Irradiated electrochemical processes for the removal of persistent organic pollutants from waters

Abstract

Recently, regulations for the control of occurrence of Persistent Organic Pollutants (POPs) on wastewater are considered as an important topic. These compounds have been found in surface, ground and drinking waters, because conventional treatments of wastewater treatment plants are not able to remove them completely. Thus, it is necessary to look for a suitable technology for the removal of POPs from waters and wastewaters efficiently. In the recent years, many works have demonstrated the efficiency and robustness of the application of Conductive-Diamond Electrochemical Oxidation (CDEO) for the treatment of wastewaters contained refractory organic compounds (Brillas et al., 2004, Boye et al., 2006, Cañizares et al., 2006, Cañizares et al., 2008, Brillas et al., 2010, Wang and Li, 2012, Abdessamad et al., 2013, Daskalaki et al., 2013). However, in the treatment of diluted wastewaters (below 1,500 mg COD dm-3), electrolyses may be controlled by the mass transfer rate of pollutant from the bulk to the anode surface and thus, the current efficiency decreases linearly with COD concentration (Comminellis and Pulgarin, 1991). This is what used to be observed in the treatment of wastewaters polluted with POPs (Robles-Molina et al., 2012, Martín de Vidales et al., 2012a, 2012b, 2012c, 2013, Indermuhle et al., 2013), in which these species are typically found at very low concentrations because of their low solubility.