H2S与CO在MFI分子筛上吸附行为的模拟研究

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摘要:分子筛因其具有均匀孔径、比表面积高、吸附能力强等优点，广泛应用于催化剂、吸附剂和离子交换等工业领域。H2S和CO是污染性极强的气体，它们的治理已成为急待解决的重大环境问题之一。因此，研究H2S和CO气体在分子筛上的微观吸附行为具有重要的理论意义和应用价值。54491

本论文运用巨正则系综蒙特卡罗（GCMC）模拟方法研究了吸附质在MFI分子筛上的吸附行为。模拟结果表明：（1）MFI型分子筛对CO和H2S的吸附量随着温度升高而减小，随压力增大而增大；（2）相同条件下MFI型分子筛对H2S的吸附量高于CO；298 K时H2S和CO的饱和吸附量为分别为3.51 mmol/g和2.81 mmol/g。（3）两者混合竞争吸附时，H2S的吸附量远大于对CO吸附量，平衡吸附量之比高达267，具有明显的选择性。

毕业论文关键词：一氧化碳，硫化氢，MFI分子筛，模拟

Abstract: Molecular sieves have been widely used in the field of catalysts, adsorbents and ion exchange due to their unique advantages of uniform pore size, high specific surface area and strong adsorption ability. H2S and CO are harmful pollutant gas that have become one of the urgent environmental issues to be solved. Therefore, it is of great theoretical significance and application prospect to study microscopic adsorption of H2S and CO on molecular sieves.

Adsorption behaviors of H2S and CO on MFI were studied using Grand Canonical Ensemble Monte Carlo (GCMC) simulation method in this paper. Simulation results are as follows: (1) Adsorption amount of H2S and CO increase with a decrease in temperature or an increase in pressure. (2) The adsorption amount of H2S is larger than that of CO under the same condition. The saturated adsorption amount of H2S and CO are 3.51 mmol/g and 2.81mmol/g, respectively. (3) The adsorption amount of H2S is much larger than that of CO during their mixture adsorption on MFI, and the ratio of equilibrium adsorption amount is up to 267, which indicates that it has obvious selectivity between them.

Keywords: CO,H2S,MFI molecular sieve,Simulation

1 前言 3

1.1 分子筛结构 3

1.2 分子筛吸附选择性 4

1.3 蒙特卡罗模拟方法 4

1.4 分子模拟在分子筛吸附中的应用 5

1.5 本文研究内容 5

2 H2S与CO在沸石中的吸附模型及方法 5

2.1 分子模型 5

2.2 模拟方法 6

2.3 模拟方法的验证 6

3 结果与讨论 7

3.1 吸附等温线 7

3.2 亨利系数与吸附热计算 9

3.3 竞争吸附 10

3.4 吸附能分布 11

3.5 吸附质分子的粒子云分布图 12

结论 15

参考文献 16

致谢 18

1 前言

沸石分子筛是一类具有独特孔道结构的微孔材料，由于其具有耐热、耐化学腐蚀、择形选择能力等, 在吸附分离等传统分子筛应用领域有着巨大的应用前景[1,2]。近年来，科学技术在不断发展，人们对沸石分子筛的吸附和扩散研究也在不断地深入。同时，随着吸附技术与计算机科学技术的进步，分子模拟已成为解决吸附领域中实际问题的重要手段[3,4]。分子模拟借助计算机的强大计算能力以及图像显示能力，帮助人们从微观角度认识物质的吸附分离，并以能够节能、保证产品高纯度的优点倍受研究者的青睐[ 5,6 ]。