Preparation of piperazine-grafted amine-functionalized UiO-66 metal organic framework and its application for CO2 over CH4 separation

UiO-66 amine functionalized was synthesized by solvothermal method. Post-synthetic modification of UiO-66-NH2 with piperazine, a known promoter to enhance the chemisorption rate of CO2 uptake, was carried out and analyzed to understand its crystalline structure, morphology and porous structure. Results show that piperazine is an effective agent for enhancing the capacity of absorption of CO2. This porous product exhibits an improved CO2 uptake at pressures up to 3000 kPa via physisorption and chemisorption mechanisms. The CH4 adsorption and desorption isotherms on UiO-66, UiO-66-NH2 and pip-UiO-66-NH2 at temperature of 298.15 K and pressures ranging from 0 to 5000 kPa were carried out. IAS theory for a mixture of 0.05 bar CO2, 0.85 bar CH4 and 0.1 bar other gas revealed a selectivity factor of 19.09 for CO2/CH4 from pip-UiO-66-NH2. Results show that these materials are effective adsorbents for CO2 and CH4 uptakes.