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Hee-Seon Kim1 *, Min-Kyung Ji2 *, Woo-Hyung Jang1 *, Khurshed Alam,3 Hyun-Seung Kim,4 Hoon-Sung Cho,3 Hyun-Pil Lim1 1Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea; 2Optoelectronics Convergence Research Center, Chonnam National University, Gwangju, 61186, Republic of Korea; 3Department of Materials Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of Korea; 4Department of Division of New Projects, KJ Meditech Co, Ltd, Gwangju, 61009, Republic of Korea*These authors contributed equally to this workCorrespondence: Hyun-Pil LimDepartment of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, 61186, Republic of KoreaTel +82-10-2645-7528Fax +82-62-530-5577Email mcnihil@jnu.ac.krHoon-Sung ChoDepartment of Materials Science and Engineering, Chonnam National University, Gwangju, 61186, Republic of KoreaTel +82-10-8545-2816Fax +82-62-530-1717Email cho.hoonsung@jnu.ac.krPurpose: This paper presents a technique for developing a novel surface for dental implants using a combination of nitriding and anodic oxidation, followed by the deposition of graphene oxide using atmospheric plasma. The effects of various surface treatments on bacterial adhesion and osteoblast activation were also evaluated.Methods: CP titanium (control) was processed into disk-shaped specimens. Nitriding was conducted using vacuum nitriding, followed by anodic oxidation, which was performed in an electrolyte using a DC power supply, to form the novel “mulberry surface.” Graphene oxide deposition was performed using atmospheric plasma with an inflow of carbon sources. After analyzing the sample surfaces, antibacterial activity was evaluated using Streptococcus mutans and Porphyromonas gingivalis bacteria. The viability, adhesion, proliferation, and differentiation of osteoblasts were also assessed. Analysis of variance (ANOVA) with Tukey’s post-hoc test was used to calculate statistical differences.Results: We observed that the mulberry surface was formed on samples treated with nitriding and anodic oxidation, and these samples exhibited more effective antibacterial activity than the control. We also found that the samples with additional graphene oxide deposition exhibited better biocompatibility, which was validated by osteoblast adhesion, proliferation, and differentiation.Conclusion: The development of the mulberry surface along with graphene oxide deposition inhibits bacterial adhesion to the implant and enhances the adhesion, proliferation, and differentiation of osteoblasts. These results indicate that the mulberry surface and graphene oxide deposition together can inhibit peri-implantitis and promote osseointegration.Keywords: nitriding, anodic oxidation, atmospheric plasma, biofilm formation, osteoblasts

We describe the first electrochemical activation of D–A cyclopropanes and D–A cyclobutanes leading after C(sp3)−C(sp3) cleavage to the formation of highly reactive radical cations. This concept is utilized to formally insert molecular oxygen after direct or DDQ-assisted anodic oxidation of the strained carbocycles, delivering β- and γ-hydroxy ketones and 1,2-dioxanes electrocatalytically. Furthermore, insights into the mechanism of the oxidative process, obtained experimentally and by additional quantum-chemical calculations are presented. The synthetic potential of the reaction products is demonstrated by diverse derivatizations.

In sharp contrast to hypervalent iodine(III) compounds, the isoelectronic bromine(III) counterparts have been little studied to date. This knowledge gap is mainly attributed to the difficult‐to‐control reactivity of λ 3‐bromanes as well as to their challenging preparation from the highly toxic and corrosive BrF3 precursor. In this context, we present a straightforward and scalable approach to chelation‐stabilized λ 3‐bromanes by anodic oxidation of parent aryl bromides possessing two coordinating hexafluoro‐2‐hydroxypropanyl substituents. A series of para‐substituted λ 3‐bromanes with remarkably high redox potentials spanning a range from 1.86 V to 2.60 V vs. Ag/AgNO3 was synthesized by the electrochemical method. We demonstrate that the intrinsic reactivity of the bench‐stable bromine(III) species can be unlocked by addition of a Lewis or a Brønsted acid. The synthetic utility of the λ 3‐bromane activation is exemplified by oxidative C−C, C−N, and C−O bond forming reactions., A straightforward electrochemical synthesis of chelation‐stabilized hypervalent bromine(III) compounds is presented. The electrolysis proceeds at room temperature in an undivided cell under galvanostatic conditions, giving λ 3‐bromanes in good yields on the gram scale from bromoarenes. The reactivity of λ 3‐bromanes can be enhanced by Lewis or Brønsted acid additives as demonstrated in λ 3‐bromane‐mediated oxidative biaryl formation.

Herein, we report an electrochemical oxidative palladium-catalyzed carbonylation-carbocyclization of enallenols to afford γ-lactones and spirolactones, which proceeds with excellent chemoselectivity. Interestingly, electrocatalysis was found to have an accelerating effect on the rate of the tandem process, leading to a more efficient reaction than that under chemical redox conditions.

