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The formation of C(sp3)-centered radicals via the electro--induced homolysis of 4-alkyl-1,4-dihydropyridines (alkyl-DHPs) is reported. The resulting alkyl radicals reacted with 4-hydroxyquinazolines or quinones to afford 2-alkyldihydroquinazolinones or alkylated quinones. A broad range of alkyl DHPs could be used as versatile radical precursors under electrolysis conditions. This alterative strategy provided a simple and effective pathway for the construction of C(sp2)–C(sp3) and C(sp3)–C(sp3) bonds under mild conditions. [ABSTRACT FROM AUTHOR]

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office 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.)

In the present work, an easy and scalable method to prepare lithium titanium oxide nanotubes with stable and reversible lithium storage properties is reported. This material could be an excellent candidate for lithium recovery from aqueous solutions or have a direct application as Li‐ion batteries electrodes in a circular economy perspective. Vertically oriented anatase nanotubes are grown by anodic oxidation in an ethylene glycol‐based electrolyte. Then, the nanotubes are hydrothermally converted into a mixed lithium titanate. Morphological and crystallographic characterizations confirm the successful shape‐preserving conversion after which the nanotubes are subjected to electrochemical cycling. XRD and XPS analyses confirm a significant lithium uptake after cycling, and its recovery is investigated by means of an acidic treatment. While allowing for an almost complete recovery of the lithium integrated in their structure, the nanotubes also showed excellent morphological and structural stability proving to be excellent candidates for lithium recovery purposes. [ABSTRACT FROM AUTHOR]

Powder bed fusion using a laser beam (PBF-LB) is a commonly used additive manufacturing (3D printing) process for the fabrication of various parts from pure metals and their alloys. This work shows for the first time the possibility of using PBF-LB technology for the production of 3D titanium substrates (Ti 3D) for surface-enhanced Raman scattering (SERS) measurements. Thanks to the specific development of the 3D titanium surface and its nanoscale modification by the formation of TiO2 nanotubes with a diameter of ~80 nm by the anodic oxidation process, very efficient SERS substrates were obtained after deposition of silver nanoparticles (0.02 mg/cm2, magnetron sputtering). The average SERS enhancement factor equal to 1.26 × 106 was determined for pyridine (0.05 M + 0.1 M KCl), as a model adsorbate. The estimated enhancement factor is comparable with the data in the literature, and the substrate produced in this way is characterized by the high stability and repeatability of SERS measurements. The combination of the use of a printed metal substrate with nanofunctionalization opens a new path in the design of SERS substrates for applications in analytical chemistry. Methods such as SEM scanning microscopy, photoelectron spectroscopy (XPS) and X-ray diffraction analysis (XRD) were used to determine the morphology, structure and chemical composition of the fabricated materials. [ABSTRACT FROM AUTHOR]

To improve the heat transfer performance (HTP) of stainless steel, the micro-nano concave chromium (Cr) coating was fabricated on the surface of 304 stainless steel by the combination technology of electrodeposition and anodic oxidation. The effects of electroplating and anodizing time on the morphology, contact angle (CA) and heat transfer coefficient (HTC) of the coating were studied. The results show that the samples with large surface area and good wettability have higher HTC. Besides, the Cr coating obtained after 2 h electroplating has silver white appearance, smooth surface and a thickness of about 37 μm. The 2-h electroplated Cr coating after anodizing for 30 min presents a concave pore structure with a pore diameter of 7.4 μm and the best wettability (a CA of 41.8°), which is 20° lower than that of the stainless steel substrate. The two-phase heat transfer efficiency of the sample with the concave Cr coating was increased by 22.84 % when the fluid mass flux is 33.3 kg m−2 s−1 and the inlet temperature is 40 °C and the fluctuations of pressure drop in the micro-channel was effectively reduced. The enhanced HTP of concave Cr coating is owing to the larger specific surface area and better wettability caused by the unique rough concave structure. [ABSTRACT FROM AUTHOR]

Furanose ring oxygen‐substituted artificial nucleosides show unique pharmacological activities even without incorporation into oligonucleotides, and are used as anticancer and antiviral agents. Practical synthetic routes to such nucleosides are of exceptional importance to enhance the development of (oligo)nucleotide therapeutics. Herein, we demonstrate that direct anodic N‐α hydroxylation is possible in aqueous media to realize the practical synthesis of these versatile intermediates for azanucleoside derivatives. [ABSTRACT FROM AUTHOR]

The preparation technology of micro-nano structure on copper surface is studied and optimized. Aqueous solution containing sodium carbonate and sodium molybdate is used as electrolyte, and the copper sample is anodized at a constant voltage to form a layer of oxidation on the copper surface. Then, the copper surface is treated with aqueous solution containing phosphate and sodium dihydrogen phosphate as corrosion solution to obtain a micro-nano structure on the copper. The surface is observed by using a scanning electron microscope. Finally, the analysis software is used to analyze the scanning electron microscope image to calculate the micro-nano structure pores on the copper surface. The results show that when the anodizing voltage is 15 V, the anodizing time is 20 min, the phosphoric acid mass fraction is 20%, and the corrosion time is 30 min, the copper surface is relatively smooth, and the porosity reaches 25.77%. Orthogonal experiments demonstrate that the type, concentration of the corrosive solution, and etching time have a great effect, while the anodizing electrolyte, voltage and electrolysis have no significant effect on the porosity. Using a combination of anodic oxidation and chemical corrosion, micro and nano junctions with uniform and high porosity can be prepared on the copper surface.

