Preparation And Pervaporation Performance Of Template-Free ZSM-5 Composite Zeolite Membrane

Pervaporation is considered to be a new type of separation technology with high efficiency and energy saving,which is widely used in organic solvent purification.ZSM-5 zeolite membrane with high silicon-to-aluminum ratio can be used in different separation environments due to excellent acid-resistivity and thermal stability.However,preparation of ZSM-5 zeolite membrane without template is particularly important in industry.For further improvement the separation performance of membrane,the Na Y type zeolite membrane with good intergrowth is used to modify the ZSM-5 zeolite membrane.Then a composite zeolite membrane with excellent separation performance can be obtained.Pervaporation performances and repeatability experiments of membrane are tested.The main results are as follows:(1)At the composition ratio of 4.454Na2O:14Si O2:Al2O3:2000H2O:12.6Na F,ZSM-5 zeolite membrane was obtained by the second hydrothermal method under the condition of no template agent,which the water content of the permeate side was 98.86wt%,the permeation flux was 1.02 kg·m-2·h-1.However,the membrane performance needs to be improved,it was necessary to improve its properties by modifying membrane.(2)According to the composition ratio of 25 Si O2: 1Al2O3: 22Na2O: 600H2 O as Na Y zeolite membrane synthesis liquid,Na Y zeolite membrane was synthesized on the ZSM-5 zeolite membrane.Preparation conditions of ZSM-5/Na Y composite zeolite membrane with good interactive growth and continuous dense were as follows: the water content of the permeate side of the ZSM-5 zeolite membrane did not exceed 70wt%,the aging time of the synthesis liquid was 18 h,the synthesis temperature was105 ?,the synthesis time was 6 h.The membrane had a permeate flux of 2.21kg·m-2·h-1 and a water content of 99.24 wt% on the permeate side in an 90 wt%isopropanol/water mixture system at 75 ?.(3)The operating temperature and feed concentration had little effect on the selectivity of zeolite membrane,but could affect the permeation flux of the membrane.The membrane permeation flux raised with the increase of temperature.And the membrane permeation flux was going down as the feed concentration increased.