Copper-based Layered Double Hydroxides as Heterogeneous Catalyst for Efficient Ozonation of 4-nitrophenol in Aqueous Solution: Synthesis, Characterization, and Performance Evaluation

ABSTRACT

Co-precipitation was employed to synthesize copper-based layered double hydroxides, which were subsequently utilized as heterogeneous catalysts for the ozonation of 4-nitrophenol in aqueous solutions. Various analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA), were utilized to characterize CuAl-CO₃ and CuAl₅₀₀.The catalytic activity of CuAl-CO₃ was evaluated under different reaction conditions. Notably, at pH 11 and 25 °C, CuAl-CO₃ exhibited high catalytic efficiency in the ozonation of 4NP. Increasing the catalyst dose, initial pH, and temperature led to enhanced 4NP degradation. An optimal pH of 11 and a catalyst dose of 0.3 g. L⁻¹ resulted in the removal of 78.6% of the initial 4NP concentration. Additionally, ozonation proved to be more efficient at temperatures of 10 °C and 55 °C. The kinetics of 4NP ozonation over CuAl-CO₃ and CuAl500 followed a pseudo-first-order reaction. Furthermore, the study demonstrated that CuAl-CO₃ and CuAl₅₀₀ exhibited stability and repeatability across multiple reaction cycles, highlighting their potential for continuous catalytic applications. Overall, this research emphasizes the effectiveness of CuAl-CO₃ and CuAl₅₀₀ as reliable heterogeneous catalysts for the ozonation of 4NP. The results contribute valuable insights into the development of advanced oxidation processes for the treatment of wastewater containing organic contaminants.

GRAPHICAL ABSTRACT

KEYWORDS:

• 4-nitrophenol
• Advanced oxidation process
• Catalytic ozonation
• Layered double hydroxides
• Ozonation
• Wastewater treatment

Acknowledgments

Abderrahmane HIRI expresses gratitude to the University of Adrar for permitting the completion of this study in its facilities. He also thanks the Technical Platform for Physicochemical Analyzes (PTAPC-Laghouat-CRAPC and PTAPC-Ouargla-CRAPC) in Algeria, the Directorate General for Scientific Research and Technological Development (DGRSDT), the Catalysis and Materials for the Environment and Processes Research Laboratory LRCMEP (LR19ES08) in university of Gabès Tunisia, and all of the staff members working at the four laboratories.

Disclosure statement

No potential conflict of interest was reported by the author(s).