Batch-scale preparation of hollow fiber supported CHA zeolite membranes and module for solvents dehydration

Abstract

CHA zeolite membranes have been successfully synthesized on thin yttria-stabilized zirconia (YSZ) hollow fiber (HF) substrates by secondary growth method. Prior to membrane synthesis, the outer surface of YSZ hollow fibers were planted with ball-milled submicron CHA zeolite seeds. Extensive investigations on batch-scale preparation of CHA zeolite membranes were carried out in terms of seeding method. Uniform and continuous seed layers were achieved by vacuum seeding with the addition of colloidal silica in seed suspension, which resulted in high reproducibility HF CHA zeolite membranes at crystallization temperature of 160 °C for 20 h. The membranes showed average water permeation flux of ca. 8.0 kg m−2 h−1 with separation factor of ca. 2500 in 90 wt% ethanol/water mixture at 75 °C. A HF CHA zeolite membrane module was fabricated for multi-cycle dehydration of iso-propanol/water mixture and acetic acid/isopropanol/water mixtures at 75 °C with high stability for over 100 h.