Mlih Rawan, Liang Yan, Zhang Miaoyue, Tombácz Etelka, Bol Roland, Klumpp Erwin
Institute of Bio- and Geosciences, Agrosphere (IBG-3), Research Centre Juelich (FZJ), 52425 Juelich, Germany.
Institute for Environmental Research, Biology 5, RWTH Aachen University, 52074 Aachen, Germany.
Nanomaterials (Basel). 2022 May 2;12(9):1536. doi: 10.3390/nano12091536.
Understanding the physicochemical factors affecting nanoparticle transport in porous media is critical for their environmental application. Water-saturated column experiments were conducted to investigate the effects of input concentration (Co), ionic strength (IS), and sand grain size on the transport of poly(acrylic acid-co-maleic acid) coated magnetite nanoparticles (PAM@MNP). Mass recoveries in the column effluent ranged from 45.2 to 99.3%. The highest relative retention of PAM@MNP was observed for the lowest Co. Smaller Co also resulted in higher relative retention (39.8%) when IS increased to 10 mM. However, relative retention became much less sensitive to solution IS as Co increased. The high mobility is attributed to the PAM coating provoking steric stability of PAM@MNP against homoaggregation. PAM@MNP retention was about 10-fold higher for smaller grain sizes, i.e., 240 µm and 350 µm versus 607 µm. The simulated maximum retained concentration on the solid phase (Smax) and retention rate coefficient (k1) increased with decreasing Co and grain sizes, reflecting higher retention rates at these parameters. The study revealed under various IS for the first time the high mobility premise of polymer-coated magnetite nanoparticles at realistic (<10 mg L−1) environmental concentrations, thereby highlighting an untapped potential for novel environmental PAM@MNP application usage.
了解影响纳米颗粒在多孔介质中传输的物理化学因素对于其环境应用至关重要。进行了水饱和柱实验，以研究输入浓度（Co）、离子强度（IS）和砂粒尺寸对聚（丙烯酸 - 马来酸）包覆磁铁矿纳米颗粒（PAM@MNP）传输的影响。柱流出物中的质量回收率在45.2%至99.3%之间。在最低Co时观察到PAM@MNP的相对保留率最高。当IS增加到10 mM时，较小的Co也导致较高的相对保留率（39.8%）。然而，随着Co的增加，相对保留率对溶液IS的敏感性大大降低。高迁移率归因于PAM涂层引发了PAM@MNP对均相聚集的空间稳定性。对于较小的颗粒尺寸，即240 µm和350 µm相对于607 µm，PAM@MNP的保留率高出约10倍。模拟的固相最大保留浓度（Smax）和保留率系数（k1）随着Co和颗粒尺寸的减小而增加，反映了在这些参数下更高的保留率。该研究首次揭示了在各种IS条件下，聚合物包覆磁铁矿纳米颗粒在实际（<10 mg L−1）环境浓度下的高迁移率前提，从而突出了新型环境PAM@MNP应用的未开发潜力。
