A Review on Adsorption Technologies for Mercury Emission Control

Area of Science:

• Environmental Science
• Chemical Engineering

Background:

• Elemental mercury (Hg) in flue gas poses significant environmental and health risks.
• Effective removal technologies are crucial for industrial emissions control.

Purpose of the Study:

• To review and compare existing adsorption technologies for elemental mercury removal.
• To identify promising carriers and modification methods for future adsorbent development.

Main Methods:

• Comparative analysis of various adsorbent carriers: active carbon (AC), pyrolyzed char, inorganic adsorbents, and fly ash.
• Evaluation of modification strategies: pore structure enhancement, oxygen-containing functional groups, and active reagent impregnation.

Main Results:

• Active carbon and char exhibited higher mercury adsorption capacity (MAC) than fly ash and inorganic adsorbents.
• Chemical modification methods, particularly impregnation with halogens, sulfur, or metal chlorides, were more effective than pore structure improvement.
• Impregnation created numerous active sites, leading to highly effective mercury adsorbents.

Conclusions:

• Carbon-based materials are promising carriers for mercury adsorption.
• Chemical modification, especially impregnation, is key to developing high-performance mercury adsorbents.
• Future research should address SO2 and H2O resistance, adsorbent separation, cost-effective modifications, and fly ash utilization.