Large-Area, High-Permeance and Acid-Resistant Zeolite Ssz-13 Membranes for Efficient Pervaporative Separation of Water/Acetic Acid Mixtures

Abstract

The development of acid-stable zeolite membrane is still a great challenge for pervaporative dehydration of water/acetic acid mixtures. Herein, we reported the fabrication of high-quality zeolite SSZ-13 membranes on the 50-cm-long tubular alumina supports via vacuum seeding method. The uniform seed layer by vacuum seeding method resulted in a uniform and intergrown zeolite membrane with thickness of 8.0-10.0 µm. The typical membrane with membrane area of 180 cm2 and Si/Al ratio of 12 displayed extremely high water permeance of 2.4 × 10-6 mol m-2 s-1 Pa-1 and high selectivity of 7700 in a 40/60 wt% water/AcOH mixture at 363 K. The corresponding water flux and separation index were 7.0 kg m-2 h-1 and 1.95 mol m-2 s-1, respectively. The overall separation performance (for example separation index) of the large-area SSZ-13 membrane was the highest one among the reported membranes for water/acetic acid separation. The effects of feed concentration and temperature on membrane performances were investigated for the separation of H2O/AcOH mixtures. Water flux increased greatly but water permeance decreased a little with increasing water content in the mixture and temperature. Permeance is a driving force normalized form and reflects the inherent property of the membrane only. Permeance and selectivity could be recommended to use for pervaporation separation performance of the membrane. Stability of the membrane in aqueous AcOH solutions was also studied in the 10-d continuous test.

Keywords: SSZ-13 membrane, Scale-up, Acetic acid, Pervaporation dehydration, Stability