Release of colloids from primary minimum contact under unfavorable conditions by perturbations in ionic strength and flow rate.
Release of colloids from primary minimum contact under unfavorable conditions by perturbations in ionic strength and flow rate.
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DOI：
10.1021/es502503y
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发表时间：
2014-07
影响因子：
11.4
通讯作者：
E. Pazmiño;J. Trauscht;W. Johnson
中科院分区：
文献类型：
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作者：
E. Pazmiño;J. Trauscht;W. Johnson
对离子强度和流动扰动对胶体从表面释放的响应进行了力学模拟。然而，这些模型没有解决胶体附着发生的机制，至少在大量胶体收集器排斥(不利条件)的情况下是这样，这是一种普遍的环境条件。我们测试了一个预测在不利条件下胶体附着的机械模型是否也预测了胶体在离子强度(IS)降低和流体速度增加(被认为是环境胶体动员的普遍条件)时的释放。该模型在平均场胶体-收集器相互作用中进行交易，以离散表示表面的非均质性，这同时解释了吸引和排斥相互作用的组合，并导致附着的胶体群体(与表面的主要最小接触)具有吸引强度的分布。该模型通过考虑空间相互作用来调节平衡分离距离。通过使用相同的模型参数来定量预测不利条件下的附着，模拟了胶体(三种尺寸)从初级最小附着对扰动的响应，定性地与实验结果相吻合，表明附着和脱离都是力学模拟的。
Colloid release from surfaces in response to ionic strength and flow perturbations has been mechanistically simulated. However, these models do not address the mechanism by which colloid attachment occurs, at least in the presence of bulk colloid-collector repulsion (unfavorable conditions), which is a prevalent environmental condition. We test whether a mechanistic model that predicts colloid attachment under unfavorable conditions also predicts colloid release in response to reduced ionic strength (IS) and increased fluid velocity (conditions thought prevalent for mobilization of environmental colloids). The model trades in mean-field colloid-collector interaction for discrete representation of surface heterogeneity, which accounts for a combination of attractive and repulsive interactions simultaneously, and results in an attached colloid population (in primary minimum contact with the surface) having a distribution of strengths of attraction. The model moderates equilibrium separation distance by inclusion of steric interactions. By using the same model parameters to quantitatively predict attachment under unfavorable conditions, simulated release of colloids (for all three sizes) from primary minimum attachment in response to perturbations qualitatively matched experimental results, demonstrating that both attachment and detachment were mechanistically simulated.