Synthesis and Characterization of NaA Zeolite Membrane on Porous α-Al_2O_3 Ceramic

NaA zeolite membrane was synthesized by seeding supported crystallization on porous α-Al2O3 ceramic,and the formation mechanism was investigated by comparing the dynamic state crystallization condition with the static one.Suitable synthetic steps were included that zeolite seeds were prepared hydrothermally at 95 ℃ for 2 h from Na2SiO3·9H2O,NaAlO2 and distilled water with the molar ratio of n(Na2O):n(SiO2):n(Al2O3):n(H2O)=3:2:1:148;and the porous α-Al2O3 plates with seeds by dip-coating were crystallized at 97 ℃ for 4 h in the solution of Na2SiO3·9H2O,Al2(SO4)3·18H2O,NaOH and distilled water with the molar ratio of nNa2O:nSiO2:nAl2O3:nH2O=7.5:2:1:600 under dynamic (stirring-assisted by 190 r/min) and static states,respectively.The final products were characterized by XRD and FESEM,and the results show that the dynamic state hydrothermal condition was more beneficial to the formation of a single-phase NaA zeolite membrane with an excellent continuity and a uniform thickness.