Dimensionally Stable Anode Research Articles

Corrosion modeling of dimensional stable anode modified by graphene compounds through a response surface methodology

The corrosion behavior of a titanium-based electrode with an electrocatalytic coating of TiO2-RuO2 modified by graphene oxide (GO)/reduced graphene oxide (rGO) nanosheets synthesized via a sol-gel method, has been investigated. For this purpose, the central composite design method (CCD) and surface response methodology (RSM) were used to simulate and optimize the graphene compounds additives and the layers of the coating on the linear polarization resistance (LPR) of a dimensionally stable anode (DSA). Also, significant parameters and their interactions were investigated. In order to characterize the synthesized coatings, XRD, FE-SEM, TEM, AFM, potentiodynamic polarization, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) curves were used. The optimal conditions includes the GO concentration of 1.0 mg ml−1, rGO concentration of 0.55 mg ml−1 and the layers of 4, demonstrated the optimal predicted LPR equal to 682.55 kΩ cm−2 and the mean value for the synthesized optimal electrode equal to 694.27 kΩ cm−2, which indicated that the model was suitable and reliable for analyzing the effect of the input parameters on the corrosion resistance of the anodes. The contribution of graphene into the coatings composition increases the corrosion resistance due to the layered structure of nanosheets. On the other hand, by distraction, the penetration of electrolyte to the substrate through the pores, the formation of the middle layer of TiO2 is prevented, which is the main cause of the deactivation of DSAs.

Electrodeposited mesh-type dimensionally stable anode for oxygen evolution reaction in acidic and alkaline media

A mesh-type dimensionally stable anode (DSA) consisting of ruthenium and iridium with low catalyst loading was prepared as an oxygen evolution reaction catalyst in acidic and alkaline media. The electrodeposition (ED) conditions, i.e., applied current density and total cycle number, and ED solutions with different precursor ratios of ruthenium to iridium are examined to fabricate various DSAs with a uniform thickness, and the effect of the iridium content on the catalytic activity is investigated. Among various DSA electrodes, the DSA electrode without iridium exhibits the highest activity and stability in the acidic medium owing to the high ratio of ruthenium. Conversely, the DSA electrode obtained using the ED solution with the ratio of 8:2 exhibits the highest performance in the alkaline medium. This is because the DSA electrode without iridium showed low stability, which is attributed to the dissolution of ruthenium oxide in the alkaline medium. In addition, two large-scale DSA electrodes optimized in the acidic and alkaline electrolytes show excellent performance, indicating the feasibility of the application of this electrode in practical electrolysis.

Electrochemical and Corrosion Characterization of TiO2-RuO2/Ti Electrodes Modified with WO3

DSA (dimensionally stable anodes)-type electrodes (TiO2-RuO2-WO3/Ti) were prepared by the thermal decomposition of proper metal precursor on titanium substrate. Electrochemical and corrosion characteristics of these electrodes were determined in [Fe(CN)6]3−/[Fe(CN)6]4− system and Na2SO4 solution with the application of cyclic voltammetry and chronoamperometry. The electrode active surface area and the activity towards oxygen evolution were evaluated. Moreover, corrosion resistance of the tested electrodes was estimated by determination of basic corrosion parameters. The introduction of WO3 into the oxide layer of the electrodes resulted in a decrease in electrode active surface area and in the number of active sites. The modified electrodes revealed lower activity towards OER but higher activity in organic oxidation. However, their stability was significantly higher in comparison with the non-modified electrode. Corrosion characteristics of the tested electrodes proved the highest corrosion resistance in the case of the electrode modified with 3% WO3. The modification of TiO2-RuO2/Ti with WO3 seems to be advantageous in the application in electrochemical and photoelectrochemical degradation of organic pollutants.Graphical Electrochemical and corrosion characterization of TiO2-RuO2/Ti electrodes modified with WO3 in order to enhance their photoelectrochemical properties in organic pollutant degradation are presented.

