Delineating the Relationship between Nanoparticle Attachment Efficiency and Fluid Flow Velocity
Delineating the Relationship between Nanoparticle Attachment Efficiency and Fluid Flow Velocity
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DOI：
10.1021/acs.est.0c02669
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发表时间：
2020-11-03
影响因子：
11.4
通讯作者：
Fortner, John D.
中科院分区：
文献类型：
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作者：
Kim, Changwoo;Pennell, Kurt D.;Fortner, John D.
从根本上描述纳米颗粒（NP）在地下传输的能力支撑着环境风险评估和成功的材料应用，包括先进的修复和传感技术。尽管取得了相当大的进展，我们对NP沉积行为的理解仍然是不完整的，因为关于流体流速对附着效率的影响有相互矛盾的报道。为了直接解决这个问题，更准确地描述NP附着行为，我们开发了一种新的协议，使用石英晶体微天平与耗散监测（QCM-D）分离和单独观察沉积机制（扩散和沉降），提供原位，实时信息颗粒扩散（从散装液体到固体表面）。通过这种技术，我们已经证实，通过扩散的NP的接近速度增加（0.8-6.7 μ m/s）与增加流速（6.1-106.0 μ m/s），导致增加NP动能，从而影响沉积过程。此外，在存在与有机表面涂层相关的二次能量最小值的情况下，二次最小沉积随流速减小，一次最小沉积随流速增大。在初级最小值处沉积的NP对流体动力学能量（包括分离相关能量）具有相对更大的抵抗力，导致观察到的附着效率增加。总之，这项工作不仅描述了一种新的方法来描绘和量化物理过程的基础颗粒的行为，但也提供了直接测量的关键因素定义的流速和颗粒附着的关系（S）。这种见解是有价值的下一代命运和运输模型的准确性，特别是在不利的附着制度，这是一个当前和关键的需要地下材料的应用和含义范例。
The ability to fundamentally describe nanoparticle (NP) transport in the subsurface underpins environmental risk assessment and successful material applications, including advanced remediation and sensing technologies. Despite considerable progress, our understanding of NP deposition behavior remains incomplete as there are conflicting reports regarding the effect of fluid flow velocity on attachment efficiency. To directly address this and more accurately describe NP attachment behavior, we have developed a novel protocol using a quartz crystal microbalance with dissipation monitoring (QCM-D) to separate and individually observe deposition mechanisms (diffusion and sedimentation), providing in situ, realtime information about particle diffusion (from the bulk liquid to solid surface). Through this technique, we have verified that the approaching velocity of NPs via diffusion increases (0.8-6.7 mu m/s) with increasing flow velocity (6.1-106.0 mu m/s), leading to an increased NP kinetic energy, thus affecting deposition processes. Further, in the presence of a secondary energy minimum associated with organic surface coatings, secondary minimum deposition decreases and primary minimum deposition increases with the flow velocity. NPs deposited at the primary minimum are relatively more resistant to hydrodynamic energies (including detachment associated energies), resulting in an increase of observed attachment efficiencies. Taken together, this work not only describes a novel method to delineate and quantify physical processes underpinning particle behavior but also provides direct measurements regarding key factors defining the relationship(s) of flow velocity and particle attachment. Such insight is valuable for next-generation fate and transport model accuracy, especially under unfavorable attachment regimes, which is a current and critical need for subsurface material applications and implication paradigms.