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New anodes consisting of zirconium-doped PbO2 coating, growth on titanium dioxide interlayer, were deposited on titanium substrates using spin coating method and have been tested for the removal of ampicillin, a β-lactam antibiotic, from water. Morphological, structural, and electrochemical properties of the prepared coatings were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and electrochemical impendence spectroscopy (EIS). Results showed that the incorporation of zirconium dopant had a noticeable modification in the morphology of anodes. An increase in the surface roughness and the specific active area were observed with Ti/TiO2/PbO2- 10% Zr electrode compared to other anodes. The electrochemical measurements indicated that the anode doped with 10% Zr showed a more protective coating performance than the undoped and 20% Zr-doped PbO2 electrodes. The experiments on ampicillin degradation revealed that doped lead dioxide anodes have excellent electrocatalytic activity. The major byproduct generated during anodic oxidation treatment has been identified as ampicilloic acid by liquid chromatography-mass spectroscopy (LC–MS) analysis. Results demonstrated that Ti/TiO2/PbO2- 10% Zr anode presents the best removal rate of ampicillin with a minimum intermediate amount, which leads to conclude that 10% is the optimum percentage of zirconium dopant for antibiotic wastewater treatment. [ABSTRACT FROM AUTHOR]

This research investigates the utilization of a modified Ti/nano ZnO-Bi2O3 electrode for the electrochemical advanced oxidation-based removal of a pharmaceutical pollutant from an aqueous solution. To analyze the surface properties of Ti/nano ZnO, Ti/nano Bi2O3, and Ti/nano ZnO-Bi2O3 electrodes made using electrophoretic deposition, various analytical methods were used. These methods included X-ray diffraction analysis, energy-dispersive spectroscopy, and field emission scanning electron microscopy confirmed the presence of ZnO nanoparticles and Bi2O3 nanoparticles in a layer that is uniformly coated on the Ti/nano ZnO-Bi2O3 electrode. Beside linear sweep voltammetry and Tafel plots confirmed the increased stability and electrocatalytic activity of the modified electrode compared to the initial electrode. Chronopotentiometry and chronoamperometry verified the stability and better conductivity of the nanocomposite electrode, and according to electrochemical impedance spectroscopy, charge transfer in the modified electrode has improved by 87%. We evaluated the effectiveness of the Ciprofloxacin removal process by considering factors, such as pH in the range of 3–11, electrolyte concentration in the range of 1–7 g L−1, and current density in the range of 1.2–5.75 mA cm−2. We selected Ciprofloxacin as the specific pollutant for evaluating pollutant removal from aqueous solutions due to its widespread use and presence in the environment. We determined the optimal parameter values to be 6.25 mA cm−2, 5, and 3 g L−1. Under these optimal conditions, the efficiency of ciprofloxacin removal reached 96.33% within 300 min. [ABSTRACT FROM AUTHOR]

The degradation of industrial dyes poses a significant environmental challenge due to their persistence and toxicity. Developing efficient and stable electrode materials for the electrochemical degradation of methylene blue (MB) is crucial for addressing environmental concerns associated with dye pollution. This paper describes the synthesis and electrochemical performance of Cu(Cr0.1,Al0.9)2O4 as a potential electrode material for the degradation of MB. The material was elaborated via nitrate synthesis and heat-treated at 900 °C. Then, characterized using various physico-chemical techniques. For all the electrochemicals tests, an anode based on Cu(Cr0.1,Al0.9)2O4 was prepared by adding activated carbon (AC), NMP and PVDF as binder agents. Preliminary electrochemical tests indicated that the degradation of MB occurred via an indirect oxidation mechanism, which needs the integration of a supporting electrolyte. In this case, the electrolyte consists of mixture of Na2SO4 and NaCl at equal proportions (in volume). The pH study showed that the degradation efficiency was found vary between 92.4% and 97.2% at pH range 2–11. The electrode also exhibited excellent performance irrespective the dye concentrations, with efficiencies ranging from 91 to 99% for solutions at 6.4 to 40 ppm of MB. The prepared electrode revealed a maximum degradation efficiency of 99% (within 50 min) at 50 mA applied current, for a 20 ppm MB solution. A higher current is required to decontaminate a concentrated solution. On the other hand, increasing the current reduces the electrolysis time. For a 40 ppm solution, the degradation efficiency reached 97.4% at an applied current of 70 mA within only 40 min. [ABSTRACT FROM AUTHOR]

The principle of Fenton reagent is to produce ·OH by mixing H2O2 and Fe2+ to realize the oxidation of organic pollutants, although Fenton reagent has the advantages of non-toxicity and short reaction time, but there are its related defects. The Fenton-like technology has been widely studied because of its various forms and better results than the traditional Fenton technology in terms of pollutant degradation efficiency. This paper reviews the electro-Fenton technology among the Fenton-like technologies and provides an overview of the homogeneous electro-Fenton. It also focuses on summarizing the effects of factors such as H2O2, reactant concentration, reactor volume and electrode quality, reaction time and voltage (potential) on the efficiency of electro-Fenton process. It is shown that appropriate enhancement of H2O2 concentration, voltage (potential) and reaction volume can help to improve the process efficiency; the process efficiency also can be improved by increasing the reaction time and electrode quality. Feeding modes of H2O2 have different effects on process efficiency. Finally, a considerable number of experimental studies have shown that the combination of electro-Fenton with ultrasound, anodic oxidation and electrocoagulation technologies is superior to the single electro-Fenton process in terms of pollutant degradation. [ABSTRACT FROM AUTHOR]

The mixed wastewater generated by anodic oxidation coating facilities contains high levels of various contaminants, including iron, aluminum, conductivity, chemical oxygen demand (COD), and sulfate. In this study, the effectiveness of the membrane distillation (MD) process using polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) membranes was investigated to treat mixed wastewater from an anodized coating factory. The results indicate that both hydrophobic membranes effectively removed targeted contaminants. However, the PTFE membrane achieved higher removal efficiencies, with over 99% removal of sulfate, conductivity, iron, and aluminum, 85.7% of COD, and 86% of total organic carbon (TOC). In contrast, the PVDF membrane exhibited a significant decline in removal efficiency as the temperature increased and performed well only at lower feed temperatures. The PTFE membranes outperformed the PVDF membranes in treating chemically intensive anodic oxidation wastewaters. This superiority can be attributed to the PTFE membrane's morphology and structure, which are less influenced by feed water temperature and chemicals. Additionally, its slippery surface imparts anti-adhesion properties, effectively preventing membrane fouling, and maintaining the treated water quality and flux for longer operation time. [ABSTRACT FROM AUTHOR]

