Study On CO₂ Adsorption Performance Of SBA-16 And Zeolite Modified HKUST-1

Excessive emissions of CO₂ have led to intensified problems such as global warming and the greenhouse effect,so measures to reduce carbon emissions are urgently needed.The capture,storage and utilization of CO₂ is considered as a promising technology to achieve CO₂ emission reduction.The efficient capture of CO₂ using solid adsorbents is considered to be the key to this technology.Among them,Metal Organic Frameworks（MOFs）materials are considered to be the most potential CO₂ adsorption materials due to their large specific surface area,tunable pore size,and tunable chemical properties.However,MOFs also have problems such as high cost,poor cyclability,low CO₂/N₂ adsorption selectivity,and the CO₂adsorption capacity needs to be further improved.Therefore,in this paper,the HKUST-1 was taken as the research object,and the porous material was used to modify HKUST-1 to construct a composite material to improve the CO₂ adsorption capacity of the adsorbent.The main research contents are as follows:1.HKUST-1 was modified with three-dimensional cage-like mesoporous Si O₂（SBA-16）,and SBA-16@HK composite was synthesized in situ by solvothermal method.The research results show that,compared with HKUST-1,the mesoporous structure of SBA-16 was introduced into the composite,which promoted the mass transfer and diffusion of CO₂.The high specific surface area,larger total pore volume,micropore volume,and additional mesoporous structure of the composite SBA-16@HK-1 enhance the CO₂ capture capability of MOFs.At 1 bar and 0℃,the CO₂ adsorption capacity of SBA-16@HK-1 is 183.13 cm³/g,which is 15%higher than that of HKUST-1.The CO₂ adsorption mechanism of the composite is still dominated by physical adsorption,and its adsorption heat is lower than that of HKUST-1,so the regeneration energy consumption is lower.Meanwhile,the composite material has good regeneration stability.2.The zeolite/HKUST-1 composites were in-situ synthesized by solvothermal synthesis with three LTA-type zeolites（5A,4A,and 3A zeolites）as modifiers.After the addition of zeolite,a composite material with a heterostructure was formed.In addition,the specific surface area and pore volume of this composite material are greatly increased,and the CO₂ adsorption sites are increased.The increase of the mesoporous structure of MOFs is beneficial to the mass transfer and diffusion of CO₂.Under the conditions of 1 bar and 0℃,the CO₂ adsorption capacities of 5A,4A,and3A zeolite-modified composites were greatly improved,reaching 202.84 cm³/g,206.07 cm³/g,and 200.01 cm³/g,respectively.Compared with HKUST-1,the composites have lower heat of adsorption,which means that the composites consume less energy during desorption and regeneration.After 5A zeolite was added to HKUST-1,the CO₂/N₂ selectivity of composite HK-3-5A was improved by 15%compared with HKUST-1.Due to the low price of zeolite,the zeolite/HKUST-1composite has good economics.In addition,the composites were found to have good regeneration stability through five CO₂ cycle adsorption tests.