Disordered MoS<sub>2</sub> Nanosheets with Widened Interlayer Spacing for Elemental Mercury Adsorption from Nonferrous Smelting Flue Gas
Hui Liu, Liu Cao, Kaisong Xiang, Chaofang Li, Xiaofeng Xie, Hao Chen, Pingshan Wang, Fenghua Shen
Abstract
The development of a sorbent with a large elemental mercury (Hg0) adsorption capacity under a high SO2 concentration atmosphere is the key point for mercury emission control from nonferrous smelting (NFS) flue gas. By controlling the degree of crystallization, oxygen incorporation and disorder engineering were simultaneously realized to improve the Hg0 adsorption capacity of MoS2 nanosheets for the first time. The interlayer spacing of oxygen-incorporated MoS2 nanosheets reaches up to 9.4 Å from 6.4 Å of normal MoS2 nanosheets, which enhances the exposure of the active sites. Oxygen-incorporated MoS2 nanosheets display a disordered structure, indicating the declined crystallinity and increased active sites. Benefiting from the above synergistic advantages, oxygen incorporation and structure disorder increases significantly the equilibrium Hg0 adsorption capacity of MoS2 nanosheets to 16.26 mg·g–1 under 6% SO2 atmosphere, which is about 2.5 times larger than that of normal MoS2 nanosheets. Both external mass transfer and chemisorption control Hg0 adsorption on MoS2. Surface Mo5+ and S22– act as the main active sites generated by disorder engineering for capturing Hg0, and HgS is the final product of Hg0 adsorption. The simultaneous optimization of structural and chemical properties in this work provides an effective and convenient strategy to improve the Hg0 adsorption capacity of MoS2 nanosheets.