Molecular simulation of adsorption and diffusion of H2/CO2/CO/MeOH/EtOH mixture into the zeolitic imidazolate framework ZIF-8

The adsorption and diffusion behaviors of H-2, CO2, CO, MeOH, and EtOH into ZIF-8 were studied in pure and mixtures (binary and total) states by grand canonical Monte Carlo and molecular dynamics simulation, respectively. In addition, the separation of MeOH over the other guest molecules was also investigated in the mentioned mixtures. The results of molecular dynamics simulations showed that the diffusion coefficients of pure guest molecules followed the trend of H-2> CO2> CO > MeOH > EtOH. Analysis of adsorption indicated that all of the guest molecules (except H-2) have S-shaped adsorption isotherms with an initial low-uptake region, which can be ascribed to the cage-filling phenomenon. However, the trend of the initial sorption plateau range is CO2> CO > MeOH > EtOH. In the mixture used guest molecules, the most separation is related to the separation of MeOH from H-2 and EtOH, which is the optimal separation of MeOH from H-2 at pressures less than 1584 kPa and the optimal separation of MeOH from EtOH at a pressure of 10,000 kPa.

Automated summary

The adsorption and diffusion behaviors of H-2, CO2, CO, MeOH, and EtOH in ZIF-8 were studied in pure and mixed states. The results showed different trends for the diffusion coefficients and adsorption isotherms of the guest molecules. The separation of MeOH from other molecules in the mixture was also investigated.