Decolorization of C.I. Basic Yellow 28 solution using supported ZnO nanoparticles coupled with photoelectro-Fenton process

The advanced oxidation processes (AOPs), which can produce oxidizing hydroxyl radicals (OH) have been proven to be an efficient method for degradation of the dyes. In this work, the decolorization of a dye solution containing C.I. Basic Yellow 28 (BY28) was performed by photoelectro-Fenton (PEF) combined with photocatalytic process. Carbon nanotube- polytetrafluoroethylene (CNT-PTFE) electrode was used as cathode. The investigated photocatalyst was ZnO nanoparticles having specific surface area (BET) 32.23 m²/g, and mean crystal size 15 nm immobilized on glass plates. A comparison of ultraviolet-C (UV-C), Electro-Fenton (EF), UV/ZnO, PEF and PEF/ZnO processes for decolorization of BY28 solution was performed. Results revealed that color removal efficiency follows the decreasing order: PEF/ZnO > PEF > UV/ZnO > EF > UV-C. The influence of the basic operational parameters including initial dye concentration, applied current, initial pH of the solution, initial Fe³⁺ concentration and kind of UV light on the decolorization efficiency of BY28 was studied. The mineralization of the dye was investigated by total organic carbon (TOC) measurements that showed 94.7% mineralization of 20 mg/l dye at 6 h using PEF/ZnO process. Furthermore, identity of the produced intermediates in the course of mineralization was assessed exploiting gas chromatography-mass spectrometry (GC-MS) analysis.