Effects of ion-exchange on the pervaporation performance and microstructure of NaY zeolite membrane

Pervaporation performance of NaY zeolite membranes is improved by ion-exchange with di-valent nitrate salt. Different nitrate salts, including Co(NO3)2, Mg(NO3)2, Zn(NO3)2, Ca(NO3)2, Cu(NO3)2, KNO3, and AgNO3, have great effects on the channel structure and water affinity of the NaY zeolite membrane. When the concentration of nitrate salt, ion-exchange temperature and time are 0.1 mol·L−1, 50 °C and 2 h, the ion-exchange degree order of NaY zeolites is Ag+ > K+ > Ca2+> Zn2+ ≫ Co2+ > Mg2+. Especially, Ag+ and K+ cation exchange degree of NaY zeolites are achieved to 96.54% and 82.77% in this work. BET surface, total pore capacity, pore size distribution and water contact angle of the ion-exchanged NaY zeolites are all disordered by mono- and di-valent cations. Di-valent nitrate salt is favor for increasing the dehydration performance of NaY zeolite membranes by ion-exchange. When the ion-exchange solution is Zn(NO3)2, the total flux variation and separation factor variation of the NaY membrane (M-5) are −45% and 230% for separation of 10% (mass) H2O/EtOH mixture by pervaporation, and the ion-exchanged membranes showed good reproducibility.