Our work presents a comparative study of morphological characteristics and the osteogenic potential of MC3T3-E1 cells on different modified surfaces of titanium: nanostructured TiO2 with 20 and 100 nm nanotube diameter, and sandblasting and acid etching, commercially known as SLA. Nanostructured TiO2surface was prepared by anodizing of titanium plates, while SLA surface was provided by commercial supplier. Surfaces were characterized by SEM, EDS, AFM, and water contact angle measurements. In order to evaluate cell response,in vitrotests of MTT, alkaline phosphatase and staining with alizarin red were performed. From the results ofin vitro tests, 100 nm nanotubular surface showed lower levels of cell mineralization, differentiation and adhesion. In general, 20 nm TiO2nanotubular and SLA surfaces promoted similar response from osteoblasts. As a result, 20 nm nanotubular surface proved to be a possible alternative to SLA surface with potential for use in oral implantology market.

With the renaissance of chemical electrosynthesis in the last decade, the electrochemistry of hypervalent iodine compounds has picked up the pace and achieved significant improvements. By employing traceless electrons instead of stoichiometric oxidants as the alternative clean “reagents”, many hypervalent iodine compounds were efficiently electro-synthesized via anodic oxidation methods and utilized as powerful redox mediators triggering valuable oxidative coupling reactions in a more sustainable way. This minireview gives an up-to-date overview of the recent advances during the past 3 years, encompassing enhanced electrosynthesis technologies, novel synthetic applications, and ideas for improving reaction sustainability.

In the last years, an increasing attention has been devoted to the utilization of anodic oxidation (AO) technologies for the treatment of wastewater polluted by recalcitrant organics. Recently, Ti4O7 was proposed as a promising anode for AO for the treatment of various organics. Here the potential utilization of commercial Ti4O7 anodes has been evaluated considering the electrochemical treatment of synthetic wastewater contaminated by three very different organic molecules (namely, oxalic acid, phenol and Acid Orange 7), all characterized by a very high resistance to AO. The performances of Ti4O7 were compared with that of two largely investigated anodes: Boron‐doped diamond (BDD), which is probably the most effective electrode for AO, and an Ir‐based anode which presents a relatively low cost. Moreover, the effect of various operative conditions (current density, mixing rate and initial concentration of the organic) was evaluated by both experimental studies and the adoption of a theoretical model previously developed for BDD anodes. It was shown that the performances of the process can be improved by a proper selection of operative conditions. Moreover, it was found that the proposed model can be effectively used to predict the effect of operative parameters at Ti4O7 anodes, thus helping the process optimization. [ABSTRACT FROM AUTHOR]

This paper proposes a slurryless, highly efficient polishing method called ultrasonic vibration assisted electrochemical mechanical polishing (UAECMP) to realize 4H–SiC wafers with subnanometer surface roughness. UAECMP involves using ultrasonic vibration to simultaneously assist anodic oxidation of the SiC surface and mechanical removal of the generated oxide layer. The performance of UAECMP was evaluated by experiments and theoretical analyses. For a 4H–SiC (0001) surface, UAECMP achieved a material removal rate (MRR) of 14.54 μm/h, which was 4.5 times greater than that of ordinary electrochemical mechanical polishing (ECMP) and 290 times greater than that of mechanical polishing. Ultrasonic vibration increased the anodic oxidation rate by introducing local transient strain to the SiC surface and increasing the temperatures of the polishing area and electrolyte. The effect increased with the amplitude of the ultrasonic vibration. However, increasing the ultrasonic vibration amplitude also increased the surface roughness due to the large fluctuations of polishing marks caused by the grinding stone and SiC surface impact and the increasing residual oxide. Therefore, we propose a high-efficiency and -quality polishing process for SiC wafers that combines UAECMP and ECMP. The proposed polishing process may help simplify the existing manufacturing process for SiC wafers. [Display omitted] • Slurryless ultrasonic vibration assisted electrochemical mechanical polishing (UAECMP) was proposed. • UAECMP achieved a material removal rate 4.5 times greater than ECMP. • Polishing mechanism of UAECMP was clarified. • A manufacturing process that combines UAECMP with ECMP was proposed. [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.)

