The interplay of particle properties and solution chemistry on aggregation kinetics of soil nanoparticles

Purpose Soil nanoparticles (NPs) are active organic-mineral complexes and have an important impact on the migration of nutrients, organic pollutants, and heavy metals. Due to their diversity and heterogeneity, researches have mainly investigated the effect of solution chemistry on the stability of soil NPs, but little attention is paid to the influences of particle properties. Methods In the present study, NPs were separated from the eluviated cinnamon soil (ECS), typical cinnamon soil (TCS), and carbonate cinnamon soil (CCS), namely ECS-NP, TCS-NP, and CCS-NP. The particle composition, surface-related properties, and the aggregation kinetics of soil NPs were investigated. Correlation analyses between soil NP properties and their critical coagulation concentrations (CCCs) were further discussed. Results The bulk ECS, TCS, and CCS differed highly in CaCO 3 content. While in soil NP fractions, the contents of soil organic matter and illite were more abundant. The particle size, specific surface area, and Hamaker constant of soil NPs followed the order of ECS-NP < TCS-NP < CCS-NP, while the yield, zeta potential (in absolute values), and the CCCs were in the reverse trend. The particle diameter, specific surface area, and zeta potential significantly correlated with the CCCs. Conclusion The present study revealed the important role of particle properties in dominating the stability (aggregation and dispersion) of soil NPs. Therefore, it is necessary to further systematically explore the composition of soil NPs on dominating their environmental behaviors.