A metal-free convergent paired electrolysis strategy to synthesize benzylic amines through direct arylation of tertiary amines and benzonitrile derivatives at room temperature has been developed. This TEMPO-mediated electrocatalytic reaction makes full use of both anodic oxidation and cathodic reduction without metals or stoichiometric oxidants, thus showing great potential and advantages for practical synthesis. This convergent paired electrolysis method provides a straightforward and powerful means to activate C-H bonds and realize cross-coupling with cathodically generated species.

The use of reactive electrochemical membranes (REM) in flow-through mode during the anodic oxidation of organic compounds makes it possible to overcome the limitations of plate anodes: in the case of REM, the area of the electrochemically active surface is several orders of magnitude larger, and the delivery of organic compounds to the reaction zone is controlled by convective flow rather than diffusion. The main problem with REM is the formation of fouling and gas bubbles in the pores, which leads to a decrease in the efficiency of the process because the hydraulic resistance increases and the electrochemically active surface is shielded. This work aims to study the processes underlying the reduction in the efficiency of anodic oxidation, and in particular the formation of gas bubbles and the recharge of the REM pore surface at a current density exceeding the limiting kinetic value. We propose a simple one-dimensional non-stationary model of the transport of diluted species during the anodic oxidation of paracetamol using REM to describe the above effects. The processing of the experimental data was carried out. It was found that the absolute value of the zeta potential of the pore surface decreases with time, which leads to a decrease in the permeate flux due to a reduction in the electroosmotic flow. It was shown that in the solution that does not contain organic components, gas bubbles form faster and occupy a larger pore fraction than in the case of the presence of paracetamol, with an increase in the paracetamol concentration, the gas fraction decreases. This behavior is due to a decrease in the generation of oxygen during the recombination reaction of the hydroxyl radicals, which are consumed in the oxidation reaction of the organic compounds. Because the presence of bubbles increases the hydraulic resistance, the residence time of paracetamol—and consequently its degradation degree—increases, but the productivity goes down. The model has predictive power and, after simple calibration, can be used to predict the performance of REM anodic oxidation systems.

In this study anodic oxidation of Cr2(SO4)3 was carried out in an air-sparged divided parallel plate cell. Variables studied were current density, Cr2(SO4)3 concentration, and superficial air veloc...

An atom-economical method for the direct B-H functionalization of nido-carboranes (7,8-nido-C2 B9 H12- ) has been developed under electrochemical reaction conditions. In this reaction system, anodic oxidation serves as a green alternative for traditional chemical oxidants in the oxidation of nido-carboranes. No transition-metal catalyst is required and different heteroatoms bearing a lone pair are reactive in this transformation. Coupling nido-carboranes with thioethers, selenides, tellurides, N-heterocycles, phosphates, phosphines, arsenides and antimonides demonstrates high site-selectivity and efficiency. Importantly, nido-carboranes can be easily incorporated into drug motifs through this reaction protocol.

The anodic oxidation (AO) of 30 pharmaceuticals including antibiotics, hormones, antihistaminics, anti-inflammatories, antidepressants, antihypertensives, and antiulcer agents, in solutions containing different supporting electrolytes media (0.05 M Na2SO4, 0.05 M NaCl, and 0.05 M Na2SO4 + 0.05 M NaCl) at natural pH was studied. A boron-doped diamond (BDD) electrode and a stainless-steel electrode were used as anode and cathode, respectively, and three current densities of 6, 20, and 40 mA cm−2 were applied. The results showed high mineralization rates, above 85%, in all the tested electrolytic media. 25 intermediaries produced during the electrooxidation were identified, depending on the supporting electrolyte together with the formation of carboxylic acids, NO3−, SO42− and NH4+ ions. The formation of intermediates in chloride medium produced an increase in absorbance. Finally, a real secondary effluent spiked with the 30 pharmaceuticals was treated by AO applying 6 mA cm−2 at natural pH and without addition of supporting electrolyte, reaching c.a. 90% mineralization after 300 min, with an energy consumption of 18.95 kW h m−3 equivalent to 2.90 USD m−3. A degradation scheme for the mixture of emerging contaminants in both electrolytic media is proposed. Thus, the application of anodic oxidation generates a high concentration of hydroxyl radicals that favors the mineralization of the pharmaceuticals present in the spiked secondary effluent sample., The authors are very grateful for the partial financial support of FONDECYT Grant 1170352 and DICYT USACh. W. Calzadilla thanks PFCHA/ANID for the National PhD scholarship 21160273. Authors also acknowledge the partial financial support of the Spanish Ministry of Science and Innovation through the Project ROUSSEAU CTM2017-89767-C3-1-R and Project CEX2018-000794-S.