Electro-Fenton (EF) oxidation has high oxidation abilities and is widely used in the treatment of biorefractory and chemically refractory organic wastewater. However, it generates a large amount of iron sludge, which limits large-scale application. In this work, the comparative study of EF oxidation and anodic oxidation (AO) of the secondary effluent of petrochemical wastewater using boron doped diamond anode is carried out. In EF oxidation, the effects of Fe2+ concentration, pH value, and current density are investigated. The optimal conditions consist of the following: Fe2+ concentration of 1.5 mmol·L−1, pH of 4, and current density of 10 mA·cm−2. In AO process, the effect of adding S O 4 2 − , Cl−, N O 3 − , P O 4 3 − , and C O 3 2 − is investigated; the optimal conditions can be obtained by adding a Na2SO4 solution (0.075 mol·L−1). When compared with AO, although EF oxidation has a higher treatment efficiency, its energy consumption is higher, and the generated effluent (with 155 g of iron sludge·m−3) dramatically increases the post-treatment cost, thereby limiting its large-scale application. For AO with Na2SO4 solution (0.075 mol·L−1) and a COD removal efficiency of 70%, the corresponding treatment time is 1.34 h and the energy consumption is 2.44 kWh·m−3. [ABSTRACT FROM AUTHOR]

Selective anodic oxidation of alcohols in the presence of other functional groups can be accomplished by using nitroxyl radical mediators. However, the electrochemical chemoselective oxidation of secondary alcohols in the presence of primary alcohols is an unsolved issue. Herein, we report an electrochemical procedure for the selective oxidation of secondary alcohols by using an inexpensive chloride salt that acts as a redox mediator and supporting electrolyte. The method is based on the controlled anodic generation of active chlorine species, which selectively oxidize secondary alcohols to the corresponding ketones when primary hydroxy groups are present. The method has been demonstrated for a variety of substrates. The corresponding ketones were obtained in good to excellent yields. Moreover, the chloride salt can be easily recovered by a simple extraction procedure for reuse, rendering the method highly sustainable. [ABSTRACT FROM AUTHOR]

Copyright of Electroplating & Finishing is the property of Electroplating & Finishing Editorial Office 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.)

Using aluminum alloy 6061-T6 as the substrate and sulfuric acid (0.3 M) anodizing technology, we formed nanoporous anodic aluminum oxide (NPAAO) films for solar absorption and photothermal sensor applications in a medium temperature range. We found that the diameter and thickness of aluminum oxide increased with increasing applied anodic voltage. The increase in the applied anodic voltage, which increased the NPAAO film thickness, enhanced absorption over the solar spectral range. Therefore, the solar absorptivity increased with the thickness of the NPAAO film, and more of the penetrating light was trapped by the thicker NPAAO film due to its greater depth and higher pore density. Moreover, the transient temperature of the NPAAO films was measured under 500 W halogen light illumination to investigate the photothermal efficiency of the films. The results indicated that the steady-state temperature increased with the absorptivity of the NPAAO films. The mean reflectance of the aluminum alloy specimens in the spectral range of 250-850 nm was greater than 72% before the anodizing oxidation process and less than 7.7% after the process. Therefore, the applied anodic voltage, which changes the pore density and the thickness of the anodized film, is an important factor determining the solar absorption performance of NPAAO films. [ABSTRACT FROM AUTHOR]

Surface modifications against the failure of titanium implants used in hard tissue repair has become a trend in recent years. In the last decade, it has been investigated that nanoscale tubular spaces on the titanium surface can be used as a local drug release reservoir without the need for any chemical binder or polymeric coating. It is possible to obtain one-dimensional structures that can be grown by electrochemical anodic oxidation by controlling the diameters of less than 100 nanometers on titanium metal surfaces. The major disadvantage of biomolecules released from titania nanotube structures to the environment is the hard control of release kinetics and more than half of the loading amount releases in the first few hours of interaction with the biological fluid. Although the studies on controlling the kinetics have been tried to overcome by covering the nanotube arrays with barriers such as polymer structures, the risk of delamination of the polymers from the surface during implantation brings additional problems. In this manuscript, vancomycin and bovine serum albumin were loaded into titania nanotubes formed by anodic oxidation technique on titanium metal plates and the tube ends has been narrowed by gold sputtering technique. With this narrowing at the tube-ends, the length of the release time and the change in diameter according to the hydrodynamic diameter of the released biomolecule were investigated. It is seen that the increased gold sputtering time prolongs the release rate of biomolecules and offers a promising approach for sustained local drug releasing implants. [ABSTRACT FROM AUTHOR]

Herein, porous titanium materials with honeycomb pore structure are prepared by freeze casting. The effect of freezing temperature on the pore structure and mechanical properties is also investigated. As the freezing temperature decreases from −10 to −50 °C, the compressive strength decreases from 79.5 ± 9.2 to 55.0 ± 4.3 MPa, and then increases to 90.1 ± 4.4 MPa. Porous titanium with an average pore size of 111.3 ± 25.2 μm and porosity over 60% are obtained at −10 °C. And the porous titanium is observed to form a neatly arranged nanopore structure with an average pore size of 28.5 ± 2.8 nm on the surface after anodizing. These nanopore structures can promote MG‐63 cell adhesion and proliferation, thus improving the biocompatibility of porous titanium. Further, in the simulated body fluid culture experiment, culturing for 3 days can induce Ca2+ and PO43− to nucleate and deposit on the surface of anodized porous titanium, while 7 days can deposit a lot of apatite on the surface. In contrast, no apatite deposition is observed on the surface of the porous titanium sample without anodizing. These prepared porous titanium materials with high porosity, large pore size, sufficient mechanical properties, good biocompatibility, and biological activity might be a potential biomedical material. [ABSTRACT FROM AUTHOR]

