Pradhan Sulena, Hedberg Jonas, Rosenqvist Jörgen, Jonsson Caroline M, Wold Susanna, Blomberg Eva, Odnevall Wallinder Inger
KTH Royal Institute of Technology, Department of Chemistry, Division of Surface and Corrosion Science, Stockholm, Sweden.
University of Gothenburg, Department of Chemistry and Molecular Biology, Gothenburg, Sweden.
PLoS One. 2018 Feb 8;13(2):e0192553. doi: 10.1371/journal.pone.0192553. eCollection 2018.
This work focuses on kinetic aspects of stability, mobility, and dissolution of bare Cu, Al and Mn, and SiO2 NPs in synthetic freshwater (FW) with and without the presence of natural organic matter (NOM). This includes elucidation of particle and surface interactions, metal dissolution kinetics, and speciation predictions of released metals in solution. Dihydroxy benzoic acid (DHBA) and humic acid adsorbed rapidly on all metal NPs (<1 min) via multiple surface coordinations, followed in general by rapid agglomeration and concomitant sedimentation for a large fraction of the particles. In contrast, NOM did not induce agglomeration of the SiO2 NPs during the test duration (21 days). DHBA in concentrations of 0.1 and 1 mM was unable to stabilize the metal NPs for time periods longer than 6 h, whereas humic acid, at certain concentrations (20 mg/L) was more efficient (>24 h). The presence of NOM increased the amount of released metals into solution, in particular for Al and Cu, whereas the effect for Mn was minor. At least 10% of the particle mass was dissolved within 24 h and remained in solution for the metal NPs in the presence of NOM. Speciation modeling revealed that released Al and Cu predominantly formed complexes with NOM, whereas less complexation was seen for Mn. The results imply that potentially dispersed NPs of Cu, Al and Mn readily dissolve or sediment close to the source in freshwater of low salinity, whereas SiO2 NPs are more stable and therefore more mobile in solution.
这项工作聚焦于在有无天然有机物（NOM）存在的情况下，裸铜、铝、锰以及二氧化硅纳米颗粒在合成淡水（FW）中的稳定性、迁移性和溶解的动力学方面。这包括阐明颗粒与表面的相互作用、金属溶解动力学以及溶液中释放金属的形态预测。二羟基苯甲酸（DHBA）和腐殖酸通过多种表面配位作用在所有金属纳米颗粒上迅速吸附（<1分钟），随后大部分颗粒通常会迅速团聚并伴随沉降。相比之下，在测试期间（21天），NOM并未诱导二氧化硅纳米颗粒发生团聚。浓度为0.1和1 mM的DHBA无法在超过6小时的时间段内稳定金属纳米颗粒，而腐殖酸在某些浓度（20 mg/L）下则更有效（>24小时）。NOM的存在增加了溶液中释放金属的量，特别是对于铝和铜，而对锰的影响较小。在NOM存在的情况下，至少10%的颗粒质量在24小时内溶解并留在溶液中。形态建模表明，释放的铝和铜主要与NOM形成络合物，而锰的络合作用则较少。结果表明，在低盐度的淡水中，潜在分散的铜、铝和锰纳米颗粒容易在靠近源头的地方溶解或沉降，而二氧化硅纳米颗粒则更稳定，因此在溶液中更具迁移性。