WOS: 000548652700007 PubMed: 32639700 Purpose: To investigate the reverse torque values of abutment screws subjected to various surface modifications. Materials and Methods: Sixty abutment screws were divided into two groups of 30 each: with thermomechanical cycling (240,000 cycles) and without thermomechanical cycling. Each group was then divided into three subgroups according to surface treatment: nontreated (NT, n = 10); anodic oxidation (AO, n = 10); and diamond-like carbon (DLC) coating (DLC, n = 10). All abutment screws were tightened to 30 Ncm using a digital torque meter. The reverse torque values of the abutment screws with and without thermomechanical cycling were then measured. The percentage of deviation (PERDEV) for reverse torque values was calculated. Two-way analysis of variance followed by Tukey Honest Significant Difference test were used for intergroup comparisons. Results: Significant differences were found among the PERDEV values of the groups based on thermomechanical cycling and surface treatment (P < .001 for each). A significant interaction was found between surface treatment and thermomechanical cycling (P < .001). Conclusion: Reverse torque values of abutment screws were found to be higher after surface treatments. The abutment screws with AO exhibited the lowest torque value loss in groups with and without thermomechanical cycling. Erciyes University Scientific Research Projects Coordination UnitErciyes University [TDH-2018-8144] This work was supported by the Erciyes University Scientific Research Projects Coordination Unit (grant no: TDH-2018-8144). The authors would like to thank Dr Halis Ali Colpak and Dr Haydar Albayrak for their valuable contributions to the editing stage of this study. Additionally, they are eager to thank to Dr Oktay Bug. ra Topuz for his support in the experimental stage.; Further details of DLC surface modification were not given for publication by Oerlikon Balzers, which supported the DLC experimental group in this study.

The photo-assisted electrochemical degradation of a real effluent of the atrazine manufacturing process containing atrazine, simazine, hydroxy-triazine and propazine was carried out galvanostatically using a pilot-scale tubular flow reactor prototype containing DSA® and Ti as cathode. The effluent was mainly characterized by a high amount of NaCl, required in the synthesis route used, and it was used as taken in the factory. The variables for process optimization were the current density (3.0, 6.0, and 9.0 mA cm−2) and flow rate (300 and 3,000 L h−1). These later values produces laminar and turbulent flow regimes, with Reynolds numbers of 1,100 and 11,000, respectively. None of the four organics contained in the waste is refractory to the photo-electrochemical treatment and they are depleted with the photo-electrolytic technology using large current densities and appropriate electric charge passed. Both direct electrochemical process and mediated anodic oxidation occur during the treatment. First process occurs at turbulent flow condition and low current densities, while the chemical oxidation process happens at laminar flow condition and high current densities. Atrazine and propazine are efficiently removed at laminar flow conditions, with an almost total depletion for the largest current densities. On the contrary, simazine is efficiently removed in turbulent flow conditions and intermediate current density, with removals higher than 90% for 20 kWh m−3. These results have great significance because they demonstrate the applicability of the electrochemical technology in the treatment of real industrial wastes with a cell specially designed to attain high efficiency in the removal of pollutants.

Highly ordered TiO2 nanotube arrays are very attractive to the dental implant due to microstructural advantage for drug loading. We have fabricated the highly ordered TiO2 nanotube arrays on the surface of the dental implant. The surface of TiO2 nanotube arrays grown by normal anodic oxidation was not clean and the window of TiO2 nanotube was closed. These closed nanotubes decrease the surface area to load the drug and also decrease the osseointegration performances. To obtain the clean surface of TiO2 nanotube arrays, two-step anodic oxidation was used. The microstructures of TiO2 nanotube arrays from two-step anodic oxidation were compared with those from normal anodic oxidation. The length and diameter of TiO2 nanotube arrays with anodizing time were measured. TiO2 nanotube arrays grown by two-step anodic oxidation had the clean surface and the diameter of TiO2 nanotubes was ~100 nm at anodizing conditions of 60V and 20 min. It was applied to the surface of dental implant to improve the osseointegration. The improved osseointegration was observed by micro CT analysis. TiO2 nanotube arrays had a promising microstructure to load some drugs such as BMP-2 and anti-inflammatory.

This work focuses on the partial anodic electro-oxidation of atrazine-polluted soil washing effluents (SWE) in order to reduce its toxicity and to improve its biodegradability. Concretely it has been evaluated the influence of the anodic material used. It is hypothesized that such partial oxidation step could be considered as a pre-treatment for a subsequent biological treatment. At first, atrazine was extracted from a polluted soil by means of a surfactant-aided soil-washing process. Then, four different anodic materials were studied in partial electro-oxidation pre-treatment batch experiments at different electric charges applied: Boron Doped Diamond (BDD), Carbon Felt (CF), and Mixed Metal Oxides Anodes with Iridium and Ruthenium. Atrazine, TOC, surfactant and sulphate species concentrations, as well as changes in toxicity and biodegradability, were monitored during electrochemical experiments, showing important differences in their evolution during the treatment. It was observed that BDD was the most powerful anodic material to completely degrade atrazine. The other materials achieve an atrazine degradation rate about 75%. Regarding mineralization of the organics in SWE, BDD overtakes clearly the rest of anodes tested. CF obtains good atrazine removal but low mineralization results. All the anodes tested slightly reduced the ecotoxicity of the water effluents. About the biodegradability, only the effluent obtained after the pre-treatment with BDD presented a high biodegradability. In this sense, it must be highlighted the mineralization obtained during the BDD pre-treatment was very strong. These results globally indicate that it is necessary to find a compromise between reaching efficient atrazine removal and biodegradability improvement, while also simultaneously avoiding strong mineralization. Additional efforts should be made to find the most adequate working conditions.

