Scale-up of high performance mordenite membranes for dehydration of water-acetic acid mixtures

Mordenite membranes have been successfully synthesized on 80-cm-long mullite supports by secondary growth method. The morphology and quality of mordenite membrane were greatly affected by fluoride concentration, water content and crystallization mode. Compact and high-flux mordenite membranes were obtained with the addition of NaF in precursor gel, which also exhibited a long-term acid stability for a 90 wt% HAc/H2O mixture at 75 degrees C. Typically, 80-cm-long mordenite membrane prepared with transverse crystallization displayed a permeation flux of ca. 0.97 kg m(-2) h(-1) and separation factor of ca. 1200 for separating a 90 wt% HAc/H2O mixture at 75 degrees C. The pervaporation performance was better than that of membranes prepared with vertical crystallization due to the negligible impact of gravity and temperature gradients. These scaled-up mordenite membranes with high reproducibility showed a promising industrial application for dehydration of water-acetic acid mixtures.