Eric M. Garcia, Hosane A. Taroco, Júlio O. F. Melo, Patrícia A. Rocha, Roseli M. Balestra, Cristiane G. Taroco, Honória F. Gorgulho
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引用次数: 0
Abstract
The increasing environmental burden posed by synthetic dyes and electronic waste demands innovative, sustainable solutions. In this work, we present a green and efficient advanced oxidation process (AOP) employing cobalt ions recovered from spent Li-ion battery (LIB) cathodes to catalyze the degradation of methylene blue (MB), a model organic pollutant. The Co2⁺/HCO₃⁻/H₂O₂ system enabled complete decolorization of a 10 ppm MB solution within 10 min under mild conditions (pH ~ 8.35), with kinetic analysis revealing pseudo-zero-order behavior in MB and half-order dependence on Co2⁺, HCO₃⁻, and H₂O₂. UV–Vis spectroscopy confirmed the formation of the [Co(CO₃)₃]3⁻ complex, while electrospray ionization mass spectrometry (ESI–MS) revealed demethylated intermediates and smaller fragments, suggesting progressive mineralization. Mechanistic insights indicate the predominant formation of carbonate radicals (•CO₃⁻), as supported by isopropanol scavenging experiments. This study highlights the dual environmental benefit of cobalt recovery and wastewater treatment, offering a sustainable pathway for the valorization of electronic waste and the mitigation of textile dye pollution.
期刊介绍:
Ionics is publishing original results in the fields of science and technology of ionic motion. This includes theoretical, experimental and practical work on electrolytes, electrode, ionic/electronic interfaces, ionic transport aspects of corrosion, galvanic cells, e.g. for thermodynamic and kinetic studies, batteries, fuel cells, sensors and electrochromics. Fast solid ionic conductors are presently providing new opportunities in view of several advantages, in addition to conventional liquid electrolytes.