Orthodontic tunnel miniscrews with and without TiO2 nanotube arrays were fabricated to improve the induction of new bone formation and osseointegration. To inject the drug of recombinant human bone morphogenetic protein, tunnels in a conventional machined miniscrew were machined by a computer-numerical-control lathe. TiO2 nanotube arrays to load the drug were also formed on the surface of the tunnel miniscrew by anodic oxidation. To obtain clean TiO2 nanotube arrays, two-step anodic oxidation was conducted. The diameters of TiO2 nanotube window and TiO2 nanotube were ∼70 nm and ∼110 nm, respectively. Three groups, i.e., a conventional machined miniscrew, a tunnel miniscrew without TiO2 nanotube arrays, and a tunnel miniscrew with TiO2 nanotube arrays, were prepared and inserted in the legs of five New Zealand White rabbits. In a histomorphometric analysis, the bone implant contact ratios of the tunnel miniscrews with the TiO2 nanotube arrays and without the TiO2 nanotube arrays were 5.84% and 5.88%, respectively. These values were higher than the value of 4.30% for the conventional machined miniscrew. The bone surface ratios in the tunnel miniscrew with and without the TiO2 nanotube were also higher than those of the conventional machined miniscrew. The measured values of the tunnel miniscrew with and without the nanotube and the conventional miniscrew were 76.75%, 73.41%, and 44.82%, respectively, although the differences were statistically insignificant. New bone at three weeks and six weeks after the operations were found in the tunnel miniscrews in fluorescent images. Both the tunnel miniscrews with and without the TiO2 nanotube arrays demonstrated greater bone formation compared to the conventional miniscrews. However, TiO2 nanotube arrays was not likely to provide additional benefit to the tunnel miniscrew. An in vivo study suggested that the tunnel fabricated in the miniscrew can be efficient drug-delivery systems to improve osseointegration.

Uric acid (UA) is one of the principal effluents of urine wastewaters, widely used in agriculture as fertilizer, which is potentially dangerous and biorefractory. Hence, the degradation of UA (2,6,8-trihydroxy purine) in aqueous solution of pH 3.0 has been studied by conductive-diamond electrochemical oxidation. Hydroxyl radicals formed from water oxidation at the surface of boron-doped diamond anodes were the main oxidizing agents. Effects of current density and supporting electrolyte on the degradation rate and process efficiency are assessed. Results show that the increase of current density from 20 to 60 mA cm(-2) leads to a decrease in the efficiency of the electrochemical process. In addition, the best degradation occurred in the presence of NaCl as conductive electrolyte. Interestingly, an almost total mineralization of 50 ppm UA was obtained when anodic oxidation was performed at low current densities (20 mA cm(-2)) and in the presence of NaCl. This result confirmed that the electrolysis using diamond anodes is a very interesting technology for the treatment of UA. The identification of UA transformation products was performed by high-performance liquid chromatography (HPLC). HPLC analysis of treated solutions revealed that oxalic acid and urea were the two intermediates found. Oxalic acid was the most persistent product. Based on detected intermediates and bibliographic research, a mechanism of UA mineralization by anodic oxidation has been proposed. Ionic chromatography analysis confirmed the release of [Formula: see text] and [Formula: see text] ions during UA mineralization.

Resumen Oxacilina (OXA), Cloxacilina (CLX) y Dicloxacilina (DCX) son antibioticos β-lactamicos usados para tratar infecciones producidas por microorganismos grampositivos y gramnegativos, estas sustancias pueden alcanzar los sistemas acuaticos debido a su inadecuada disposicion o a deficiencias de los sistemas de tratamiento de aguas, originando un serio riesgo de proliferacion en el ambiente de bacterias resistentes a estos antibioticos. El presente trabajo investigo la degradacion de OXA, CLX y DCX mediante oxidacion anodica, empleando un anodo de Ti/IrO2. Un diseno experimental, evaluando las variables ‘corriente aplicada’, ‘concentracion de NaCl’ y ‘concentracion de sustancia’, permitio determinar las condiciones mas favorables para la degradacion de los β-lactamicos ensayados. Las mejores eficiencias, en terminos de la remocion del contaminante y su actividad antibiotica, fueron obtenidas a altos niveles de corriente aplicada (121 mA) y concentracion media de NaCl (0,225 mol L−1) como electrolito soporte, mientras que la concentracion del antibiotico no ejercio un efecto significativo sobre el desempeno del sistema. Los antibioticos OXA, CLX y DCX (203 μmol L−1) experimentaron, en forma independiente, una completa remocion a los 5 min de tratamiento, por una via de degradacion mediada por especies reactivas de cloro electrogeneradas en la superficie del anodo. De manera interesante, se observo una perdida completa de la actividad antimicrobiana tan pronto como desaparecio el compuesto padre, indicando que los productos de degradacion no presentan potencia antibiotica, inclusive algunos de estos productos formados inicialmente son tambien degradados por el sistema electroquimico. Los resultados indicaron que la oxidacion electroquimica tiene gran proyeccion para el tratamiento de aguas que contienen antibioticos β-lactamicos, debido a su alta eficiencia tanto para remover el contaminante como para eliminar la actividad antimicrobiana de estos compuestos en periodos cortos de tiempo. Abstract Oxacillin (OXA), cloxacillin (CLX) and Dicloxacillin (DCX) are β-lactam antibiotics, used to treat infections caused by gram-positive and gram-negative microorganisms, which can reach aquatic systems due to improper disposal or deficient water system treatments, thus representing a risk to the environment. With this work, the degradation of these -lactam antibiotics was investigated by anodic oxidation using a DSA anode Ti/IrO2. An experimental design with variables assessing current density, supporting electrolyte, and the concentration of substance, allowed to evaluate the most favorable conditions for the degradation of the β-lactams tested. The best eciencies in terms of pollutant and antibiotic activity removals, were obtained at high current level (121 mA) and average concentration of NaCl (0.225 mol L

