Reciclagem de lama abrasiva e baterias de íon-lítio para síntese de óxidos mistos aplicados em fotocatálise e armazenamento de energia
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Data
2025-11-24
Autores
Moura , Mayra Nicoli
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Universidade Federal do Espírito Santo
Resumo
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 CoFe₂O₄/γ-Fe₂O₃@SiO₂/NaAlSi₃O₈ 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 LiCoO₂ and graphite carbon. The mixed oxide CoFe₂O₄/γ-Fe₂O₃@SiO₂ was characterized by XRD, ICP-OES, Fouriertransform 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·L⁻¹) at pH 3, using H₂O₂ (0.003 mol·L⁻¹) and 30 mg of catalyst in 50 minutes. The reaction kinetics follow a pseudo-first-order model. After catalysis, XRD and ICPOES 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·g⁻¹, an energy density of 36.4 Wh·kg⁻¹, 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.
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Química ambiental , Reciclagem de lixo eletrônico , Corantes , Catálise , Eletroquímica , Lithium-ion battery , Abrasive sludge , Pseudocapacitor , Fenton reactions