Catalytic behaviour and copper leaching of Cu_0.10Zn_0.90Al_1.90Fe_0.10O₄ spinel for catalytic wet air oxidation of phenol

Abstract

A Cu_0.10Zn_0.90Al_1.90Fe_0.10O₄ spinel catalyst prepared by the sol–gel method was tested for catalytic wet air oxidation (CWAO) of phenol. The catalyst showed high activity for phenol degradation. During successive test at 170 °C, 100% phenol conversion and 95% chemical oxygen demand (COD) removal were observed. Results from scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) indicated that the catalyst structure remained unchanged during reaction. From the analysis of temperature programmed reduction (TPR), diffuse reflectance UV-Vis spectra (DR UV-Vis) and activity assay at basic solution pH, it can be suggested that the highly dispersed copper ions on the catalyst surface were almost completely dissolved into the reaction solution, whereas the tetra-coordinated copper ions were not only stable against leaching but also active towards phenol degradation.

Keywords:

• catalytic wet oxidation
• spinel
• phenol
• copper
• leaching

Acknowledgements

The authors wish to thank Dr. Xiaoxia Li for the SEM photographs and the FT-IR spectroscopy, and Dr. Songbo He for the TPR analysis.