Simultaneous enhancement of dye removal and reduction of energy consumption is critical for electrochemical oxidation in treating dyeing wastewater. To address this issue, this work presented a novel process termed biocathode-electrocatalytic reactor (BECR). The dual-chamber BECR employed O2-reducing biocathode instead of normal stainless steel (SS) cathode and MnOx/Ti anode to reduce O2 in the cathode chamber and treat methylene blue (MB) in the anode chamber, respectively. BECR successfully started up at 0.7 and 1 V and substantially improved MB and total organic carbon (TOC) removal compared with the electrocatalytic reactor with SS cathode (ECR-SS), e.g., removal of MB (150 mg L−1) increased from 27.0 ± 0.2% to 78.1 ± 0.4% at 1 V. To achieve the same TOC removal, BECR reduced the energy consumption by approximately 45.7% compared with ECR-SS (19.5 and 35.9 kWh (kg TOC) −1 for BECR and ECR, respectively). To explain the above merits of BECR, M(·OH) (·OH adsorbed on the anode surface) generation, potential of MnOx/Ti anode (Ea), and their correlation were investigated. When coupled with O2-reducing biocathode, MnOx/Ti anode considerably accelerated M(·OH) generation because Ea increased. The increased Ea in BECR was due to the fact that its cathodic reaction was converted to the four-electron O2 reduction, which exhibited a higher cathodic potential than hydrogen evolution reaction on SS cathode in ECR-SS. Thereby, BECR simultaneously promoted dye removal and reduced energy consumption, showing promise in treating dyeing wastewater.

Made available in DSpace on 2020-12-12T01:39:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Vulcan Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The objectives of this study were to determine the viability of removing Orange II (OII) dye by simulated solar photoelectro-Fenton (SSPEF) and to evaluate the stability of a WO2.72/Vulcan XC72 gas diffusion electrode (GDE) and thus determine its best operating parameters. The GDE cathode was combined with a BDD anode for decolorization and mineralization of 350 mL of 0.26 mM OII by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF) at 100, 150 and 200 mA cm−2 and SSPEF at 150 mA cm−2. The GDE showed successful operation for electrogeneration, good reproducibility and low leaching of W. Decolorization and OII decay were directly proportional to the current density (j). AO-H2O2 had a reduced performance that was only half of the SSPEF, PEF and EF treatments. The mineralization efficiency was in the following order: AO-H2O2 < EF < PEF ≈ SSPEF. This showed that the GDE, BDD anode and light radiation combination was advantageous and indicated that the SSPEF process is promising with both a lower cost than using UV lamps and simulating solar photoelectro-Fenton process. The PEF process with the lowest j (100 mA cm−2) showed the best performance-mineralization current efficiency. Centro de Ciências Naturais e Humanas (CCNH) Universidade Federal Do ABC (UFABC), Rua Santa Adélia, 166 Centro de Engenharia Modelagem e Ciências Sociais Aplicadas (CECS) Universidade Federal Do ABC (UFABC), Rua Santa Adélia, 166 Instituto Federal de Educação Ciência e Tecnologia Do Maranhão (IFMA) Campus Açailândia, R. Projetada, s/n Instituto de Química de São Carlos (IQSC) Universidade de São Paulo (USP), Caixa Postal, 780 Instituto Nacional de Tecnologias Alternativas Para Detecção Avaliação Toxicológica e Remoção de Micropoluentes e Radioativos (INCT-DATREM) Instituto de Química UNESP Instituto Nacional de Tecnologias Alternativas Para Detecção Avaliação Toxicológica e Remoção de Micropoluentes e Radioativos (INCT-DATREM) Instituto de Química UNESP FAPESP: #2014/50945-4 FAPESP: #2015/10314-8 FAPESP: #2016/00819-8 FAPESP: #2017/10118-0 FAPESP: #2017/21846-6 FAPESP: #2017/22976-0 FAPESP: #2017/26288-1 CAPES: 001 CNPq: 302874/2017-8 CNPq: 406612/2013-7 CNPq: 427452/2018-0 CNPq: 465571/2014-0

