University of Oulu

Phys. Chem. Chem. Phys., 2022, 24, 2934,

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

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Author: Pelimanni, Eetu1; Saak, Clara-Magdalena2,3; Michailoudi, Georgia1;
Organizations: 1Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Box 3000, Finland
2Department of Physics and Astronomy, Uppsala University, Box 516, 75120 Uppsala, Sweden
3University of Vienna, Department of Physical Chemistry, Währinger Straße 42, 1090 Vienna, Austria
4Center for Atmospheric Research, Faculty of Information Technology and Electrical Engineering, University of Oulu, P. O. Box 4500, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 6.3 MB)
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Language: English
Published: Royal Society of Chemistry, 2022
Publish Date: 2022-04-25


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⁺, Mg² ⁺, Ca² ⁺, 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 Mg² ⁺ 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.

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Series: PCCP. Physical chemistry chemical physics
ISSN: 1463-9076
ISSN-E: 1463-9084
ISSN-L: 1463-9076
Volume: 24
Article number: 2934
DOI: 10.1039/D1CP04953D
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
Funding: The research leading to this result has been financially supported by the Academy of Finland (Grants 296338, 306984, 328467, 308238, 314175, and 335649), the Finnish Cultural Foundation (North Ostrobothnia Regional fund), the Tauno Tönning Foundation, the University of Oulu Graduate School, the Magnus Ehrnrooth Foundation and the Swedish Foundation for International Cooperation in Research and Higher Education. CMS acknowledges funding from the EU Horizon 2020 program under the Marie Sklodowska-Curie grant agreement No. 847693 through the REWIRE program at the University of Vienna. This work has received funding from projects under the European Union's Horizon 2020 research and innovation programme, the European Research Council (ERC) project SURFACE (grant Agreement No. 717022), project I4FUTURE under the Marie Skoldowska-Curie grant agreement (No. 713606) and project CALIPSOplus (grant Agreement 730872). We acknowledge SOLEIL for provision of synchrotron radiation facilities (proposal No. 20171195) and we would like to thank Dr Aleksandar Milosavljevi for assistance in using beamline PLÉIADES.
EU Grant Number: (717022) SURFACE - The unexplored world of aerosol surfaces and their impacts.
(713606) I4FUTURE - Novel Imaging and Characterisation Methods in Bio, Medical, and Environmental Research and Technology Innovations
Academy of Finland Grant Number: 296338
Detailed Information: 296338 (Academy of Finland Funding decision)
306984 (Academy of Finland Funding decision)
328467 (Academy of Finland Funding decision)
308238 (Academy of Finland Funding decision)
314175 (Academy of Finland Funding decision)
335649 (Academy of Finland Funding decision)
Copyright information: © 2022 The Authors. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.