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

Abstract

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 m 2/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 Fe 3+ 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.