Mg-rare earth (RE) alloy, i.e., Mg-1Zn-1Gd (ZG11), was treated by a conventional pulse anodization process. The effect of electrical parameters (processing time, duty cycle and applied current) on the microstructure and corrosion resistance of anodized film was investigated by orthogonal method. SEM and XRD were used to characterize the microstructures and compositions of anodized films. Polarization curve, electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) were performed to evaluate the corrosion resistances of anodized samples. The results show that with the employment of appropriate electrical parameters, corrosion resistance of ZG11 alloy can be significantly enhanced (icorr decreases by nearly three orders of magnitude) after anodized for less than 2 min. Besides, the optimal sample selected from orthogonal experiments in terms of the thickness and porosity of anodized film appropriately matches with the sample with the best corrosion resistance determined by electrochemical corrosion measurements, indicating the strong relationship between the thickness and porosity of anodized film and its corrosion resistance. Additionally, results of cell proliferation tests demonstrate that the varied surface morphologies and microstructure characteristics of the anodized samples in the present study do not necessarily influence the related cytocompatibilities. The study helps to further understand the effect orders of different current parameters on the structure and properties of anodized film and therefore provides a high-efficiency and low-energy consumption way to manufacture Mg alloys with excellent corrosion resistances. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The electrochemical behavior of the biologically active redox chemicals is essential in point of view antibacterial activity. In some cases, the electronic exchanges are coupled to chemical reactions that produce new oxidative or reductive species, which might form electrodeposits. This contribution presents a comparative study of the antibacterial activities and the anodic oxidation of S-triazino-benzimidazole derivatives substituted at the triazine ring with phenyl, 4-fluorophenyl and pentafluorophenyl groups. By combining bactericidal screening against E. coli, P. aeruginosa, S. aureus, and S. typhimurium, to a cyclic voltammetry investigation, it was revealed that the fluorine phenyl substituents in the S-triazine benzimidazole derivatives enhance the electrons ejection to the platinum disk and the subsequent chemical reactions. Additionally, by cycling of potential the non-fluorinated chemical produces a rather passive film on the electrode surface, whereas the fluorinated ones generate electroactive and electrocatalytic coatings. Comparing the results obtained with S-triazino-benzimidazole derivatives to those with 2-aminobenzimidazole, plausible mechanisms of their bactericidal action are suggested. [ABSTRACT FROM AUTHOR]

The electrochemical behavior of a flat gold electrode in an acetonitrile solution of 3-(1,4-dimethyl-2,3,5,6-tetraoxabicyclo[2.2.1]hept-7-yl)propanoic acid was studied by cyclic voltammetry. The formation of colloidal gold particles was detected during the anodic oxidation. The kinetics of their formation was studied by the gravimetric method. Peroxide bonds in the cyclic peroxide molecule were found to be reduced on the cathode surface with the subsequent formation of the diketone fragment. [ABSTRACT FROM AUTHOR]

The recent advances in the area of electrophotocatalysis (EPC) show that it is a highly suitable technique to yield greener and more sustainable organic synthesis. The overall productivity of EPC however is constrained by a multitude of practical limitations, which impose difficulties in effectively harmonizing the photochemical and electrochemical steps, let alone in accelerating both steps simultaneously. In this contribution, we have tackled these limitations by developing a parallel plate flow cell that permits the execution of EPC in continuous flow. By using a transparent electrode, such as fluorine-doped tin oxide (FTO) or indium tin oxide (ITO) coated glass, the interelectrode distance could be reduced while improving photon absorption. By enhancing both the photochemical and electrochemical steps simultaneously, a notable increase in productivity and space–time-yield (a ten-fold and 300-fold improvement, respectively) of the N-arylation of different azoles was observed. In addition, this was achieved in a single-pass process under electrolyte-free conditions. Highlights: • We have created a flow cell that incorporates a transparent electrode, allowing simultaneous photochemical and electrochemical activation. • By using a parallel energy input, a productivity increase for the N-arylation of different azoles under electrolyte-free conditions was observed. • A single pass sufficed to reach high conversions, rendering this a true continuous flow process. [ABSTRACT FROM AUTHOR]

The electrocatalytic activity of electrode materials synthesized by anodic selective dissolution of Ag–Pd alloys based on silver (4 and 8 at % Pd) was studied. Kinetic regularities of formic acid electrooxidation on palladium and anodically modified Ag–Pd alloys in an acidic sulfate solution have been established. The process includes the diffusion of HCOOH, its dissociative chemisorption, and irreversible ionization of atomic hydrogen. The conditions for formic acid anodic oxidation on Pd and Ag–Pd alloys were determined depending on the composition of the electrode system and the mode of preliminary electrochemical modification (selective dissolution) of the alloy using transient electrochemical measurements. The role of the surface development of an alloy in the kinetics of anodic degradation of formic acid was revealed. It was shown that the selective dissolution of Ag–Pd alloys contributes to a noticeable increase in the rate of the kinetic stage of atomic hydrogen ionization. A necessary condition for the activation of the anodically modified alloy in relation to the electrooxidation of HCOOH is the excess of both critical parameters (charge and potential) corresponding to the onset of morphological development and phase transformations in the surface layer of the Ag–Pd systems. [ABSTRACT FROM AUTHOR]

The results of studying the processes of formation of silicon oxide nanolayers by the method of molecular layering (atomic layer deposition) on the surface of films of tantalum and niobium oxides obtained by electrochemical oxidation of the corresponding metals are presented. Studying the electrical strength of metal-dielectric-metal (MDM) structures based on tantalum and niobium oxides shows that the introduction of an additive dielectric layer (SiO2) allows us to significantly increase the electrical strength of these structures. [ABSTRACT FROM AUTHOR]

In recent years, clean water has become increasingly scarce because of the highly consumption by human and industry. Therefore, a huge amount of wastewater was discharged to the environment and their treatment is essential by using cost-effective methods. In this study, wastewater from petroleum refinery was processed by an electrochemical oxidation using two types of anodic materials graphite and SnO2 film deposited on Cu substrate. SnO2 anode was prepared from nitrate media and characterized by XRD and SEM. Experiments were conducted to determine the performance of each electrode at a current density of 12 mA/cm2 in the absence of NaCl addition. The SnO2 electrode showed better processing ability than the graphite electrode at the same current density in case of no addition of NaCl. Addition NaCl resulted in increasing the activity of graphite in the treatment of wastewater but never exceeded the efficiency of SnO2. The best removal of chemical oxygen demand (COD) at a current density of 12 mA/cm2 and 150 min was 79% in case of SnO2 in comparison with 72% in case of using graphite with addition of NaCl. Energy consumption in case of SnO2 was 9.93 kWh/kg COD which is very low in comparison with the using of graphite (49.6 kWh/kg COD). The decay of COD was found to obey pseudo first order for anodic oxidation using SnO2 or graphite electrodes. [ABSTRACT FROM AUTHOR]

