| In our daily life,we cannot do without air,and various gases in the air have their own meaning and value.For example,O2 is not only a necessary gas for human breathing,but also has a very important role in the metallurgical industry and the medical industry.H2 and CH4 are rich in natural gas.As new fuels,they have the advantages of cleanness and high efficiency.Therefore,it is very necessary to screen out their respective materials that can effectively adsorb and store gas.In nature,many substances that can form crystals also have their own amorphous forms,and generally speaking,the reactivity of amorphous forms is greater than that of crystals of the same material.Porous amorphous materials have many applications in gas storage,separation,water purification and other fields.Although the material has great application value,the detailed calculation research on amorphous porous materials at this stage lags behind crystalline materials by a large margin.In this paper,using the method of grand canonical ensemble Monte Carlo molecular simulation(GCMC),the adsorption properties of 205 nanoporous rigid amorphous materials for 9 kinds of gases are studied under the temperature condition of 298 k and atmospheric pressure.The 205 types of amorphous materials studied in this paper include 1 type of amorphous zeolite imidazolate framework(a-ZIF),68 types of amorphous carbon(including activated carbon,coal and carbide-derived carbon models),respectively.75 kinds of intrinsic microporous polymers(PIM),44 kinds of hyper-crosslinked polymers(HCP),16 kinds of kerogen(Kerogen)and cement.The main work of this paper is as follows:1.First,verify the GCMC used in this article and the selected gas force field parameters.The calculated data results fit well with the experimental results in the literature,indicating that the gas force field parameters and GCMC can accurately simulate the gas The adsorption process.2.In this paper,the adsorption behavior of nine gases CH4,CO,N2,H2,O2,Ar,Kr,Rn and Xe in amorphous porous nanomaterials is studied in detail.The results showed that,except for H2 which obtained the largest adsorption capacity in Kerogen,which reached 0.56 mmol/g,the other eight gases all achieved their respective maximum adsorption capacity in amorphous carbon.The absolute adsorption capacity of Rn can reach 11.9 mmol/g at 1 bar,which far exceeds some traditional MOF materials,indicating that amorphous nanoporous materials are a kind of materials with great potential for storing rare gases under normal temperature and pressure.3.This paper uses the IAST method to predict the adsorption isotherm and adsorption selectivity of the Xe/Kr binary mixture system in four amorphous nanoporous materials of aCarbon,Kerogen,PIM,and HCP.Finally,the adsorption selectivity of the Xe/Kr binary mixture in different molar ratios is studied.The influence of meta-mixtures on material adsorption selectivity.The relationship of the adsorption selectivity of the four amorphous materials to the Xe/Kr binary mixed system is studied as aCarbon>Kerogen>PIM>HCP.Among them,aCarbon has a large adsorption capacity and a great adsorption selectivity at the same time.Its S value under the three molar ratios of 20:80,50:50,and 80:20 all reached about 140,which fully shows that the amorphous carbon material is an excellent material for Xe gas storage and separation.4.This paper divides the data of 988 MOF materials into machine learning training set and test set,and then uses the random forest algorithm to predict and verify the adsorption properties of CH4 on the four descriptors of the new material,and finally uses the trained RF The model predicts the methane adsorption capacity of the 205 amorphous nanoporous materials studied in this paper,thereby efficiently screening the materials with the best adsorption performance. |
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