Concentrating water-soluble ionic liquids from aqueous solutions: Osmotic distillation with hydrophobic membranes
Concentrating water-soluble ionic liquids from aqueous solutions: Osmotic distillation with hydrophobic membranes
复制标题
从水溶液中浓缩水溶性离子液体：使用疏水膜的渗透蒸馏
DOI：
10.1016/j.memsci.2020.118222
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发表时间：
2020-08-01
影响因子：
9.5
通讯作者：
Xu, Zhi-Kang
中科院分区：
文献类型：
--
作者：
An, Yun-Peng;Liu, Chang;Xu, Zhi-Kang
离子液体作为“绿色”溶剂在新时代显示出广泛的应用前景，回收水溶性离子液体已成为一个迫切需要解决的问题。本文首次将渗透蒸馏技术应用于疏水膜浓缩回收水溶性离子液体。对聚偏氟乙烯垂直孔和不锈钢网状膜进行疏水性改性，并与市售膜进行比较，验证了不同孔结构对渗透蒸馏浓缩过程的影响。以膜两侧的蒸汽压差为驱动力，在水通量为7.8 kg m(-2)h(-1)的条件下，24 h后ILS的稀水溶液可浓缩到84wt%左右。通过这种渗透蒸馏过程，它还能够实现对ILS和MgCl2(>；99.99%)的超高截留率。尽管对浓度很高的ILS溶液进行脱水有一定的局限性，最终得到的ILS纯度不能达到100%，但这种方法对离子的高截留率，在常温下易于操作，以及所使用的疏水膜具有显著的普适性，因此具有很好的实际应用前景。
Ionic liquids (ILs) show a wide range of applications as "green" solvents in the new era and the recovery of watersoluble ILs has become an urgent issue. Herein, for the first time, osmotic distillation is applied to concentrate and recover water-soluble ILs with a series of hydrophobic membranes. Poly(vinylidene fluoride) membrane with vertically oriented pores and stainless steel mesh were hydrophobically modified and then compared with commercial membranes to demonstrate the influence of different pore structures on the osmotic distillation concentration process. With the vapor pressure difference between two sides of the membrane being the driving force, the dilute aqueous solutions of ILs can be concentrated to about 84 wt% after 24 h with a water flux of 7.8 kg m(-2) h(-1). It is also able to achieve ultra-high rejections to ILs and MgCl2 (>99.99%) by this osmotic distillation process. Although there exists a limitation for dewatering the ILs solutions with very high concentrations and thus the final ILs purity cannot reach 100%, this method is promising for practical applications benefiting from its high rejection to ions, easy operability at ambient temperature and remarkable universality in terms of hydrophobic membranes used.