Mixed matrix blend membranes of sodium carboxy methyl cellulose (NaCMC)/hydroxy propyl cellulose (HPC) were prepared using solution casting method by incorporating 5, 10, and 15 Wt. % of phosphotungstic acid (PWA) particles. The membranes thus prepared were crosslinked with glutaraldehyde and tested for the pervaporation (PV) dehydration of aqueous isopropyl alcohol (IPA) at 30 °C. The phosphotungstic acid, with its hydrophilic nature as well as its molecular sieving effect and its favorable interaction with hydrophilic NaCMC and HPC, was responsible to enhance the PV dehydration of aqueous isopropanol in terms of selectivity (α), flux (J), and pervaporation separation index (PSI). The membranes were characterized by Fourier transform infrared spectroscopy (FTIR) to confirm crosslinking and assess the intermolecular interactions present between membranes and PWA. Thermal stability and crystallinity of these membranes were determined from thermo gravimetric analysis (TGA) and X-ray diffraction (X-RD) studies. The morphology of membranes was characterized by SEM studies, which indicated good compatibility of these membranes. Swelling studies were carried out to evaluate the extent of hydrophilicity with and without PWA particles and also based on their nature. The pervaporation performance was evaluated by varying experimental parameters such as feed composition, different polymer compositions and found to be promising membrane for separation of water- isopropanol mixtures. The results pertaining to the 15 wt% PWA loaded blend membrane (M-3) had the highest selectivity 11,241 which was attributed to the combined effect of molecular adhesion between PWA and NaCMC-HPC blend matrix as well as hydrophilicity.