Three-dimensionally interconnected titanium foam anode for an energy-efficient zero gap-type chlor-alkali electrolyzer

Chlor-alkali (CA) electrolysis is used to generate high-purity (>99.999%) chlorine and hydrogen gas, in addition to caustic soda (NaOH). Despite its usefulness, the electrochemical process consumes a large amount of electric energy. In this study, Ti foam was employed as the anode, and its morphological and electrochemical properties were compared with those of a dimensionally stable anode (DSA), which is commonly used in CA industries. The morphology and chemical composition of these anodes were examined with scanning electron microscopy (SEM). Porosity was determined by mercury porosimetry. Surface elemental characterization and crystallographic analysis of the electrodes were performed using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The electrochemical performances of the cells employing each electrode were evaluated in terms of chlorine and hydrogen production rate, energy consumption, and hydrogen current efficiency. Finally, chronopotentiometry was carried out to verify the potential of the Ti foam as an energy-efficient anode.

Optimization the selectivity property of graphene oxide modified dimensionally stable anode (DSA) produced by the sol–gel method

The novel mixed metal oxide (MMO) coatings of TiO2–RuO2 modified with graphene oxide (GO)/reduced graphene oxide (rGO) nanosheets were synthesized and investigated on the Ti substrate by the sol–gel approach. Central composite design (CCD) and response surface methodology (RSM) were used to simulate and optimize the graphene compounds additive in the coating. The slope difference in the transpassive region at NaCl and H2SO4 solutions was considered as the significant factor for the selectivity of anode between the competitive evolution reactions of oxygen and chlorine. In order to characterize the coating, XRD, FTIR, FESEM, TEM, AFM tests, CV, polarization, and EIS curves were carried out. The obtained optimal condition included the GO concentration of 0.56 mg ml−1, the rGO concentration of about 0.56 mg ml−1, and the layers number of 4. It was predicted that the optimal selectivity of the graphene modified electrode is approximately 83.189, which was measured to be about 84.944 at the reproducible level. Indeed, the model for simulating the graphene modification was suitable and reliable.

La2O3-CuO2/CNTs electrode with excellent electrocatalytic oxidation ability for ceftazidime removal from aqueous solution

Carbon nanotubes are recognized as an advanced anode material for electrocatalysis oxidation recalcitrant antibiotics in wastewater. In this study, a novel La2O3-CuO2/CNTs electrode was synthesized by solvothermal method and calcination in nitrogen atmosphere. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were conducted to illustrate the structure and elemental composition, and the La and Cu bimetallic composite oxide (La3O2, Cu2O) were observed on the surface of carbon nanotubes. Cyclic voltammetry analysis showed that the modified electrode had better catalytic activity and stable working lifetime. The Tafel curves indicated that the corrosion potential of the electrode increased while the corrosion current density decreased. The degradation of ceftazidime by modified electrode was studied through optimization of five parameters, including current density, electrode space, electrolyte concentration, pH and volume of solution. The results demonstrated that La2O3-CuO2/CNTs electrode exhibited the electrochemical degradation efficiency of 90% towards 1 mg L−1 ceftazidime within 30 min, which is much higher than those of pristine CNTs and dimensional stable anode. The optimal operating conditions were: volume of 100 mL, 1 g L−1 Na2SO4 as electrolyte, current density of 0.8 mA·cm-2, and electrode space is 2 cm. The degradation intermediates and routes of ceftazidime under modified electrode were deduced by LC–MS analysis. These results suggest that La2O3-CuO2/CNTs electrodes can be considered as promising catalysts for treating bio-refractory antibiotics with relatively low concentration.

Possibilities and Constraints of the Electrochemical Treatment of Thiophene on Low and High Oxidation Power Electrodes

In this research, the electrochemical oxidation of thiophene at platinum and dimensionally stable anode (DSA) electrodes as low oxidation power anodes and at lead/lead oxide (Pb/PbOx) and boron-dop...

