The influencing factors and mechanism of degradation of hypersaline tobias acid in electro-catalytic oxidation

Naphthalene organic compounds are produced and consumed widely in China recently, which has brought about great pressure to the local environment. How to cope with naphthalene organic intermediate wastewater (NOIW) effectively becomes an urgent task in the coming years. Electro-catalysts oxidation (ECO), a kind of efficient and convenient technology without secondary pollution, has been broadly applied in biorefractory wastewater treatment. In this paper, Tobias acid was selected as a typical naphthalene organic compound to be treated through ECO, during which sodium chloride was invoked as the electrolyte. The degradation law was investigated under various electrolysis conditions including concentration of tobias acid, current density, concentration of supporting electrolyte sodium chloride, initial pH of the solution. The optimal conditions were as follows: the current density was 150 mA/cm(2), concentration of supporting electrolyte sodium chloride was 5000 mg/L and initial pH was 10.0. In addition, the experiment was carried out to explore the mechanisms of electro-catalytic oxidation in which the electrolyte was changed to sodium sulfate. Results showed that indirect oxidation contributed more to the electrochemical reaction in the tobias acid degradation compared with direct oxidation. Furthermore, some active oxidants such as chlorine, hypochlorous acid and hypochlorite generated by electrolysis of chlorine ions played decisive roles in the indirect oxidation as well as the whole electrolysis process.