Effects of the induced charge on CO₂ adsorption in Cu-BTC at different temperature: A combined experimental and molecular simulation study

Molecular simulation has been done to study the effects of induced charge on CO₂ adsorption and SO₂/CO₂ separation at different temperature in a typical metal organic framework Cu-BTC. The amount and isosteric heat of adsorption were tested synchronously on the combined PCTProE&E with Calver Calorimeter at different pressure and temperature of 35°C to validate the simulation. The effects of the temperature (range from 25°Cto 105°C), pressure (10 kPa, 100 kPa and 1000 kPa) and induced charge (between guest and host, guest and guest) on the process of CO₂ adsorption were studied by molecular simulation. The selectivity of SO₂/CO₂ was also evaluated. The simulation results agreed well with the experimental data. The amount and isosteric heat of adsorption declined with increase of temperature because of molecular motion enhancement. The electrostatic contribution could reach up to 23.8%-51.6% for amount of adsorption and 5.4%-30.4% for isosteric heat of adsorption. The form of CO₂ adsorption in Cu-BTC was Cu²⁺⋯O=C=O due to the induced electrostatic interactions between CO₂ and Cu-BTC. The selectivity of SO₂/CO₂ was sensitive to induced charge at different temperature. The competitive adsorption existed between the SO₂ and CO₂ in Cu-BTC.