Synthesis of Fe3O4, CoFe2O4 and ZnFe2O4 from ion-Li and Zn-MnO2 spent batteries and their applications as catalysts in heterogeneous photo Fenton reactions
Name: MAYRA NICOLI MOURA
Type: MSc dissertation
Publication date: 22/03/2017
Advisor:
Name |
Role |
|---|---|
| MARCOS BENEDITO JOSÉ GERALDO DE FREITAS | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| DENISE ROCCO DE SENA | External Examiner * |
| MARCOS BENEDITO JOSÉ GERALDO DE FREITAS | Advisor * |
| RAFAEL DE QUEIROZ FERREIRA | Internal Examiner * |
Summary: Cathode cobalt of the lithium-ion battery (LIBs) depleted of Samsumg® cell phones was recycled as cobalt doped ferrite. Anode zinc of alkaline batteries (Zn-MnO2) Duracell® AA was recycled for the formation of zinc doped ferrite. The ferrites were applied as catalysts in heterogeneous photo Fenton reactions for the discoloration of the blue dye of methylene. The X-ray diffraction (XRD) analysis revealed the formation of ferrites spinel no doped, cobalt doped and zinc doped. With the aid of the techniques: scanning electron microscopy (SEM) and transmission electron microscopy (TEM), it was verified that the no doped, cobalt doped and zinc doped ferrites form agglomerates of nanometric particles. By the analysis of Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES) and Flame Atomic Absorption Spectroscopy (F AAS) it was possible to determine the concentrations of the metals present in the ferrites. The cobalt concentrations were 70.0 ± 4.0 mg.g-1 and 65.0 ± 2.0 mg.g-1 in cobalt doped ferrites from analytical reagent and lithium-ion battery, respectively. The zinc concentrations in the zinc doped ferrites from the analytical reagent and the alkaline battery were respectively 26.0 ± 1.0 mg.g-1 and 89.0 ± 4.0 mg.g-1. The optimized condition for the discoloration of the dye was evaluated by a factorial planning. The best condition for the catalytic reaction using CoFe2O4 as catalyst was pH 3.0, 30 mg of catalyst and 8 mL of H2O2, obtaining the percentage of degradation efficiency equal to 61.5%, 87.3% and 87.7% for no doped ferrite, cobalt doped from analytical reagents and cobalt doped from Li-ion and CoFe2O4-LIBs leached solution, respectively, after 420 minutes. The doping improved the discoloration efficiency of the methylene blue solution. The best optimized experimental condition for ZnFe2O4 was pH 6.0, 30 mg of catalyst and 8 mL of H2O2, with discoloration efficiency in the study of 45.9%, 92.2% and 37.0% for no doped ferrite, zinc doped from analytical reagent and zinc doped from leached alkaline battery, after 240 minutes of reaction.
