Preparation Of UTSA-16/Polyacrylate Composites And Their CO₂ Adsorption Properties

With the rapid development of the economy,the rapid increase of CO₂generated by the burning of fossil fuels has caused a series of environmental problems.Metal-organic framework（MOF）materials have a large surface area and adjustable pore structure,which makes them highly promising for CO₂capture.UTSA-16,which contains a large number of micropores,has excellent CO₂adsorption performance and is regarded as a highly potential MOF for CO₂capture.Therefore,this study synthesized UTSA-16 with different metal salts and investigated its CO₂adsorption performance under various conditions.To address the issue of the decreased adsorption performance of MOFs after molding,UTSA-16/polyacrylic ester composites were prepared,and comprehensive evaluation of CO₂adsorption performance of composite materials.The main findings are as follows:（1）UTSA-16（Co）and UTSA-16（Zn）were prepared using the solvent thermal method,and the two materials were characterized and tested for their adsorption performance.It was found that UTSA-16（Co）had a better pore structure and thermal stability,with a specific surface area of 839.14 m²/g.The CO₂adsorption isotherms of the two materials were fitted using the Langmuir model,with a correlation coefficient R²greater than 0.997.The Qst values of UTSA-16（Co）and UTSA-16（Zn）were calculated using the Clausius-Clapeyron equation to be 34.5 and 33.6 k J/mol,respectively,falling within the range of physical adsorption heats.The CO₂adsorption amount of UTSA-16（Co）and UTSA-16（Zn）decreased as the temperature increased,with adsorption amounts of 183 and 161 mg/g at 25℃,respectively.The adsorption amount increased with increasing CO₂pressure,with adsorption amounts of73 and 98 mg/g at 0.2 bar,respectively,displaying good cycling stability.（2）A spherical polyacrylic acid ester matrix was prepared by emulsion suspension polymerization,and UTSA-16（Co）was grown in situ on the amine-functionalized polyacrylic acid ester matrix using vacuum impregnation and solvothermal method.Three types of UTSA-16（Co）/polyacrylic acid ester composite materials,namely direct impregnation,separate impregnation,and secondary growth,were obtained and characterized and their adsorption properties were tested.Results showed that UTSA-16（Co）was successfully synthesized inside the pores of the polyacrylic acid ester matrix,as evidenced by XRD,FT-IR,and SEM characterization tests.Among the three composite materials,UTSA-16（Co）/PAA-S had the highest loading rate of 53%,a sorption capacity of 95 mg/g at 25°C and 53 mg/g at 30°C、0.2 bar.The CO₂adsorption capacity only decreased by 1.36%after 10 cycles,indicating good cycling stability and providing a new approach for the practical application of MOFs in the adsorption field.（3）Further investigated the effects of gas flow rate,bed temperature,initial concentration,relative humidity of the gas flow and bed height on the CO₂adsorption performance of UTSA-16（Co）/PAA-S composite material.The results showed that the breakthrough time was negatively correlated with gas flow rate,bed temperature,initial concentration and humidity of the gas flow,and positively correlated with bed height.When the bed height was 5 cm,the breakthrough time could reach 128 min,providing a basis for process design.The pseudo-first-order,pseudo-second-order,and Avrami kinetic models were used for fitting,and it was found that the adsorption process of UTSA-16（Co）/PAA-S composite material conforms to the Avrami kinetic model,with a correlation coefficient of R²=0.997.（4）The influence of gas stripping flow rate and desorption temperature on CO₂desorption rate was discussed.The study showed that the desorption rate of CO₂was positively correlated with gas stripping flow rate and temperature.When the gas stripping flow rate was 0.6 L/min and the desorption temperature was between 90-110℃,the best desorption effect of CO₂can be achieved.This article used vacuum impregnation and solvothermal method to synthesize UTSA-16/polyacrylic acid ester composite materials,which have good CO₂adsorption performance.It provided a new solution to the difficulty of forming MOFs and occupied an important position in the industrial application of MOFs composite materials.