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

Sulfur abundant S/FeS2 prepared by a hydrothermal method was employed for removing elemental mercury (Hg-0) from coal-fired flue gas at low temperature. The S/FeS2 exhibited optimal Hg-0 adsorption performance at 80 degrees C, which matched the temperature window between the flue gas desulfurization (FGD) and wet electrostatic precipitator (WESP) systems. The adverse effects of H2O and SO2 on Hg-0 adsorption were slight. The Hg-0 adsorption capacity of S/FeS2 was up to 2732 mu g/g when achieved 50% breakthrough threshold. Both elemental sulfur (S) and FeS2 in the S/FeS2 contributed to the excellent Hg-0 adsorption capacity. The mercury leaching tests show that only 0.00076% mercury adsorbed on the S/FeS2 was leached out. The mercury concentration in leachate was 0.694 mu g.L-1, which was much lower than that for a commercial AC (1.214 mu g.L-1). Furthermore, the S/ FeS2 presented about 95% oxidized mercury (Hg2+) adsorption efficiency from WESP effluent. The Hg2+ concentration could decreased rapidly from 50 mu g.L-1 to below 2.5 mu g.L-1 in 30 min, which was much lower than the World Health Organization (WHO) guideline (6 mu g.L-1). With these advantages, S/FeS2 appears to be a promising material for co-beneficial gaseous Hg-0 and aqueous Hg2+ removal from power plants by injecting upstream of a WESP system.