Sun Bin, Zheng Dalong, Song Xin
School of Arts, Taishan University, Tai'an, 271000, China.
Department of Building Engineering, Zibo Vocational Institute, Zibo, 255300, China.
J Mol Model. 2025 Aug 13;31(9):243. doi: 10.1007/s00894-025-06472-y.
In this study, the effects of metal doping (Al, Cu, Fe) on the performance of MFI for adsorption and removal of organic sulfur (carbonyl sulfide (COS), methyl sulfide (CHSH), carbon disulfide (CS), and ethyl mercaptan (CHSH)) were systematically investigated. The mechanisms of metal doping on the adsorption sites and the competing adsorption behaviors were revealed. Under the independent adsorption conditions, Al doping resulted in an enhancement in the adsorption of COS and CS. Cu doping led to a preferential enhancement in the adsorption of COS, while concurrently inhibiting the adsorption of other molecules. Fe doping results in a slight reduction in the amount of adsorption. However, it concomitantly leads to a decrease in the stable adsorption escape from 607.43 to 470.32 kPa. Under the simultaneous adsorption conditions, Fe-MFI demonstrated optimal industrial adaptability, characterized by a low adsorption fugacity demand (130.87 kPa) and effective separation of the four molecules through a variable pressure process. Furthermore, the variation of organic sulfur concentration exerts a significant effect on the migration of the respective adsorption sites and the alteration of the adsorption configurations. The present study provides a theoretical basis for the application of metal-modified MFI zeolites in the field of organic sulfur removal and variable pressure adsorption separation.
The theoretical study is based on the density functional theory (DFT) method for geometric structure optimization and the grand canonical Monte Carlo (GCMC) method for simulation of adsorption properties. This geometric structure (MFI, metal-doped MFI, COS, CS, CHSH, and CHSH) optimization is carried out using the Dmol module in the Material Studio 2017. In this study, the GGA/PBE method was employed in conjunction with the DNP basis set, a spin-polarized set, and a DFT-D correction. The translational and rotational partition functions of the gas-phase molecules have been taken into account. This sorption behaviors of COS, CS, CHSH, and CHSH on MFI and metal-doped MFI are carried out using the Sorption module in the Material Studio 2017. The fugacity range is from 101.33 to 1013.25 kPa, and the temperature is 298 K.
在本研究中，系统地研究了金属掺杂（铝、铜、铁）对MFI型沸石吸附和去除有机硫（羰基硫（COS）、甲硫醚（CH₃SH）、二硫化碳（CS₂）和乙硫醇（C₂H₅SH））性能的影响。揭示了金属掺杂对吸附位点和竞争吸附行为的作用机制。在独立吸附条件下，铝掺杂导致COS和CS₂的吸附增强。铜掺杂导致COS的吸附优先增强，同时抑制其他分子的吸附。铁掺杂导致吸附量略有降低。然而，它同时导致稳定吸附逸度从607.43 kPa降至470.32 kPa。在同时吸附条件下，铁改性MFI型沸石表现出最佳的工业适应性，其特点是吸附逸度需求低（130.87 kPa），并且通过变压过程能有效分离这四种分子。此外，有机硫浓度的变化对各个吸附位点的迁移和吸附构型的改变有显著影响。本研究为金属改性MFI型沸石在有机硫去除和变压吸附分离领域的应用提供了理论依据。
理论研究基于用于几何结构优化的密度泛函理论（DFT）方法和用于吸附性能模拟的巨正则蒙特卡罗（GCMC）方法。使用Material Studio 2017中的Dmol模块对这种几何结构（MFI型沸石、金属掺杂的MFI型沸石、COS、CS₂、CH₃SH和C₂H₅SH）进行优化。在本研究中，采用GGA/PBE方法并结合DNP基组、自旋极化集和DFT-D校正。考虑了气相分子的平动和转动配分函数。使用Material Studio 2017中的吸附模块对COS、CS₂、CH₃SH和C₂H₅SH在MFI型沸石和金属掺杂的MFI型沸石上的吸附行为进行研究。逸度范围为101.33至1013.25 kPa，温度为298 K。
