个人信息Personal Information
教授
博士生导师
硕士生导师
任职 : 精细化工国家重点实验室主任,教育部智能材料化工前沿科学中心执行主任,大连理工大学膜科学与技术研究开发中心主任
性别:女
毕业院校:中国科学院大连化物所
学位:博士
所在单位:化工学院
学科:化学工程. 膜科学与技术. 生物医学工程
联系方式:hgaohong@dlut.edu.cn
电子邮箱:hgaohong@dlut.edu.cn
Effect of oil phase transition on freeze/thaw-induced demulsification of water-in-oil emulsions
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论文类型:期刊论文
发表时间:2008-05-20
发表刊物:LANGMUIR
收录刊物:PubMed、SCIE、EI
卷号:24
期号:10
页面范围:5291-5298
ISSN号:0743-7463
摘要:Recently, there has been an increasing interest in the breakage-of water-in-oil (W/O) emulsions by the freeze/thaw method. Most of the previous works focused on the phase transition of the water droplet phase. This paper emphasizes the effect of continuous oil phase transition. A series of oils with different freezing points were used as oil phases to produce model emulsions, which were then frozen, and thawed. The emulsion whose oil phase froze before the water droplet phase did (OFBW) on cooling was readily demulsified with a dewatering ratio as high as over 80%, but the emulsion whose oil phase did not freeze when the water droplet phase did (NOFBW) was relatively hard to break. The difference in demulsification performance between them resulted from the distinction between their demulsification mechanisms via the analyses of the emulsion stability, emulsion crystallization/melting behaviors, oil phase physical properties, and wettability of the frozen oil phase, etc. For the OFBW emulsion, the first-frozen oil phase was ruptured by the volume expansion of the subsequently frozen droplet phase, and meanwhile, some liquid droplet phase was drawn into the fine gaps/crevices of the frozen oil phase to bridge droplets, which were considered to be essential to the emulsion breakage, whereas for the NOFBW emulsion, the demulsification was attributed to the collision mechanism proposed in our previous work. The findings may provide some criteria for selecting a proper oil phase in the emulsion liquid membrane (ELM) process and then offer an alternative approach to recycle the oil phase for continuous operation. This work may also be useful for emulsion stability against temperature cycling.