TiO2 films with a 1D nanotube structure were obtained by electrochemical anodic oxidation of titanium foil. Electrochemical reductive activation of the TiO2-nanotube-based electrodes was carried out using the method of cyclic voltammetry. The activated electrodes showed significantly higher current density and quantum efficiency of the photoelectrochemical water splitting as compared to native TiO2 nanotubes. Electrochemical treatment of the electrodes by the cyclic voltammetry leads to increase in the photocurrent density by a factor of 4 to 14, depending both on the used wavelength and applied potential. The analysis of electrochemical impedance spectra showed that the increase in the photoelectrochemical process performance is due to increase in the charge transfer rate at the semiconductor/electrolyte interface, as well as improved electronic conductivity of the oxide layer, which contributes to better charge carrier separation and decrease in their recombination rate. [ABSTRACT FROM AUTHOR]

Organic pollutant removal can be realized via electrochemical degradation, and anodic oxidation plays an important role in the degradation process. However, the degradation process is hindered by low removal efficiency and reusability. In this study, a PbO2 electrode and a Mn-doped PbO2 (Mn-PbO2) electrode were prepared via electrodeposition. Different from the traditional method of increasing the oxygen evolution potential (OEP) of PbO2 electrode, such as introducing Ce, Bi, and La in PbO2 electrode, introducing Mn in PbO2 electrode promoted the generation of strong oxidant MnO4 under electrolytic conditions to remove organic pollutants. The Mn-PbO2 electrode was used for anthracene (ANT) degradation and the results showed that an ANT removal efficiency of 91.28% was achieved in 120 min under the most suitable operational variables, namely, a Na2SO4 concentration of 0.1 M, initial pH of 7, and current density of 20 mA/cm2. In addition, the ANT degradation mechanism was analyzed. Given that the Mn-PbO2 electrode exhibited better removal efficiency in the wide pH range and remarkable degradation efficiency compared with the PbO2 electrode, the Mn-PbO2 electrode has practical application prospects for organic pollutant degradation. [ABSTRACT FROM AUTHOR]

The textile industry contributes significantly to environmental pollution through dyeing and finishing processes that release dyes into wastewater. Even small amounts of dyes can have harmful effects and cause negative impacts. These effluents have carcinogenic, toxic, and teratogenic properties and can take a long time to be naturally degraded through photo/bio-degradation processes. This work investigates degradation of Reactive Blue 21 (RB21) phthalocyanine dye using anodic oxidation process with PbO2 anode doped with iron III (0.1 M) (marked as Ti/PbO2-0.1Fe) and compared with pure PbO2. Ti/PbO2 films with and without doping were successfully prepared by electrodeposition technology on Ti substrates. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS) was used to characterize the electrode morphology. Also, linear scanning voltammetry (LSV) and cyclic voltammetry (CV) tests were conducted to investigate the electrochemical response of these electrodes. The influence of operational variables on the mineralization efficiency was studied as a function of pH, temperature, and current density. Doping Ti/PbO2 with Fe3+ (0.1 M) could reduce the particle to a smaller dimension and slightly increase the oxygen evolution potential (OEP). A large anodic peak was found for both electrodes prepared in the CV test, indicating that oxidation of the RB21 dye was easily achieved on the surface of the prepared anodes. No significant effect of initial pH on the mineralization of RB21 was observed. RB21 decolorization was more rapid at room temperature and increases with increasing current density. A possible degradation pathway for the anodic oxidation of RB21 in aqueous solution is proposed based on the identified reaction products. In general, it can be said that from the findings it was observed that the Ti/PbO2 and Ti/PbO2-0.1Fe electrodes show good performance on RB21 degradation. However, it was noted that the Ti/PbO2 electrode tends to deteriorate over time and exhibits poor substrate adhesion, while the Ti/PbO2-0.1Fe electrode displays superior substrate adhesion and stability. [ABSTRACT FROM AUTHOR]

Dyeing wastewater treatment remains a challenge. Although effective, the in-series process using electrochemical oxidation as the pre- or post-treatment of biodegradation is long. This study proposes a compact dual-chamber electrocatalytic biofilm reactor (ECBR) to complete azo dye decolorization and mineralization in a single unit via anodic oxidation on a MnOx/Ti flow-through anode followed by cathodic biodegradation on carbon felts. Compared with the electrocatalytic reactor with a stainless-steel cathode (ECR-SS) and the biofilm reactor (BR), the ECBR increased the chemical oxygen demand (COD) removal efficiency by 24 % and 31 % (600 mg/L Acid Orange 7 as the feed, current of 6 mA), respectively. The COD removal efficiency of the ECBR was even higher than the sum of those of ECR-SS and BR. The ECBR also reduced the energy consumption (3.07 kWh/kg COD) by approximately half compared with ECR-SS. The advantages of the ECBR in azo dye removal were attributed to the synergistic effect of the MnOx/Ti flow-through anode and cathodic biofilms. Catalyzed by MnIV=O generated on the MnOx/Ti anode under a low applied current, azo dyes were oxidized and decolored. The intermediate products with improved biodegradability were further mineralized by the cathodic aerobic heterotrophic bacteria (non-electrochemically active) under the stimulation of the applied current. Taking advantage of the mutual interactions among the electricity, anode, and bacteria, this study provides a novel and compact process for the effective and energy-efficient treatment of azo dye wastewater. [ABSTRACT FROM AUTHOR]

Fe3+ and/or carbon black-doped Ti/PbO2 electrodes were successfully synthesized via electrodeposition technology. The morphology and crystal structure of the electrodes were characterized by Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy (SEM/EDS) and X-ray Diffraction (XRD), respectively. Furthermore, Linear Sweep Voltammetry, Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy tests were also performed to analyze the electrochemical performance of the electrodes. The electrocatalytic activity of electrodes was examined by electrocatalytic oxidation of Reactive Yellow 14 (RY14) azo dye's model pollutant. The SEM showed that the morphology and size of PbO2 particles are strongly affected by doping with Fe3+ and carbon black. The EDS confirmed the existence of Fe and C elements. The XRD patterns show that samples were composed of higher content of β-PbO2. Ti/PbO2-0.1Fe (0.1 M Fe3+ + 0 g C) electrode exhibits the highest oxygen evolution potential (1.64 V/SCE). The CV test indicated that the presence of the anodic peak at 1.45 V/SCE means that the oxidation of RY14 dye was easily achieved on the surface of all prepared electrodes. The Nyquist plots show the presence of two semicircles, one in the high-frequency domain describes the electron transfer process, while the second in the low-frequency domain explains the adsorption of the intermediate. Ti/PbO2 and Ti/PbO2-0.1Fe electrodes showed the best performance on degradation of RY14. [ABSTRACT FROM AUTHOR]