Reviews the research on some dimensionally stable anodes (DSA) based on titanium

The metal mixed oxides (MMO) such as RuO2, IrO2, TiO2 as excellent catalysts on the surface of dimensionally stable anodes (DSAs) preparing by aqueous solutions of platinum-group metals (PGMs) chlorides for the copper electrolysis has been discussed. One of the possible surface modifications of the new titanium DSAs could be the alloying of the PGMs at low temperatures. This possibility has been described using the synthesis of catalysts for the reaction of crotonaldehyde hydrogenation and their characterization. The discussed results are related to the increase of current density by using alternative types of anodes and charge transfer between specific PGMs as well as chemical reaction engineering, and surface acidity in the catalysts.

Influence of Supporting Electrolytes on Electrochemical Treatability of Reactive Black 5 Using Dimensionally Stable Anode

Dye wastewaters contain significant amounts of toxic organic species and intense color. Electrochemical oxidation has a proven potential to degrade these bio-resistant pollutants. This paper presents the results of indirect electrochemical oxidation of Reactive Black 5 (RB 5) recalcitrant dye wastewater using NaCl, KBr and Na2SO4 as supporting electrolytes. The studies were performed in an undivided batch reactor using indigenously prepared Ti/CoOx–RuO2–SnO2–Sb2O5 electrode classified as dimensionally stable anode (DSA). Characterization of the catalytic coating was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray (EDAX) analysis. Similar operating conditions like electrolyte concentration, pH, current density and electrolysis time were used for all studies. The progress of dye degradation was monitored by estimating reduction in chemical oxygen demand (COD), total organic carbon (TOC) and color. Other performance indicators like average current efficiency (ACE) and energy consumption (EC) were also analyzed. The rate of COD removal followed pseudo-first-order kinetics. The present investigation exhibited highest treatment effectiveness in the presence of chloride compared to bromide and sulfate as degradation was dependent on the generation of highly electroactive oxidative species.

Improving the Stability of DSA Electrodes by the Addition of TiO2 Nanoparticles

Dimensionally stable anodes (DSA) are widely used in water electrolysis, cathodic protection, wastewater treatment, metal electrowinning and chlor-alkali industry. An important parameter of these anodes is their lifetime under harsh anodic conditions. In this work, the incorporation of TiO2 nanoparticles into a thermally prepared IrO2 anode as a way of improving its service lifetime was investigated. The results show that incorporation of up to 25 wt% TiO2 nanoparticles into the coating formed crack-free structure during the thermal decomposition process and thus enhances the service lifetime of modified electrode dramatically by up to 10x compared to the pure IrO2 anode. Importantly, these nanoparticle additions have minimal effect of the anodes performance toward the oxygen evolution reaction. Further addition of TiO2 nanoparticles reduced the lifetime of the anode due to uneven distribution of the active coating over the substrate leading to electrolyte penetration to, and passivation of, the underlying titanium substrate. It is proposed that adding the right quantity of nanoparticles into the IrO2 layer improved the anodes lifetime by minimising electrolyte penetration to the substrate while increasing the mechanical strength of the layer.

The Degradation Behavior of Brightener on Dimensionally Stable Anodes during the Copper Electrodeposition

This study shows the first work that in the copper electroplating bath containing brighteners, the degradation and lifetime of brighteners are mainly determined by the mixed metal oxide (MMO) coating on the anode. We demonstrate that the depolarizing ability and lifetime of bis-3-sulfopropyl-disulfide (SPS), a typical brightener in the copper electroplating bath, are strongly affected by the oxidative activity of the anode. Here, the commercially available IrO2-based and Ta2O5-based dimensionally stable anodes (DSA) are employed in the Cu plating, and the oxidation rate of SPS during the deposition is analyzed. The results reveal the prolonged depolarizing ability and lifetime of SPS in the plating bath when the relatively inert anode, Ta2O5-DSA, is used. The degradation rate of brighteners can be quantified by the voltammetric stripping method and consequently, the variation in the brighteners activity during electrodeposition can be precisely tracked to ensure their functions. Moreover, the inert anode is highly recommended to prolong the function and lifetime of SPS, which is cost-effective and beneficial for circumventing the bath aging issue.

