Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2G6, Canada.
Langmuir. 2010 Mar 2;26(5):3050-7. doi: 10.1021/la9029563.
In our previous study, ethylcellulose (EC), an effective, nontoxic, and biodegradable natural polymer, was found effective in dewatering water-in-diluted bitumen emulsions. In this study, the demulsification mechanism of water-in-diluted bitumen emulsions by EC is investigated. In situ experiments using a micropipet apparatus provided direct evidence on both flocculation and coalescence of water droplets in diluted bitumen by EC. The addition of EC was found to decrease naphtha-diluted bitumen-water interfacial tension significantly. At the molecular level, AFM imaging revealed disruption of the continuous interfacial films formed from surface-active components of bitumen by EC. Our study clearly indicates that the demulsification by EC is through both flocculation and coalescence of water droplets, attained by competitive adsorption of EC at the oil-water interface and disruption of the original protective interfacial films formed from the surface-active components of bitumen.
在我们之前的研究中，乙基纤维素（EC）作为一种有效、无毒且可生物降解的天然聚合物，被发现能够有效脱水水包油型稀释沥青乳液。在本研究中，我们研究了 EC 使水包油型稀释沥青乳液破乳的机理。使用微量进样器装置进行的原位实验提供了直接证据，表明 EC 能够使稀释沥青中的水滴絮凝和聚结。添加 EC 可显著降低石脑油稀释沥青-水界面张力。在分子水平上，原子力显微镜成像显示 EC 破坏了由沥青表面活性成分形成的连续界面膜。我们的研究清楚地表明，EC 的破乳作用是通过 EC 在油水界面的竞争吸附和破坏由沥青表面活性成分形成的原始保护性界面膜，使水滴絮凝和聚结来实现的。