The exceptional electronic, thermal, optical and mechanical properties of graphene make it ideal for the next generation of electronic and optoelectronic devices. So, it is particularly important to research and develop high-quality, large-scale and low-cost technology of graphene preparation. Electrochemical exfoliation of graphite has emerged as a promising wet chemical approach with advantages such as scalability, solution processability and eco-friendliness. In this paper, research progress of preparation of graphene by electrochemical method was reviewed. The effects of anodic oxidation and cathodic intercalation of graphite on the yield, morphology, quality and defect level of graphene were emphatically described, and the exfoliation mechanisms of the two processes were briefly summarized. Moreover, the preparation and application of functionalized graphene by electrochemical approach were introduced. Finally, it was pointed out that the future development direction of electrochemical preparation of graphene is the design of electrolyte system, optimization of exfoliation conditions, understanding of the exfoliation mechanism, rational design of electrochemical cells.

An anodic oxidation process with graphite anode coated with lead dioxide (G/β-PbO2) was optimized for the degradation of methylene blue (MB) and the treatment of real textile wastewater. The G/β-PbO2 anode was prepared by the electrochemical precipitation method. The scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses confirmed the successful coating of graphite substrate with the β-PbO2 film. The effect of four independent variables including pH, reaction time, current density, and electrolyte concentration of Na2SO4 on the performance of the electrochemical oxidation system was modeled by using a complete central composite design and was then optimized by genetic algorithm method. The accuracy of the proposed quadratic model by CCD was confirmed with p-value 0.9. The optimum conditions for solution pH, reaction time, current density, and Na2SO4 electrolyte concentration were obtained to be 5.75, 50 min, 10 mA/cm2, and 78.8 mg/L, respectively. In these conditions, the experimental removal efficiencies of MB using G/β-PbO2 and graphite anodes were 96.2% and 68.3%, respectively. The electrochemical removal of MB using both G/β-PbO2 and graphite anodes well followed the pseudo-first-order reaction (R2 > 0.9). Cyclohexane, cyclohexa-2,5-dien-1-ylium, and N-(sec-butyl) aniline were the most abundant intermediates identified by LC-MS analysis. However, the complete mineralization of MB was achieved in 60 min. The optimized anodic oxidation process successfully improved the biodegradability of real textile wastewater (BOD/COD>0.4).

Abstract Most of the active pharmaceutical ingredients like Metoprolol are oxidatively metabolized by liver enzymes, such as Cytochrome P450 monooxygenases into oxygenates and therefore hydrophilic products. It is of utmost importance to identify the metabolites and to gain knowledge on their toxic impacts. By using electrochemistry, it is possible to mimic enzymatic transformations and to identify metabolic hot spots. By introducing charged‐tags into the intermediate, it is possible to detect and isolate metabolic products. The identification and synthesis of initially oxidized metabolites are important to understand possible toxic activities. The gained knowledge about the metabolism will simplify interpretation and predictions of metabolitic pathways. The oxidized products were analyzed with high performance liquid chromatography‐mass spectrometry using electrospray ionization (HPLC‐ESI‐MS) and nuclear magnetic resonance (NMR) spectroscopy. For proof‐of‐principle, we present a synthesis of one pyridinated main oxidation product of Metoprolol.

To improve the growth of hydroxyapatite (HA) coating on the Ti-6Al-4V substrate, a solution containing calcium acetate (CA), calcium glycerophosphate hydrate (Ca-GP), and different concentrations of Na2SO4 as the electrolyte for anodic treatment was investigated in this study. The results found that the anodic method is suitable for Ti-6Al-4V titanium alloy to form an HA coating with the electrolyte consisting of CA, Ca-GP, and Na2SO4. These anodic oxide films display a greater rough structure on the surface of films and the addition of Na2SO4 into the electrolyte during the anodic oxidation process contributes to an increase in the atomic ratio (at%) of Ca in the anodic film. These Ca-containing films are considered bioactive and tend to dissolve into simulated body fluid (SBF) solution and then enhance the degree of the supersaturation of SBF solution with respect to the apatite. Therefore, increasing the concentration of Na2SO4 increases the growth of HA following immersion into SBF. In addition, prior to immersion into SBF solution, the contact angle measurement using an SBF droplet was also investigated for HA growth. The results indicate that when the contact angle of anodic surface is larger, the formation time of HA coating is shorter and it will easily grow a thicker HA.

The climate change imposes to mankind a severe management of CO2 emissions in atmosphere. CO2 valorization through electrocatalysis revealed to be a valuable solution to this global issue. SnO2 is an electrocatalyst widely investigated for its capability to reduce CO2 to formic acid. In particular, mesoporous SnO2 offers a high adsorption capability, resulting in a high catalytic activity. In order to improve its performance, Fe-doping is here investigated for the first time. We observed that Fe-doped SnO2 exhibits a remarkable 100% enhancement of the partial current density for HCOOH production at relatively low overpotentials, although keeping the selectivity unchanged.

