Direct Measurements of the Forces between Silver and Mica in Humic Substance-Rich Solutions
Direct Measurements of the Forces between Silver and Mica in Humic Substance-Rich Solutions
复制标题
直接测量富含腐殖质溶液中银和云母之间的力
DOI：
10.1021/acs.est.0c05334
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发表时间：
2020
影响因子：
11.4
通讯作者：
Morales, Verónica L.
中科院分区：
文献类型：
--
作者：
Patiño, Janis E.;Kuhl, Tonya L.;Morales, Verónica L.
工程纳米颗粒从流动悬浮液沉积到多孔介质上对于土壤和地下水质量非常重要。沉积机制由颗粒和收集器之间的相互作用力控制。我们使用表面力装置直接测量，研究了与农业土壤相关的解决方案中银和云母表面（代表纳米银和沙粒）之间相反力的起源和大小。使用不同浓度的 NaNO3、Ca(NO3)2 和腐殖酸 (HA) 溶液来区分各个贡献力并量化表面特性。测量的银-水-云母的 Hamaker 常数与 Lifshitz 理论一致。我们的结果表明，HA 形成吸附表面层，但其电荷、厚度、压缩性和质量在云母上明显大于银。 Ca2+ 主要减少了每个表面上最初吸附的 HA 层特性之间的差异，使它们更加相似。力-距离分布表明，当银-云母系统暴露于HA时，渗透力-空间力、静电力和范德华力占主导地位。软粒子理论被认为不适合该系统。利用 Derjaguin 近似将力测量结果转化为纳米银颗粒和云母收集器之间的相互作用能。我们根据测量的表面特性提出了附着效率估计，这表明当纳米银应用于离子强度适中、富含透明质酸的农业土壤时，颗粒具有较高的迁移率。
Deposition of engineered nanoparticles onto porous media from flowing suspensions is important for soil and groundwater quality. The deposition mechanism is controlled by interaction forces between particles and collectors. We investigated the origin and magnitude of opposing forces between silver and mica surfaces (representing nanosilver and sand grains) in solutions relevant to agricultural soils with direct measurements using a surface force apparatus. Solutions of variable NaNO3, Ca(NO3)2, and humic acid (HA) concentrations were used to differentiate individual contributing forces and quantify surface properties. The measured Hamaker constant for silver–water–mica was consistent with Lifshitz theory. Our results indicate that HA forms an adsorbed surface layer, but its charge, thicknesses, compressibility, and mass are significantly larger on mica than silver. Ca2+primarily reduced the differences between the initially adsorbed HA layer properties on each surface, making them more similar. Force–distance profiles indicate that, when silver–mica systems were exposed to HA, osmotic–steric, electrostatic, and van der Waals forces dominate. Soft particle theory was deemed inappropriate for this system. Derjaguin’s approximation was utilized to translate force measurements into interaction energy between nanosilver particles and mica collectors. We propose attachment efficiency estimates from measured surface properties, which suggest high particle mobility when nanosilver is applied to HA-rich agricultural soils with modest ionic strength.