On-Demand Separation of Oil-Water Mixtures
On-Demand Separation of Oil-Water Mixtures
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DOI：
10.1002/adma.201201364
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发表时间：
2012-07-17
影响因子：
29.4
通讯作者：
Tuteja, Anish
中科院分区：
文献类型：
--
作者：
Kwon, Gibum;Kota, Arun. K.;Tuteja, Anish
随着环境意识的提高和更严格的法规，非常需要从工业废水沃茨、污染的海洋沃茨和溢油混合物中分离油的新策略，特别是在表面活性剂存在下。基于膜的技术对于反乳化（即将乳液转化为自由油水混合物）来说很有吸引力，因为它们相对节能并且适用于广泛的工业过程。然而，破乳之后通常是重力驱动分离或撇渣以完全分离游离油-水混合物。[1]在这项工作中，我们首次展示了一种重力驱动的、基于膜的单一单元操作，用于分离所有类型的油水混合物，分离效率≥ 99.9%，其中可以按需触发分离，即在施加电场时。我们设想，我们的按需分离方法将是有用的，为广泛的应用，包括清理石油泄漏，燃料净化，一系列商业乳液的分离，废水处理，远程操作的油-水分离单元，微流体阀和芯片上的实验室device.A电场提供了一个简单的路线，用于调整极性（或导电）液体的润湿性。介电质上固着极性液滴响应于电场的宏观接触角的减小通常称为介电质上的电润湿（EWOD）。[2-4]EWOD由杨-李普曼方程表示为：[5]
With increasing environmental awareness and tighter regulations, novel strategies to separate oils from industrial wastewaters, polluted oceanic waters, and oil-spill mixtures, especially in the presence of surfactants, are highly desired. Membranebased technologies are attractive for demulsification, ie, the conversion of an emulsion to a free oil-water mixture, because they are relatively energy-efficient and applicable across a wide range of industrial processes. However, demulsification is typically followed by either gravity driven separation or skimming for the complete separation of free oil-water mixtures.[1] In this work, we demonstrate for the first time a gravity driven, membrane-based, single unit operation to separate all types of oil-water mixtures, with≥ 99.9% separation efficiency, where the separation can be triggered on-demand, ie, upon applying an electric field. We envision that our on-demand separation methodology will be useful for a wide range of applications including clean up of oil-spills, fuel-purification, separation of a range of commercial emulsions, waste-water treatment, remote operation of oil-water separation units, microfluidic valves and lab on a chip devices.An electric field provides a facile route for tuning the wettability of polar (or conducting) liquids. The decrease in the macroscopic contact angle for a sessile polar liquid droplet on a dielectric in response to an electric field is commonly known as electrowetting on a dielectric (EWOD).[2–4] EWOD is expressed by the Young-Lippmann equation as:[5]