Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Department of Systems Design Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
Water Res. 2017 May 1;114:286-295. doi: 10.1016/j.watres.2017.02.010. Epub 2017 Feb 7.
Although it is widely believed that media/collector roughness can enhance particle deposition on surfaces, this effect has not been consistently observed nor systematically described. Here, column tests were conducted to: 1) evaluate media roughness impacts on particle deposition in the presence of an energy barrier (i.e., at low ionic strength conditions), and 2) describe the concurrent impacts of collector surface roughness and suspension fluid ionic strength on particle deposition in packed beds. This work presents a first, systematic demonstration that media/collector surface roughness consistently influences particle deposition in a non-linear, non-monotonic manner, irrespective of the presence of an energy barrier. Notably, ionic strength-associated changes in DLVO interaction energy could not solely explain observed differences in particle deposition associated with collector surface roughness. Particle-to-roughness element and particle-to-smooth/bottom surface interactions contributed to a critical roughness size associated with a minimum DLVO interaction energy; however, that critical size is not necessarily the same as the critical size associated with minimal particle deposition rates. Surface roughness and ionic strength concurrently affected particle deposition in a manner that is not simply additive; rather, particle deposition rates were highly correlated with inverse Debye-Hückel length (i.e., ln [κ]) using second-order polynomial functions. Notably, the secondary energy minimum alone appears inadequate for explaining the observed particle deposition behavior. These relationships may provide insight for further development of physico-chemical filtration models for describing particle deposition on surfaces.
尽管普遍认为介质/集尘器的粗糙度可以增强颗粒在表面上的沉积，但这种效果并未得到一致观察或系统描述。在这里，进行了柱测试，以：1）评估在存在能量障碍（即低离子强度条件下）时介质粗糙度对颗粒沉积的影响，以及 2）描述集尘器表面粗糙度和悬浮液离子强度对填充床中颗粒沉积的并发影响。这项工作首次系统地证明，无论是否存在能量障碍，介质/集尘器表面粗糙度始终以非线性、非单调的方式影响颗粒沉积。值得注意的是，与 DLVO 相互作用能相关的离子强度变化不能单独解释与集尘器表面粗糙度相关的颗粒沉积的差异。颗粒与粗糙元素以及颗粒与光滑/底部表面之间的相互作用导致与 DLVO 相互作用能相关的最小粗糙度尺寸存在一个临界值；然而，该临界尺寸不一定与最小颗粒沉积速率相关的临界尺寸相同。表面粗糙度和离子强度以一种不是简单相加的方式同时影响颗粒沉积；相反，使用二次多项式函数，颗粒沉积速率与逆德拜-休克尔长度（即 ln [κ]）高度相关。值得注意的是，单独的二次能量最小值似乎不足以解释观察到的颗粒沉积行为。这些关系可能为进一步开发描述表面颗粒沉积的物理化学过滤模型提供了启示。
