Recycling of abrasive sludge and lithium-ion batteries for the synthesis of mixed oxides applied in photocatalysis and energy storage
Name: MAYRA NICOLI MOURA
Publication date: 24/11/2025
Examining board:
Name |
Role |
|---|---|
| ANA PAULA DE CARVALHO TEIXEIRA | Examinador Externo |
| DENISE ROCCO DE SENA | Examinador Externo |
| FABIELLE CASTELAN MARQUES | Coorientador |
| GEISAMANDA PEDRINI BRANDAO ATHAYDE | Examinador Interno |
| MARCOS BENEDITO JOSE GERALDO DE FREITAS | Presidente |
Pages
Summary: The improper disposal of solid waste is one of the major environmental challenges to be addressed. A sustainable and environmentally responsible alternative is to add value to these wastes by using them in advanced applications, such as pollutant degradation and energy storage. The present study investigates the sustainable reuse of industrial wastes—abrasive sludge from marble and granite processing and spent lithium-ion battery cathodes—for the synthesis of mixed oxides. This study aimed to synthesize and evaluate CoFeO/-FeO@SiO/NaAlSiO mixed oxides derived from marble and granite industry abrasive sludge and spent lithium-ion battery cathodes, targeting their application as photocatalysts and pseudocapacitors. The abrasive sludge exhibited phases such as quartz, steel shot, magnetite, albite, mica, calcite, and dolomite, as identified by X-ray diffraction. It was also characterized by inductively coupled plasma optical emission spectroscopy, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The catalytic properties of the samples were evaluated through Fenton and photo-Fenton reactions at pH 3 and at natural pH. The GRM catalyst achieved approximately 95% discoloration in only 5 minutes under photo-Fenton reaction at pH 3, maintaining performance above 95% after five consecutive 30-minute cycles. Cathode characterization revealed the presence of LiCoO and graphite carbon. The mixed oxide CoFeO/-FeO@SiO was characterized by XRD, ICP-OES, Fourier transform infrared spectroscopy, Raman spectroscopy, SEM, EDX, TEM, and UV–Vis spectroscopy, with a band gap of 3.2 eV identified. When applied as a heterogeneous catalyst in the photo-Fenton process, it achieved 100% discoloration of methylene blue (15 mg·L¹) at pH 3, using HO (0.003 mol·L¹) and 30 mg of catalyst in 50 minutes. The reaction kinetics follow a pseudo-first-order model. After catalysis, XRD and ICP OES analyses indicated possible albite leaching and the presence of Al, Ca, Fe, K, Mg, Si, and Na in solution, without compromising material stability, which maintained its performance after six cycles. The material also exhibited highly reversible pseudocapacitive behavior, with a capacitance of 45.5 F·g¹, an energy density of 36.4 Wh·kg¹, and a coulombic efficiency of 88.8%. The proposed approach represents a sustainable solution for the reuse of industrial and electronic waste, contributing to clean technologies, the circular economy, and sustainable development.
