Study on the effect of process parameters on CO2/CH4 binary gas separation performance over NH2-MIL-53(Al)/cellulose acetate hollow fiber mixed matrix membrane

The aim of current work is to study the interaction of process parameters including, temperature, CO2 feed composition and feed pressure were towards CO2 separation from CO2/CH4 binary gas mixture over hollow fiber mixed matrix membrane using design of experiment (DoE) approach. The hollow fiber mixed matrix membrane (HFMMM) containing NH2-MIL-53(Al) filler and cellulose acetate polymer was successfully spun and fibers with outer diameter of approximately 250–290 nm were obtained. The separation results revealed that the increment of temperature from 30 °C to 50 °C reduced the CO2/CH4 separation factor while, increasing feed pressure from 3 bar to 15 and increment of CO2 feed composition from 15 to 42.5 vol% increased the separation factor of HFMMM. The DoE results showed that the feed pressure was the most significant process parameter that intensely affected the CH4 permeance, CO2 permeance and CO2/CH4 separation factor. Based on the experimental results obtained, maximum CO2 permeance of 3.82 GPU was achieved at feed pressure of 3 bar, temperature of 50 °C and CO2 feed composition of 70 vol%. Meanwhile, minimum CH4 permeance of 0.01 GPU was obtained at feed pressure of 15 bar and temperature of 30 °C and CO2 feed composition of 70 vol%. Besides, maximum CO2/CH4 separation factor of 14.4 was achieved at feed pressure of 15 bar and temperature of 30 °C and CO2 feed composition of 15 vol%. Overall, the study on the interaction between separation processes parameters using central composite design (CCD) coupled with response surface methodology (RSM) possesses significant importance prior to the application of NH2-MIL-53(Al)/Cellulose Acetate HFMMM at industrial scale of natural gas purification.