Kinetic Study of 4-Nitrophenol Sonocatalytic Degradation

• Ahmad ADO

  Author

• Abdullahi YAHAYA

  Author

• Abubakar J. MUHAMMAD

  Author

• Zaharaddeen G. SANI

  Author

• Baba A. OLUWA

  Author

• Abdulazeez A. YUSUF

  Author

A heterogeneous CuO/Al₂O₃ (9CuA) catalyst was synthesized by the impregnation method and used in the heterogeneously catalyzed, ultrasonically enhanced degradation of 4-nitrophenol (4-NP). The produced catalyst was characterized using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Brunauer-Emmett-Teller (BET) analysis. The effects of operating variables such as catalyst dosage (0 -1.4 g/L), hydrogen peroxide dosage (0 - 40 mM), initial pH (3.0 - 6.0), degradation system temperature (50 - 70 ^oC), and initial concentration of 4-NP (25-300mg/L) on the degradation of 4-NP were investigated at constant ultrasonic power and frequency of 240 W and 40 kHz respectively. The rate of degradation was found to increase with increases in system temperature from 50-70 °C, in the initial solution pH from 3.0-6.0, and in the initial concentration of 4-NP from 300–25 mg/L. The results also showed that the 4-NP initial concentration of 25 mg/L was degraded to 0.03 mg/L, which is below the United States Environmental Protection Agency (USEPA) acceptable limit of 0.06 mg/L in potable water. Furthermore, the degradation of 4-NP in the system followed pseudo-second-order kinetics with respect to 4-NP, with a rate constant of 0.062 ppm^-1min^-1 at 70 °C. Catalyst stability, assessed by reusability, was good, as 4-NP degradation slightly declined from 99% to 94% after five consecutive experimental runs. The results demonstrate that the ultrasonic-enhanced CuO/Al₂O₃ system is an efficient and reusable treatment method for reducing 4-nitrophenol in water to environmentally acceptable levels.

• FJET_21_52_52

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