Comparing Permanent vs. Regenerable Mercury Adsorbents

There are 2 main types of mercury adsorbent: Permanent (Non-Regenerable) & Regenerable. One is not necessarily “better” than the other; it depends on what is important to the client.

Permanent Hg adsorbents are simple to use; they do not generate mercury-contaminated waste streams that require further treatment.

Regenerable Hg adsorbent is typically loaded into the same vessels as the molecular sieve gas desiccant. The Hg captured from the gas then enters the mol. sieve regeneration gas stream, which then must be sent to a Permanent Hg adsorbent to prevent environmental contamination.

Permanent & Regenerable Hg adsorbents can both be used for high or low inlet mercury concentrations. The table below summarizes the properties, benefits, & requirements of both types of mercury adsorbent to help clients make their own evaluation of what type of Hg adsorbent or what combination of Hg adsorbents will best meet their process & environmental needs.






 Hg reacts with
 S-impregnant to form HgS
 Removes organo-mercury  cpds

 Hg reacts with precious metal (Ag)  to form weaker M-Hg bond


 High Bond Energy: Hg–S
 Hg is captured as HgS

 Low Bond Energy,
 Hg easily removed

Hg Adsorption

 Essentially Permanent

 Reversible - Regenerable

Process Location

 Requires its own Vessel
 • At Plant inlet, or
 • Downstream of driers

 Must Put adsorbent Inside
 ALL the Gas-Drying desiccant  vessels

Waste Streams that contain Hg

 None, No Waste Streams Gas  does not require any additional  treatment

 Regeneration Gas contains  HG
 • Condenser OVHD Gas
 • Condensed Water
 • Condensed Liquid Hg

Adsorbent Life

 2 to 20+ years depending on Hg  conc. in feed gas

 Usually replace when gas  desiccant is replaced:
 every 2 to 4 years

The above comparison is based on the best knowledge & experience of Selective Adsorption Associates, Inc. (SAAI), & is not to be considered a performance claim for or against, or product warrantee for, any particular type or brand of mercury adsorbent.

SAAI accepts no liability for the information above, or for any conclusions or consequences of clients’ decisions regarding their selection of Hg adsorbents or any other adsorbents.

Providing Solutions to remove mercury for emission control, corrosion prevention and catalyst protection.

Selective Adsorption Associates, Inc. (SAA) offers over 40 years of experience in Process Engineering of Adsorption Systems for Gas and Liquid Drying, Sulfur Compound Removal, Emission Control, and over 20 years of Process Design experience in Mercury Removal Systems.

CAUTION: Wet activated carbon removes oxygen from air. Thus, an asphyxiation hazard exists inside enclosed spaces containing activated carbon. Use appropriate safety precautions when entering vessels or other enclosed spaces containing activated carbon. Exposure to strong acids and oxidizers can cause formation of toxic H2S gas.

MERSORB® is a trademark of Nucon International, Inc. (NUCON®) for impregnated activated carbons used to remove mercury from gases and liquids. NUSORB® is a trademark of NUCON for its activated carbons. Information presented herein is believed to be accurate and reliable but does not provide any guarantee or warrantee by NUCON® or by Selective Adsorption Associates, Inc. Nothing herein shall be construed as an invitation to use processes covered by patents without proper arrangements with individuals or companies owning those patents.

AntiMercure® is a Registered Trademark of Selective Adsorption Associates, Inc. (SAA) for its Process for removing mercury from water; AntiMercure™ is a trademark of SAA for its pre-Engineered Systems for removing mercury from water. All Rights Reserved.