Porous hydrophobic-hydrophilic Janus membranes for nondispersive membrane solvent extraction
Porous hydrophobic-hydrophilic Janus membranes for nondispersive membrane solvent extraction
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DOI：
10.1016/j.memsci.2021.119633
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发表时间：
2021-11
影响因子：
9.5
通讯作者：
Lydia N. Rodrigues;K. Sirkar;K. Weisbrod;John C. Ahern;U. Beuscher
中科院分区：
文献类型：
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作者：
Lydia N. Rodrigues;K. Sirkar;K. Weisbrod;John C. Ahern;U. Beuscher
多孔膜具有特殊的润湿特性，无论是疏水的还是亲水的，用于非分散膜溶剂萃取(MSX)，其中两个不相容的相流在膜的两侧。发生溶剂萃取/反萃取的水-有机相界面仍然固定在膜的一个表面上。这一过程要求不存在于膜孔中的相的压力等于或高于存在于膜孔中的相的压力；超额相压力不应超过突破压力。在逆流MSX中，每一相都有显著的流动压降，这通常会带来问题。为了克服这一问题，人们用基础聚丙烯(PP)、聚偏氟乙烯(PVDF)或聚酰胺(尼龙)膜开发了平坦的多孔Janus膜，膜的一侧是疏水的，另一侧是亲水的。用接触角、液滴进入压力(LEP)和液滴穿透压力对膜进行了表征，并用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)对膜进行了表征。成功地进行了辛醇-苯酚(溶质)-水、甲苯-丙酮(溶质)-水两个体系的非分散溶剂萃取，其中一个流动相的压力高于另一个相的压力。苯酚萃取体系具有较高的溶质分配系数，而丙酮倾向于几乎相同的两个相。通过Janus MSX膜，MSX技术的潜在实用价值将大大增强。
Porous membranes having a particular wetting characteristic, hydrophobic or hydrophilic, are used for nondispersive membrane solvent extraction (MSX) where two immiscible phases flow on two sides of the membrane. The aqueous-organic phase interface across which solvent extraction/back extraction occurs remains immobilized on one surface of the membrane. This process requires the pressure of the phase not present in membrane pores to be either equal to or higher than that of the phase present in membrane pores; the excess phase pressure should not exceed a breakthrough pressure. In countercurrent MSX with significant flow pressure drop in each phase, this often poses a problem. To overcome this problem, flat porous Janus membranes were developed using either a base polypropylene (PP) or polyvinylidene fluoride (PVDF) or polyamide (Nylon) membrane, one side of which is hydrophobic and the other being hydrophilic. Such membranes were characterized using the contact angle, liquid entry pressure (LEP) and the droplet breakthrough pressure from each side of the membrane along with characterizations via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR). Nondispersive solvent extractions were carried out successfully for two systems, octanol-phenol (solute)-water, toluene-acetone (solute)-water, with either flowing phase at a pressure higher than that of the other phase. The phenol extraction system had a high solute distribution coefficient whereas acetone prefers both phases almost identically. The potential practical utility of the MSX technique will be substantially enhanced via Janus MSX membranes.