Made available in DSpace on 2018-12-11T16:55:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 Made available in DSpace on 2018-12-11T16:55:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-01 In this study, ordered and uniform TiO2 nanotubular structures were obtained on the surface of the Ti15Mo alloy by anodic oxidation. The amorphous state of TiO2 nanotubes formed under different anodization conditions was investigated. Crystallization of TiO2 into anatase phase occurs during annealing at temperatures of around 400°C, whereas anatase to rutile transformation starts around 500°C and is completed at 800°C. Phase transformations in annealed samples led to morphological changes of tubular nanostructures, suggesting that the oxide layer formed at the nanotube/substrate interface serves as nucleation sites for more stable phases of TiO2. The proliferation of fibroblasts cells under annealing conditions of 450°C, and of untreated samples (control group), was evaluated after 1, 4, and 7 days in cell culture using fluorescence microscopy images. A gradual increase in the number and size of cells was observed, indicating a non-toxic alloy. There was also better surface coverage on anodized samples compared with the untreated group; as well as increased development of the cytoskeleton in samples after anodization. The results of this study showed that the growth of TiO2 nanotubular structures associated with annealing allow better cell adhesion on the Ti15Mo alloy surface. Department of Materials and Technology School of Engineering São Paulo State University (UNESP) Department of Mechanical Engineering School of Biomedical Engineering Colorado State University Department of Materials and Technology School of Engineering São Paulo State University (UNESP)

International audience; Electro-oxidation processes are promising options for the removal of organic pollutants from water. The major appeal of these technologies is the possibility to avoid the addition of chemical reagents. However, a major limitation is associated with slow mass transfer that reduces the efficiency and hinders the potential for large-scale application of these technologies. Therefore, improving the reactor configuration is currently one of the most important areas for research and development. The recent development of a reactive electrochemical membrane (REM) as a flow-through electrode has proven to be a breakthrough innovation, leading to both high electrochemically active surface area and convection-enhanced mass transport of pollutants. This review summarizes the current state of the art on REMs for the electro-oxidation of organic compounds by anodic oxidation. Specific focuses on the electroactive surface area, mass transport, reactivity, fouling and stability of REMs are included. Recent advances in the development of sub-stoichiometric titanium oxide REMs as anodes have been made. These electrodes possess high electrical conductivity, reactivity (generation of •OH), chemical/electrochemical stability, and suitable pore structure that allows for efficient mass transport. Further development of REMs strongly relies on the development of materials with suitable physico-chemical characteristics that produce electrodes with efficient mass transport properties, high electroactive surface area, high reactivity and long-term stability.

Advanced Oxidation Processes (AOPs) are called to fill the gap between the treatability attained by conventional physico-chemical and biological treatments and the day-to-day more exigent limits fixed by environmental regulations. They are particularly important for the removal of anthropogenic pollutants and for this reason, they have been widely investigated in the last decades and even applied in the treatment of many industrial wastewater flows. However, despite the great development reached, AOPs cannot be considered mature yet and there are many new fields worthy of research. Some of them are going to be briefly introduced in this paper, including hybrid processes, heterogeneous semiconductor photocatalysis, sulphate-radical oxidation and electrochemical advanced oxidation for water/wastewater treatment. Moreover, the use of photoelectrochemical processes for energy production is discussed. The work ends with some perspectives that can be of interest for the ongoing and future research., Los Procesos de Oxidación Avanzada (POAs) están llamados a llenar el vacío entre la tratabilidad alcanzada por los tratamientos físico-químicos y biológicos convencionales y los límites cada día más exigentes fijados por la normativa medioambiental. Son particularmente importantes para la remoción de contaminantes antropogénicos y por esta razón han sido ampliamente investigados en las últimas décadas e incluso aplicados en el tratamiento de muchos flujos de aguas residuales industriales. Sin embargo, a pesar del gran desarrollo alcanzado, los POA aún no pueden considerarse maduros y existen muchos campos nuevos dignos de investigación. Algunos de ellos se presentarán brevemente en este artículo, incluidos los procesos híbridos, la fotocatálisis de semiconductores heterogéneos, la oxidación por radicales de sulfato y la oxidación electroquímica avanzada para el tratamiento de agua/aguas residuales. Además, se discute el uso de procesos fotoelectroquímicos para la producción de energía. El trabajo finaliza con algunas perspectivas que pueden ser de interés para las investigaciones en curso y futuras.

In the overreview, the effects of anodic oxidation parameters on the characterstics of TiO2 nanotube array are discussed at first. Then, the wettability modification methods of the TiO2 nanotube array and its application in anit-corrosion, photocatalysis and medical science are presented.

