New insights into elemental mercury removal from flue gas by a MoS2 heterogeneous system

Herein, MoS 2 was used in a MoS 2 /H 2 O heterogeneous system for the heterogeneously catalyzed removal of Hg 0 from flue gas. Hg 0 removal efficiency reached 77.6% at 25 °C when the dosage of MoS 2 was 0.200 g/L in aqueous suspension. The observed effects of MoS 2 dosage and inlet Hg 0 concentration on Hg 0 removal efficiency revealed that the gas–liquid mass transfer process is the limiting step of Hg 0 removal. Low pH and low temperature were conducive to Hg 0 removal. SO 2 in the flue gas was absorbed by MoS 2 , and the simultaneous decrease in solution pH resulted in a slight increase in Hg 0 removal efficiency. The presence of NO in the flue gas enhanced Hg 0 removal efficiency. Common anions, such as NO 3 − , SO 4 2− , and CO 3 2− , have no obvious effect on Hg 0 removal. However, Cl − improved Hg 0 removal efficiency by 11% because of the production of HgCl n 2−n . The kinetics and mechanism of Hg 0 removal were studied, and the results indicated that Mo acted as a bridge and catalyst for Hg 0 oxidation, while S immobilized Hg 2+ by formation of HgS on MoS 2 .