Kinetic and thermodynamic studies for oxidation of rosaniline hydrochloride dye by persulfate in ambient temperatures

Abstract

The kinetics of the oxidative decolorization of rosaniline hydrochloride by potassium persulfate was studied spectrophotometrically over a pH range of 3.5–9.5 at 30–45°C. The reaction was of second order with respect to dye and half order with respect to persulfate. Increasing the pH of the medium increased the rate of decolorization drastically in alkaline medium. Activation parameters were found to be 62.11 kJ mol⁻¹, 90.33 kJ mol⁻¹, and −98.44 J K⁻¹ mol⁻¹, with respect to activation energy, free energy, and entropy, respectively. The addition of sodium chloride and sodium sulfate had no effect on the rate of decolorization.

Keywords:

• Kinetics
• Mechanism
• Degradation
• Rosaniline
• Persulfate