Preparation of inexpensive NaA zeolite membrane on pozzolan support at low temperature for dehydration of alcohol solutions

In this paper, inexpensive NaA zeolite membrane was hydrothermally prepared by in situ crystallization on flat pozzolan support at low temperature, and applied for dehydration of ethanol and isopropanol solutions through pervaporation process. The thin zeolite layer was grown on seeded support via secondary growth method using molar composition of synthesis batch of Al2O3: 2 SiO2: 15 Na2O: 800 H2O.The effect of operating parameters such as synthesis temperature and crystallization time on NaA zeolite membrane was investigated. X ray diffraction and scanning electron microscope analysis have confirmed, on the one hand, that zeolite synthesized at 60 °C is pure and has the typical NaA zeolite morphology (cubic form), and have shown on the other hand that the zeolite membrane is homogeneous and free from defects. Optimized membrane (prepared at 60 °C during 24 h) was studied in dewatering of ethanol and isopropanol aqueous solutions varying water content from 10 to 50 wt.% by pervaporation 75 °C. At 10 wt.% of water content, experimental results showed that separation performance of the membrane is excellent in terms of separation factor (11,100 and 14,400 respectively for ethanol and isopropanol) and permeate flux (9.5 and 10.1 kg/h.m2 respectively for ethanol and isopropanol). The findings of this research suggest that the prepared NaA zeolite membrane could be useful for high separation performance of alcohol/water mixtures at low cost (using cheaper pozzolan support as well as NaA zeolite crystallization at low temperature).