PERSONAL DE APOYO
NAJERA juan jose
artículos
Título:
Phase Transition Behaviour of Sodium Oleate Aerosol Particles
Autor/es:
JUAN J. NAJERA
Revista:
ATMOSPHERIC ENVIRONMENT
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2007 vol. 41 p. 1041 - 1052
ISSN:
1352-2310
Resumen:
Field measurements have shown that organic surfactants are significant components of atmospheric aerosols. While
fatty acids, among other surfactants, are prevalent in the atmosphere, the influence of these species on the chemical and
physical properties of atmospheric aerosols remains not fully characterized. In order to assess the phase in which particles
may exist, a detailed study of the deliquescence of a model surfactant aerosol has been carried out. Sodium oleate was
chosen as a surfactant proxy relevant in atmospheric aerosol. Sodium oleate micelle aerosol particles were generated
nebulizing a sodium oleate aqueous solution. In this study, the water uptake and phase transition of sodium oleate aerosol
particles have been studied in a room temperature aerosol flow tube system (AFT) using Fourier transform infrared
(FTIR) spectroscopy. Aerosol morphology and elemental composition were also analysed using scanning electron
microscopy/energy dispersive X-ray analysis (SEM/EDX) techniques. The particles are homogeneously distributed as
ellipsoidal-shape aggregates of micelles particles with an average size of 1.1 mm. The deliquescence by the sodium oleate
aerosol particles was monitored by infrared extinction spectroscopy, where the dried aerosol particles were exposed to
increasing relative humidity as they passed through the AFT. Observations of the infrared absorption features of
condensed phase liquid water enable to determine the sodium oleate deliquescence phase transition at 8872%.