Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L7.
ACS Appl Mater Interfaces. 2012 Sep 26;4(9):4882-90. doi: 10.1021/am301215h. Epub 2012 Aug 16.
The ability of polystyrene nanoparticles to promote glass bead flotation was measured as a function of nanoparticle diameter. In all cases, smaller nanoparticles were more effective flotation collectors, even when compared at constant nanoparticle number concentration. The superior performance of smaller particles was explained by two mechanisms, acting in parallel. First, smaller particles deposit more quickly giving more effective flotation in those cases where nanoparticle deposition kinetics is rate determining; the sensitivity of nanoparticle deposition rates to particle size was illustrated by kinetic measurements on a quartz crystal microbalance silica surface. Second, for a given coverage of nanoparticles on the glass beads, the mean distance between neighboring nanoparticle surfaces decreases with particle diameter. We propose that the expansion of the three phase contact line, after initial bead/bubble attachment, is favored with decreasing the distance between neighboring hydrophobic particles.
我们研究了聚苯乙烯纳米粒子的直径对其促进玻璃珠浮选能力的影响。在所有情况下，较小的纳米粒子都是更有效的浮选捕集剂，即使在比较固定的纳米粒子数浓度时也是如此。较小颗粒表现出更好的性能，可以用两种协同作用的机制来解释。首先，较小的颗粒更快地沉积，从而在纳米颗粒沉积动力学起决定作用的情况下提供更有效的浮选；通过在石英晶体微天平硅表面上进行动力学测量，说明了纳米颗粒沉积速率对颗粒尺寸的敏感性。其次，对于在玻璃珠上给定的纳米粒子覆盖率，相邻纳米粒子表面之间的平均距离随粒径的减小而减小。我们提出，在初始珠/气泡附着后，三相接触线的扩展在相邻疏水性颗粒之间的距离减小的情况下更有利。