TiO2 nanotube arrays (TNAs) prepared by the traditional methods are prone to peeling off from the underlying titanium due to the weak interfacial adhesion between the nanotube layers and Ti substrates, which greatly restricts their applications. Here, 2.5 mm titanium plates are cold rolled to the Ti sheets of various thicknesses by controlling the cold-rolling reduction process. Ti sheets are then anodized in an electrolyte that was composed of water, NH4F, and ethylene glycol. It is discovered that after the cold-rolling process, not only are the pore sizes of the nanotubes smaller, but also the tube length is longer, indicating different growth behavior for the rolled Ti sheets. The results of XRD, EBSD, and metallographic microstructure analysis revealed mechanical anchorage at grain boundaries and decreased F contents, which leads to release stress at the TNAs/Ti interface. Most probably the released stress, finer grain sizes and increased dislocation density are responsible for the improved adhesion.

Anodic TiO2 nanotube (TNT) films show promises for photon-driven catalytic, electricity storage and chemical processes. The film thickness of anodic TNT is known to affect its performance in optical and electronic applications. Also, factors affecting the morphology and dimensions of anodic TNT films are rather well-known. However, the knowledge on phase transition and composition in the growth of anodic TiO2 from the titanium metal is very limited. In this work, the anodization time is controlled in intervals of 10, 60, 300, 1000, 2000 and 5000 s to investigate its effect on phase composition and transition, and the morphology of the anodic TNT during the growth process. Even though the mechanism of anodic TNT formation is still under debate, the scanning electron microscope results support bottom-up tube growth with evidence of a compact layer. It was also found that the Richards growth model is applicable to correlate growth time and film thickness. Finally, the phase transition, crystal orientation and pore formation during the anodic process are further discussed.

Additive technologies allowed for the development of medicine and implantology, enabling the production of personalized and highly porous implants. Although implants of this type are used clinically, they are usually only heat treated. Surface modification using electrochemical methods can significantly improve the biocompatibility of biomaterials used for implants, including printed ones. The study examined the effect of anodizing oxidation on the biocompatibility of a porous implant made of Ti6Al4V by the SLM method. The study used a proprietary spinal implant intended for the treatment of discopathy in the c4–c5 section. As part of the work, the manufactured implant was assessed in terms of compliance with the requirements for implants (structure testing—metallography) and the accuracy of the pores produced (pore size and porosity). The samples were subjected to surface modification using anodic oxidation. The research was carried out for 6 weeks in in vitro conditions. Surface topographies and corrosion properties (corrosion potential, ion release) were compared for unmodified and anodically oxidized samples. The tests showed no effect of anodic oxidation on the surface topography and improved corrosion properties. Anodic oxidation stabilized the corrosion potential and limited the release of ions to the environment.

The electrochemical oxidation of amines is an essential alternative to the conventional chemical transformation that provides critical routes for synthesising and modifying a wide range of chemically useful molecules, including pharmaceuticals and agrochemicals. As a result, the anodic reactivity of these compounds has been extensively researched over the past seven decades. However, the different mechanistic aspects of the electrochemical oxidation of amines have never been discussed from a comprehensive and general point of view. This review examines the oxidation mechanism of aliphatic amines, amides, aniline and aniline derivatives, carbamates, and lactams, either directly oxidised at different electrode surfaces or indirectly oxidised by a reversible redox molecule, in which the reactive form was generated in situ. The mechanisms are compared and simplified to understand all possible pathways for the oxidation of amines using only a few general mechanisms. Examples of the application of these oxidation reactions are also provided.

The characteristics such as microtopography, physical and chemical properties influence the behavior of an implant in a soft tissue. Anodization—as a potent method of titanium alloy surface modification—of the transgingival abutment or healing screw, has achieved some improvement. One of the possible surface treatment method is low-pressure radiofrequency oxygen plasma treatment. The aim of the study was to evaluate the chemical properties and cytocompatibility of the experimental surface. Titanium discs made of grade-23 titanium alloy (Ti-6Al-4V) anodized (A sample) with different voltage parameters (28, 67, 78, and 98 V) were included in the study. Half of the samples regarded as the “S” group were additionally treated with low-pressure radiofrequency oxygen plasma treatment. The surfaces were characterized using scanning electron microscopy, X-ray spectroscopy and Raman spectroscopy, and electrochemically investigated via a corrosion test. Furthermore, two cell lines were used, including the CHO-compatible reference line and a primary human fibroblast line for the MTT assay; direct (contact) cytotoxicity of the materials was tested with the cells, and the growth of fibroblasts on the surfaces of the different materials was tested. The morphology of the “S”-treated samples did not differ from the morphology of only-anodized samples. However, the oxygen concentration on the surface in that group slightly increased by about 1% as a result of post-trial treatment. The highest corrosion resistance was observed for both A-78 V and S-78 V samples. The cytotoxicity assay revealed no changes in cell morphology or vitality. The MTT test proved comparable culture viability among all groups; however, the “S” samples showed statistically significantly higher fibroblast proliferation and adhesion scores compared to the “A” samples. Through the in vitro study, the low-pressure radiofrequency oxygen plasma treatment of the anodized Ti-6Al-4V alloy presented itself as an auspicious option in the field of transgingival element surface modification of implants.

