Discoloration of dye solution induced by the photolysis of pyruvate

Key words: 
• pyruvate /
• dye /
• Orange Ⅱ /
• photodegradation /
• Fe(Ⅲ)

Abstract: Discoloration of dye Orange Ⅱ, induced by pyruvate under UV irradiation was preliminarily investigated. The effects of pH value, initial concentration of sodium pyruvate, dye and Fe(Ⅲ) on the discoloration were studied in detail. Comparison of the discoloration of four dyes was conducted and the discoloration mechanism was preliminarily studied. A higher discoloration rate of dye in present of pyruvate was obtained. Over the pH range of 3.0～8.0, Orange Ⅱ had very high discoloration rate. The higher initial concentration of pyruvate, the higher discoloration rate and initial discoloration reaction rate were. The higher initial concentration of Orange Ⅱ, the lower discoloration rate was, but the change of initial discoloration reaction rate was small. Adscititious Fe(Ⅲ) could restrain the discoloration of Orange Ⅱ. The result showed that iron(Ⅲ) pyruvate complex could produce ·OH, and the discoloration of Orange Ⅱ was induced by active radicals produced by the photolysis of sodium pyruvate instead of ·OH.