Transport properties of mixed matrix membranes encompassing zeolitic imidazolate framework 8 (ZIF-8) nanofiller and 6FDA-durene polymer: Optimization of process variables for the separation of CO2 from CH4

In this work, the incorporation of ZIF-8 nanofiller for the improvement of the transport properties of 6FDA-durene membrane in CO2/CH4 separation is investigated. Central composite design (CCD) coupled with response surface methodology (RSM) were utilized for the optimization of the separation process variables over ZIF-8/6FDA-durene MMM in CO2/CH4 separation. Three models correlating the independent parameters including, pressure (3.5-12.5 bar), temperature (30-50 °C) and CO2 concentration (10-90 vol%) with the responses including, CO2 permeability, CH4 permeability and CO2/CH4 selectivity were developed based on the experimental data. The optimum parameters for achieving the highest separation performance were obtained at pressure of 4.76 bar, temperature of 30 °C and CO2 concentration of 90 vol%, which resulted in CO2 permeability of 687.20 Barrer, CH4 permeability of 71.03 Barrer and CO2/CH4 selectivity of 8.92. The deviation of the corresponding experimental data was found to be in an acceptable range, confirming the suitability of RSM for predicting the membrane performance and consequently optimizing the separation process variables.