Physical and chemical study of lattice kaolinites and their interaction with orthophosphate

Abstract

This study covers the evaluation of the structure and the capacity in adsorbing orthophosphate ions of kaolinites collected from sampling sites in Manaus (Brazil). The kaolinites were obtained using physical fractioning (sieving/siphoning) techniques and chemical treatment with HCl, H 2 SO 4 , H 2 O 2 and KCl. The investigation of the kaolinite lattices involved the Hinckley and Plançon indexes determined from X-ray diffraction data, Fourier transformed infrared spectroscopy, scanning electron microscopy and Mössbauer spectroscopy. The absorption capacity of orthophosphate ions was calculated by Freundlich and Langergren isotherms. A transitional state was observed in the crystallographic structure from kaolinites because of the isomorphic substitution of Al 3+ by Fe 3+. This isomorphic substitution occurs accompanied by the optical pleochroism behavior, but it also reduces the mean particle sizes and increases the number of structural defects and magnetic properties of these kaolinites. Mössbauer spectroscopy showed that the substituting Fe 3+ preferentially occupies octahedral sites. In the kaolinite lattices there are different octahedral sites of

Intensive evaluation of radiation stability of phlogopite single crystals under high doses of γ-ray irradiation

“…Simultaneously, a partial breakdown of the Si-OH groups or defects on the surface or edges could be recovered, 60,61 also elevating the hydrophilicity. From the structure, however, it is evident that Si-OH groups should not exist on the surface, but partial Si-OH groups generally exist on silicate 2 or oxide surfaces such as SiO 2 particles, [62][63][64] glass, etc. In addition, defects introduced by irradiation might increase surface roughness.…”

Adsorption of Dyes Indosol Blue, Indosol Orange and Drimarene Red in Aqueous Solution by White Clay

“…A difusão Intrapartícula admite que a transferência de massa é limitada pela difusão nos poros do adsorvente, e a adsorção ocorre na parte externa do adsorvente, dentro dos poros de fase solida até o equilíbrio, assumindo três estágios. 8,24,25 O estudo do equilíbrio da adsorção é baseado em isotermas, diagramas que mostram a relação entre a concentração de adsorvato em solução e a quantidade de adsorvato retida sobre o adsorvente no equilíbrio em uma determinada temperatura. 14 Por meio das isotermas de adsorção é possível determinar a quantidade máxima de material retido sobre a superfície do adsorvente e a forma como adsorvente e adsorvato interagem.…”

“…Onde q e é a quantidade de corante adsorvido no equilíbrio (mg. g −1 ) e, C e a concentração de corante no equilíbrio da solução (mg. L −1 ). 29,30 Os modelos de isotermas de cinética de adsorção, pseudo-primeira ordem, 21,22 pseudo-segunda ordem 21-23 e difusão intrapartícula 8,24,25 foram aplicados segundo as Equações 3, 4 e 5 respectivamente:…”