Effect of energy density, pH and temperature on de-aggregation in nano-particles/water suspensions in high shear mixer
Effect of energy density, pH and temperature on de-aggregation in nano-particles/water suspensions in high shear mixer
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DOI：
10.1016/j.powtec.2007.01.006
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发表时间：
2007-04-30
影响因子：
5.2
通讯作者：
Utomo, A. T.
中科院分区：
文献类型：
--
作者：
Pacek, A. W.;Ding, P.;Utomo, A. T.
研究了能量输入、pH值和温度对亲水性二氧化硅粉末（粒径12 nm）在高剪切混合器中解聚的影响。已经发现，解聚集是两步过程。最初，在低能量输入下，非常大的聚集体（3-1000 μ m）逐渐破碎成具有单一模态尺寸分布的较小的二次聚集体（2-100 μ m）。随着能量输入的增加，初级聚集体（0.03-1 μ m）从次级聚集体中被侵蚀，导致双峰尺寸分布，第一模式在0.03 μ m和1 μ m之间，对应于初级聚集体，第二模式在2 μ m和100 μ m之间，对应于次级聚集体。在足够高的能量密度下，所有次级聚集体都破碎成初级聚集体，然而，即使在所采用的最高能量密度下，初级聚集体也不能破碎成单个纳米颗粒。温度和pH影响解聚动力学，但不改变解聚模式。在低温下增加pH加速解聚，而在高温下增加pH减慢解聚过程。(c)2007 Elsevier B. V.保留所有权利。
The effect of energy input, pH and temperature on de-aggregation of hydrophilic silicon dioxide powder (particle size 12 nm) in a high shear mixer was investigated. It has been found that de-aggregation is a two step process. Initially, at low energy input very large aggregates (3-1000 mu m) are gradually broken into smaller secondary aggregates (2-100 mu m) of a single modal size distributions. As the energy input increases primary aggregates (0.03-1 mu m) are eroded from the secondary aggregates leading to bimodal size distributions with the first mode between 0.03 mu m and 1 mu m corresponding to the primary aggregates and the second mode between 2 mu m and 100 mu m corresponding to the secondary aggregates. At a sufficiently high energy density all secondary aggregates are broken into primary aggregates however, even at the highest energy density employed the primary aggregates could not be broken into single nano-particles. The temperature and the pH affect deaggregation kinetics but do not alter de-aggregation pattern. Increasing pH at low temperature speeds up de-aggregation, whilst increasing pH at high temperature slows down de-aggregation process. (c) 2007 Elsevier B.V. All rights reserved.