Miscibility studies of sodium carboxymethylcellulose/poly(vinyl alcohol) blend membranes for pervaporation dehydration of isopropyl alcohol

摘要

Miscibility studies of sodium carboxymethylcellulose/poly(vinyl alcohol) (NaCMC/PVA) blends of different compositions (100/0, 80: 20, 60: 40, 50: 50, 40: 60, 20: 80, and 0: 100) were investigated using viscometric method. NaCMC, PVA, and their blend membranes were prepared by solution-casting technique and were then crosslinked with glutaraldehyde (GA). The effect of blend composition on mechanical, swelling, and pervaporation results (flux and selectivity) was also investigated in this study. Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) results showed that the blends are miscible over the entire studied composition range and further confirmed the crosslinking reaction with GA. FTIR studies reveal that the blends containing 50: 50 (NaCMC/PVA) are an optimum miscible blend. Thermogravimetric analysis confirms that the thermal stability increased with increase in NaCMC content in NaCMC/PVA blend membrane. XRD and DSC showed a corresponding decrease in crystallinity and increase in melting point with increase in NACMC content, respectively. NaCMC/PVA blends of all the composition under study were used for dehydration of isopropyl alcohol at different compositions of IPA/water mixture (90: 10, 87.5: 12.5, 85: 15, and 82.5: 17.5) at 35°C. Swelling studies and PV results reveal that increase in NaCMC content in the blend leads to an increase in flux of water, whereas selectivity decreases. The optimum flux and selectivity were observed for the blend containing 50: 50 NaCMC/PVA content at a feed ratio of 87.5: 12.5 IPA/water.