Photodegradation Study of Sodium Usnate Solution: Influence of pH

Abstract

Photodegradation of 2.6 × 10⁻⁵ M aqueous solutions of sodium usnate at various pH was studied. Photodegradation appeared to follow first-order kinetics and was found to be pH dependent. The degradation rate constant was calculated to be 9.20 × 10⁻⁴ min⁻¹, 5.93 × 10⁻⁴ min⁻¹, 9.69 × 10⁻⁴ min⁻¹, and 9.88 × 10⁻⁴ min⁻¹ at pH 6, pH 7, pH 8, and pH 9, respectively.