Synthesis of a self-supporting faujasite zeolite membrane using geopolymer gel for separation of alcohol/water mixture

• A faujasite zeolite membrane was synthesized with geopolymer by hydrothermal process.
• The FAU zeolite membrane had BET of 63.3 m2/g and compressive strength of 19.6 MPa.
• The geopolymer micropore changed from 0 to 7 m2/g after hydrothermal process.
• The FAU zeolite membrane is effect pervaporation membrane to separate alcohol/water.

A self-supporting faujasite (FAU) zeolite membrane was synthesized by in situ hydrothermal method at 90 °C for 15 h from a Na2O–3SiO2–Al2O3 geopolymer gel that was prepared from the raw materials metakaolin and sodium silicate solutions (molar ratio of SiO2/Na2O=1). The results revealed that the BET surface area and the compressive strength of the FAU zeolite membrane were 63.31 m2/g and 19.6 MPa, respectively. The pervaporation study of its separation performance in a C2H5OH/H2O mixture demonstrated that the permeate flux and separation factor can reach 1.41 kg/(h·m2) and 16.8, respectively, at a feed temperature of 50 °C and an alcohol composition of 70 wt%, making it an effective pervaporation membrane for the separation of alcohol/water mixtures.