Utilizing discarded SiC heating rod to fabricate SiC/Sb-SnO2 anode for electrochemical oxidation of wastewater

A novel green dimensionally stable anode (DSA) material was fabricated by firstly adopting the discarded SiC heating rod as Supporting material (SiC/Sb-SnO2) for the electrochemical oxidation of wastewater. The obtained SiC/Sb-SnO2 was characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and atomic force microscope (AFM) and its electrochemical properties were studied by cyclic voltammetry (CV), linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The electrode stability, deactivation mechanism and electrochemical oxidation performances of SiC/Sb-SnO2 electrode towards dyes (acid red G and methylene blue) were further investigated and compared with those of Ti/Sb-SnO2 electrode. The results showed that the replacement of Ti substrate with the discarded SiC could effectively increase the loading amount of Sb-SnO2 coating, enhance the compactness of the coating, enlarge the real surface area of electrode and improve the electrooxidation capability of the electrode. Moreover, SiC/Sb-SnO2 electrode exhibited the lower impedance and the higher stability than Ti/Sb-SnO2 electrode. Therefore, the prepared SiC/Sb-SnO2 is a promising anode material that has the merits in the combination of saving electric energy and ensuring the long-term treating efficiency for the practical applications.

Ternary semiconductor metal oxide blends grafted Ag@AgCl hybrid as dimensionally stable anode active layer for photoelectrochemical oxidation of organic compounds: Design strategies and photoelectric synergistic mechanism.

The development of ultra-efficient, sustainable, and easily accessible anode with relative non-precious semiconducting metal oxides is highly significant for application in the practical treatment of organically polluted water. Herein, we report SnO2, TiO2, and Ag2O ternary semiconductor metal oxide blend grafted Ag@AgCl hybrids, prepared with the one-step sol-gel method and applied as a dimensionally stable anode (DSA)-active layer on a SnO2-Sb/Ti electrode. Factors affecting crystal formation, including the presence or absence of O2 during calcination, the calcination temperature, and Ag@AgCl additive dosage were discussed. The micromorphology, phase composition, and photoelectrochemical activity of the newly designed anode were comprehensively characterized. The optimized preparation, which yielded a solid-solution structure with flat and smooth surface and well-crystallized lattice configuration, occurred in the absence of O2 during calcination at 550 ℃ with an Ag@AgCl additive dosage of 0.2 g in the sol-gel precursor. The newly designed DSA displayed improved electrocatalysis (EC) and photoelectrical catalysis (PEC) capacity. The phenol and its TOC removal efficiency reached 90.65% and 58.17% for 10 mA/cm2 current density with a metal halide lamp in 3 h. The lifespan was four times that of SnO2-Sb/Ti electrode. This proposed DSA construction strategy may support improved EC and PEC reactivities toward the decomposition of organic pollutants.

Polarity reversal electrochemical process for water softening

• Polarity reversal has been tested for scale detachment in the electrochemical water softening process. • Effective scale detachment was achieved. • High softening efficiency and low energy consumption could be obtained stably. • The DSA used could keep active steadily in polarity reversal condition. Electrochemical precipitation has attracted widespread attention in the treatment of recirculating cooling water in recent years. In order to guarantee continuous water softening efficiency, periodic scale detachment of cathode is indispensable. Nevertheless, periodic mechanical scrapping, prevalent scale detachment technique currently, increases the interelectrode gap, resulting in the decline of water softening efficiency and the rise of energy consumption. In this paper, polarity reversal was applied in the electrochemical precipitation process for removing scale deposits. The results showed that scale deposits were removed effectively and high water softening efficiency were accomplished steadily. The precipitation rate obtained was 53.9–73.4 g/h/m 2 . The reactor still could remove hardness ions efficiently after the scale detachment by polarity reversal. The energy consumption maintained in the range of 17.3–23.6 kWh/kg CaCO 3 . The total hardness removal efficiency was 16.4–21.4%. Repeated experimental results demonstrated that the electrochemical precipitation process adopting polarity reversal for scale detachment could operate steadily without any performance degradation detected. Cyclic voltammetric investigation showed good electrochemical stability of dimensionally stable anode (DSA) used. Accelerated life test indicated that it could keep active steadily in polarity reversal condition.

