CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Unidad Ejecutora - UE
congresos y reuniones científicas
Photo-evolution of organic/inorganic particles of atmospheric interest using a levitation technique coupled to the Raman microscope
YENY A. TOBÓN; S SENG; ROSANA M. ROMANO; A. LORENA PICONE; MYRIAM MOREAU; SOPHIE SOBANSKA; J. BARBILLAT
Conferencia; Photocatalysis: Science and Application for Urban Air Quality; 2014
In atmospheric chemistry, aerosols play an essential role mainly concerning the heterogeneouschemistry in the atmosphere (Andreae and Crutzen 1997). However, studying the aerosol properties remains a challenge and it?s indispensable to try to understand the chemical processes which occur at the particle or at the surface scale. Laboratory experiments are the most common way to go towards to real processes under controlled conditions, and it?s necessary to look for techniques or combination of techniques which permit to simulate the conditions occurring in the atmosphere.Raman spectroscopy is a non‐destructive technique that provides detailed molecular and structural information with a spatial resolution of about 1μm3, and it is a valuable tool to follow real‐time evolutions of volume or surface structures under controlled conditions. Micro‐Raman spectroscopy, coupled to an environmental levitation cell, is especially useful for studying, at micrometric scale, the in‐situ modifications of aerosol when exposed to reactive environments or humidity without the influence of a contacting surface (Krieger, et al. 2012). Moreover, photochemical transformation can be followed by irradiation of the particles.In this presentation, we will show an environmental acoustic levitation cell coupled to the micro‐Raman spectroscopy to monitor the physical and chemical processes occurring in single particles of atmospheric interest when exposed both, to humidity and UV‐Vis light. Physical and chemical changes can be followed at the interface or deeper depending on the optical properties of the particle. Particles, as small as 20 μm, can be levitated and studied by micro‐Raman spectroscopy. The influence of mixing state of particles (inorganic/organic) on the photo‐transformation within individual particles when irradiated with UV‐Vis light will be presented.