KI Impregnated Activated Carbon
Potassium-iodide (KI) impregnated activated carbon for capturing gaseous elemental mercury (Hg⁰) from flue gas and natural gas, and radioactive iodine (I₂ / CH₃I) from nuclear off-gas. The iodide reacts chemically with mercury and iodine to lock them permanently into the carbon pore structure.
⚡ Quick Answer
KI impregnated activated carbon is coal-pellet or coconut-granular carbon loaded with 1–5% potassium iodide that chemically fixes gaseous elemental mercury (Hg⁰) as stable mercuric iodide and traps radioactive iodine (I₂ / CH₃I). This dual physical-plus-chemical mechanism captures contaminants plain carbon releases, making it the standard media for flue-gas mercury control and nuclear off-gas iodine trapping.
- KI Loading
- 1 – 5% by weight
- Hg⁰ Capture
- > 90% efficiency
- Iodine Number
- 600 – 900 mg/g base
- Targets
- Hg⁰, I₂, CH₃I (I-131)
Related: All Impregnated Carbon · Mercury Removal · Sulfur Impregnated (hot flue gas) · Get a Quote
The Removal Challenge
Why gaseous mercury and iodine need KI-impregnated carbon
Elemental mercury vapor (Hg⁰) and radioactive iodine species pass straight through plain activated carbon — physical adsorption alone cannot hold them. KI (potassium iodide) impregnation solves this by adding a reactive chemical layer: iodide ions react with mercury to form stable, non-volatile mercuric iodide, and with iodine/methyl-iodide to fix radioactive isotopes in place. The result is a dual-mechanism adsorbent — physical adsorption plus chemisorption — that captures contaminants standard carbon releases. It is the standard media for coal-fired power plant mercury control, natural gas mercury guard beds, and nuclear facility off-gas iodine trapping.
How KI Carbon Works
Chemisorption locks mercury and iodine in place
Base coal-pellet or coconut-granular carbon is impregnated with 1–5% potassium iodide, distributing reactive iodide evenly across the pore network.
Gaseous Hg⁰ reacts with iodide to form stable mercuric iodide (HgI₂); radioactive I₂ and CH₃I exchange onto the iodide, fixing them permanently in the pores.
Unlike physical adsorption, the chemisorbed mercury and iodine will not desorb when temperature or gas composition shifts — no secondary release downstream.
Where It's Used
Applications for KI-impregnated carbon
Carbon Selection
Choosing KI carbon by duty
Match base carbon, form and KI loading to your gas stream and target contaminant. Every lot ships with a batch COA — iodine number, KI content, ash, moisture and mercury/iodine capacity.
| Removal Duty | Recommended Base | KI Loading | Form |
|---|---|---|---|
| Flue gas mercury (power plant) | Coal-based granular | 3–5% | Granular 4×8 / 12×40 |
| Natural gas mercury guard bed | Coal-based pellet | 2–5% | Pellet Φ3–4mm |
| Nuclear off-gas iodine | Coconut-based granular | 2–5% (+TEDA option) | Granular |
| General industrial Hg control | Coal-based granular | 1–3% | Granular |
Process Design
Maximum capture at lowest cost
KI loading vs cost
Higher iodide loading (3–5%) gives higher mercury capacity but raises cost. Guard beds with low inlet Hg run economically at 1–2%. We size loading to your inlet concentration and target breakthrough.
Bed contact time (EBCT)
Gaseous Hg⁰ capture needs adequate empty-bed contact time — typically 1–2 seconds for guard beds. Under-sized beds break through early. Share your flow rate for a bed-sizing calculation.
Temperature & moisture
KI carbon works best at moderate temperature; very high flue-gas temperature reduces capacity. For hot streams we advise a cooling or downstream placement strategy.
Nuclear-grade TEDA co-impregnation
For radioactive methyl-iodide (CH₃I) trapping, KI can be co-impregnated with TEDA (triethylenediamine) to meet nuclear off-gas standards. Available on request.
Technical Specifications
| Parameter | Coal Pellet (Hg) | Coconut Granular (Iodine) |
|---|---|---|
| Impregnant | KI (Potassium Iodide) | KI (±TEDA) |
| KI Content | 1–5% by weight | 2–5% by weight |
| Iodine Number | ≥600 mg/g | ≥900 mg/g |
| Form | Pellet Φ3–4mm | Granular 4×8 / 12×40 |
| Mercury Capacity | High (Hg⁰) | — |
| Ash Content | ≤12% | ≤5% |
| Moisture | ≤5% | ≤5% |
| Bulk Density | 0.45–0.55 g/cm³ | 0.45–0.55 g/cm³ |
Field Performance
Proven mercury and iodine capture
Case: natural gas processor installs KI mercury guard bed
A gas-processing plant added a KI-impregnated coal-pellet guard bed upstream of its cryogenic section to protect aluminum heat exchangers from mercury attack. At 3% KI loading the bed reduced inlet mercury from measurable levels to below detection at the outlet, with a multi-year service life before the first change-out — protecting downstream equipment from costly mercury-induced failure.
Related Products
Explore other impregnated grades and base carbons. Contact us for a tailored recommendation.
Impregnated Activated Carbon (Overview)
All impregnant types — KOH, sulfur, silver, KMnO₄, KI
Sulfur Impregnated Activated Carbon
Alternative mercury capture media for power plants
Coal-Based Pellet Activated Carbon
Base carbon for KI impregnation, low pressure drop
KI Carbon — Frequently Asked Questions
What is KI impregnated activated carbon used for?
KI (potassium iodide) impregnated activated carbon is used to capture gaseous elemental mercury (Hg⁰) from flue gas, natural gas and industrial exhaust, and to trap radioactive iodine (I₂ and methyl-iodide CH₃I) in nuclear power plant off-gas. The iodide reacts chemically with mercury and iodine, holding them permanently rather than just physically adsorbing them.
Why does mercury need KI carbon instead of plain activated carbon?
Elemental mercury vapor is not effectively held by physical adsorption alone — it can desorb when temperature or gas composition changes. KI impregnation adds a chemical reaction: iodide converts Hg⁰ into stable, non-volatile mercuric iodide that stays locked in the carbon pores, giving reliable long-term capture.
What KI loading should I choose?
Typical KI loading ranges from 1% to 5% by weight. Higher loading (3–5%) gives higher mercury capacity for high-inlet flue gas or guard beds protecting sensitive equipment; lower loading (1–2%) is economical for low-inlet polishing duty. We match loading to your inlet concentration and target breakthrough.
Can KI carbon remove radioactive iodine?
Yes. KI-impregnated carbon, often co-impregnated with TEDA (triethylenediamine), is used in nuclear facility off-gas systems to trap radioactive iodine species including elemental I₂ and organic methyl-iodide (CH₃I). Nuclear-grade formulations are available on request.
What base carbon and form is available?
We supply KI impregnation on coal-based pellet (Φ3–4mm, low pressure drop for guard beds) and coconut-based granular (4×8 / 12×40, high iodine number for iodine trapping). We select the base and form to match your process.
What is the MOQ and lead time?
MOQ is 1 ton with custom KI loading. Standard lead time is 10–15 days factory-direct. Packaging: sealed 25 kg bags or 500 kg jumbo bags with PE liner, private-label available. Every lot ships with a batch COA.
Need KI carbon sized for your mercury or iodine duty?
Tell us your gas composition, flow rate, temperature and inlet mercury or iodine concentration. Our engineers will recommend the base carbon, KI loading and bed size — and ship a free sample for evaluation.
Request a KI Carbon Quote