The synthesis of aryl iodides from commercially available raw chemicals by simple, cheap and green strategies is of fundamental significance. Aryl iodides can undergo a series of homo-/cross-coupling reactions for the synthesis of important industrial chemicals and materials. Traditional methods require the electrophilic substitution on aromatic compounds by iodine or hypervalent iodine compounds, which suffers from the use of erosive halogens or hazardous oxidants. With the development of green chemistry in the field of electrochemical synthesis, anodic oxidation-derived I+ cations have been used for substitution reactions. However, the selectivity of the iodination by these electrochemical methods remains unsatisfactory. We believed that the anolyte is contaminated by trace platinum species from the working electrode. Herein, we report the generation of active I+ species from the anodic oxidation of I2 in acetonitrile using a glassy carbon electrode. With the presence of H+, electrolyte prepared with a glassy carbon anode can react with anisole to selectively form 4-iodoanisole with a yield as high as 97%. On contrast, the electrolytes prepared from Pt and graphite anodes finished the reaction with yields of 16% and 60% for 4-iodoanisole, respectively. This electrochemical method also applies to the iodination of toluene, benzonitrile and bromobenzene, delivering the target para-iodination products with 92%, 84%, and 73% yields, respectively. Thus, an atom-efficient and highly selective aryl iodination method was developed without the use of excessive oxidants. [ABSTRACT FROM AUTHOR]

Anodic oxidation of silver–zinc alloys with a concentration of zinc of up to 30 at.% (alpha phase) in a deaerated aqueous solution of 0.1 M KOH was studied by voltammetry and chronoamperometry with synchronous registration of the photocurrent. A preliminary modification of the alloy surface due to the selective zinc dissolution, with monitoring of the potential and charge, was carried out in a deaerated aqueous solution of 0.01 M HNO3 + 0.09 M KNO3. As a result of the modification, the surface layer of the alloy was enriched with an electropositive component and vacancies, whose concentration exceeded the equilibrium concentration. The anodically formed Ag(I) oxide was characterized by an n-type conductivity and the predominance of donor defects in the crystal lattice. Their concentration increased and the width of the space charge region of the semiconductor oxide decreased with an increase in the concentration of non-equilibrium vacancies in the surface layer of the alloy. [ABSTRACT FROM AUTHOR]

The modification of an iron electrode was carried out according to the following two steps. In a first step, a cathodic reduction is performed to form a film of metallic lead on a bare iron electrode, in 5 mol m−3 + 50 mol m−3 KNO3 solution, at −0.8 V/SCE during 300 s. In a second step, the film of metallic lead is converted to PbO2 in 100 mol m−3 NaOH solution, at + 0.7 V/SCE during 150 s. EDX, X-ray diffraction and scanning electron microscopy analysis, confirm that Pb metal and α-PbO2 are successfully deposited. The electrocatalytic activity of the resulting oxide is assessed for the indigo-carmine (IC) dye degradation reaction, using potentiostatic method. The IC dye was successfully oxidized by hydroxyl radical electrogenerated from oxidation of water on the Fe/Pb/α-PbO2 electrode. These results suggest that Fe/Pb/α-PbO2 electrode is a promising candidate for electrocatalytic degradation of IC wastewater. [ABSTRACT FROM AUTHOR]

Maskless anodic oxidation with a continuous free jet of electrolyte can be used for the local surface functionalization and structuring of aluminum materials. In this study, a two-phase jet was applied with the aim of enhanced lateral confinement of the anodic oxide on the aluminum alloy EN AW-7075. The two-phase jet was realized by a coaxial arrangement. While the inner electrolyte nozzle with a diameter of 100 µm acted as the cathode and was used to provide the electrolyte with a flow rate of 10 ml min−1 resulting in an average jet velocity of approximately 21 m s−1, the outer nozzle with a diameter of 3000 µm was used to provide deionized water with a flow rate of 383 ml min−1 resulting in an average water jet velocity of 1 m s−1, which is sufficient to realize a continuous free two-phase jet. Process voltages from 10 to 60 V were investigated. The realized oxide layers were characterized by non-destructive as well as destructive methods to determine their microstructure and their thicknesses. Optically transparent anodic oxide layers were achieved in the voltage range between 10 and 25 V. Maximum total layer thicknesses between 1.1 µm and 16.9 µm were measured in these cases. Thicknesses of more than 50 µm were determined for higher voltages up to 60 V; however, burning effects and stronger discolorations were determined for voltages ranging from 30 to 60 V. Consequently, 25 V was derived as best suitable voltage for two-phase anodizing with high growth rate leading to oxide layers with low defects.Graphical abstract: Maskless anodic oxidation with a continuous free jet of electrolyte can be used for the local surface functionalization and structuring of aluminum materials. In this study, a two-phase jet was applied with the aim of enhanced lateral confinement of the anodic oxide on the aluminum alloy EN AW-7075. The two-phase jet was realized by a coaxial arrangement. While the inner electrolyte nozzle with a diameter of 100 µm acted as the cathode and was used to provide the electrolyte with a flow rate of 10 ml min−1 resulting in an average jet velocity of approximately 21 m s−1, the outer nozzle with a diameter of 3000 µm was used to provide deionized water with a flow rate of 383 ml min−1 resulting in an average water jet velocity of 1 m s−1, which is sufficient to realize a continuous free two-phase jet. Process voltages from 10 to 60 V were investigated. The realized oxide layers were characterized by non-destructive as well as destructive methods to determine their microstructure and their thicknesses. Optically transparent anodic oxide layers were achieved in the voltage range between 10 and 25 V. Maximum total layer thicknesses between 1.1 µm and 16.9 µm were measured in these cases. Thicknesses of more than 50 µm were determined for higher voltages up to 60 V; however, burning effects and stronger discolorations were determined for voltages ranging from 30 to 60 V. Consequently, 25 V was derived as best suitable voltage for two-phase anodizing with high growth rate leading to oxide layers with low defects. [ABSTRACT FROM AUTHOR]

