title: Effect of sonication conditions: solvent, time, temperature and reactor type on the preparation of micron sized vermiculite particles.
abstract: The effects of temperature, time, solvent and sonication conditions under air and Argon are described for the preparation of micron and sub-micron sized vermiculite particles in a double-jacketed Rosett-type or cylindrical reactor. The resulting materials were characterized via X-ray powder diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Fourier Transform Infrared (FTIR) Spectroscopy, BET surface area analysis, chemical analysis (elemental analysis), Thermogravimetry analysis (TGA) and Laser Granulometry. The sonicated vermiculites displayed modified particle morphologies and reduced sizes (observed by scanning electron microscopy and laser granulometry). Under the conditions used in this work, sub-micron sized particles were obtained after 5h of sonication, whereas longer times promoted aggregation again. Laser granulometry data revealed also that the smallest particles were obtained at high temperature while it is generally accepted that the mechanical effects of ultrasound are optimum at low temperatures according to physical/chemical properties of the used solvent. X-ray diffraction results indicated a reduction of the crystallite size along the basal direction [001]; but structural changes were not observed. Sonication at different conditions also led to surface modifications of the vermiculite particles brought out by BET surface measurements and Infrared Spectroscopy. The results indicated clearly that the efficiency of ultrasound irradiation was significantly affected by different parameters such as temperature, solvent, type of gas and reactor type.
authors.affiliation: Laboratoire de Chimie Moléculaire et Environnement, Université de Savoie, 73376 Le Bourget du Lac Cedex, France; Department of Chemistry, Hazara University, Mansehra 21120, Pakistan; Department of Metallurgy and Materials Engineering (DMME), Pakistan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad 45650, Pakistan.
authors.forename: Farman
authors.initials: F
authors.lastname: Ali
authors.affiliation: Laboratoire de Chimie Moléculaire et Environnement, Université de Savoie, 73376 Le Bourget du Lac Cedex, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Reinert
authors.affiliation: Laboratoire de Chimie Moléculaire et Environnement, Université de Savoie, 73376 Le Bourget du Lac Cedex, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Levêque
authors.affiliation: Laboratoire de Chimie Moléculaire et Environnement, Université de Savoie, 73376 Le Bourget du Lac Cedex, France. Electronic address: laurent.duclaux@univ-savoie.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Duclaux
authors.affiliation: ISTO, 1A Rue de la Férollerie, 42071 Orléans Cedex 2, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Muller
authors.affiliation: Department of Metallurgy and Materials Engineering (DMME), Pakistan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad 45650, Pakistan.
authors.forename: Shaukat
authors.initials: S
authors.lastname: Saeed
authors.affiliation: Department of Chemistry, Hazara University, Mansehra 21120, Pakistan.
authors.forename: Syed Sakhawat
authors.initials: SS
authors.lastname: Shah
keywords: Na-vermiculite; Rosett; Sonication; Sub-micron particles; Temperature effect; Ultrasound