Electrochemical technologies coupled with biological treatments

Abstract

Manuscript submitted to Current Opinion in Electrochemistry journal for consideration(Special issue "Electrochemical technologies for wastewater treatment")

Review: Clay-Modified Electrodes in Heterogeneous Electro-Fenton Process for Degradation of Organic Compounds: The Potential of Structural Fe(III) as Catalytic Sites

“…In most of these processes, hydroxyl radicals (•OH) are used as the oxidizing agent that nonselectively degrade pollutants into water, carbon dioxide and inorganic salts [9]. However, the most cost-effective techniques to achieve mineralization of pollutants in wastewater involve using AOPs associated with electrochemical technology that are namely electrochemical advanced oxidation processes (EAOPs) as a pre-or post-treatment to biological treatment in order to convert pollutants into intermediate organic compounds [10]. The fundamental features of AOPs are recalled in the following topic with emphasis in Fenton-based processes and related technologies, such as the electro-Fenton process.…”

Nanostructured electrodes for electrocatalytic advanced oxidation processes: From materials preparation to mechanisms understanding and wastewater treatment applications

“…Hybrid processes coupling EAOPs with biological process were developed in order achieve cost-effective treatments [14]. The goal is to decrease the treatment time in order to save electrical energy or to produce electrical energy that is needed for EF treatment.…”

“…Those based on the generation of very strong oxidizing agents such as hydroxyl radical (  OH) (E 0 (  OH/H2O) = 2.80 V / SHE), namely electrochemical advanced oxidation processes (EAOPs), have shown impressive efficiency [7][8][9][10][11][12][13]. They have the ability to generate continuously and in situ the reactive agents in order to remove partially or completely -according to the treatment strategy [14] -a wide variety of organic pollutants, especially the most biorecalcitrant ones present either at high concentration (chemical oxygen demand (COD) = 1 -100 g-O2 L -1 ) or very low concentrations (i.e. micropollutant concentration in the range of ng L -1 to µg L -1 ) [15][16][17][18][19][20][21][22][23][24].…”

“…There are existing reviews on nanostructured carbon-based materials for some electrochemical applications, but mainly for fuel cell, water splitting and electro-analysis [4,[25][26][27][28][29][30][31]. There are also few reviews on electrocatalytic treatments but the use of nanostructured electrode materials is not developed at all [5,[7][8][9]11,14,22,[32][33][34][35]. Thus, there is no detailed and systematic review on nanostructured (carbon-based, metallic-based) electrodes for EAOPs applications.…”

Cost comparison of advanced oxidation processes for wastewater treatment using accumulated oxygen-equivalent criteria

“…Still, the high removal efficiencies (>80-100%) of xenobiotics compounds obtained with AOPs has been emphasized in the comparative work (Rizzo et al, 2020), which explains the increasing deployment of AOPs as advanced physico-chemical treatments (Oturan and Aaron, 2014). Their combination with a biological treatment to remove the biodegradable fraction is particularly encouraged when possible, to decrease the global cost of the treatment (Mousset et al, 2018c;Mousset et al, 2021;Oller et al, 2011;Olvera-Vargas et al, 2016;Rizzo et al, 2020). For all AOPs, the main oxidant -produced in mild conditions (Buxton et al, 1988) -is the hydroxyl radical ( • OH), the strongest oxidizing agent (E o ( • OH/H2O) = 2.80 V / standard hydrogen electrode (SHE)) after fluorine (E 0 (F2/F -) = 3.03 V/SHE), but less hazardous (Pignatello et al, 1999).…”