Pervaporation dehydration of acetic acid through hollow fiber supported DD3R zeolite membrane

Abstract

Abstract All-silica Decadodecasil 3R (DD3R) zeolite membranes were prepared on four-channel ceramic hollow fibers by seeding with ball-milled Sigma-1 zeolites and hydrothermal synthesis method. Effect of synthesis time on membrane structure and morphology was investigated and the membrane quality was evaluated by CO2/CH4 binary gas separation. The as-prepared membranes were further used in pervaporation dehydration of acetic acid (AcOH) for the first time. Although behaving strong hydrophobicity, the defect-free DD3R zeolite membrane exhibited a good water-selective permeability based on molecular-sieving mechanism. A water permeation flux of 0.58 kg m−2 h−1 as well as a separation factor of 800 was achieved in dehydration of 70 wt% water/AcOH mixture at 368 K. Both experimental and molecular simulation studies were explored to investigate the influence of pervaporation condition on membrane separation performance. The results showed that both high temperature and feed water content were beneficial for improving the water flux and separation factor. The long-term pervaporation test revealed that hydrophobic DD3R zeolite membrane behaved stable permeation flux and separation factor in dehydration of AcOH, even in the presence of inorganic acid, confirming the excellent acid-resistance of its all-silica framework structure.