The electrochemical degradation of the nonsteroidal anti-inflammatory drug ketoprofen in tap water has been studied using electro-Fenton (EF) and anodic oxidation (AO) processes with platinium (Pt) and boron-doped diamond (BDD) anodes and carbon felt cathode. Fast degradation of the parent drug molecule and its degradation intermediates leading to complete mineralization was achieved by BDD/carbon felt, Pt/carbon felt, and AO with BDD anode. The obtained results showed that oxidative degradation rate of ketoprofen and mineralization of its aqueous solution increased by increasing applied current. Degradation kinetics fitted well to a pseudo-first-order reaction. Absolute rate constant of the oxidation of ketoprofen by electrochemically generated hydroxyl radicals was determined to be (2.8 ± 0.1) × 10(9) M(-1) s(-1) by using competition kinetic method. Several reaction intermediates such as 3-hydroxybenzoic acid, pyrogallol, catechol, benzophenone, benzoic acid, and hydroquinone were identified by high-performance liquid chromatography (HPLC) analyses. The formation, identification, and evolution of short-chain aliphatic carboxylic acids like formic, acetic, oxalic, glycolic, and glyoxylic acids were monitored with ion exclusion chromatography. Based on the identified aromatic/cyclic intermediates and carboxylic acids as end products before mineralization, a plausible mineralization pathway was proposed. The evolution of the toxicity during treatments was also monitored using Microtox method, showing a faster detoxification with higher applied current values.

Magnesium and its alloys have excellent physical and mechanical properties for a number of applications. Unfortunately, magnesium and its alloys are highly susceptible to corrosion, which greatly restricts their further application. Anodic oxidation treatment is an effective method to improve the corrosion resistance of magnesium and its alloys. In the anodic oxidation process, organic additives have significantly effects on the performance of the oxide film. This paper reviews the research progress on organic additives, in order to provide some references for the research of the electrolyte in the anodic oxidation process of magnesium and its alloys.

TiO2 nanotube arrays were made on the titanium foil by the method of anodic oxidation. Large-area crystallized free-standing TiO2 nanotube arrays were fabricated by a two-step anodization, and then crystallized by different heat-treatment processes. The morphology and structure of the TiO2 nanotube arrays were characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). The results show that the diameter of the TiO2 nanotube at the voltage range of 50V~65V was about 100nm. Anatase phase is the unique phase observed in free-standing TiO2 arrays annealed at the temperature of 400°C~610°C. However, crystallographic orientation of anatase phase is influenced by the annealing temperature.

Microhardness is a basic controlled quality parameter according to functional coatings, which is linked with a number of physico-chemical properties, such as coating strength, abrasion resistance, resistance to deformation, life. Life of the coating from a diagnostic point of view is influenced by chemical, physical, technological and material conditions of the process of creating film. The paper deals with analysis of the microhardness coating created by anodic oxidation of aluminum with a direct link to the chemical and physical factors controlled by the Design of Experiments methodology at constant anode current density 2 A.dm-2.

Purpose In the past few years there has been growing interest in memristive devices. These devices rely on thin metal oxide films with a peculiar structure and composition, making precise control of oxide features vital. To this end, anodic oxidation allows a very large range of oxides to be formed on the surface of valve metals, whose thickness, structure and functional properties depend on the process parameters introduced. This work reports how memristive anodic oxides were obtained on titanium and other valve metals, such as niobium and tantalum. Methods Anodic oxidation was performed on valve metals by immersion in H2SO4 or H3PO4 electrolytes and application of voltages ranging from 10 to 90 V. The memristive behavior was evaluated by cyclic voltammetry. Results The behavior of differently grown oxides was compared to identify the best conditions to achieve good memristive performances. High voltages were identified as not suitable due to the excessive oxide thickness, while below 20 V the film was not thick and uniform enough to give a good response. Surface preparation also played a major role in the observation of memristive properties. Conclusions Optimal surface preparation and anodizing conditions were seen to give high memristive perfomances on both titanium and niobium oxides, while on tantalum oxides no reproducibility was achieved.

International audience; Introduction: The degradation and mineralization of two triketone (TRK) herbicides, including sulcotrione and mesotrione, by the electro-Fenton process (electro-Fenton using Pt anode (EF-Pt), electro-Fenton with BDD anode (EF-BDD) and anodic oxidation with BDD anode) were investigated in acidic aqueous medium. Methods: The reactivity of both herbicides toward hydroxyl radicals was found to depend on the electron-withdrawing effect of the aromatic chlorine or nitro substituents. The degradation of sulcotrione and mesotrione obeyed apparent first-order reaction kinetics, and their absolute rate constants with hydroxyl radicals at pH 3. 0 were determined by the competitive kinetics method. Results and discussion: The hydroxylation absolute rate constant (kabs) values of both TRK herbicides ranged from 8. 20 × 108 (sulcotrione) to 1. 01 × 109 (mesotrione) L mol-1 s-1, whereas those of the TRK main cyclic or aromatic by-products, namely cyclohexane 1,3-dione, (2-chloro-4-methylsulphonyl) benzoic acid and 4-(methylsulphonyl)-2-nitrobenzoic acid, comprised between 5. 90 × 108 and 3. 29 × 109 L mol-1 s-1. The efficiency of mineralization of aqueous solutions of both TRK herbicides was evaluated in terms of total organic carbon removal. Mineralization yields of about 97-98% were reached in optimal conditions for a 6-h electro-Fenton treatment time. Conclusions: The mineralization process steps involved the oxidative opening of the aromatic or cyclic TRK by-products, leading to the formation of short-chain carboxylic acids, and, then, of carbon dioxide and inorganic ions.

