(189cl) Prediction of Hg0 and HgCl2 Adsorption Properties in UiO-66 Using Optimized Force-Fields

Hongjian Tang,^{†‡} Hanjun Fang,^‡ Yufeng Duan,*^{, â€}  and David S. Sholl*^{, ‡}

^†Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing, Jiangsu 210096, China

^‡School of Chemical & Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100, United States

Abstract: We propose the optimized force fields to effectively describe the vapor–liquid coexistence properties of Hg⁰ and HgCl₂. For HgCl₂, an excellent agreement between theoretical and experimental data can be obtained using the Lennard-Jones potential. The pair potential of HgCl₂ predicted by LJ force field showed good consistence with that derived from CCSD(T). Since regular two-body pair potentials failed to reduplicate experimental density of Hg⁰ in the bulk phase, Schwerdtfeger potential with multibody effect corrections was introduced to better describe the metallic interaction among Hg⁰ atoms. For the sake of simulating Hg⁰/HgCl₂ adsorption manners in UiO-66, generic force-field and mixing rules were applied to the GCMC calculation of HgCl₂ in UiO-66. While for Hg⁰, a set of LJ force field parameters were obtained based on PBE-D3 method via random sampling and single-point energy calculations in the full range of accessible volume of void UiO-66 framework. Adsorption isotherms predicted by GCMC calculation showed that UiO-66 possessed an extremely high capacity for HgCl₂ adsorption but scarcely any loading of Hg⁰ was observed in the framwork. UiO-66 was verified as a qualified material to selectively separate Hg⁰ from HgCl₂ in industrial flue gas. Furthermore, the force field developed in the will be pioneering and promising in predicting adsorption behaviors of Hg⁰ and HgCl₂ in MOFs and other porous materials through molecular simulation methods.

Key words: Hg⁰; HgCl₂; Force field; Isotherms prediction; Selective separation;