Influence of the operating conditions on the electrochemical disinfection process of natural waters at BDD electrodes

Abstract

Results are reported of an investigation of the oxidation products formed during electrolyses of aqueous solutions of NaCl, in which the initial concentration of chloride ions was maintained at levels normally present in natural waters. The Design of Experiments (DOE) technique has been used effectively to plan a framework of experiments, in which the main operative parameters: current density, electrolyte stirring rate, and cell geometry, were varied at two levels. Their effects, as well as their possible interactions have been evaluated on the yield of chloride oxidation and on the selectivity of the reaction towards the formation of hypochlorite

Boron-doped diamond electrodes in organic media: Electrochemical activation and selectivity effects

“…2A. The FeðCNÞ 3À=4À 6 redox system is known to provide a sensitive probe for the surface state and reactivity of the boron-doped diamond electrode [38,39]. Curve (i) in Fig.…”

Phenol removal from wastewaters by electrochemical oxidation using boron doped diamond (BDD) and Ti/Ti0.7Ru0.3O2 dsa® electrodes

“…Biological treatment of polluted water is the most economical process and it is used for the elimination of biodegradable organic pollutants present in wastewater; however, when the wastewater contains toxic and refractory organic pollutants, other processes must be employed ( Bevilaqua et al, 2002;Azevedo et al, 2009). One interesting possibility is to couple partial oxidation and biological treatment in order to decrease the toxicity and to increase the biodegradability of the wastewater before biological treatment (Palmas et al, 2007;Anglada et al, 2009).…”

“…In the indirect oxidation process, strong oxidants such as hypochlorite/ chlorine, ozone, and hydrogen peroxide are electrochemically generated and react with the organic molecules in the bulk (Rajkumar and Kim, 2006;Rajkumar et al, 2007). Particularly, chloride has been considered for indirect oxidation since chloride salts are usually found in wastewaters (Oliveira et al, 2001, Palmas et al, 2007. Moreover, the role of active chlorine has been intensively investigated for dye degradation (Ruotolo et al, 2007;Panizza et al, 2007;Montanaro and Petrucci, 2009).…”

Influence of operating conditions and wastewater-specific parameters on the electrochemical bulk disinfection of biologically treated sewage at boron-doped diamond (BDD) electrodes

“…Since it is known that free chlorine can react with organic material to form chlorinated organic compounds on the one hand and can be oxidized to chlorite, chlorate and perchlorate on the other, the formation of such unwanted disinfection by-products (DBPs) has to be investigated prior to each application of this technology [20,21]. The formation of adsorbable organically bound halogens (AOX) was proven in our previous studies [19].…”