INVESTIGADORES
AVILA Eldo Edgardo
artículos
Título:
The role of natural mineral particles collected at one site in Patagonia as immersion freezing ice nuclei
Autor/es:
LÓPEZ, MARÍA LAURA; BORGNINO, LAURA; ÁVILA, ELDO E.
Revista:
ATMOSPHERIC RESEARCH
Editorial:
ELSEVIER SCIENCE INC
Referencias:
Año: 2018 vol. 204 p. 94 - 101
ISSN:
0169-8095
Resumen:
This work studies the role of mineral particles collected in the region of Patagonia (Neuquén, Argentina) as icenuclei particles (INPs) by immersion freezing mode. The particle immersion-freezing ability was analyzed underlaboratory conditions by using an established drop-freezing technique. Mineralogical composition was characterizedby using X-ray diffraction and electron micro probe analysis. Dynamic light scattering was used todetermine the grain size distribution of particles, while the N2 adsorption and methylene blue adsorptionmethods were applied to determine their specific surface area. Water droplets of different volumes containingdifferent concentrations of particles were cooled until droplets were frozen. For all the analyzed drop volumes,an increase in the freezing temperature of the drops was observed with increasing dust concentration. In thesame way, the freezing temperature increased when the drop volume was increased at constant dust concentration.Both behaviors were linked to the availability of active sites in the particles. A plateau in the freezingtemperature was observed at high suspension concentration for all the drop volumes. This plateau was related tothe aggregation of the particles when the suspension concentration was increased and to the consequent decreasein the number of active sites. The active sites per unit of surface area were calculated and reported. For thestudied range of temperature, results are in agreement with those reported for different sites and particles. Fromthe chemical and morphological analysis of the particle components and the results obtained from the literature,it was concluded that even though montmorillonite was the main mineral in the collected sample, the accessoryminerals deserve to be analyzed in detail in order to know if they could be responsible for the ability of thecollected soil particles to act as INPs. Considering that the region of Patagonia has been identified as an importantsource of natural mineral particles in the atmosphere, it is important to analyze the ability of theseparticles to act as INP. As far as we know, this is the first study carrying out this investigation.