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Theory-Guided Targeted Delivery of Nanoparticles in Advective Environmental Porous Media
Environmental Science & Technology Letters ( IF 8.9 ) Pub Date : 2019-09-05 , DOI: 10.1021/acs.estlett.9b00474
Cesar A. Ron 1 , Mei Dong 2 , Karen L. Wooley 2 , William P. Johnson 1
Affiliation  

For near-neutrally buoyant colloids, retention on surfaces is dramatically reduced for radii in the range from approximately 100 nm to 1 μm (i.e., n−μ transition) under unfavorable conditions (energy barrier present). Given that unfavorable conditions are predominant in the environment, the above-described characteristic is underutilized in strategies for targeted delivery of nano- to microscale particles (colloids) in porous media. We present herein, a strategy that involves tuning colloid size within the n−μ transition range to minimize retention in non-target porous media, followed by solution chemistry-triggered disaggregation to yield nanoscale colloids and promote retention in target porous media. Toward this purpose we examined the transport properties of aggregated and disaggregated carboxylate-modified latex (CML) nanospheres (55 nm radius) and novel shell cross-linked knedel-like (SCK) nanoparticles (10–50 nm radius). Colloid retention was measured on soda-lime glass (silica) in an impinging jet system representing upstream sides of porous media grains. Continuum scale attachment rate coefficients (kf) were determined from the experimental colloid retention and were then utilized to predict the distribution of retained colloids from source in target porous media at field scales. These experiments and simulations demonstrate the viability of size-tuning colloids to the n−μ transition range in order to facilitate their transport through non-target porous media. Disaggregation triggered by, for example, reduced ionic strength achieved by preferential advection of colloids, was demonstrated to greatly increase retention in target porous media, with an expectation of increased surface area and enhanced reactivity.

中文翻译:

理论指导的纳米粒子在环境渗透性多孔介质中的靶向递送

对于近中性浮力胶体,在不利条件下(存在能垒),半径在大约100 nm至1μm(即n-μ跃迁)范围内时,表面保留率显着降低。假定不利的条件在环境中占主导地位,上述特性在多孔介质中靶向输送纳米级至微米级颗粒(胶体)的策略中未得到充分利用。我们在本文中提出了一种策略,该策略涉及在n-μ过渡范围内调整胶体大小以最小化在非目标多孔介质中的保留,然后进行溶液化学触发的分解以产生纳米级胶体并促进在目标多孔介质中的保留。为了达到这个目的,我们检查了聚集和解聚的羧酸盐修饰的乳胶(CML)纳米球(半径为55 nm)和新型壳交联的Knedel状(SCK)纳米颗粒(半径为10-50 nm)的传输特性。在表示多孔介质颗粒上游侧的撞击式喷射系统中,在钠钙玻璃(二氧化硅)上测量了胶体保留率。连续标度附着率系数(k f)是根据实验胶体保留率确定的,然后用于在田间尺度上预测来源的保留胶体在目标多孔介质中的分布。这些实验和模拟证明了尺寸调节胶体在n-μ过渡范围内的可行性,以促进它们通过非目标多孔介质的传输。已证明,例如,由于胶体优先平流而降低的离子强度会触发分解,从而大大提高了在目标多孔介质中的保留率,并有望增加表面积并增强反应性。
更新日期:2019-09-05
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