PERSONAL DE APOYO
NAJERA Juan Jose
artículos
Título:
Infrared Spectroscopic Study of the Effect of Oleic Acid on the Deliquescence Behaviour of Ammonium Sulfate Aerosol Particles
Autor/es:
J.J. NAJERA; A.B. HORN
Revista:
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Editorial:
ROYAL SOC CHEMISTRY
Referencias:
Lugar: CAMBRIDGE; Año: 2008 vol. 11 p. 483 - 494
ISSN:
1463-9076
Resumen:
In order to accurately assess the impact of fatty acids on the hygroscopic properties of
atmospheric aerosol particles, (NH4)2SO4 (ammonium sulfate) and oleic acid (cis-9-octadecenoic
acid) were chosen to perform this study as components of the particle phase. Micron-sized
(700?900 nm) particles containing (NH4)2SO4 and oleic acid were generated by nebulising
aqueous solutions of (NH4)2SO4 and sodium oleate. In this study, the effect of oleic acid on the
deliquescence phase transition of particles was investigated in a room temperature aerosol flow
tube (AFT) system using Fourier transform infrared (FTIR) spectroscopy. Particles morphologies
and their chemical compositions were also analysed using a variety of techniques, including
attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and scanning
electron microscopy/energy dispersive X-ray analysis (SEM/EDX). The deliquescence relative
humidity (DRH) of the (NH4)2SO4 component, determined at 81 2%, was slightly lowered or
not affected by the presence of different thickness of oleic acid (21 nm, 44 nm and 109 nm)
present in the particles. Analyses of the results presented here are consistent with earlier studies
about the possible effects of water?insoluble fatty acids coatings on the phase transitions of
atmospheric aerosol particles.