Speaker
Dr
Markus Lampimäki
(Paul Scherrer Institute)
Description
Metal oxides as a common part of mineral dust have an important role in the heterogeneous reactions of dust particles in the presence of ozone or acidic gases. Furthermore, mineral dust particles serve as a primary external iron source to the open ocean and the bioavailability of iron from these particles is highly dependent on the oxidation state of the metal [1,2]. In the present study we have investigated both pure and nitric acid treated iron oxide particles by Scanning transmission X-ray microscopy and Near edge X-ray absorption fine structure (NEXAFS) techniques to observe changes in morphology and functional groups of pure Fe(III)-, Fe(II,III)- and mineral dust particles. In order to follow the chemical and morphological changes in situ, particles were measured in the environmental micro reactor after exposure to ozone and nitrogen oxides [3]. Characteristic features corresponding to different oxidation states of iron were monitored by following changes at oxygen K- and iron L-edges.
[1] Duce R. A. et al. Limnol. Oceanogr. 36 (1991)
[2] P. Falkowski et al. Science 281 (1998)
[3] T. Huthwelker et al. Rev. Sci. Instrum. 81 (2010)
Please specify poster or talk
poster
Please specify the session
Poster session I
Primary author
Dr
Markus Lampimäki
(Paul Scherrer Institute)
Co-authors
Dr
Adela Krepelova
(Paul Scherrer Institute)
Dr
Markus Ammann
(Paul Scherrer Institute)
Ms
Sarah Steimer
(Paul Scherrer Institute)
Dr
Veronika Zelenay
(Paul Scherrer Institute)
