Oxidation of 2,6-dimethylaniline by the Fenton, electro-Fenton and photoelectro-Fenton processes

Abstract

Fenton technologies for wastewater treatment have demonstrated their effectiveness in eliminating toxic compounds. This study examines how hydrogen peroxide concentration and ultraviolet (UV) light affects oxidation processes. However, total mineralization through these Fenton technologies is expensive compared with biological technologies. Therefore, partial chemical oxidation of toxic wastewaters with Fenton processes followed by biological units may increase the application range of Fenton technologies. Using 2,6-dimethylaniline (2,6-DMA) as the target compound, this study also investigates oxidation intermediates and their biodegradable efficiencies after treatment by Fenton, electro-Fenton and photoelectron-Fenton processes. Analytical results show that the UV light-promoting efficiency, r_PE-F/r_E-F, was 2.02, 2.55 and 2.67 with initial hydrogen peroxide concentrations of 15, 20 and 25 mM, respectively. We conclude that UV irradiation promoted 2,6-DMA degradation significantly. The same tendency was observed for biochemical oxygen demand/total organic carbon (BOD₅/TOC) ratios for each process, meaning that 2,6-DMA can be successfully detoxified using the electro-Fenton and photoelectro-Fenton processes. Some organic intermediates aminobenzene, nitrobenzene, 2,6-dimethylphenol, phenol and oxalic acid—were detected in different oxidation processes.

Keywords:

• 2
• 6-dimethylaniline
• photoelectro-Fenton process
• electro-Fenton process
• mineralization
• biodegradation

Acknolwledgment

The authors would like to thank the National Science Council of Taiwan for financially supporting this research under Contract No. NSC96-2628-E-041-002-MY3.