Comparative characterization study of diatomites from different Brazilian locations and their application in dye adsorption

Abstract

Diatomites are natural materials that are easily found around the world and require further study to achieve a systematic application in industry. In this study, we compared three Brazilian diatomites from different locations and found some similarities in their intrinsic characteristics that may be useful for removing contaminants, such as rhodamine B and methylene blue. The samples were analyzed by X-ray diffraction, X-ray fluorescence, microscopy, thermogravimetry and mercury intrusion-extrusion porosimetry. Our findings on their porous structures were very interesting and explain their different behavior when adsorbing different dyes, thus, establishing a direct relationship between diatomite structure and application.

LTA zeolite synthesis using natural materials and its evaluation by Green Star methodology

“…The traditional LTA zeolite was synthesized according to the standard procedure proposed by the International Zeolite Association (IZA) [22]. In the synthesis using the alternative materials, the different diatomites (RN, Bahia and D4 from CETEM, zeolitic products named 'Diato_RN' , 'Diato_Bahia' and 'Diato_D4' , respectively, fully characterized in da Silva Filho et al [23]) and the expanded perlite (Schumacher Insumos, zeolitic product named 'Perlite' , fully characterized in da Silva Filho et al [24]) directly replaced sodium metasilicate and sodium aluminate. For the synthesis of the zeolitic materials using alternative substances, 1.8 g of NaOH (Química Moderna, 97%) was added in 27 g of H 2 O and stirred until complete dissolution.…”