Bazyar Hanieh, van de Beek Noor, Lammertink Rob G H
Soft Matter, Fluidics and Interfaces, MESA+Institute for Nanotechnology , University of Twente , P.O. Box 217, 7500 AE Enschede , The Netherlands.
Wetsus, European Centre of Excellence for Sustainable Water Technology , P.O. Box 1113, 8900 CC Leeuwarden , The Netherlands.
Langmuir. 2019 Jul 23;35(29):9513-9520. doi: 10.1021/acs.langmuir.9b01055. Epub 2019 Jul 10.
Liquid-infused membranes have been introduced to membrane technology recently. The infusion liquid can be expelled, opening the pore, in response to an immiscible feed liquid pressure. In the open state, the pore wall is still covered with the infusion liquid forming the so-called liquid-lined pores. Liquid lining is expected to give anti-fouling properties to these membranes. The pressure-responsive pores can be used for efficient sorting of fluids from a mixture based on interfacial tension. For example, in a two-phase mixture of immiscible liquids, the required liquid entry pressure is different for the constituent liquids. Here, we investigate the capability of liquid-infused membranes for selective permeation of the dispersed phase, that is, oil from an oil-in-water (O/W) emulsion. The separation experiments are conducted in a dead-end pressure-controlled filtration cell using liquid-infused and non-infused membranes. In order to permeate the dispersed phase, oil droplets should come in contact with the membrane surface which is accomplished here by gravity-driven creaming. Our results reveal that by setting the feed pressure between the entry pressure of oil and that of the surfactant solution, oil can be successfully permeated. For high concentrations of surfactants, water also permeated partly. The amount of water permeated through liquid-infused membranes is lower than that through non-infused membranes, caused by the corresponding interfacial tensions. The results suggest that the presence of the infusion liquid in the membrane gives rise to the formation of three-phase interfaces in the pore, namely, the interface between surfactant solution-oil (γ) and that between oil-infusion liquid (γ). Based on the interfacial energy contributions, the additional interface between oil and the infusion liquid gives rise to an increase in the liquid entry pressure for the surfactant solution based on the combined interfacial tension (γ + γ) leading to less water permeation.
液体注入膜是最近引入膜技术的。注入的液体可响应不混溶的进料液体压力而排出，从而打开孔隙。在开放状态下，孔壁仍覆盖着注入液体，形成所谓的液衬孔。预计液衬会赋予这些膜抗污染性能。压力响应孔可用于基于界面张力从混合物中高效分离流体。例如，在不混溶液体的两相混合物中，组成液体所需的液体进入压力不同。在此，我们研究了液体注入膜对分散相（即水包油（O/W）乳液中的油）的选择性渗透能力。分离实验在死端压力控制过滤池中使用液体注入膜和未注入液体的膜进行。为了使分散相渗透，油滴应与膜表面接触，这里通过重力驱动的乳析来实现。我们的结果表明，通过将进料压力设置在油的进入压力和表面活性剂溶液的进入压力之间，油可以成功渗透。对于高浓度的表面活性剂，水也会部分渗透。通过液体注入膜渗透的水量低于通过未注入液体的膜渗透的水量，这是由相应的界面张力引起的。结果表明，膜中注入液体的存在导致孔隙中形成三相界面，即表面活性剂溶液 - 油之间的界面（γ）和油 - 注入液体之间的界面（γ）。基于界面能贡献，油和注入液体之间的额外界面导致基于组合界面张力（γ + γ）的表面活性剂溶液的液体进入压力增加，从而导致更少的水渗透。
