Effective Degradation of Methyl Orange dye by UV/PS Process: kinetics and mechanism

Abstract

This work present photochemical degradation of methyl orange (MO), an azo dye used in textile industry and pH indicator by UV/PS process. In UV/PS process 90.68% degradation of MO occur using, [MO]₀ = 6 mg/L, PS = 0.5 mM and [pH]₀ = 6, for 60 mins, with a maximum k_obs of 0.0407 min^‒1. Similarly the highest degradation was observed at pH 7 with a rate constant of 0.0326 min^‒1, employing MO = 8 mg/L, PS = 0.5 mM and pH = 7, after 60 min. However, the degradation efficiency decreases with increase in methyl orange concentration. Inorganic ions also effect the degradation of methyl orange. The decreasing scavenging effect of ions were: Carbonate> chloride> nitrite> bicarbonate> nitrate. Nevertheless, this study suggests the UV/PS process can be effectively used for the removal of dyes from wastewater.