The 2024 anodized aluminum alloy film was sealed by KAl(SO4)2 solution and the effect of sealing on corrosion resistance was investigated by means of potentiodynamic polarization curves, electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. The experimental results show that the optimal parameters for KAl(SO4)2 sealing are 35 °C, with the pH value of 8, the concentration of 8 g/L, and the sealing time of 3 min. The corrosion resistance of the KAl(SO4)2 sealed sample can be significantly improved than that of unsealed one, and is obviously superior to that of the conventional hydrothermal sealed sample. Furthermore, X-ray photoelectron spectroscopy demonstrates that more Al(OH)3 will be formed in the process of KAl(SO4)2 sealing, which will shrink the diameter of the microporous and therefore results in the excellent corrosion resistance. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigated the morphology, structure and tribological properties of the three samples produced by anodic oxidation of Ti10V2Fe3Al in a sulfuric/phosphoric acid electrolyte (SPA), a near-neutral sodium tartrate electrolyte without nanoparticles (STA) and a near-neutral sodium tartrate electrolyte with polytetrafluoroethylene (PTFE) nanoparticles (CA) in suspension. The STA film had a surface full of bulges and cracks, the SPA film was porous, and the CA film was nanoporous. The SPA film was mainly composed of anatase TiO2, whereas the STA and CA films were mainly amorphous TiO2 with little anatase. The tribological tests indicated that the SPA sample had a lower wear resistance than the titanium alloy substrate, which was attributed to the shedding of abrasive debris, leading to rapid wear. Both STA and CA samples exhibited much lower wear rates than the titanium alloy substrate, and CA sample displayed the lowest wear rate attributed to the formation of a lubricating layer by PTFE nanoparticles. The wear mechanisms are proposed. [ABSTRACT FROM AUTHOR]

How to improve the corrosion resistance and icing-delay ability of metal in practice is still a big challenge. Herein, a ZnO surface with superhydrophobicity was fabricated by combining anodic oxidation and surface modification on zinc substrate. The effects of topographies and chemical composition on surface wettability were discussed in detail. The water contact angle and roll-off angle on the optimal superhydrophobic ZnO surface is about 161.0° and 5°, respectively. The results reveal the self-cleaning property, the corrosion resistance and icing-delay ability of the as-prepared sample were improved due to the superhydrophobic treatment. The method adopted here is facile and the cost is low, which is believed to afford a new idea for the design and construction of superhydrophobic surface on metal-based materials and broaden its potential application in anti-corrosion and icing-delay fields. [ABSTRACT FROM AUTHOR]

4-Hydroxybenzophenone (4-OH-BP), a highly toxic and widely used pharmaceutical and personal care products (PPCPs), has been obtained growing concern recently. Electrochemical anodic oxidation technology has been confirmed efficient in eliminating organics from aqueous solution. In this work, we constructed two novel PbO2 electrodes by modifying the middle or active layer with graphene oxide (GO) to degrade aquatic 4-OH-BP. Compared with the pristine PbO2 electrode, the modification by GO could enhance the anchor of the active layer (PbO2 particles) onto the middle layer and improve the isolation of the titanium matrix from the active layer and solution. Therefore, we might obtain the better performance of PbO2 electrodes after modification. Under the experimental conditions optimized by the Box-Behnken design model, as we expected, two novel electrodes (with modified middle layer: 99.85%; with modified active layer: 100%) outperformed the pristine electrode (95.46%) for 4-OH-BP degradation. We proposed the catalytic mechanism of GO-modified electrodes for 4-OH-BP and the degradation pathway of 4-OH-BP and evaluated the toxicity of intermediates based on the quantitative structure-activity relationship model. Furthermore, two GO-modified PbO2 electrodes consumed less energy than commercial boron-doped diamond electrode, reflecting the prominent practicability of GO-modified PbO2 electrode. [ABSTRACT FROM AUTHOR]

Starting from the urgent need for water pollution treatment, TiO2 nanotube arrays (TNAs) and Ce-doped TNAs have been prepared on TC4 titanium alloy substrate via anodic oxidation. Several properties of TNAs and Ce-doped TNAs were characterized utilizing field emission scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction and ultraviolet-visible spectrophotometer to analyze their morphology, phase structure, distribution of element and optical property respectively. The photocatalytic performance was evaluated by the photo-degradation of methylene blue (MB) under simulated visible light irradiation. The result indicated that the best photodegradation rate of the Ce-doped TNAs on MB reached to 90.4%, which was a huge improvement compared with pristine TNAs. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printed titanium alloy implants hold enormous potential in orthopedic applications to avoid stress shielding. However, titanium alloy is bioinert, limiting its application and making surface modification a necessity. In this paper, porous implants were treated by acid etching and anodizing to improve the bioactivity, which was evaluated by simulated body fluid (SBF) immersion test. The results showed that, after surface modification, micro–nanocomposite structures were obtained on the titanium surface, and after immersing in SBF for 2 weeks, the implants showed a drastically enhanced apatite forming ability, confirming improved bioactivity. However, the surface structures were different at different positions and it is believed that this phenomenon is closely related to the different current densities of the surfaces during anodic oxidation. Our research evaluates the effect of anodic oxidation at different voltages on the surface modification and provides a reference for improving the bioactivity of the medical porous implant surface prepared by 3D printing. [ABSTRACT FROM AUTHOR]

The present article reports synthesis of zinc oxide (ZnO) nanostructures by the single step electrochemical anodization process at room temperature in an aqueous bicarbonate solution. Structural characterizations indicated that the material has grown in the wurtzite phase. Morphological study revealed formation of ZnO nanoflowers with ZnO nanoflakes acting as flower petals having an average width of 53 ± 2 nm and average length of 120 ± 3 nm. ZnO nanoflowers exhibited improved photo electrochemical ability compared to zinc oxide nanowires. The enhanced photo electrochemical ability of nanoflowers could be accounted to the presence of numerous active edge sites in 2D flakes (petals) together with large oxygen vacancy content on the surface of zinc foil revealed by Raman spectroscopy. Additionally, as-fabricated zinc oxide nanoflowers were studied for better light absorption through diffuse reflectance spectroscopy which showed the material possess an optical band gap ~ 3.16 eV. Moreover, Photo electrochemical ability of as fabricated zinc oxide nanoflowers were studied using photo electrochemical analyser and it showed a current density of ~ 60 μA cm− 2. This indicated potential ability of ZnO nanoflowers to serve as UV–visible sunlight-driven photoelectrode materials. [ABSTRACT FROM AUTHOR]

