The Simulation Of Absorption And Adsorption Of Carbon Dioxide Gas In The Slurry System Of ZIF-8/Glycol+2-Methylimidazole Aqueous Solution

The addition of water to the ZIF-8/glycol-2MI（2-methylimidazole）slurry system can significantly increase the CO₂absorption.After CO₂is dissolved in water,most of it exists in molecular form,and a small amount exists in the form of ions.In this paper,the phase equilibrium data of CO₂absorption in solution and CO₂adsorption by ZIF-8were collected,and a thermodynamic model for the absorption and adsorption of CO₂in ZIF-8/glycol-2MI aqueous slurry system was established.The effect of separating the gas mixture using ZIF-8/glycol-2MI aqueous solution slurry was further predicted.The subject is studied from the following aspects:（1）Establishing the absorption-adsorption model:The fugacity coefficients of gas and liquid phase were calculated by the Patel-Teja equation of state（PT EOS）combined with the Kurihara mixing rule.The Langmuir isotherm adsorption equation was used to calculate the adsorption capacity for CO₂in ZIF-8.The selective osmotic pressure of solvent film surrounding ZIF-8 associated the absorption equilibrium of CO₂in the solution with the adsorption equilibrium of CO₂in solid materials.The predictive model of the system is established by writing programs.（2）Fitting parameters in the EOS and the Langmuir equation.The phase equilibrium experimental data of CO₂absorption in water,glycol,2MI aqueous solution and glycol-2MI solution were collected to determine the binary interaction parameters in the Kurihara mixing rule for PT EOS.The parameters in the Langmuir equation were determined based on the phase equilibrium data of ZIF-8 adsorbing CO₂.（3）The absorption and adsorption process was correlated by the selective osmotic pressure of the solvent membrane.The relationship between osmotic pressure and gas-liquid equilibrium fugacity was established by calculating the solubility of CO₂gas in the systems of ZIF-8/glycol-2MI and ZIF-8/water-2MI using the EOS and Langmuir equations with known parameters.In this paper,the effect of absorption and adsorption of CO₂by ZIF-8/glycol-2MI aqueous slurry system was predicted,and further the separation of the mixture in the slurry system.The calculated results are in agreement with the experimental values,which illustrates the accuracy of the model parameters and the predictability of the sorption-adsorption coupling model.