Mineralization of C.I. Acid Red 14 azo dye by UV/Fe‐ZSM5/H₂O₂ process

Abstract

The zeolite Fe‐ZSM5 was applied as a heterogeneous catalyst in the photo‐Fenton process for mineralization of azo dye Acid Red 14 (AR14). Under optimal conditions (20 mM of H₂O_2, 0.25 g L⁻¹ of catalyst and initial natural pH of the solution) 76% of total organic carbon (TOC) of a solution containing 40 mg L⁻¹ of the dye could be removed after 120 min in a 1.0 L tubular, closed‐circulation batch photoreactor. Leaching tests and comparative experiments indicated that the application of the heterogeneous catalyst could increase the photo‐Fenton process efficiency. A kinetic model was developed for this process and showed that the dye mineralization rate obeyed the pseudo‐first order kinetic when the initial concentration of the dye was low. It was also observed that the catalytic behaviour of Fe‐ZSM5 could be reproduced in consecutive experiments without a considerable drop in the process efficiency. Estimation of electrical energy consumption (EE/O) of the process as a function of mineralization efficiency revealed that the UV/Fe‐ZSM5/H₂O₂ process not only increased the mineralization efficiency of the process, but also decreased the cost of electrical energy consumed by the process.

Keywords:

• dye degradation
• kinetic model
• activation energy
• heterogeneous photo‐Fenton
• electrical energy consumption