The School of Mining Engineering, The University of NSW, Sydney, NSW 2052, Australia.
The School of Mining Engineering, The University of NSW, Sydney, NSW 2052, Australia.
Adv Colloid Interface Sci. 2015 Nov;225:114-33. doi: 10.1016/j.cis.2015.08.008. Epub 2015 Aug 22.
Particle-stabilised foams (or froths) form the fundamental framework of industrial processes like froth flotation. This review provides an overview of the effects of particles on bubble surfaces. The characteristics of the particles have a profound effect on the stability of the bubbles although the stabilisation mechanisms may differ. It is well known that layers of particles may provide a steric barrier between two interfaces, which prevents the coalescence of bubbles. Although perhaps considered of lesser importance, it is interesting to note that particles may affect the bubble surface and momentarily suppress coalescence despite being absent from the film separating two bubbles. Foams are at best metastable and coalescence occurs to achieve a state of minimum energy. Despite this, particles have been reported to stabilise bubbles for significant periods of time. Bubble coalescence is accompanied by a release of energy triggered by the sudden change in surface area. This produces a distinctive oscillation of the bubble surface, which may be influenced by the presence of incompressible particles yielding unique surface properties. A survey of the literature shows that the properties of these composite materials are greatly affected by the physicochemical characteristics of the particles such as hydrophobicity and size. The intense energy released during the coalescence of bubbles may be sufficient to expel particles from the bubble surface. It is noted that the detachment of particles may preferentially occur from specific locations on the bubble surface. Examination of the research accounts again reveals that the properties of the particles may affect their detachment upon the oscillation of the bubble surface. However, it is believed that most parameters affecting the detachment of particles are in fact modifying the dynamics of the three-phase line of contact. Both the oscillation of a coalescing bubble and the resulting detachment of particles are highly dynamic processes. They would greatly benefit from computer simulation studies.
颗粒稳定的泡沫（或泡沫）构成了浮选等工业过程的基本框架。本综述概述了颗粒对气泡表面的影响。尽管稳定化机制可能不同，但颗粒的特性对气泡的稳定性有深远的影响。众所周知，颗粒层可能在两个界面之间提供一个空间障碍，从而阻止气泡的聚并。尽管可能被认为不太重要，但有趣的是，尽管颗粒不在分离两个气泡的薄膜中，但它们可能会影响气泡表面并暂时抑制聚并。泡沫充其量是亚稳的，聚并发生是为了达到能量最小的状态。尽管如此，据报道，颗粒可以稳定气泡很长一段时间。气泡聚并伴随着能量的释放，这是由表面积的突然变化触发的。这会导致气泡表面产生独特的振荡，而这可能会受到不可压缩颗粒的存在的影响，从而产生独特的表面特性。文献综述表明，这些复合材料的性质受颗粒的物理化学特性如疏水性和尺寸的强烈影响。气泡聚并时释放的能量可能足以将颗粒从气泡表面驱逐出去。值得注意的是，颗粒的脱附可能优先发生在气泡表面的特定位置。再次检查研究报告还表明，颗粒的性质可能会影响它们在气泡表面振荡时的脱附。然而，人们认为，影响颗粒脱附的大多数参数实际上是在改变三相接触线的动力学。聚并气泡的振荡和由此产生的颗粒脱附都是高度动态的过程。它们将从计算机模拟研究中受益匪浅。
