CFD simulation of pervaporation of organic aqueous mixture through silicalite nanopore zeolite membrane

Nanopore silicalite type membranes were prepared on the outer surface of a porous-mullite tube by in situ liquid phase hydrothermal synthesis. The hydrothermal crystallization was carried out under an autogenously pressure, at a static condition and temperature of 180 °C with tetrapropylammonium bromide (TPABr) as a template agent. The molar composition of the starting gel of silicalite zeolite membrane was: Na2O/SiO2=0.287- 0.450, H2O/SiO2 = 8-15, TPABr/SiO2 = 0.01-0.04. The zeolites calcinations were carried out in air at 530°C, to burn off the template (TPABr) within the zeolites. X-ray diffraction (XRD) patterns of the membranes consisted of peaks corresponding to the support and zeolite. The crystal species were characterized by XRD, and morphology of the supports subjected to crystallization was characterized by scanning electron microscopy (SEM). Performance of silicalite nanoporous membranes was studied for separation of water-unsymmetrical dimethylhydrazine (UDMH) mixtures using pervaporation (PV). Finally, a comprehensive steady state model was developed for the pervaporation of a water-UDMH mixture by COMSOL Multiphysics software version 5.2. The developed model was strongly capable of predicting the effect of various dimensional factors on concentration and velocity distribution within the membrane module. The best silicalite zeolite membranes had a water flux of 3.34 kg/m^2.h at 27 °C. The best PV selectivity for silicalite membranes obtained was 53.