Floating microplastics (MPs) have recently become a major concern in marine pollution; however, current filter‐based technology is hardly effective for directly removing such MPs from the water surface because of specific mesh size and clogging issues. This paper introduces a new skimming concept for removing floating MPs utilizing capillary force mediated by the elevation of a hydrophilic ratchet at the air−water interface. MPs floating near the ratchet surface are spontaneously forced toward the ratchet with a concave water meniscus, driven by the Cheerios effect. The MPs can then be skimmed and temporarily held by the deforming concave water meniscus as the ratchet rises. Here, it is found that the stability of the water bridge plays a crucial role in skimming success because it provides capillary adhesion between the MP and the ratchet. The proposed capillary skimming method is observed to be effective across nearly all types of floating MPs, ranging in size from 1 to 4 mm, and with densities varying from 0.02 to 0.97 g cm−3, which is also demonstrated by a prototype of marine robot cleaner.

中文翻译：

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通过水桥棘轮对漂浮的微塑料进行毛细管撇去


漂浮的微塑料 （MP） 最近已成为海洋污染的主要问题;然而，由于特定的网孔尺寸和堵塞问题，目前基于过滤器的技术几乎无法有效地从水面上直接去除此类 MP。本文介绍了一种新的撇脂概念，用于利用由气-水界面处亲水棘轮的升高介导的毛细管力去除浮动 MP。漂浮在棘轮表面附近的 MP 在 Cheerios 效应的驱动下，通过凹水弯月面自发地被迫向棘轮移动。然后，当棘轮上升时，MP 可以被变形的凹水弯月面撇去并暂时固定。在这里，发现水桥的稳定性对撇脂的成功起着至关重要的作用，因为它在 MP 和棘轮之间提供了毛细管粘附。据观察，所提出的毛细管撇去方法对几乎所有类型的浮动 MP 都有效，尺寸从 1 到 4 毫米不等，密度从 0.02 到 0.97 g cm-3 不等，这也被船用机器人清洁器的原型所证明。