当前位置：
X-MOL 学术
›
Soft Matter
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Size dependent droplet interfacial tension and surfactant transport in liquid-liquid systems, with applications in shipboard oily bilgewater emulsions.
Soft Matter ( IF 2.9 ) Pub Date : 2020-03-03 , DOI: 10.1039/c9sm01892a Yun Chen 1 , Cari S Dutcher
Soft Matter ( IF 2.9 ) Pub Date : 2020-03-03 , DOI: 10.1039/c9sm01892a Yun Chen 1 , Cari S Dutcher
Affiliation
|
Many liquid-liquid emulsions, including shipboard oily bilgewater (oil-in-water) and water entrained in diesel fuels (water-in-oil), are chemically stabilized by surfactants and additives and require treatment to destabilize and separate. The interfacial tension (IFT) of surfactant-laden interfaces between the continuous and dispersed phase, as well as the size of the dispersed droplets, are significant factors in determining emulsion stability. In particular, the timescale associated with a dynamic change in IFT due to surfactant transport is indicative of how fast the emulsion will stabilize. In the present work, the dynamic IFT of droplets at micro-scale (∼80 μm) and milli-scale (∼2 mm) is measured with simulated bilgewater with soluble surfactant systems. It is found that the IFT of micro-scale droplets decays faster than that of the milli-scale droplets due to smaller diffusion boundary layer thickness. The change in IFT was also studied for water-soluble surfactants added into the dispersed phase and continuous phase for both milli- and micro-scaled droplets. The results show that the IFT of micro-scale droplets decreases to the equilibrium value faster when the surfactant is in outer phase than in the inner phase, while the IFT does not change significantly for the milli-scale droplets. The observations are explained by the change in diffusion limited to kinetic limited surfactant transport. Finally, the surfactant diffusivities, adsorption and desorption rate constants are calculated using Langmuir's equation. The results presented here provide insight into the fundamental mechanism of the surfactant transport and helps improve mitigation strategies of oil-water emulsions.
中文翻译：
液-液系统中液滴尺寸取决于液滴界面张力和表面活性剂的运输，并应用于船用油性舱底水乳液中。
许多液-液乳液，包括船用油性舱底水（水包油）和夹带在柴油燃料中的水（油包水），都被表面活性剂和添加剂化学稳定，需要进行处理以使其不稳定和分离。连续相和分散相之间的表面活性剂负载界面的界面张力（IFT），以及分散液滴的大小，是决定乳液稳定性的重要因素。特别地，与由于表面活性剂运输引起的IFT的动态变化相关的时间标度表明乳液将稳定多快。在目前的工作中，使用模拟的舱底水和可溶性表面活性剂系统测量了微尺度（约80μm）和毫尺度（约2 mm）的液滴动态IFT。已经发现，由于较小的扩散边界层厚度，微尺度液滴的IFT的衰减比毫微尺度液滴的IFT的衰减更快。还研究了添加到分散相和连续相中的水溶性表面活性剂（对于毫微级和微米级液滴）的IFT变化。结果表明，当表面活性剂在外相中时，微尺度液滴的IFT更快地下降到平衡值，而在内相中，而毫微滴的IFT没有明显变化。观察结果由扩散变化限制为动力学受限的表面活性剂传输来解释。最后，使用朗缪尔方程计算表面活性剂的扩散率，吸附和解吸速率常数。
更新日期：2020-03-26
中文翻译：
液-液系统中液滴尺寸取决于液滴界面张力和表面活性剂的运输，并应用于船用油性舱底水乳液中。
许多液-液乳液，包括船用油性舱底水（水包油）和夹带在柴油燃料中的水（油包水），都被表面活性剂和添加剂化学稳定，需要进行处理以使其不稳定和分离。连续相和分散相之间的表面活性剂负载界面的界面张力（IFT），以及分散液滴的大小，是决定乳液稳定性的重要因素。特别地，与由于表面活性剂运输引起的IFT的动态变化相关的时间标度表明乳液将稳定多快。在目前的工作中，使用模拟的舱底水和可溶性表面活性剂系统测量了微尺度（约80μm）和毫尺度（约2 mm）的液滴动态IFT。已经发现，由于较小的扩散边界层厚度，微尺度液滴的IFT的衰减比毫微尺度液滴的IFT的衰减更快。还研究了添加到分散相和连续相中的水溶性表面活性剂（对于毫微级和微米级液滴）的IFT变化。结果表明，当表面活性剂在外相中时，微尺度液滴的IFT更快地下降到平衡值，而在内相中，而毫微滴的IFT没有明显变化。观察结果由扩散变化限制为动力学受限的表面活性剂传输来解释。最后，使用朗缪尔方程计算表面活性剂的扩散率，吸附和解吸速率常数。
京公网安备 11010802027423号