以EMT为晶种外延生长制备NaY分子筛膜及其渗透蒸发性能研究

Synthesis of NaY Membrane by Epitaxial Growth Using EMT as Seeds and the Study of Its Pervaporation Performance

以EMT为晶种,通过二次生长法制备出NaY分子筛膜并进行了表征,考察了二次生长液的碱度和铝含量对膜微结构的影响。将制备的膜材料应用于碳酸二甲酯与甲醇混合体系的分离,考察了原料液的浓度以及渗透蒸发温度对分离效果的影响,确定了膜层的稳定性。结果表明:二次生长液中,当n(SiO_2)/n(Na_2O)=1/1.4,n(SiO_2)/n(Al_2O_3)=10时,所得到的膜层质量最好。该膜对MeOH/DMC混合体系的分离效果受原料液的浓度和渗透汽化温度的影响显著。在50℃时,随着原料液质量分数的增加(20%~80%),膜材料的分离因子由34.1值降低至5.2,渗透通量由114.7增加至135.5g/(m^2·h);随着渗透汽化温度的升高(20~80℃),对于组成为甲醇质量分数50%的混合体系,膜材料的分离因子由29.8降低至2.8,渗透通量由96.3增加至180.8g/(m^2·h).膜材料稳定性良好,在14h内分离因子和渗透通量无明显改变。

Using EMT zeolite grains as seeds,NaY membranes were synthesized by secondary hydrothermal reaction method.The effect of alkalinity and the amount of Al in the secondary growth sol on the microstructure of the membranes was investigated.The effect of the concentration of the feed mixture and the pervaporation temperature on the separation performance was investigate when the membranes were applied to separate MeOH/DMC mixture.The stability of the membrane was also investigated.The results show that,when the molar ratio of n（SiO_2）/n（Na_2O）=1/1.4and n（SiO_2）/n（Al_2O_3）=10in the secondary growth sol,the membrane was of the highest quality in all the membranes we prepared.The separation performance was effected by the composition of feed mixture and pervaporation temperature.At 50℃,with the increase of feed mixture concentration（20%~80%）,the separation factor decreased from 34.1to 5.2,the flux increased from 114.7to 135.5g/（m^2·h））;with the increase of pervaporation temperature（20~80 ℃）,for the feed mixture with 50% methanol,the separation factor decreased from 29.8to 2.8and the flux increased from 96.3to 180.8g/（m^2·h）.The membrane was stable.Within14 hpervaporation period,no change on the separation factor and flux was observed