incinerators and cement kilns |
| Industrial hydrogen | Cleanup of mercury traces from electrolysis |
| Laboratory ventilation | Mercury spills and amalgam work |
Bed design and exhaustion monitoring
Because mercury capture is irreversible chemisorption, a spent bed is not regenerated; the carbon is replaced and disposed of under hazardous waste procedures. Designs therefore include a safety margin, and mercury is measured continuously or periodically at the outlet. Critical lines run two beds in series: as the first approaches exhaustion, the second acts as a safety barrier.
You can find the general logic of impregnated carbons in our impregnated carbon guide. For the gas stream giving you mercury trouble, see our sulfur-impregnated product; share your gas composition and we will support the bed sizing.