Degradation of pesticide mixture by electro-Fenton in filter-press reactor

The efficiency of a prototype equipped with a dimensionally stable anode (DSA) and a carbon felt cathode was analysed by means of H2O2 production and removal of the herbicides diuron (DIU) and glyphosate (GLY) from 0.05 M Na2SO4 solutions, pH 3.0, by electrochemical oxidation (EO), EO with H2O2 electrogeneration and electro-Fenton (EF). Mineralisation current efficiencies and specific energy consumption were also determined. The best performance under galvanostatic conditions was found to be that of the EF, with 1 mM of Fe2+, compressed air flux of 1 L min–1 and current intensity of 1.00 A, for 180 min of treatment, 34% of mineralisation, with 5% current efficiency and specific energy consumption of 0.85 kW h g–1 of total organic carbon was found. A maximal accumulated concentration of 78 mg L–1 of electrolysed H2O2 was achieved in 60 min, and the concentrations of DIU and GLY were reduced by 8% and 94%, respectively. There is a good correlation between the studied flux dispersion in the residence time distribution and the conversion rate verified on degradation, with 100% for GLY and 66.2% for DIU. Two organic by-products as well as short chain carboxylic acids, namely formic, citric and oxalic acid, were detected by LC–MS, and therefore, DIU and GLY degradation mechanisms were proposed.

Electrochemical oxidation disinfects urban stormwater: Major disinfection mechanisms and longevity tests

Although electrochemical oxidation (ECO) has shown excellent potential for disinfecting wastewater and surface waters, its application on urban stormwater has been rarely tested. In order to improve stormwater ECO design, this paper explores the major inactivation processes using Boron Doped Diamond (BDD) and titanium Dimensional Stable Anodes (DSA). Both BDD and DSA showed comparable disinfection rates. The mechanism study suggested that BDD relied on hydroxyl radical and the presence of chloride ions, while DSA disinfected stormwater mainly via the production of free‑chlorine. A deterioration study carried out at a catchment in Melbourne, showed a steady performance for BDD and revealed that DSA's performance degraded with time, likely linked to the high operational voltage required for specific chemistry of stormwater. Scanning Electron Microscopes and an Energy Dispersive X-ray Detector tests confirmed elemental losses occurred on the DSA surface, together with an aluminium/silicon coating layer potentially sourced from the stormwater clayish sediments. Furthermore, disinfection by-products in electrochemical disinfected stormwater using either BDD or DSA were at least one order of magnitude lower than the Australia Drinking Water Guidelines limits. The mechanism and long-term study demonstrated that careful anode selection is required as some anodes will deteriorate in stormwater matrices faster than others.

Synthesis of Ti|IrO2-SnO2-Sb2O3 electrodes without Chloride Precursors and Their Electrochemical Applications

Electrochemical oxidation depends enormously on the electrode materials used during electrolysis. Dimensionally Stable Anodes (DSA) represent a good option for electrochemical oxidation applied to wastewater treatment due to the ability of generating hydroxyl radicals. These radicals are strong, non-selective oxidizing agents, which are able to react with organic pollutants and mineralize them. However, this kind of electrodes is commonly synthesized from chloride precursors, which represents an environmental problem, because they can form undesirable chlorinated by-products during the electrolysis. Some DSA electrodes such as PbO2, SnO2-Sb2O5 and TiO2 are promising anodes due to their high over-potential for oxygen evolution, which leads to the ability of OH radical production; however, their main drawback is the low chemical stability [1, 2]. This disadvantage prevents their use in environmental applications and causes the search for other materials with better properties. In this work we present the synthesis as well as its electrochemical application of a DSA electrode composed of Ti|IrO2-SnO2-Sb2O3. The purpose is enhancing the chemical stability and prolonging the electrode lifetime. The Pechini concept was used to this material, but with the advantage that no chloride precursors were employed [3]. Cyclic voltammetry (CV), X-ray diffraction (DRX), Energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) were used to characterize the as-prepared electrode. The electrocatalytic properties were evaluated by electrochemical degradation of tartrazine in aqueous media as well as dibenzothiophene in organic media. Results showed that noncracked oxide layers were obtained and that the electrode has a great capability for the electrochemical degradation of both molecules. Keywords: DSA electrode, Ti|IrO2-SnO2-Sb2O3, tartrazine, dibenzothiophene X. Chen, G. Chen, Anodic oxidation of dyes at novel Ti/B-diamond electrodes, Chem. Eng. Sci. 58 (2003) 995.X. Chen, G. Chen, F. Gao, P. Yue, High-performance Ti/BDD electrodes for pollutant oxidation, Environ. Sci. Technol. 37 (2003) 5021.M. H. P. Santana, L. M. Da Silva, L. A. De Faria, (2003). Investigation of Surface Properties of Ru-Based Oxide Electrodes Containing Ti, Ce and Nb. Electrochim. Acta, 48 (13), 1885.

Electrocatalytic Coating Electrodes in the All-Vanadium Redox Flow Battery

Redox flow batteries (RFB) are used to reversibly transform electrical energy into chemical energy that can be stored for long periods. They are adaptable and are used for a wide range of storage capacities depending on the electrode areas and the amount of electrolyte used. RFB system’s flexibility and modularity allows them to be easily transported to different environments (at any charge/discharge level) and increase or decrease their capacity to the desired level [1]. One of the most developed RFB systems is the all-vanadium redox flow battery (VRFB) which uses carbon electrodes. However, carbon degrades when used as the positive electrode during charging, which significantly decreases the lifetime of the battery and increases maintenance costs [2]. This is the main reason to test different electrode materials that have been successfully used in other electrochemical applications with similar extreme conditions of operation such as electrowinning and the chlor-alkali industry. In this sense, the so-called Dimensional Stable Anodes (DSA), introduced by Beer in the 1970’s [3], consists in a metallic substrate coated with different oxides which provide improved electrocatalytic properties and high resistance to corrosion. The Pechini and ionic liquid [4] methods of preparation of DSA-type electrodes were chosen to manufacture the electrocatalytic coating electrodes with a composition of on a titanium plate substrate and tested in the positive electrolyte of the VRFB (0.01 mol dm-3 V2O5 in 5 mol dm-3 H2SO4). These methods have proven good morphology and electrochemical performance in the final coating in previous studies [5]. In this particular coating composition, iridium dioxide behaves as the electrocatalytic oxide for the V(IV)/V(V) redox reactions, tin oxide provides stability to the coating oxides solution and the antimony oxide helps to increase the electrical conductivity of the coating. The morphology and physical characteristics of the coating are related to the lifetime of the electrode due to deactivation by detachment of the coating. This failure of the electrode could happen when oxygen passes through the coating to the titanium substrate and leads to the formation of titanium oxides/hydroxides between the substrate and the coating. In this study, the effect of the different preparation methods of electrodes on their morphology and composition were studied through physical characterization (SEM, EDS, XRD). Figure 1 a) and b) show the characteristic mud-cracked morphology obtained by the Pechini method [5] where the width of the cracks are between 1 and 2 µm. Moreover, a semi-homogeneous distribution of the oxides is also seen. In Figure 1 c) and d), the surface of the electrocatalytic coating electrode prepared by the ionic liquid method is more homogeneous with the presence of cracks with a width below 1 µm. The presence of more cracks in the electrode prepared by the Pechini method could lead to a shorter lifetime due to the easier passage of oxygen from the surface of the coating to the titanium substrate. Cyclic voltammetry measurements were used to compare the electrocatalytic properties of the electrodes prepared by both methods towards the V(IV)/V(V) redox reaction. The presentation includes the influence of the preparation method to manufacture the electrocatalytic layer in the electrochemical performance of the electrodes in the positive electrolyte of the VRFB. [1] C. Ponce de León, A. Frías-Ferrer, J. González-García, D. A. Szánto, and F. C. Walsh, "Redox flow cells for energy conversion," Journal of Power Sources, vol. 160, pp. 716-732, 9/29/ 2006. [2] M. Skyllas-Kazacos and F. Grossmith, "Efficient Vanadium Redox Flow Cell," Journal of The Electrochemical Society, vol. 134, pp. 2950-2953, December 1987 1987. [3] H. B. Beer, "Electrode and coating therefor," United States of America Patent 3,632,498, 1972. [4] D. T. Araújo, M. de A. Gomes, R. S. Silva, C. C. de Almeida, C. A. Martínez-Huitle, K. I. B. Eguiluz, et al., "Ternary dimensionally stable anodes composed of RuO2 and IrO2 with CeO2, SnO2, or Sb2O3 for efficient naphthalene and benzene electrochemical removal," Journal of Applied Electrochemistry, vol. 47, pp. 547-561, 2017. [5] T. É. S. Santos, R. S. Silva, C. Carlesi Jara, K. I. B. Eguiluz, and G. R. Salazar-Banda, "The influence of the synthesis method of Ti/RuO2 electrodes on their stability and catalytic activity for electrochemical oxidation of the pesticide carbaryl," Materials Chemistry and Physics, vol. 148, pp. 39-47, 2014. Figure 1

A Basic Study on Accelerated Life Test Method and Device of DSA (Dimensionally Stable Anode) Electrode

A Basic Study on Accelerated Life Test Method and Device of DSA (Dimensionally Stable Anode) Electrode

Non-selective rapid electro-oxidation of persistent, refractory VOCs in industrial wastewater using a highly catalytic and dimensionally stable Ir[sbnd]Pd/Ti composite electrode

Volatile organic compounds (VOCs) are highly toxic contaminants commonly dissolved in industrial wastewater. Therefore, treatment of VOC-containing wastewater requires a robust and rapid reaction because liquid VOCs can become volatile secondary pollutants. In this study, electro-oxidation with catalytic composite dimensionally stable anodes (DSAs)—a promising process for degrading organic pollutants—was applied to remove various VOCs (chloroform, benzene, toluene, and trichloroethylene). Excellent treatment efficiency of VOCs was demonstrated. To evaluate the VOC removal rate of each DSA, a titanium plate, a frequently used substratum, was coated with four different highly electrocatalytic composite materials (platinum group metals), Ir, IrPt, IrRu, and IrPd. Ir was used as a base catalyst to maintain the electrochemical stability of the anode. Current density and electrolyte concentration were evaluated over various ranges (20–45 mA/cm2 and 0.01–0.15 mol/L as NaCl, respectively) to determine the optimum operating condition. Results indicated that chloroform was the most refractory VOC tested due to its robust chemical bond strength. Moreover, the optimum current density and electrolyte concentration were 25 mA/cm2 and 0.05 M, respectively, representing the most cost-effective condition. Four DSAs were examined (Ir/Ti, IrPt/Ti, IrRu/Ti, and IrPd/Ti). The IrPd/Ti anode was the most suitable for treatment of VOCs presenting the highest chloroform removal performance of 78.8%, energy consumption of 0.38 kWh per unit mass (g) of oxidized chloroform, and the least volatilized fraction of 4.4%. IrPd/Ti was the most suitable anode material for VOC treatment because of its unique structure, high wettability, and high surface area.