Multilayer graphene oxide was synthesized by anodic oxidation of dispersed graphite, and the efficiency of its use as an electrode material for a supercapacitor was shown. In an alcohol suspension, the thickness of multilayer graphene oxide particles is less than 0.1 μm with an area of more than 100 μm2. The multilayer graphene oxide electrode has a high specific capacity of 107 F g–1 and a high charge retention rate of 97% after 5000 cycles at a current of 2 A g–1. The multilayer graphene oxide electrode demonstrated a maximum specific energy of 8.7 W h kg–1 at a current density of 0.1 A g–1 and a maximum power of 2291.1 W kg–1 at a current density of 4 A g–1. The impedance data at various DC voltages showed that after 5000 cycles, the charge transfer resistance increases by 26%. It was found that multilayer graphene oxide synthesized by the electrochemical method is a promising electrode material for producing a symmetric supercapacitor. [ABSTRACT FROM AUTHOR]

It is found that the thickness of aluminum oxide (Al2O3) film forming in distilled water linearly increases during 2000 s high-voltage anodization and that its electroluminescence (EL) is reliably detected at the Al2O3 film thickness of 120 nm. It is shown that Al2O3 electrolytically formed in distilled water and its deuterium-containing analogue—deuterium water can have an ordered cellular-nanoporous structure identical to the structure formed in aqueous solutions of electrolytes. At the same time, it is found that the existence of this oxide structure is not a necessary condition for its EL. The EL spectra of Al2O3 in distilled and deuterium water, as well as in water-like electrolytes (ethylene glycol, N,N-dimethylethanolamine, and isopentanol) are recorded for the first time. Considerable discrepancies in the luminescence of aluminum oxide in water and aforementioned alcohols are observed in the range of 400–700 nm. The short-wavelength EL component (at a wavelength near 440 nm) dominates in the EL spectra in the first two liquids, and the long-wavelength component peaking at 625 nm is dominant in the other three cases. Both the luminescence spectral composition and intensity in individual spectral ranges were observed to vary during aluminum anodization. [ABSTRACT FROM AUTHOR]

The MIS-structures of InSb with anodically grown dielectric coating in galvanostatic mode in sodium sulfide solution were studied. Fast and slow surface states extracted by using the C–V characteristics method. The extracted values of Dit and NF were 2 × 1011 cm–2 eV–1 and 9.2 × 1010 cm–2, respectively. The hysteresis behavior was investigated. Additional sulfidation pretreatment using (NH4)2S–ethylenglycol solution lower the value of hysteresis and 25% reduce the interface state density. The arithmetic average roughness after anodizing increases from 0.6 to 0.9 nm, but preliminary sulfidation does not significantly affect this parameter. The formed dielectric coating has sufficient film continuity for its use as a passivating coating of InSb based FPA's. [ABSTRACT FROM AUTHOR]

A 3C production uses Al–Zn–Mg alloy as the material of its housings which appeared with black lines on the surface after anodic oxidation treatment. Through appearance observation, 3D outline scanning, SEM section observation, EDS composition test, inclusion analysis, and chemical composition, the cause of the black lines and the solution was brought forward. The results show that the black lines were induced by particles rich in Ti and B in the anodic oxidation film along the extrusion direction. The particles were TiB2 which came from the grain refiner Al–Ti–B during the Al–Zn–Mg alloy manufacture. [ABSTRACT FROM AUTHOR]

Kinetic and environmental aspects related with the mineralization of a commercial glyphosate (GP) formulation in a pre-pilot-scale reactor were assessed. Assays were performed at an acidic pH using Na2SO4 as support electrolyte at five different current densities. GP removal can be achieved in 60 min and is not dependent on the applied current density; however, the reduction of organic carbon (TOC) and chemical oxygen demand (COD) from the sample evidence the impact of the limitations of mass transfer in aspects like energy consumption, effluent quality, and sustainability of the process. Assays at 120 and 240 mg L−1 revealed that it is feasible to improve the biodegradability of the effluent after 300 min of treatment using higher current densities (80 and 100 mA cm−2). At 360 mg L−1, neither the current density nor the time of treatment had an impact on the biodegradability of the effluent at all the assessed current densities. GP removal could have an environmental footprint (1.3 kg CO2 Eqv/kg TOC) in countries where the energy matrix depends on hydropower. In countries where electricity is generated from non-renewable raw materials, like gas or coal, the emissions of greenhouse gasses (GHG) could increase 170% and 439%, respectively. The use of renewable energy sources, like wind power or solar, could reduce the GHG emission to 0.3 kg CO2 Eqv/kg TOC. The cost of treatment ranged between US$ 0.7 and 2.1 g TOC−1 removed; this variability is due to the selected energy source and the subsidies established in each country. [ABSTRACT FROM AUTHOR]

The 'water reuse' option is increasingly becoming crucial in the context of global warming and water scarcity. Water reuse consists in the recycling of water toward sectors requiring different water qualities, such as industry, agriculture and human consumption. Water treatment by biological methods is cheap, yet they do not to remove completely recalcitrant pollutants. Alternatively, advanced oxidation processes (AOP) for wastewater treatment are more efficient because a strong oxidizing agent such as the hydroxyl radical (•OH) is generated under mild conditions. In particular, processes of electrochemical advanced oxidation have recently attracted attention because they allow continuous and in situ electrocatalytic generation of strong oxidizing species under mild conditions, with the advantage of avoiding external addition of chemicals. In addition, energy can be provided by solar light in photochemical electrolysis systems. Here we review photoelectrochemical reactors. We present reactions and synergetic mechanisms. Under optimal conditions, eight •OH production sites are identified in photoelectro-Fenton combined with photoanodic oxidation and photocatalysis or photoelectrocatalysis. Reactions are controlled by pH, applied wavelength, and competition between reactions requiring the same reagent. Then we discuss reactor design and catalysis. Various reactor configurations are presented: sequential and hybrid reactors, divided and undivided cells, flow cell and stirred tank reactor; and light source positioning can be external, immersed, vertical, horizontal, at the top, at the bottom, or on the side of the reactor. The distance between the light source and the electrode should be minimized to obtain maximal synergy and maximum quantum yields. Hybrid reactors in undivided flow cells are best for the lower footprint, the possibility to regenerate iron catalysts, and the enhancement of mass transfer, compared with stirred tank reactors. Moreover, the interelectrode gap can be easily controlled in flow cell, which allows the optimization of the penetration depth when the light is applied through the reactor. [ABSTRACT FROM AUTHOR]

It is shown that the formation of anodic oxides in the galvanostatic mode of electrolytic anodizing of Si, SiC, and Si3N4 proceeds with the activation control of the process. It is suggested that the limiting stage of the oxidation process of these materials is the anodic reaction of the formation of intermediate monoxide SiO. [ABSTRACT FROM AUTHOR]

