High-efficiency adsorption of elemental mercury from flue gas by K-intercalated 1T&2H MoS2

Abstract

Alkali metal K is widely present in the earth's crust (the seventh abundant element), which can improve the activity and stability of the adsorbent. This study explored a simple calcination method, using the intercalation of K ions, successfully partially transformed commercial molybdenum disulfide (2H-MoS2) into 1T-MoS2, and used it for the adsorption of Hg0 in the flue gas. The experimental results showed that when the K ratio was 2:1(MK-3), the removal rate of Hg0 can reach 90.5 in a wide temperature range. Compared with 2H-MoS2, the mercury removal efficiency of MK-3 was increased by about 40%. After long-term and cycles experiments, the mercury removal efficiency of the MK-3 remained largely unchanged. In the simulated flue gas experiment, HCl could promote the mercury removal efficiency of sample MK-3, SO2 had no obvious effect on the mercury removal efficiency of sample MK-3, while SO2 and low concentration NO have no obvious effect on the mercury removal efficiency of the sample. It was found that during the intercalation of K ions, the interlayer spacing of MK-3 increased, and holes and cracks appeared on the base surface, which made it possible for Hg0 to enter the MoS2 interlayer and adsorb, thereby expanded the adsorption space of Hg0. DFT simulations showed that 1T-MoS2 significantly improves the surface activity of the adsorbent, thereby enhancing the stability of the sample to adsorb Hg0. Therefore, K intercalated in MoS2 can provide a promising method to capture Hg0 in coal-fired flue gas.