Effective removal of mercury from flue gas using flower-like MoS2 doped with rod-shaped MnO2

Abstract

Generally, injecting activated carbon in front of an air preheater is a common method for removing mercury in coal-fired power plants. However, high cost and low efficiency limit the practical application of this procedure. As one of the transition metal dihalides, molybdenum disulfide (MoS2) has attracted much attention. Herein, density functional theory calculation was applied to explore the mercury removal properties of MoS2 due to its good affinity for mercury. MoS2 was prepared using hydrothermal methods, while MoS2 doped with MnO2 (Mm adsorbent) was prepared using an ultrasonic mixing method. The prepared Mm adsorbent was characterized using X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM),and X-ray photoelectron spectroscopy. Rod-shaped MnO2 successfully appeared on the surface of flower-shaped MoS2. The adsorption of mercury (Hg0) on the MoS2/MnO2 (Mm) surface matched the Mars–van Krevelen reaction mechanism, indicating the consumption of lattice oxygen in the adsorbent. Additionally, the mercury removal efficiency of 3-Mm (MoS2 doped with 30 wt. % MnO2) adsorbent can still reach 90% under N2 + 200 ppm SO2.