In this work, the features of the formation of electrolyte plasma and its influence on the structure of the surface of Ti are investigated. It is revealed that the formation of plasma in the process of the anodic polarization of Ti in an aqueous solution of sulfuric acid leads to the formation of a porous oxide on the surface. It is shown that the porous nature of the formed oxide layers predetermine the specific behavior of the plasma. The topology of the surface of the formed porous titanium-oxide film is studied by scanning-electron- and atomic-force microscopy. It is established that the distribution of pores on the surface is of a complex stochastic nature and their maximum sizes did not are around 200–300 nm. [ABSTRACT FROM AUTHOR]

Core–shell Fe@Fe3O4 nanowires (NWs) were successfully prepared on a homemade anodic aluminum oxide (AAO) template by the anodic oxidation of Fe NWs followed by annealing reduction. A field-emission scanning electron microscope was used to observe the morphology of the AAO template, which shows that the diameter of AAO template was 30 nm. TEM results confirm a thin oxide layer was formed on Fe NWs, confirming the core–shell nature of Fe NWs. The TEM analysis shows that with the increase in anodizing time, the oxide layer thickness was increased from 2.4, 4.6, 5.9 nm, respectively. The elemental composition of core–shell Fe NWs was confirmed by energy-dispersive X-ray spectrometer. The oxide phase of Fe could not be easily distinguished by X-ray analysis, because of the line width broadening of nanocrystals; thus, the valence states of Fe in Fe@Fe2O3 and Fe@Fe3O4 NWs were further analyzed by X-ray photoelectron spectroscopy (XPS). XPS results confirm the oxide nature of Fe2O3 and Fe3O4 in core–shell Fe NWs. The influence of oxide layer thickness on the magnetic properties of core–shell Fe@Fe3O4 NWs was investigated by vibrating sample magnetometry. Magnetic measurement revealed that the coercivity and squareness values of core–shell Fe@Fe3O4 NWs gradually increased with the increase in the Fe3O4 shell thickness. Results clearly showed that the size and magnetism of the core–shell Fe@Fe3O4 NWs can be adjusted to a certain extent by this synthetic method, so as to meet different requirements in desired biomedical applications. [ABSTRACT FROM AUTHOR]

In this paper, we develop the thermodynamic models of electrochemical oxidation of niobium and tantalum that allow predicting the composition of their anodic oxides depending on the electrolyte composition. The reactivity of metals with respect to electrolyte anions was evaluated. It was revealed that doping additives can be included in the composition of anodic oxide films of Nb and Ta depending on the nature of the anions supplied by the electrolyte components. The thermodynamic modeling results will allow predicting the component compositions of anodizing solutions to obtain anodic oxide films of these elements with a specified composition. [ABSTRACT FROM AUTHOR]

Surface modification of titanium alloys expands the range of their applicability in medicine, particularly in the form of various implants. Present work reports the results of the electrochemical formation of self-ordered oxide nanotubes on Ti13Nb13Zr alloy. Due to its relatively low Young modulus (77–79 GPa) this alloy can be attractive material for orthopedic application. The experiments were conducted in the (NH4)2SO4 + NH4F electrolyte at room temperature. Anodization of the alloy samples was carried out for 2 h under variable external potential U (in the range from 10 to 45 V) and the current versus time transients were recorded. Obtained surface morphology was investigated by the scanning electron microscopy and the X-ray techniques. The morphological parameters of the obtained nanotubes such as the inner (din) and outer (dout) diameters were determined. The tubes diameter dependence on the voltage of anodization process was derived. The dependence d[nm] = f(U)[V] was established at constant temperature 25 °C. It provides the basis for controlled oxide nanotubes layer growth. It was also demonstrated that these nanotubes exhibit photocatalytic activity. [ABSTRACT FROM AUTHOR]

This paper presents growth of micro- and nanostructured TiO2 layers on Ti6Al4 V by thermal and anodic spark oxidation for photocatalysis. Effects of anodization parameters on surface morphology and photocatalytic behavior were investigated. The photocatalysts divided into two groups consisting of four samples were prepared for growth of micro- and nanostructured TiO2 layer on Ti6Al4 V. The microstructured surfaces were obtained in 1 M H2SO4 electrolyte in 5 min at the anodization voltage in the range of 100–400 V, whilst the nanostructured TiO2 layers were prepared in 1% HF solution in the range of 10–40 V in equal time. Surface morphology, phase structure, band gap and surface roughness values of the micro- and nanostructured TiO2 photocatalysts were analyzed by scanning electron microscope, X-ray diffraction, UV–Vis diffuse reflectance spectroscopy and surface profilometer, respectively. Photocatalytic performances of TiO2 photocatalysts obtained with different anodization parameters were investigated via methylene blue aqueous solution. It was observed that the anodization voltage has a great effect on photocatalytic performances due to the formation of different crystallinity and morphology. Among the samples, the layer prepared at 100 V exhibited the best photocatalytic activity with 91.15% degradation efficiency and 95.5 × 10−4 min−1 kinetic rate constant. Moreover, the further investigation determining active species were carried out using ammonium oxalate, benzoquinone, and isopropyl alcohol. In this process, the photocatalytic mechanism revealed that the superoxide radicals (· O 2 -) play a very important role during the photodegradation process. The TiO2 layer on Ti6Al4 V anodized at 100 V also showed high activity and stability, suggesting its potential for wastewater treatment. [ABSTRACT FROM AUTHOR]

Ti alloys are widely applied in implanted biomedical devices due to their unique mechanical and biological performances. A strategy employed to improve bone integration on orthopedic and dental implants is to grow a self-organized TiO2 nanotube layer on the surface of titanium alloy implants. This paper describes the formation of self-organized TiO2 nanotubes on Ti–35Nb–2Zr and Ti–35Nb–4Zr alloys by the anodization process, as well as the effects of Zr content on TiO2 phase stability. The morphological and chemical characteristics of the nanotubes were analyzed by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron microscopy. In addition, a comparison was made of the electrochemical stabilities of TiO2 nanotube-coated surfaces and surfaces without nanotubes, which revealed higher corrosion resistance for the nanotube-modified surface. The electrochemical impedance spectroscopy results were fitted with two-time constant equivalent circuit representing the barrier layer (nanotube bottom) and the porous layer (nanotube wall). The addition of Zr suppressed ω-phase formation, preserving the alloy's low elastic modulus (64 GPa). This Zr addition also delayed the anatase-to-rutile transformation and slightly increased the nanotubes' length to 1.14 µm. These features make the Ti–35Nb–4Zr alloy a very good candidate for use in the biomedical field, especially for applications that require low elastic modulus with enhanced corrosion resistance. [ABSTRACT FROM AUTHOR]

