Key Laboratory for Biological Effects of Nanomaterials and Nanosafety, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2021 Nov 2;55(21):14649-14657. doi: 10.1021/acs.est.1c04660. Epub 2021 Oct 15.
The time-course association of soil physicochemical properties and fate of CeO nanoparticles (NPs) is not well understood. This study for the first time investigated the dissolution and retention of CeO NPs (<25 nm) during soil short-term (6 h) and long-term (30 d) aging processes with dynamic redox conditions. Under the additional reductant-induced initial reductive condition, theoretically, up to 220‰ of Ce(IV) was temporarily reductively dissolved within 10 min, accompanied by a slow retention process (180 min) of Ce species in soil solutions. Conversely, the dissolution and slow retention of Ce species were not significant in soil solutions without added reductant. X-ray absorption near edge spectroscopy (XANES) shows that most of Ce species were present as Ce(IV) (94.0%-97.8%) in all soils after a long-term aging process. These results indicate that the soil dynamic redox conditions induced by oxidant/reductant intrinsically determined the different time-course dissolution and retention of CeO NPs, highlighting the occasional reductive condition in soil solution that may contribute to the migration and diffusion of Ce species. The time-course study should be also adopted to develop a comprehensive understanding of the nano-soil interactions.
土壤物理化学性质与 CeO 纳米颗粒（NPs）命运之间的时程关联尚不清楚。本研究首次在动态氧化还原条件下，研究了 CeO NPs（<25nm）在土壤短期（6h）和长期（30d）老化过程中的溶解和保持情况。在额外还原剂诱导的初始还原条件下，理论上，在 10 分钟内可暂时还原溶解高达 220‰的 Ce(IV)，同时在土壤溶液中 Ce 物种经历缓慢的保留过程（180 分钟）。相反，在没有添加还原剂的土壤溶液中，Ce 物种的溶解和缓慢保留并不显著。X 射线吸收近边光谱（XANES）表明，在长期老化过程后，所有土壤中的 Ce 物种主要以 Ce(IV)（94.0%-97.8%）形式存在。这些结果表明，氧化剂/还原剂引起的土壤动态氧化还原条件从本质上决定了 CeO NPs 不同的时程溶解和保持情况，突出了土壤溶液中偶尔的还原条件可能会促进 Ce 物种的迁移和扩散。时程研究也应被采用，以全面了解纳米-土壤相互作用。
