The colloidal and chemical stability of CeO₂ nanoparticles used in a diesel additive (viz. Envirox™) was studied at different stages of their lifecycle (formulation, use, end of life). After combustion at a temperature close to that of diesel engines, the size of the CeO₂ crystallites increased significantly without detectable Ce(III) in the structure and remaining organic compounds at the surface. Regardless of the aging conditions (salinity, light, pH), the dissolution kinetics of the combusted particles were slowed down compared to that of the initial CeO₂ nanoparticles. After 2 days at 0.1 g L⁻¹ of salts, no more than 0.01% of the total Ce was released from the 850 °C-combusted Envirox™ versus 1.5% for the uncombusted Envirox™. Both the crystal growth during combustion and the degradation of the organic matrix will govern the aggregation and dissolution kinetics/mechanisms once the CeO₂ particles are released into the environment at different stages of their lifecycle. Such a study is a prerequisite needed before any assessment of the environmental risks of CeO₂ nanoparticle-based diesel additives is performed.

中文翻译：

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燃烧和环境释放过程中基于CeO ₂纳米颗粒的柴油添加剂的结构和物理化学行为

研究了在柴油添加剂（即Envirox™）中使用的CeO ₂纳米颗粒在其生命周期的不同阶段（配方，用途，寿命终止）的胶体和化学稳定性。在接近柴油机的温度下燃烧后，CeO ₂晶粒的尺寸显着增加，而在结构中没有可检测到的Ce（III）且在表面残留有机化合物。不管老化条件（盐度，光照，pH）如何，与初始CeO ₂纳米颗粒相比，燃烧颗粒的溶解动力学都变慢了。2天后以0.1 g L ^-1盐的，总的Ce不大于0.01％是从850℃燃烧的的Envirox™释放与1.5％未燃烧的Envirox™。一旦CeO ₂颗粒在其生命周期的不同阶段释放到环境中，燃烧过程中的晶体生长和有机基质的降解都将控制聚集和溶解动力学/机理。进行任何有关CeO ₂纳米颗粒柴油添加剂的环境风险评估之前，此类研究是必要的前提条件。