Solvent and cosolute dependence of Mg surface enrichment in submicron aerosol particles.

ABSTRACT: The formation of multicomponent aerosol particles from precursor solution droplets often involves segregation and surface enrichment of the different solutes, resulting in non-homogeneous particle structures and diverse morphologies. In particular, these effects can have a significant influence on the chemical composition of the particle-vapor interface. In this work, we investigate the bulk/surface partitioning of inorganic ions, Na⁺, Mg^{2 +}, Ca^{2 +}, Cl^- and Br^-, in atomiser-generated submicron aerosols using synchrotron radiation based X-ray photoelectron spectroscopy (XPS). Specifically, the chemical compositions of the outermost few nm thick surface layers of non-supported MgCl₂/CaCl₂ and NaBr/MgBr₂ particles are determined. It is found that in MgCl₂/CaCl₂ particles, the relative abundance of the two species in the particle surface correlates well with their mixing ratio in the parent aqueous solution. In stark contrast, extreme surface enrichment of Mg^{2 +} is observed in NaBr/MgBr₂ particles formed from both aqueous and organic solution droplets, indicative of core-shell structures. Structural properties and hydration state of the particles are discussed.

SUBMITTER: Pelimanni E 

PROVIDER: S-EPMC8809137 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature