Zhang Guihua, Song Xin
Department of Mechanical Engineering, Wuhan Vocational College of Software and Engineering Wuhan 430205 China.
Faculty of Environmental Science and Engineering, Kunming University of Science and Technology Kunming 650500 China
RSC Adv. 2024 Aug 9;14(34):24970-24976. doi: 10.1039/d4ra03801k. eCollection 2024 Aug 5.
The purification and removal of organic sulfur from natural gas is conducive to increasing the added value of natural gas and reducing environmental pollution. In this study, the adsorption properties of methyl mercaptan (CHSH), dimethyl sulfide (CHS) and HO on the surface of hydroxyl-modified ZrO were investigated using density functional theory (DFT) calculations. Additionally, a reaction mechanism was proposed for hydroxyl-modified ZrO catalyzing the hydrolysis of CHSH and CHS. The chemisorption of HO molecules on the catalyst surface is attributed to H-O and H-Zr bonds. The chemisorption of CHSH and CHS on the catalyst surface is attributed to Zr-S bonds. Competitive adsorption between the three gases exists only between CHSH and CHS. It reveals the water-resistant properties of hydroxyl-modified ZrO in desulfurization. The adsorption energies of the three gas molecules on the hydroxyl-modified ZrO surface are in the order of CHSH - (Zr) > CHS - (Zr) > HO - (OH). The natural hydrolysis of CHSH and CHS is a heat-absorbing process that cannot occur spontaneously. The rate-determining step for CHSH catalytic hydrolysis is the formation of CHO. The fracture of CHSHO is the rate-determining step for CHS catalytic hydrolysis. The depletion of the surface hydroxyl groups can be replenished by the dissociation of HO molecules. Hydroxyl-modified ZrO facilitated the hydrolysis process of CHSH to a greater extent than that of CHS. This study provides theoretical guidance for industrial applications and the design of hydroxyl-containing hydrolysis catalysts.
从天然气中提纯和去除有机硫有利于提高天然气的附加值并减少环境污染。在本研究中，使用密度泛函理论（DFT）计算研究了甲硫醇（CH₃SH）、二甲基硫醚（CH₃）₂S和H₂O在羟基改性ZrO₂表面的吸附特性。此外，还提出了羟基改性ZrO₂催化CH₃SH和（CH₃）₂S水解的反应机理。H₂O分子在催化剂表面的化学吸附归因于H—O和H—Zr键。CH₃SH和（CH₃）₂S在催化剂表面的化学吸附归因于Zr—S键。三种气体之间的竞争吸附仅存在于CH₃SH和（CH₃）₂S之间。这揭示了羟基改性ZrO₂在脱硫过程中的耐水性能。三种气体分子在羟基改性ZrO₂表面的吸附能顺序为CH₃SH—（Zr）＞（CH₃）₂S—（Zr）＞H₂O—（OH）。CH₃SH和（CH₃）₂S的自然水解是一个吸热过程，不能自发发生。CH₃SH催化水解的速率决定步骤是CH₃OH的形成。（CH₃）₂SHO的断裂是（CH₃）₂S催化水解的速率决定步骤。表面羟基的消耗可以通过H₂O分子的解离来补充。羟基改性ZrO₂对CH₃SH水解过程的促进作用大于对（CH₃）₂S的促进作用。本研究为工业应用和含羟基水解催化剂的设计提供了理论指导。
