Imaging Techniques and Scanning Electron Microscopy as Tools for Characterizing a Si-Based Material Used in Air Monitoring Applications

Suárez-Peña Beatriz; Negral Luis; Castrillón Leonor; Megido Laura; Marañón Elena; Fernández-Nava Yolanda

doi:10.3390/ma9020109

Imaging Techniques and Scanning Electron Microscopy as Tools for Characterizing a Si-Based Material Used in Air Monitoring Applications

Materials (Basel). 2016 Feb 11;9(2):109. doi: 10.3390/ma9020109.

Authors

Suárez-Peña Beatriz¹, Negral Luis², Castrillón Leonor³, Megido Laura⁴, Marañón Elena⁵, Fernández-Nava Yolanda⁶

Affiliations

¹ Department of Materials Science and Metallurgical Engineering, Polytechnic School of Engineering, Gijón Campus, University of Oviedo, 33203 Gijón, Spain. bsuarez@uniovi.es.
² Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Gijón Campus, University of Oviedo, 33203 Gijón, Spain. negralluis@uniovi.es.
³ Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Gijón Campus, University of Oviedo, 33203 Gijón, Spain. cleonor@uniovi.es.
⁴ Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Gijón Campus, University of Oviedo, 33203 Gijón, Spain. megidolaura@gmail.com.
⁵ Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Gijón Campus, University of Oviedo, 33203 Gijón, Spain. emara@uniovi.es.
⁶ Department of Chemical and Environmental Engineering, University Institute of Industrial Technology of Asturias, Gijón Campus, University of Oviedo, 33203 Gijón, Spain. fernandezyolanda@uniovi.es.

Abstract

This paper presents a study of the quartz fibrous filters used as a substrate for capturing the particulate matter (PM) present in the air. Although these substrates are widely used in environmental applications, their microstructure has been barely studied. The behavior of these devices during the filtration process was investigated in terms of their microstructure and the quartz fibers. Surface and cross sections were monitored. Scanning electronic microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), imaging and stereology techniques were used as tools for this purpose. The results show that most of the quartz filter fibers have sizes that allow them to be classified as nanofibers. It was also observed that, while the mechanisms of the mechanical capture of particles via impaction, interception and diffusion operate simultaneously in the outer zones of the filter cross section, the mechanism of capture by impaction is virtually non-existent in the innermost zones. Particles between 0.1 and 0.5 μm are known to be the most difficult to have captured by means of fibrous substrates. The fibers in inner zones were highly efficient in capturing this type of particle.

Keywords: Si-based materials; air monitoring applications; filtration behavior; imaging; microstructure characterization; scanning electron microscopy.