Co3O4 nanoparticles synthesized from waste Li-ion batteries as photocatalyst for degradation of methyl blue dye

Abstract

Cobalt oxide nanoparticles were synthesized from waste Li-ion batteries and characterized using XRD, EDX and FE-SEM. The FE-SEM images depict a spherical shape and a particle size of 47 nm for Co 3 O 4 nanoparticles. The band gap energy of the synthesized cobalt oxide particles was evaluated. The synthesized particles were used for the degradation of methyl blue dye (MYB) under different sources of light. The progress of degradation was monitored using UV–Vis spectroscopic analysis. The effect of various experimental parameters such as catalyst loading, initial concentration of methyl blue, pH of the solution and type of light source were systematically studied in order to achieve maximum degradation efficiency. Experiments were also carried out to investigate the recyclability of the Co 3 O 4 particles for photodegradation. Pseudo first-order kinetics was followed for photodegradation of methyl blue. The synthesized Co 3 O 4 catalyst allowed >86 % dye removal within 45 min. under solar light irradiation. • Co 3 O 4 NPs recovered from waste Li-ion battery used for photo degradation. • Methyl blue is degraded efficiently under solar light in presence of Co 3 O 4 NP. • Quantitative degradation of the dye is achieved at neutral pH. • Co 3 O 4 NPs have been successfully recovered and reused. • Product of a waste being used for remediation of environmental contamination.