Evaluation and synthesis of Nano-pore Hydroxysodalite (HS) zeolite membranes: Application to pervaporation of Ethanol/water mixture

Effect of crystallization time and temperature on the membrane structure and performance has been investigated for Nano-pore Hydroxysodalite (HS) zeolite membranes. Molar composition of the starting gel of the HS zeolite membranes were: SiO2/Al2O3=1.0-5.0, Na2O/Al2O3=15-65, and H2O/ Al2O3=500-1500. X-ray diffraction (XRD) patterns of the membranes exhibited peaks corresponding to the support and the zeolite. The crystal species was characterized by XRD and the morphology of the supports subjected to crystallization was characterized by Scanning Electron Microscopy (SEM). Separation performance of HS zeolite membranes was studied for water-Ethanol mixturesusing pervaporation (PV). The membranes showed good selectivity towards water in the water-Ethanol mixtures. Water permeates faster because of its preferential adsorption into the Nanopores of the hydrophilic zeolite membrane. In PV of water-Ethanol mixtures, the membrane exhibits a hydrophilic behavior, with a high selectivity towards water and a good flux. The best flux and separation factor of the membranes were 2.05 kg/m2.h and 10000, respectively. Effect of operating condition (temperature, flow rate and pressure) on the membrane performance was investigated for HS zeolite membranes grown onto seeded mullite supports. Finally, a comprehensive 2D model was developed for the PV of water-Ethanol mixture through HS zeolite membrane using Finite Element Method (FEM). Effect of varying dimensional factors, temperature and feed flow rate on the PV performance was studied. The proposed model was masterfully capable of predicting concentration distribution within two sub-domains of feed and membrane.

Keywords:

Ethanol , FEM , Hydroxysodalite , Pervaporation , Zeolite Membrane