The Application of Liquid Marbles in the Removal of Pollutants and Contaminants from the Environment and Within Industrial Processes

这项博士研究将集中在液体弹珠上，更具体地说，是包裹液滴的颗粒决定其能力和大小的方式。它将试图回答这个问题：如何使用液体弹珠来去除液体中的污染物？最终目标是形成一种液体大理石，能够从水和水中去除塑料颗粒。将使用几个目标，第一个是覆盖液滴的颗粒的形态如何影响大理石的最大尺寸。其次，所使用的颗粒如何改变水蒸气离开液体大理石的速度。在最终设计出去除塑料的液体大理石之前，这两个问题都需要得到回答。塑料污染在世界上所有的海洋中都很普遍，使用过滤来去除纳米颗粒是不可能的。因此，解决这个问题的方法变得更加必要--液体弹珠可以做到这一点。液体大理石的现象在过去20年里引起了人们的极大兴趣，被描述为完全不润湿的软固体，与固体表面的粘附性降低。这发生在添加覆盖液滴的疏水颗粒时，防止内部液体与外部表面之间的接触。许多粉末和液体的组合是可能的，允许在不同的环境中使用。我将把这个项目分成几个领域。我的初步研究将考察水液体大理石的临界尺寸如何随着不同的涂层而变化。现有的关于液体弹珠的文献着眼于5-20uL的尺寸范围，很少有更大的弹球形成，1000uL。关于这种关系的描述很少，目前的文献主要集中在液体大理石作为微型反应堆。研究表明，颗粒的大小和结构对液态大理石的寿命有重要影响，但对大理石的最大尺寸没有影响。使用体积较大的液体大理石可以捕获更多的塑料，这意味着从过程中移除大理石的频率将会降低。第二个目标是研究大理石的水蒸气损失率及其对颗粒的依赖。这一点很重要，原因有两个。首先，如果大理石蒸发得太快，它将无法保持其大小，因此提取的污染物较少。其次，由于两种流体之间的表面张力梯度引起的Marangoni效应，含有酒精水溶液的液体弹珠可以在水中自动推进。利用这一运动将有助于快速定位水滴。液体周围颗粒的排列将根据所用颗粒的不同而变化，这意味着颗粒的紧密堆积程度不同，它们之间的间隙越大，意味着蒸发速度越快。了解这一行为将有助于管理蒸气损失。此外，可以将液滴包裹成两种粒子类型，这样的涂层可以增加大理石的方向性和控制性。然后我将研究微塑料捕获的机理。这个项目背后的主要驱动力是微塑料在两者接触时从水到油的移动方式。这允许塑料从水中分离，而不需要过多的能量输入。挑战在于能够轻松地去除油塑溶液，而液体弹珠将是有益的。这一部分将是最耗时的，因为要考虑很多因素。对于主要的问题，大理石是在塑料吸收之前形成还是在塑料吸收之后形成更好？将选择用于去除塑料的最佳液体类型和要去除的塑料类型；目标可能是最丰富的。一旦确定，就很容易从以前的研究中选择要包裹的颗粒。剩下的需要考虑的因素是涂层将如何阻止塑料进入大理石。

This doctoral research will focus on liquid marbles and more specifically the way in which the particles coating the droplet dictate its abilities and size. It will try and answer the question; how can liquid marbles be used to remove pollutants from liquids? With the end objective being the formation of a liquid marble capable of removing plastic particles from water and. Several aims will be used, the first is how the morphology of the particles coating the droplet impacts the maximum marble size. Secondly, how do the particles used alter the rate at which vapour leaves the liquid marble. Both need to be answered before the final design of a plastic removal liquid marble can be achieved.Plastic pollution is prevalent in all of the world's oceans and the use of filtration to remove nano particles is not possible. Therefore, a method to tackle this issue is becoming more necessary - liquid marbles could do this. The phenomena of liquid marbles have generated much interest in the past 20 years and are described as a completely non-wetting soft solid, with reduced adhesion to a solid surface. This occurs upon addition of hydrophobic particles which coat the liquid droplet, preventing contact between the internal liquid and the external surface. Numerous combinations of powders and liquids is possible, allowing for use in different environments.I will be breaking this project into several areas. My preliminary research will examine how the critical size of a water liquid marble changes with different coatings. The existing literature on liquid marbles looks at a size range of 5-20uL with few instances of larger marbles, 1000uL, being formed. Little description about this relationship exists, with current literature focusing on liquid marbles as miniaturised reactors. It has been shown that the size and structure of particles have a key role in the lifetime of a liquid marble, but not on maximum marble size. Using a liquid marble with a large volume will allow for the capture of more plastic, meaning removal of the marble from the process will be less frequent. The second aim looks at the rate of vapour loss from the marble and its dependence on the particle. This is important for two reasons. Firstly, if a marble evaporates too quickly it will not retain its size, therefore, less pollutants are extracted. Secondly, liquid marbles containing an aqueous alcohol solution can self-propel on water due to the Marangoni effect, caused by a surface tension gradient between the two fluids. Harnessing this motion will be useful in positioning droplets quickly. The arrangement of the particles around the liquid will change based on the particles used, this means how closely packed the particles will differ, larger gaps between them should mean a higher evaporation rate. Understanding this behaviour will allow for management of vapour loss. Moreover, it is possible to coat the droplet in two particle types, coating in this manner could add directionality and control of the marbles.I will then look into the mechanism of microplastic capture. The main driving force behind this project is the way in which microplastics move from water to oil when the two are in contact. This allows for the separation of plastic from water without requiring excessive energy input. The challenge lies in being able to easily remove the oil-plastic solution and is where liquid marbles will be beneficial. This section will be the most time intensive as lots of factors are to be considered. With the main question, is it better to form the marble before or after plastic uptake? The best type of liquid for plastic removal will be selected and the types of plastics to remove; it may be beneficial to target the most abundant. Once identified it will be easy to select the particles to coat with from previous investigations. The remaining factor that needs to be considered is then how the coating will hinder the movement of plastic into the marble.