Co₃O₄/TiO₂ hetero-structure for methyl orange dye degradation

Area of Science:

• Environmental Science
• Materials Science
• Catalysis

Background:

• Advanced oxidation processes (AOPs) utilizing sulfate radicals from peroxymonosulfate (PMS) activation show promise for environmental remediation.
• Heterogeneous PMS activation often suffers from catalyst instability and metal ion leaching, hindering practical applications.

Purpose of the Study:

• To develop a stable heterogeneous catalyst for PMS activation with minimized cobalt leaching.
• To investigate the role of Ti substitution in Co3O4 for enhanced catalyst stability and performance in methyl orange degradation.

Main Methods:

• A novel organic binder-mediated route was employed to synthesize Co3O4:TiO2 composite catalysts.
• Catalyst characterization included X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
• Methyl orange degradation efficiency, cobalt leaching, and radical species were evaluated using kinetic studies and quenching tests.

Main Results:

• The Co3O4:TiO2 composite (70:30 ratio) exhibited minimal cobalt leaching (0.9 mg/L) compared to pristine Co3O4 (26.7 mg/L).
• The composite catalyst demonstrated significant catalytic activity for methyl orange degradation, with a rate constant of 0.41 min⁻¹.
• Cobalt ion leaching and catalyst morphology were found to be temperature-dependent, with an optimal temperature ensuring a strong Co-O-Ti bond.

Conclusions:

• The developed Co-O-Ti bond is effective in suppressing cobalt leaching during PMS activation.
• The Co3O4:TiO2 composite catalyst shows good activity, stability, and recyclability for degrading organic pollutants.
• This catalyst presents a promising candidate for commercial applications in environmental remediation.