Sulfur abundant S/FeS2 for efficient removal of mercury from coal-fired power plants.

Sulfur abundant S/FeS 2 prepared by a hydrothermal method was employed for removing elemental mercury (Hg 0 ) from coal-fired flue gas at low temperature. The S/FeS 2 exhibited optimal Hg 0 adsorption performance at 80 °C, which matched the temperature window between the flue gas desulfurization (FGD) and wet electrostatic precipitator (WESP) systems. The adverse effects of H 2 O and SO 2 on Hg 0 adsorption were slight. The Hg 0 adsorption capacity of S/FeS 2 was up to 2732 μg/g when achieved 50% breakthrough threshold. Both elemental sulfur (S) and FeS 2 in the S/FeS 2 contributed to the excellent Hg 0 adsorption capacity. The mercury leaching tests show that only 0.00076% mercury adsorbed on the S/FeS 2 was leached out. The mercury concentration in leachate was 0.694 μg·L −1 , which was much lower than that for a commercial AC (1.214 μg·L −1 ). Furthermore, the S/FeS 2 presented about 95% oxidized mercury (Hg 2+ ) adsorption efficiency from WESP effluent. The Hg 2+ concentration could decreased rapidly from 50 μg·L −1 to below 2.5 μg·L −1 in 30 min, which was much lower than the World Health Organization (WHO) guideline (6 μg·L −1 ). With these advantages, S/FeS 2 appears to be a promising material for co-beneficial gaseous Hg 0 and aqueous Hg 2+ removal from power plants by injecting upstream of a WESP system. [ABSTRACT FROM AUTHOR]