Fabrication of low cost and high performance NaA zeolite membranes on 100-cm-long coarse macroporous supports for pervaporation dehydration of dimethoxymethane

Low cost and high performance NaA zeolite membranes have been successfully prepared on 100-cm-long coarse macroporous alumina supports using industrial grade reagents and chemicals. A simple and efficient sandpaper polishing method can effectively reduce the support surface roughness and the formation process of NaA zeolite membranes was investigated on inexpensive coarse supports by secondary growth, which was more conducive to the preparation of high performance membranes. For separation of a 90 wt% EtOH/H2O mixture at 348 K, the scaled-up NaA zeolite membrane showed a permeation flux of 4.67 kg m−2h−1 and a high separation factor of more than 10,000. Simultaneously, these membranes were used for pervaporation (PV) dehydration of a dimethoxymethane/water (DMM/H2O) mixture for the first time, which exhibited a permeation flux of 0.89 kg m−2h−1 and together with a separation factor of more than 23,000 at 313 K for dehydration of a 96 wt% DMM/H2O mixture. Moreover, the membrane also showed a superior long-term stability for running over 10 d. Importantly, the study on the recovery of permeation flux of scaled-up NaA zeolite membranes after long-term PV experiment to produce high-concentration DMM product (water content was less than 0.1%) found that the permeation flux was recovered to more than 85% of the fresh membranes after the membranes was cleaned using PV test with a methanol aqueous solution. These 100-cm-long NaA zeolite membranes with low cost and high performance demonstrated a promising industrial application prospects for PV dehydration of DMM/H2O mixtures and other organic water mixtures.