This article explores the benefits of electrochemical oxidation in pulsed mode, using potential, current, and power pulses. While potential and current pulse electrochemical technology has been previously studied for wastewater treatment, no study has included power pulses until now. The objective of this work is to highlight the advantages of power pulses by applying this pulse type to the electrochemical oxidation of a probe molecule, alachlor. For this aim, the influence of operating parameters and the comparison of the different pulse modes were investigated and compared to the results obtained with the electrochemical oxidation of alachlor in continuous mode. The study shows that the best results were obtained with the power pulse electrochemical oxidation with 100% alachlor degradation after 180 min and a mineralisation yield of 38.3% after 240 min. These results were better than those reported in the literature for treatments with continuous current input using platinum electrodes. This new technique could be an effective and efficient way to treat contaminated water and reduce the pressure on freshwater reserves.

A novel facile approach to N -arylpyridoindazolium salts is proposed, based on direct oxidation of the ortho -pyridine substituted diarylamines, either using bis(trifluoroacetoxy)iodobenzene as an oxidant, or electrochemically, via potentiostatic oxidation. Electrochemical synthesis occurs under mild conditions; no chemical reagents are required except electric current. Both approaches can be considered as a late-stage functionalization; easily available ortho -pyridyl-substituted diarylamines are used as the precursors., (Copyright © 2024, Levitskiy et al.)

A general and efficient intramolecular halo‐amination of unactivated alkenes for the synthesis of various halogenated N‐heterocycles was developed via electrochemical anodic oxidation. This protocol proceeds in a simple undivided cell by employing LiI or LiBr as redox mediums and halogen sources. A wide range of halogenated N‐heterocycles, including three‐, five‐, and six‐membered N‐heterocycles were constructed in moderate to good yields at room temperature. Notably, this electrochemical oxidative transformation avoids the utilization of external oxidants and strong bases, therefore represents an environmentally benign approach. [ABSTRACT FROM AUTHOR]

FeCrAl stainless steel was anodized in ammonium fluoride-glycol electrolyte at 20℃ to prepare a nano-porous structure. The influences of oxidation voltage and time on the porous structure of oxide film were studied, and the operating parameters were optimized. Aluminum oxide gel was coated on the surface of pretreated FeCrAl samples, and the coating strength was tested by high-frequency ultrasonic . It was concluded that the optimum anodic oxidation condition was 10 min and 50 V, and the coating mechanical strength over FeCrAl pretreated via anodic oxidation is better than that of high-temperature pretreatment. [ABSTRACT FROM AUTHOR]

The effect of chalcogenophosphoryl fragments on the anodic oxidation of 9-chalcogenophosphoryl-9,10-dihydroacridines was studied in detail. The data of X-ray structural analyses, quantum chemical calculations, and cyclic voltammetry measurements obtained for these compounds provide an explanation of the observed features. The direct electrochemical phosphorylation of acridine was first carried out successfully. [ABSTRACT FROM AUTHOR]

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]

A simple and sustainable one-step strategy for the preparation of electron-deficient aryl trifluoromethyl ethers (ArOCF3) from the corresponding phenols by electrochemical synthesis is presented. Anodic oxidation of trifluoromethane sulfinate (Langlois reagent) leads to direct O-trifluoromethylation of phenol-derivatives bearing fluorine, chlorine, bromine and nitrile substituents under mild conditions in yields up to 75% and in gram-scale. This electrochemical protocol provides an economic and green synthesis for an otherwise inaccessible class of molecules without the need for expensive or toxic reagents, oxidants or metal catalysts.

Caffeine is one of the most widely detected and reported emerging contaminant in wastewater, groundwater as well as fresh and marine water bodies owing to its massive consumption, which has led to the bioaccumulation of caffeine in different aquatic environment. Hazardous effects of caffeine have been reported on aquatic biota, coral reefs, soil and microorganisms along with the detrimental health impact on humans. Conventional wastewater treatment plants have shown fairly high removal of caffeine ranging from 64% to 100%. However, caffeine is only partially biodegraded in biological units and is often reported in primary and secondary sludge. The present review article elucidates different electrochemical advanced oxidation processes (EAOPs), namely anodic oxidation (AO) and electro-Fenton (EF) process as alternative techniques for caffeine removal from wastewater and highlights their major findings. Additionally, information regarding performance of integrated systems comprising EAOPs and conventional technologies as well as state-of-art hybrid technologies, such as bioelectro-Fenton (BEF), photoelectron Fenton (PEF) have also been discussed to incorporate a broader perspective of EAOPs as a promising wastewater treatment technique. The review also intends to assist the readers in understanding the key challenges encountered during the operation of EAOPs and the critical parameters affecting removal efficiency along with the potential areas for future investigations for overcoming the drawbacks of EAOPs to make it sustainable technology for field-scale applications.

