Abstract:
Electrochemical oxidation (EO), electro-Fenton (EF), and photoelectro-Fenton (PEF) with a BDD anode have been comparatively assessed to remediate solutions of Red CL and/or Red WB azo dyes from real raw water. For the EO process in 50 mM Na2SO4 at pH 3.0, the main oxidant was the heterogeneous •OH generated at the anode, whereas in EF and PEF, the cathodic production of H2O2 and the addition of 0.50 mM Fe2+ catalyst additionally originated homogeneous •OH that enhanced the oxidation of organics. In PEF, the solution was illuminated with a 6 W UVA light. An almost total discoloration was always found operating with a 1:1 mixture of 200 mg L-1 of both dyes in 60 min, whose efficiency increased in the order of EO < EF < PEF. The HPLC analysis of the dye mixture treated by PEF disclosed that its degradation process agreed with its discoloration. A high 74% of COD was reduced due to the oxidative action of hydroxyl radicals and the photolysis of final Fe(III)-carboxylate species with UVA irradiation. The process was accompanied by an energy consumption of 0.76 kWh (g COD)-1, a value similar to the energy consumed by the applied UVA light.
摘要:
电化学氧化(EO),电子芬顿(EF),已对具有BDD阳极的光电Fenton(PEF)进行了比较评估,以从实际原水中修复RedCL和/或RedWB偶氮染料的溶液。对于pH3.0的50mMNa2SO4中的EO过程,主要氧化剂是阳极产生的异质•OH,而在EF和PEF中,H2O2的阴极产生和0.50mMFe2催化剂的添加还产生了均相·OH,从而增强了有机物的氧化。在PEF中,用6W的UVA光照射该溶液。用200mgL-1两种染料的1:1混合物在60分钟内总是发现几乎完全变色,其效率按EO