Novel catalyst from two-phase olive mill wastes using hydrothermal carbonisation for the removal of methylene blue by heterogeneous Fenton-like oxidation

ABSTRACT

In this study, hydrochars were prepared by hydrothermal carbonisation of two phases olive mill wastes (TPOMW) impregnated with FeCl₃. The produced hydrochars have been used as catalysts in advance oxidation processes for the removal of methylene blue (MB). The effect of residence time, carbonisation temperature and FeCl₃ ratio on hydrochar mass yield and MB removal have been studied and optimised using the response surface methodology. The increase in carbonisation temperature increases the MB removal and induces a reduction in the mass yield. HTC of TPOMW at 250°C during 4 h and with the ratio of FeCl₃ to TPOMW of 1.5 allowed for the production of hydrochar with high mass yield (66%) that was effectively used as a catalyst in heterogeneous Fenton-Like oxidation achieving an MB removal of about 91%. The optimal catalyst can be reused for successive cycles as the catalyst material is stable and have very less iron leaching property.

KEYWORDS:

• Hydrochar
• hydrothermal carbonisation
• catalyst
• response surface methodology
• advance oxidation processes
• MB removal

Acknowledgments

The authors are grateful to the Center of Analyses and Characterization (CAC) of Cadi Ayyad University, Marrakech, Morocco.

Disclosure statement

No potential conflict of interest was reported by the authors.