Germanides are an interesting class of two-component systems which consist of metal and germanium. They are similar in their structure with silicides but have the specific properties. The target of the investigation was finding the main anodic electrochemical behaviour mechanisms for magnesium germanide Mn5Ge3 in an Na2SO4 aqueous solution. Electrochemical behaviour of manganese germanide obtained by Czochralski method was investigated by polarization curves and electrochemical impedance spectroscopy methods and accomplished by microscopy data. Individual manganese and germanium were investigated in the same way for comparison. It was established that in the anodic oxidation process germanium is the potential-determining component. The passivation process associated with the formation of surface oxide films was accomplished by the current density oscillations appearing due to the bad adhesion of oxide film to the surface of the sample, its imperfection and discontinuity. The nature of oxide film formed in the polarization process was partially established. The dependence of the anodic behaviour of the sample on the sulphate concentration was established: in the diluted solutions the passivation occurs at more positive potentials than in the concentrated. This phenomenon can be explained by the different mechanisms of anodic oxidation in the solutions of different concentrations.

The oxidation of chlorobenzene (CB) was studied by electrochemical electrolysis using boron-doped diamond (BDD), PbO2 or platine (Pt) as anode and graphite bar as cathode. The effect of applied current density, supporting electrolyte and initial pH value were also studied. The results demonstrated that BDD anode had the best effectiveness and accomplishment of electrochemical degradation of CB compared to PbO2 and Pt anodes. For a current density of 20 mA/cm2 and at pH = 3, the elimination of COD and TOC were about 97% and 98%, respectively, after 360 min of electrolysis with the BDD anode. Pseudo-first order kinetics appears to be the most appropriate to describe the degradation of chlorobenzene. The electrochemical mechanism of chlorobenzene on BDD was proposed based on the identified intermediates.

Lead dioxide-based electrodes have shown a great performance in the electrochemical treatment of organic wastewater. In the present study, modified PbO2 anodes supported on stainless steel (SS) with a titanium oxide interlayer such as SS/TiO2/PbO2 and SS/TiO2/PbO2-10% Boron (B) were prepared by the sol–gel spin-coating technique. The morphological and structural properties of the prepared electrodes were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It was found that the SS/TiO2/PbO2-10% B anode led to a rougher active surface, larger specific surface area, and therefore stronger ability to generate powerful oxidizing agents. The electrochemical impedance spectroscopy (EIS) measurements showed that the modified PbO2 anodes displayed a lower charge transfer resistance Rct. The influence of the introduction of a TiO2 intermediate layer and the boron doping of a PbO2 active surface layer on the electrochemical degradation of ampicillin (AMP) antibiotic have been investigated by chemical oxygen demand measurements and HPLC analysis. Although HPLC analysis showed that the degradation process of AMP with SS/PbO2 was slightly faster than the modified PbO2 anodes, the results revealed that SS/TiO2/PbO2-10%B was the most efficient and economical anode toward the pollutant degradation due to its physico-chemical properties. At the end of the electrolysis, the chemical oxygen demand (COD), the average current efficiency (ACE) and the energy consumption (EC) reached, respectively, 69.23%, 60.30% and 0.056 kWh (g COD)−1, making SS/TiO2/PbO2-10%B a promising anode for the degradation of ampicillin antibiotic in aqueous solutions.

Magnesium-matrix implants can be detected by X-ray, making post-operative monitoring easier. Since the density and mechanical properties of Mg alloys are similar to those of human bones, the stress-shielding effect can be avoided, accelerating the recovery and regeneration of bone tissues. Additionally, Mg biodegradability shields patients from the infection risk and medical financial burden of needing another surgery. However, the major challenge for magnesium-matrix implants is the rapid degradation rate, which necessitates surface treatment. In this study, the ZKX500 Mg alloy was used, and a non-toxic and eco-friendly anodic oxidation method was adopted to improve corrosion resistance. The results indicate that the anodic coating mainly consisted of magnesium phosphate. After anodic oxidation, the specimen surface developed a coating and an ion-exchanged layer that could slow down the degradation and help maintain the mechanical properties. The results of the tensile and impact tests reveal that after being immersed in SBF for 28 days, the anodic oxidation-treated specimens maintained good strength, ductility, and toughness. Anodic coating provides an excellent surface for cell attachment and growth. In the animal experiment, the anodic oxidation-treated magnesium bone screw used had no adverse effect and could support the injured part for at least 3 months.

Although Ti-Cu alloys have been shown to possess good antibacterial properties, they are still biologically inert. In this study, sandblasting and acid etching combined with anodic oxidation were applied to roughen the surface as well as to form a TiO2/CuO/Cu2O composite film, which would benefit both the antibacterial properties and the biocompatibility. The surface morphology, the phase composition, and the physicochemical properties were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Electrochemical testing and inductively coupled plasma spectrometry (ICP) were used to determine the corrosion resistance and Cu ion release, the plate counting method was used to evaluate the antibacterial performance, and the CCK-8 method was used to evaluate the cytocompatibility. It was revealed that a rough surface with densely porous double layer composed of TiO2/CuO/Cu2O was produced on Ti-Cu alloy surface after the combined surface modification, which enhanced the corrosion resistance significantly. The plate counting results demonstrated that the modified sample had strong long-term antibacterial performance (antibacterial rate > 99%), which was attributed to the formation of TiO2/CuO/Cu2O composite film. The cell compatibility evaluation results indicated that the surface modification improved the cytocompatibility. It was demonstrated that the combined modification provided very strong antibacterial ability and good cytocompatiblity, potentially making it a good candidate surface modification technique for Ti-Cu alloy for biomedical applications.

