Modeling of Electrochemical Process for Water Treatment Using Diamond Films

Single and Coupled Electrochemical Processes and Reactors for the Abatement of Organic Water Pollutants: A Critical Review

“…Conversely, if the oxidation of organics occurs by “direct” processes or by active chlorine whose formation is mass transport controlled, the current efficiency for the mineralization of organics should decrease upon enhancement of the current densities and decrease of the flow or the mixing rate. Interestingly, these considerations on the effect of various operating parameters were confirmed by various studies, , including one on the electrochemical incineration of oxalic acid at BDD and Ir-based anodes . In the absence of chlorides, a high current efficiency was obtained when the process was mainly under charge transfer control (i.e., when low current densities and high flow rates were imposed) .…”

“…Despite the scarcity of comparative data in the literature, in the presence of large amounts of Cl – and organics easily oxidized by electrogenerated active chlorine, metal oxide anodes (particularly active anodes such as RuO 2 and IrO 2 ), which are characterized by high current efficiency for the active chlorine generation, low formation of chlorate and perchlorate, high porosity, as well as long-term mechanical and chemical stability, are usually good candidates for the oxidation of organics. Notably, the selection of the anode should be performed having regard to the formation of undesired organochlorinated compounds. , …”

“…Let us individuate these two cases: (b1) the formation of active chlorine in the bulk and ICE AC are usually reported to increase at higher chloride concentrations ,,,, (Figure ) and at higher current density ,,, at BDD, Pt, and metal oxide anodes. As a consequence, under these conditions, an increase of the current density is expected to yield higher abatement of organic pollutants. ,, The effect of the flow or stirring rate on ICE AC is more complicated. Indeed, Polcaro and coauthors reported higher and lower current efficiencies for the generation of active chlorine in dilute aqueous solution of chlorides (from 3.4 to 12 mM) upon increase of the flow or stirring rates (for batch reactors) using BDD and Ti/IrO 2 –RuO 2 , respectively. , The different effect of the flow rate at the DSA and BDD anodes was attributed to the fact that at the BDD anode there is a much more relevant formation of chlorate and perchlorate, which is favored by low flow rates .…”