Influences of inorganic salts on the pervaporation properties of zeolite NaA membranes on macroporous supports
Influences of inorganic salts on the pervaporation properties of zeolite NaA membranes on macroporous supports
复制标题
无机盐对大孔载体NaA沸石膜渗透汽化性能的影响
DOI：
10.1016/j.micromeso.2013.11.013
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发表时间：
2014-07-01
影响因子：
5.2
通讯作者：
Yin, Dehong
中科院分区：
文献类型：
--
作者：
Yang, Jianhua;Li, Huazheng;Yin, Dehong
采用变温热浸涂晶种法在大孔载体上水热合成了NaA沸石膜，并将其用于不同温度下醇/水/盐混合物的渗透蒸发脱水，考察了盐对渗透蒸发性能的影响。以NaCl、NaNO 3、KCl、MgCl 2和CaCl 2为实验材料，考察了盐浓度、阳离子和阴离子对膜性能的影响。对于乙醇/水/氯化钠混合物模型体系，随着盐浓度的增加，水通量显著下降，这是由于水驱动力/活性降低和盐对膜外表面的负物理阻挡作用所致。对于不同阳离子，钾离子导致的通量下降最大，达58.10%，而钠离子、钙离子和镁离子分别为25.88%、22.31%和24.91%。这可能主要归因于联合静电相互作用/离子交换作用。NaA膜的冲洗再生表明，不同的盐观察到复杂的通量行为。NaCl和NaNO 3体系的水通量分别恢复到91.23%和82.47%，表明物理盐阻塞对通量下降的影响可以消除，因此是可逆的。KCl和CaCl 2盐的水通量分别恢复到50.00%和116.92%。不可逆转的通量下降可能是由离子交换和离子阻挡效应造成的。这项工作表明，在醇/H2O混合物中的无机盐降低了通量或分离选择性，在工业应用中应避免。(C)由Elsevier Inc.出版。
Zeolite NaA membranes were hydrothermally synthesized on the macroporous supports using varying-temperature hot dip-coating seeding methods, and then were applied to pervaporative dehydration of the alcohol/water/salt mixtures at various temperatures to investigate the influences of salts on the pervaporation performance. Five kinds of salts NaCl, NaNO3, KCl, MgCl2, and CaCl2 were chosen to examine the effects of salt concentration, cations, and anions on the membrane performance. For the model system of ethanol/H2O/NaCl mixture, the water flux decreased largely with increasing salt concentrations which resulted from the reduced water driving force/activity and negative salt physical blocking on the outer membrane surface. For different cations, potassium ion led to the largest flux drop of 58.10%, while sodium ion, calcium ion, and magnesium ion for 25.88%, 22.31%, and 24.91%, respectively. This could be mainly attributed to a joint electrostatic interaction/ion exchange action.Flushing regeneration of the NaA membranes showed that complex flux behaviors were observed for the different salts. The water flux recovered up to 91.23% and 82.47% for the NaCl and NaNO3 system, respectively, indicating that the physical salt blocking effect on the flux drop can be removed therefore is reversible. The water flux recovered to 50.00% and 116.92% for salts of KCl and CaCl2, respectively. The irreversible flux drop probably resulted from the ion exchange and ion blocking effects. This work demonstrates that inorganic salts in the alcohol/H2O mixture decreased the flux or separation selectivity and should be avoided in industrial applications. (C) 2014 Published by Elsevier Inc.