Complementary colloid and collector nanoscale heterogeneity explains microparticle retention under unfavorable conditions,Environmental Science: Nano

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Complementary colloid and collector nanoscale heterogeneity explains microparticle retention under unfavorable conditions
Environmental Science: Nano ( IF 5.8 ) Pub Date : 2020-11-19 , DOI: 10.1039/d0en00815j
Cesar A. Ron _{1,

2,

3,

4} , William P. Johnson _{1,

2,

3,

4}

Affiliation

Nano- and micro-scale particle (colloid) retention in environmental granular media is greatly reduced when the profile of colloid–grain surface interactions as a function of their separation distance includes a repulsive barrier. Under such unfavorable attachment conditions, typical of environmental settings, simulation of colloid retention predicts zero retention unless nanoscale heterogeneity is included to locally reduce or eliminate the repulsive barrier and allow attachment to the grain (collector). Simulations previously incorporated nanoscale heterogeneity on either the collector or the colloid, whereas complementary contributions of collector and colloid nanoscale heterogeneity have not been previously examined to the knowledge of the authors. The sizes and surface coverages of nanoscale heterogeneity on colloid (carboxylate modified polystyrene latex, CML) and collector (silica) surfaces that act complementarily to explain experimentally-observed retention in impinging jet experiments was herein examined for colloid sizes ranging from 0.11 to 6.8 μm at pH ranging 6.7 to 8.0 and ionic strength (IS) ranging 6.0 to 20.0 mM. We demonstrate that complementary contributions of power law size-distributed nanoscale heterogeneity; 25 to 90 nm radii on the collector; 5 to 60 nm radii on the colloids, captured the observed retention across the entire colloid size range (including previously uncaptured retention of >2.0 μm CML) for all pH and IS conditions. This approach greatly reduced the required maximum size of heterodomains (nanoscale attractive zones) from 320 nm radii required when heterogeneity was incorporated solely on either the collector or colloid surface and constrains the scales of spectroscopically-observed surface heterogeneity relevant to colloid retention.

中文翻译：

互补的胶体和捕集剂纳米级异质性解释了在不利条件下微粒的保留

当胶体-颗粒表面相互作用的轮廓（作为它们的分离距离的函数）包括排斥屏障时，纳米和微米级颗粒（胶体）在环境颗粒介质中的保留会大大降低。在这种不利的附着条件下（典型的环境设置），胶体保留的模拟预测保留为零，除非包括纳米级异质性以局部减少或消除排斥性障碍并允许附着至谷物（收集器）。模拟先前在收集器或胶体上并入了纳米级异质性，而收集器和胶体纳米级异质性的互补作用先前尚未被作者了解。本文研究了胶体（羧酸改性聚苯乙烯胶乳，CML）和收集器（二氧化硅）表面上的纳米级异质性的尺寸和表面覆盖，这些胶体可互补地解释在喷射实验中实验观察到的保留，其胶体尺寸范围为0.11至6.8μm。 pH范围为6.7至8.0，离子强度（IS）为6.0至20.0 mM。我们证明幂律大小分布的纳米异质性的互补贡献；收集器上的半径为25至90 nm；在所有pH和IS条件下，胶体上半径为5至60 nm的半径在整个胶体尺寸范围内捕获到的保留值（包括先前未捕获的> 2.0μmCML保留值）。

更新日期：2020-12-09

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