| Journal: | Anais da Academia Brasileira de Ciencias |
| Database: | PERIÓDICA |
| System number: | 000412234 |
| ISSN: | 0001-3765 |
| Authors: | Silva, Marcondes Silva e1 Lages, Anderson S1 Santana, Genilson P1 |
| Institutions: | 1Universidade Federal do Amazonas, Instituto de Ciencias Exatas, Manaus, Amazonas. Brasil |
| Year: | 2017 |
| Season: | Sep |
| Volumen: | 89 |
| Number: | 3 |
| Pages: | 1391-1402 |
| Country: | Brasil |
| Language: | Inglés |
| Document type: | Artículo |
| Approach: | Experimental, aplicado |
| English abstract | his 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, H2SO4, H2O2 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 Al3+ by Fe3+. 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 Fe3+ preferentially occupies octahedral sites. In the kaolinite lattices there are different octahedral sites of Al bounded by cis-OH-Fe3+ and trans-OH-Fe3+ octahedral sites. The kaolinite from the Kao1 sample has a higher number of cis-OH-Fe3+ from octahedral sites and is able to adsorb higher contents of orthophosphate ions than those from samples Kao2 and Kao3 |
| Disciplines: | Química |
| Keyword: | Química organometálica, Caolinita, Capacidad de adsorción, Adsorción de iones, Sustitución isomórfica, Espectro Mossbauer, Modelo de Freundlich |
| Keyword: | Chemistry, Organometallic chemistry, Kaolinite, Adsorption capacity, Ion adsorption, Isomorphic substitution, Freundlich's model, Mossbauer spectra |
| Full text: | Texto completo (Ver HTML) |