Background. In modern microelectronics, silicon remains the main material in the production of semiconductor devices and integrated microcircuits. This is largely due to the physicochemical properties of silicon oxide - SiO2, which determines a wide range of its application as an universal dielectric. Due to the possibility of forming porous layers, silicon is also a promising material for the creation of lithium-ion batteries, supercapacitors, solar cells, etc. One of the main methods for preparing silicon for such purposes is the method of electrochemical anodic etching. The patterns of coatings formation by this method are largely determined by the modes of anodic treatment and the microstructure of the treated surface. Materials and methods. To analyze the growth features of anodic oxide films, we used n-type Si single crystal samples. Distilled water was used as an electrolyte. To obtain a higher concentration of defects in the surface layer of silicon, some of the samples were subjected to isothermal annealing at a temperature of 900 °C for 90 min under 4 reference loads of ~ 4.8 N. The analysis of the surface topology of oxide films was carried out by atomic force microscopy (AFM). Results. It is shown that as a result of anodic treatment, the silicon surface is covered with a nanostructured oxide film. The surface of the film is presented in the form of islands, with a base size of ~ 180-600 nm and a height of ~ 25-80 nm. The nonplanar nature of the oxide layer is associated with the formation of oxide islands at electrical active sites, namely, the emergence of dislocations on the surface. The similar nature of the growth of the passivating layer on silicon opens up the possibility of a simple controlled growth of structured thin films both by changing the defectiveness of the substrate and the composition of the electrolyte used for anodizing. Conclusions. Thus, we have investigated the morphology of silicon oxide formed by electrochemical anodic oxidation. It was shown by AFM that the film is not planar and is covered with many oxide islands. Moreover, the formation of islands occurs in the places where dislocations emerge on the surface, which is confirmed by the data of analysis of samples with different dislocation densities. The observed kinetics of silicon oxide growth opens up the possibility of forming nanostructured layers with controlled morphology. The defect-selective dissolution of the Si substrate discovered in this work upon changing the working solution (for example, based on HF) can also lead to the formation of macroporous silicon, which remains a promising and actively studied material for electrodes of lithium-ion batteries.

Abstract Oxidative functionalization of alkenes is a versatile strategy for the preparation of many oxygen‐containing scaffolds, such as epoxides, diols, or carbonyl‐containing compounds. In addition to conventional chemical methods, which rely on the utilization of stoichiometric amounts of oxidizing reagents, some electrochemical procedures have been developed to achieve these transformations. Typical electrochemical procedures employ tailored and often complex redox mediators to achieve the target transformation. Herein we present a modular approach for the synthesis of epoxides, diols, and aldehydes from a single set of reaction components. With sodium bromide as an inexpensive electrocatalyst and water as the oxygen donor, the outcome of the reaction (epoxide, 1,2‐diol, or aldehyde) can be selected by simply tuning the electrolysis conditions. This convenient platform has been accomplished by developing a selective one‐pot three‐step bromide‐electrocatalyzed epoxidation/ring opening/carbon‐carbon cleavage sequence. Its modularity permits the selection of the desired product, as the sequential reaction can be ended when the target compound has been formed. The method has been applied to a diversely functionalized terminal and non‐terminal olefins.

Anodised titanium has a long history as a coating structure for implants due to its bioactive and ossified surface, which promotes rapid bone integration. In response to the growing literature on anodised titanium, this article is the first to revisit the evolution of anodised titanium as an implant coating. The review reports the process and mechanisms for the engineering of distinctive anodised titanium structures, the significant factors influencing the mechanisms of its formation, bioactivity, as well as recent pre- and post-surface treatments proposed to improve the performance of anodised titanium. The review then broadens the discussion to include future functional trends of anodised titanium, ranging from the provision of higher surface energy interactions in the design of biocomposite coatings (template stencil interface for mechanical interlock) to techniques for measuring the bone-to-implant contact (BIC), each with their own challenges. Overall, this paper provides up-to-date information on the impacts of the structure and function of anodised titanium as an implant coating in vitro and in/ex vivo tests, as well as the four key future challenges that are important for its clinical translations, namely (i) techniques to enhance the mechanical stability and (ii) testing techniques to measure the mechanical stability of anodised titanium, (iii) real-time/in-situ detection methods for surface reactions, and (iv) cost-effectiveness for anodised titanium and its safety as a bone implant coating.

This study aims to compare differential pulse voltammetry as a tracking method with chromatography and photometry. The three methods were used to track the degradation of the model compound hydrochlorothiazide (HCT) where 250ml of 0.50mM HCT solution (pH of 3.50 and ionic strength of 0.010M) was electrolyzed with 50.0mAmp constant current. The degradat ion process demonstrated great fit (R2 >0.99) with pseudo-first-order kinetics when the three tracking methods were utilized. However, different rate constants were reported for these methods: 0.032min-1, 0.016 min-1, and 0.0052min-1 for the chromatographic, photometric, and voltammetric techniques, respectively. The observed variation was attributed to the nature of the utilized probing methods. The differential pulse voltammetry is promising as an electrolytic decomposition tracking method; however, the working probe to target pollutants needs to be improved. [ABSTRACT FROM AUTHOR]