Highly selective adsorption and separation of dichloromethane/trichloromethane on a copper-based metal–organic framework

Abstract

A copper-based metal–organic framework (MOF), also known as HKUST-1, was successfully synthesized, characterized, and evaluated for selective adsorption and separation of dichloromethane (DCM) and trichloromethane (TCM). The adsorption equilibria and kinetics of DCM and TCM were systematically investigated on the HKUST-1. Results showed that HKUST-1 has a high adsorption capacity for DCM (13.12 mmol g⁻¹) and TCM (8.53 mmol g⁻¹) at 298 K, respectively. From the kinetics results, the diffusion coefficients of DCM and TCM in HKUST-1 were estimated to be 3.73 × 10⁻⁹ cm² s⁻¹ and 0.44 × 10⁻⁹ cm² s⁻¹ at 318 K. In addition, their binary adsorption selectivity and diffusivity selectivity were predicted via the ideal adsorbed solution theory (IAST) method. The high adsorption selectivity (3.04) and diffusivity selectivity (8.93) at 318 K and 2.8 kPa indicated that HKUST-1 is a great candidate for selective adsorption and separation of DCM and TCM. Based on these results, the mechanism of adsorption and separation process has been discussed.