Nombre: LUANA MIRANDA DE SOUZA
Tipo: MSc dissertation
Fecha de publicación: 30/03/2020
Supervisor:
Nombre |
Rol |
|---|---|
| EDUARDO PERINI MUNIZ | Advisor * |
| PAULO SÉRGIO DA SILVA PORTO | Co-advisor * |
Junta de examinadores:
| Nombre |
Rol |
|---|---|
| ANDRÉ GUSTAVO DE SOUSA GALDINO | External Examiner * |
| EDSON PASSAMANI CAETANO | External Examiner * |
| EDUARDO PERINI MUNIZ | Advisor * |
| PAULO SÉRGIO DA SILVA PORTO | Co advisor * |
Resumen: Boron is an important component in several segments of the industry and its absence is harmful to both plants and animals. However, in high oncentrations, boron can become harmful, causing health problems in humans. The removal of boron from effluents can be carried out through a series of processes, among which stand out the selective adsorbents containing hydroxyl. In aqueous solution, magnesium oxide reacts with water and acquires a layer of magnesium hydroxide, making it one of the best boron adsorbents listed in the literature. Similarly, the calcium oxide present in the eggshell after calcination hydrolyzes and there are reports of its great boron adsorption capacity. Thus, the present work developed a methodology for obtaining magnetic composites, from the mixture of cobalt ferrite (CoFe2O4) with magnesium oxide (MgO) or calcined eggshell rich in calcium oxide (CaO). The adsorption tests showed that the magnesium oxide adsorbed more than the calcined eggshell, about 45% more, consequently, the composite prepared with magnesium oxide also adsorbed more than the composite prepared with the calcined eggshell, about 35% more. All materials were analyzed by X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) before and after boron adsorption. It was observed that adsorption occurs mainly by the formation of hydroxides on the surface of the ferrite, both for the composite CaO/CoFe2O4 and for the composite MgO/CoFe2O4. Scanning Electron Microscopy (SEM) identified that the MgO/CoFe2O4 composite prepared with calcined ferrite at a temperature of 1123 K over a period of 3.5 h, after boron adsorption, has well-defined elongated needle-shaped structures in its composition, similar to the anowhiskers described in the literature. The kinetic study using Lagergren's pseudo-first order model revealed that in a solution with an initial oncentration of 6 ppm of boron, this material is capable of adsorbing about 82% of boron. Thus, for an industrial effluent containing 6 ppm of boron, it would be ossibleto carry out the treatment of this water leaving it in conditions to be used in irrigation, as recommended by the world health organization (WHO).