The structure of the products of anodic oxidation of triphenylphosphine in the presence of camphene carried out in acetonitrile with sodium perchlorate as supporting electrolyte has been studied. The major product, triphenylphosphine oxide, has been isolated from the solution in the form of cocrystals of free triphenylphosphine oxide and its complex with sodium perchlorate. The molecular structure of the cocrystals has been studied by X-ray diffraction analysis. Triphenylcamphenylphosphonium perchlorate, bornylacetamide, and a terpene compound with triphenylphosphonium and acetamide substituents in the cycle have been detected by NMR 13C as the electrolysis side products. [ABSTRACT FROM AUTHOR]

This paper suggests a new alternative for the acceleration of dye removal by adopting alternating current instead of direct current in the treatment of methylene blue solutions and industrials effluents, using anodic oxidation on Pb/PbO2 and stainless steel (SS)/PbO2 anodes. A comparative study of the influence of electrolyte support (NaCl, NaNO3, and Na2SO4) on the anodic oxidation performance and the anode stability was performed. The best results were obtained in presence of NaCl where the color removal percentage reached about 80.13% and 55.8%, for Pb/PbO2 anodes, and 89.5% and 60.4% for the SS/PbO2 anodes for alternating and direct current, respectively. Treatment in alternating current conditions enhanced the removal speed. Atomic absorption analysis confirmed the decrease of the release of (Pb2+) ions to much lower values compared with direct current and to those allowed by the Standards. LC/MS and phytotoxicity analyses confirmed the non-toxicity of the generated by-products during the anodic oxidation of methylene blue and the possibility of the reuse of the treated water. [ABSTRACT FROM AUTHOR]

This study presents a comparative investigation of supporting electrolyte effect on the surface corrosion and anodic oxidation performance of graphite electrode. The effect of electrolyte on the electrochemical behavior is investigated in solution containing 0.05 mol L−1 sodium salt, using current-overpotential curves and Tafel lines. The surface morphology and composition of the graphite anodes before and after electrolysis are characterized by scanning electron microscopy, X-ray diffraction, and Raman spectra. In aqueous solution, graphite anode is positive polarized, functionalizes the surface, and releases soluble organics. The light-absorbing corrosion products of graphite anode are recorded by a UV-Vis spectrophotometer in the ultraviolet wavelength range. Batch experiments on atrazine oxidation show that NaCl is more efficient than Na2SO4 and NaNO3 to promote the combustion of organics due to the mediated oxidation of the electrogenerated active chlorine species. The oxidation process is confirmed to employ a non-radical mechanism in which the organics are degraded at the active sites of graphite anode. [ABSTRACT FROM AUTHOR]

The presented contribution deals with the application of the method for removal of hexavalent chromium from an industrial effluent. The experimental approach followed the path from a laboratory towards a pilot-scale unit. Initially, the laboratory unit was used for optimization of the most important process parameters and it was demonstrated that hexavalent chromium could be efficiently removed from the treated effluent using the technology. Optimization experiments revealed high efficacy in the removal of Cr6+ together with its reduction towards Cr3+, and total removal efficacy exceeded 95%. Experiments with industrial effluent revealed a reduction in Crtot. below detection limit. Pilot-scale unit was used for long-term trials focused on the treatment of the industrial effluent. A continuous pilot-scale unit (0.5 m3/h) was operated on contaminated industrial site and revealed removal efficiencies of all contaminants below detection limit. Power consumption during the process was only 0.24 kWh/m3; all the contaminants were reduced below their detection limit. [ABSTRACT FROM AUTHOR]

Existence of an organic compounds, especially aromatic compounds in wastewater is observed as an emerging environmental problem because of their harmful effects on living organisms even at low concentration. Conventional wastewater treatment processes are ineffectual for an elimination of refractory organic compounds. Nowadays, it's a challenge to reduce negative impact of such hazardous compounds on environment. So, Advanced Oxidation Processes (AOPs) have received more attention over a year of decades towards removal of an aromatic compounds. Among AOPs, Electrochemical Advanced Oxidation Processes (EAOPs), especially "Anodic Oxidation" and "Electro-Fenton," have revealed good potential for mitigation of pollution caused by the presence of aqueous organic compounds in wastewater. This review has introduced an innovative collection of current knowledge on Electro-Fenton and Anodic oxidation type of processes. Fundamentals of these processes, electrolysers used, reaction mechanisms, experimental parameters affecting these electro-chemical treatment technologies with various applications are discussed in detail. This report also discusses effectiveness of EAOPs for elimination of organic compounds in aqueous systems. [ABSTRACT FROM AUTHOR]

Anodic formation in deoxygenated 0.1 М KOH solution of Ag(I) oxide on Ag–Zn alloys with zinc atomic fraction from 5 to 30 at % and its properties were examined using cyclic voltammetry supplemented by photoelectrochemical measurements. Phase composition of the alloys is confirmed by X-ray diffraction analysis. Surface morphology is studied using scanning electron microscope. Ag(I) oxide anodically formed on silver–zinc alloys is shown possessing n-type conductance, with dominating donor defects. The donor defect concentration in the Ag(I) oxide increases, as the zinc content in the alloy grows, and this leads to a decrease in the maximum photocurrent and to narrowing of the space charge region. With the increasing of the zinc concentration in the alloy, the Ag2O particles' size decreases and their surface density increases. [ABSTRACT FROM AUTHOR]

Vertically aligned TiO2/ZnO nanotube (NT) arrays were developed for application to photoanodes in mesoscopic solar cells. By a two-step anodic oxidation, vertically aligned TiO2 NT arrays with highly ordered surface structure were prepared, followed by deposition of a ZnO shell with a precisely controlled thickness using atomic layer deposition (ALD). When applied to a photoanode of dye-sensitized solar cells (DSSCs), the photovoltage is gradually enhanced as the ZnO shell thickness of the TiO2/ZnO NT electrodes is increased. Furtheremore, the electron lifetime in photoanodes is significantly enhanced due to the ZnO shell, which is examined by open-circuit voltage decay (OCVD) measurement. Photocurrent density-voltage (J-V) curves under the dark condition and OCVD spectra reveal that a negative shift in TiO2 conduction band potential and an energy barrier effect owing to the ZnO shell concurrently contribute to the enhancement of VOC and electron lifetime. [ABSTRACT FROM AUTHOR]