The influence of chemical and thermal treatments on the fluoride removal from water by three mineral structures and their characterization

• Published in: Journal of fluorine chemistry 2018-09, Vol.213, p.42-50
• Main Authors: Corral-Capulin, N.G., Vilchis-Nestor, A.R., Gutiérrez-Segura, E., Solache-Ríos, M.
• Format: Article
• Language: English
• Subjects: Adsorption; Aluminum; Aqueous solutions; Calorimetry; Differential scanning calorimetry; Diffraction; Energy dispersive X ray spectroscopy; Fluoride; Fluorides; Geomaterials; Iron; Leaching; Minerals; Modification; Montmorillonite; Organic chemistry; Pumice; Scanning electron microscopy; Thermogravimetric analysis; Water treatment; X ray powder diffraction; X-ray spectroscopy
• ISSN: 0022-1139; 1873-3328
• DOI: 10.1016/j.jfluchem.2018.07.002

[Display omitted] •Natural and modified materials with Al and Fe were studied for fluoride removal.•The materials employed were characterized by different techniques.•Adsorption capacity of each material and leaching of iron and aluminum were evaluated.•Aluminum was found in the remaining solutions after adsorption.•Aluminum-modified materials could not be used for water treatments. In the present work three different natural materials and their modifications were studied for fluoride removal from aqueous solutions. The materials employed were: clinoptilolite (C), montmorillonite (M) and pumice (P), the minerals were modified with Fe3+ and Al3+ and heated at temperatures of 200, 500 and 800 °C. They were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), specific surface area by Branauer Emmett and Teller method (BET) and points of zero charge (pzc). Adsorption experiments were carried out in batch system to obtain the adsorption capacity of each material and evaluate the leaching of iron and aluminum after adsorption processes, throughout the quantification of Fe3+ and Al3+ in the supernatants. The results obtained indicated the following adsorption capacity order: M (1.008 mg/g)>aluminum-modified materials > iron-modified materials > C > P.