Electrochemical treatment of aqueous solutions of catechol byvarious electrochemical advanced oxidation processes: Effect ofthe process and of operating parameters

Catechol, one of the most abundant compounds in olive mills wastewaters, which is generated inthe Fenton degradation of various aromatic compounds, is a toxic, possible carcinogen, persistentpollutant and it is not readily biodegradable. Hence, its degradation requires the utilization ofadvanced oxidation processes (AOPs). Here, the electrochemical treatment of aqueous solutions ofcatechol was investigated. The utilization of various electrochemical processes, such as electroFenton(EF), direct anodic oxidation (AO), indirect oxidation by electro-generated active chlorineand coupled processes was investigated. Furthermore, the effect of various operating conditions(including the nature of anode for AO, the initial pH and the current density) was widely studied inorder to optimize the selected electrochemical processes. For EF process, the effect of the nature ofthe catalyst (homogeneous FeSO4 and heterogeneous pyrite and chalcopyrite) was also analysed. It was shown that both EF and AO, under proper operating conditions, allow a very high removal ofthe TOC, while the indirect oxidation by electro-generated active chlorine is poorly effective. Theutilization of a coupled EF-AO process allowed to enhance the abatement of both catechol ad TOCwith respect to single processes.