| Pure hydrogen has a great impact on technological production,and the reduction of carbon dioxide is also very important to the social environment.Porous materials show superior adsorption performance for methane,and at the same time have immeasurable application prospects for greenhouse gases,due to characteristics of large surface area inside the pore,resulting in low atomic density,and stable structure in different chemical environments.Among them,zeolite molecular sieves（referred to as zeolites）with neat crystal structure as well as structure-controllable material of metal-organic frameworks（MOFs）has won the hearts of materials scientists.In the data age,with the amazing performance of computing performance of computers,the continuous advancement of algorithms,and the perfection of theoretical physics are violently promoting molecular simulation technology to grow into an emerging subject,compared to traditional chemical experiments and mathematical logic derivation.Using methodology of computer simulation computing technology,crystal geometric properties and"structure-property"relationships can be obtained and the research direction for material design and synthesis can be pointed out.Based on this background,there are two aspects of specific research in this article.By adopting a high-throughput computing strategy to obtain four geometric descriptors（Largest cavity diameter,Pore volume,Surface area,Void fraction）,one energy descriptor（heat of adsorption）,and working capacity and adsorption selectivity coefficient of 199zeolite molecular sieves for CH4 and CO2,the quantitative structure property relationship（QSPR）between inherent geometric characteristic properties of the material and the target performance is analyzed in detail.Subsequently,six ultra-microporous zeolites are obtained by pore size restriction conditions,and the simulation method of grand canonical Monte Carlo（GCMC）is utilized to accomplish the single component adsorption isotherms,isosteric heat of adsorption,preferential adsorption sites and selectivity curve of mixed components of CH4/H2 and CO2/N2.Study on the connection between geometric descriptors and adsorption separation performance:Through the analysis of the simulation data,we have obtained the knowledge that when the LCD is about 6?and the pore volume is 0.2 cm3/g,zeolite has better adsorption capacity and adsorption selectivity for CH4.In addition,it is found that the LCD and void fraction of zeolite have a certain non-negative correlation,and there is a manifest linear relationship between the working capacity and the adsorption selectivity coefficient for CH4.When the LCD is 4～8?and the pore volume is 0.2～0.4 cm3/g,the zeolite has a higher storage performance for CO2.Moreover,when the LCD is 4?,there is a higher CO2separation property with respect to the zeolite.Study on the adsorption and separation performance of materials with ultra-micropore size:The research results show that CH4preferentially occupies the space of the smaller pore window,while H2 is distributed in the entire pore without obvious adsorption sites.At the same time,the selectivity of zeolite to CH4 is almost independent of adsorption pressure and initial feed ratio.The pore windows of zeolites are more favorable to capture CO2,and zeolites have higher adsorption selectivity in the low amount of CO2mixed system.By adopting a high-throughput computing strategy to obtain four geometric descriptors,one energy descriptor,and uptake and selectivity coefficient of 2735 metal organic frameworks for CH4 and CO2,the QSPR between inherent geometric characteristic features of the material and the target performance is analyzed in detail.Subsequently,three ultra-microporous metal organic frameworks are obtained through the pore size restriction condition and six ultra-microporous anion hybrid MOFs are added.The GCMC simulation method is utilized to accomplish the pure component adsorption isotherms,isosteric heat of adsorption,preferential adsorption sites and selectivity curve of mixed components for CH4/H2 and CO2/N2.Study on the relationship between pore structure and adsorption as well as separation performance:When the LCD is about 5?and the POAV is 0.4 cm3/g,the MOF has a good adsorption capacity for CH4,and when ASA is 600～2600 m2/g,POAV is 0.1～0.5 cm3/g,and Porosity is between 0.1～0.3 and 0.4～0.6,the MOF has the best adsorption selection performance for CH4.Study on the adsorption and separation performance of materials with ultra-micropore size:The uptake of PARMIG for CH4 is much greater than that of JAVTAC,but the heat of adsorption is reversed.The distribution of adsorption sites illustrates that the influence of the MOF geometry on the adsorption behavior is higher than the energy effect.For the anion-pillared MOFs,the non-interpenetrating structure has a better adsorption effect on CO2 and N2 than the interpenetrating type,and gas molecules are mainly distributed in the electron-rich area.SIFSIX＿3＿Cd with higher heat of adsorption has excellent separation performance in CO2/N2 mixed system. |
