Decolourization and mineralization of commercial reactive dyes by using homogeneous and heterogeneous Fenton and UV/Fenton processes

摘要

The oxidative decolourization and mineralization of three reactive dyes in separately prepared aqueous solutions C.I. Reactive Yellow 3 (RY3), C.I. Reactive Blue 2 (RB2) and C.I. Reactive Violet 2 (RV2) by using homogeneous and heterogeneous Fenton and UV/Fenton processes have been investigated. The effects of H_2O_2, Fe~(2+) and Fe~0 concentrations, Fe~(2+)/H_2O_2 and Fe~0/H_2O_2 molar ratios at pH 3 and T=23 ± 1 ℃ have been studied. Optimal operational conditions for the efficient degradation of all three dye solutions (100 mg L~(-1)) were found to be Fe~(2+)/H_2O_2 - 0.5 mM/20 mM and Fe~0/H_2O_2 = 2 mM/1 mM. The experimental results showed that the homogeneous Fenton process employing UV irradiation was the most effective. By using this process, the high levels of mineralization (78-84%) and decolourization (95-100%) were achieved. Pseudo-first-order degradation rate constants were obtained from the batch experimental data.