Attachment of solid particles to air bubbles in surfactant-free aqueous solutions
Attachment of solid particles to air bubbles in surfactant-free aqueous solutions
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DOI：
10.1016/j.ces.2004.04.001
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发表时间：
2004-07-01
影响因子：
4.7
通讯作者：
Rowson, NA
中科院分区：
文献类型：
--
作者：
Fan, X;Zhang, Z;Rowson, NA
本文通过研究微气泡的力学性质和氢氧化物在气泡表面的吸附，提出了一种解释固体颗粒在无表面活性剂的水溶液中附着于气泡的机理，其中固体和气泡具有相同的zeta电位符号。在哈里蒙德管中测量颗粒气泡附着。结果表明，在不含表面活性剂的去离子水中，纯化后的石英颗粒附着在气泡上，并随着水溶液pH的增加而增加。采用一种新型的微操作技术对水溶液中微气泡的力学性能进行了测量。结果表明，溶液中的微气泡具有伪弹性和球形特征。气泡的刚性随溶液pH值的增加而降低。当具有一定动能的运动粒子与无表面活性剂水溶液中的气泡碰撞时，气泡的变形随溶液的pH值而变化。在碱性溶液中，微气泡比酸性溶液中更柔软，变形更大。较软的气泡变形较大，导致固体颗粒与气泡接触面积较大，从而增加了附着，减少了回弹。在无表面活性剂的水溶液中，纯化的石英颗粒附着在气泡上可能是由于氢键的形成。气泡表面的OH-离子与dropSi-O-Sidrop中的硅原子和氧原子或与石英表面吸附的OH基形成氢键。(C) 2004 Elsevier Ltd.版权所有。
This paper presents a mechanism to explain the attachment of solid particles to air bubbles in surfactant-free aqueous solutions where both solids and air bubbles have the same sign of zeta potential via investigating the mechanical properties of micro air bubbles and the adsorption of hydroxide on air bubble surfaces. Particle-bubble attachment was measured in a Hallimond tube. The results indicate that purified quartz particles attached to air bubbles in surfactant-free deionised water, and the attachment increased with the pH of the aqueous solutions. The mechanical properties of micro air bubbles in aqueous solutions were measured using a novel micromanipulation technique. It was found that the micro air bubbles were pseudo-elastic and spherical in the solutions. The rigidity of the air bubbles decreased with increasing pH of the solutions. When a moving particle with a certain kinetic energy collided with an air bubble in a surfactant-free aqueous solution, the deformation of the air bubble varied with pH of the solution. In an alkaline solution, the micro air bubble was much softer and the deformation was larger than that in an acidic solution. The larger deformation of the softer air bubble resulted in a large contact area between the solid particle and the air bubble, therefore increasing the attachment, and reducing the rebound. The attachment of purified quartz particles to air bubbles in surfactant-free aqueous solutions was possibly due to hydrogen bond formation. The OH- ions on air bubble surfaces formed hydrogen bonds with silicon and oxygen atoms in dropSi-O-Sidrop or with the adsorbed OH group on quartz surfaces. (C) 2004 Elsevier Ltd. All rights reserved.