Adsorption and diffusion of carbon dioxide on the metal-organic framework CuBTB

Abstract

The metal-organic framework (MOF) CuBTB was synthesized and used to study adsorption and diffusion of carbon dioxide (CO2) in the crystal. Experimentally measured CO2 adsorption isotherms can be successfully fitted using the Toth adsorption model. The maximum adsorption capacity at 300K and 350K is 2.08 and 1.08mmol/g, respectively. The isosteric heat of adsorption of CO2 on CuBTB is about 26.4kJ/mol. The intracrystalline diffusivity of CO2 on CuBTB, obtained with a one-dimensional micropore diffusion model, is in the range of 1.57–9.85×10−12m2/s from 280K to 350K, while the diffusion time constant (De/r2) is in the range of 24.6–3.93×10−3s−1, which is higher than some zeolites. A dual linear-driving force (LDF) model used to estimate the kinetic constants provides an overall better fit to the experimental data than the one-dimensional micropore diffusion model.