Electrochemical advanced oxidation processes: today and tomorrow. A review

Abstract

In recent years, new advanced oxidation processes based on the electrochemical technology, the so-called electrochemical advanced oxidation processes (EAOPs), have been developed for the prevention and remediation of environmental pollution, especially focusing on water streams. These methods are based on the electrochemical generation of a very powerful oxidizing agent, such as the hydroxyl radical ((•)OH) in solution, which is then able to destroy organics up to their mineralization. EAOPs include heterogeneous processes like anodic oxidation and photoelectrocatalysis methods, in which (•)OH are generated at the anode surface either electrochemically or photochemically, and homogeneous processes like electro-Fenton, photoelectro-Fenton, and sonoelectrolysis, in which (•)OH are produced in the bulk solution. This paper presents a general overview of the application of EAOPs on the removal of aqueous organic pollutants, first reviewing the most recent works and then looking to the future. A global perspective on the fundamentals and experimental setups is offered, and laboratory-scale and pilot-scale experiments are examined and discussed.

Anodic Oxidation of Chlorinated Pesticides on BDD and PbO2 Electrodes: Kinetics, Influential Factors and Mechanism Determination

“…Such as conventional techniques (filtration, coagulation, flocculation, sedimentation and biological processes), adsorption, membrane processes, chemical oxidation, etc [5]. Its stability and toxicity have caused increased use of advanced oxidation processes (AOPs) for its degradation [6]. Advanced oxidation processes often apply a chemical oxidant for generating reactive radicals to destruct the organic compounds.…”

“…Advanced oxidation processes often apply a chemical oxidant for generating reactive radicals to destruct the organic compounds. Hydroxyl radical ( • OH), a powerful oxidant (E0=2.7 V) [6], is the main oxidative agent in AOPs. There are several techniques used for generating the hydroxyl radical, including chemical, photochemical, sonochemical, and electrochemical processes [7][8][9][10].…”

Removal of atrazine and its by-products from water using electrochemical advanced oxidation processes

“…The hydrogen peroxide can be electrochemically generated at the electrode cathode by oxygen 277 reduction (Brillas et al 2009, Sirés et al 2014, Komtchou et al 2015. This reduction of 278 dissolved oxygen was more favourable in acidic condition for which H 2 O 2 is more stable 279 (Komtchou et al 2015).…”

“…Likewise, in the 290 electrolytic cell H 2 O 2 can be decomposed into hydroxyl radical (Eq. (13)) in the presence UV 291 light (Sirés et al 2014): 292…”

Degradation of the Dye Reactive Blue 4 by Coupled Photoassisted Electrochemistry at DSA®-Type Electrode

“…[16][17][18][19][20][21] To this end, it is necessary to irradiate TiO 2 nanoparticles (in the form of a colloidal suspension or as a thin TiO 2 film deposited onto a conductive substrate) with UV photons of suitable energy, to promote an electron from the valence to the conduction band, and create a positively charged vacant site. 22,23 Thereafter, organic compounds can be oxidized directly by a stable positive hole or (indirectly) by a hydroxyl radical, which is generated from the reaction between the positive hole and a hydroxyl anion/water molecule. 24 In this work, we investigated a photoassisted electrochemical oxidation system employing a homemade Ti/Ru 0.3 Ti 0.7 O 2 electrode.…”