A method of removal of chloride in reinforced concrete was proposed by anodic oxidation of silver in the pore solution with chloride content over 0.4% by weight. The result shows that after anodic oxidation of silver plate the polarisation resistance of rebar will increase to the range of safety. The silver plate can be applied repeatedly.

Electrochemical treatment of oleate using RuO2 and IrO2 type dimensionally stable anodes in alkaline medium was performed to develop a feasible anaerobic pre-treatment of fatty effluents. The results showed that the pre-treated solutions over RuO2 were faster degraded by anaerobic consortium than the raw oleate solutions or the electrolysed solutions using IrO2. In batch experiments carried out with pre-treated solutions over RuO2 (100–500 mg/L), no lag phases were observed before the methane production onset. On the other hand, raw oleate and pre-treated oleate over IrO2 had originated lag phases of 0–140 and 0–210 h, respectively. This study demonstrated that it is advantageous to apply the electrochemical treatment carried out on the RuO2 type DSA in order to achieve a faster biodegradation of lipid-containing effluent and consequently to obtain a faster methane production., ELTECH Systems Corporation., Fundação para a Ciência e Tecnologia (FCT)

Efficient carbon–carbon bond-forming reaction at the 5- and 6-positions of catechol skeleton was achieved through anodic oxidation of catechol, 3-methylcatechol, and 4-methylcatechol in the presenc...

Urea can be oxidised electrochemically in chlorine solution to carbon dioxide, water and nitrogen. The microkinetics of this hypochlorite-mediated urea oxidation are elucidated. Urea destruction by hypochlorite is a relatively slow reaction and needs either high reactor volumes or a high stationary temperature to proceed with a high degree of conversion. Based on this kinetic information, the optimal working conditions and construction principles of a cheap disposable oxidation cell as well as necessary auxiliary equipment are described. Data in vitro are reported for urea removal simulating a 3 h treatment of a 60 kg kidney patient. The technical and economical possibilities for haemofiltrate regeneration are discussed.

Tetramer (I) is obtained by anodic oxidation of 2,4-dimethylphenol as reported in a previous paper.

Electrochemistry provides a powerful tool for the late-stage functionalization of complex lactams. A two-stage protocol for converting lactams, many of which can be prepared through the intramolecular Schmidt reaction of keto azides, is presented. In the first step, anodic oxidation in MeOH using a repurposed power source provides a convenient route to lactams bearing a methoxy group adjacent to nitrogen. Treatment of these intermediates with a Lewis acid in dichloromethane permits the regeneration of a reactive acyliminium ion that is then reacted with a range of nucleophilic species.

Nickel oxyhydroxide, NiOOH, anode has been shown to be an effective tool for the oxidation of aminofurazans to azofurazans in ca. 1% aqueous alkali at room temperature. The electrochemical reaction is simple and convenient, eliminating the use of expensive and toxic organic or inorganic oxidants. The green economic preparation of desired azo compounds is very clean, producing only H2 as a result of cathodic reduction.

2-Pyrimidyloxybenzenes and their thio analogues are subjected to anodic oxidation in a H-type divided cell under constant current.

In this work, the electrochemical oxidation of synthetic urine by anodic oxidation using boron-doped diamond as anode and stainless steel as cathode was investigated. Results show that complete depletion of chemical oxygen demand (COD) and total organic carbon (TOC) can be attained regardless of the current density applied in the range 20–100 mA cm−2. Oxalic and oxamic acids, and, in lower concentrations, creatol and guanidine were identified as the main intermediates. Chloride ions play a very important role as mediators and contribute not only to obtain a high efficiency in the removal of the organics but also to obtain an efficient removal of nitrogen by the transformation of the various raw nitrogen species into gaseous nitrogen through chloramine formation. The main drawback of the technology is the formation of chlorates and perchlorates as final chlorine products. The increase of current density from 20 to 60 mA cm−2 led to an increase in the rate of COD and TOC removals although the process becomes less efficient in terms of energy consumption (removals of COD and TOC after applying 18 Ah dm−3 were 93.94 and 94.94 %, respectively, at 20 mA cm−2 and 89.17 and 86.72 %, respectively, at 60 mA cm−2). The most efficient conditions are low current densities and high temperature reaching total mineralization at an applied charge as low as 20 kAh m−3. This result confirmed that the electrolysis using diamond anodes is a very interesting technology for the treatment of urine. - University of Gabes (Tunisia) - partial financial support. - Spanish government project No. CTM2013-45612-R. - The Spanish government and EU project No. FEDER 2007–2013 PP201010. (Planta Piloto de Estación de Estación de Regeneración de Aguas Depuradas).

Potentiostatic electrolysis of NH4SCN in an undivided cell is used to perform the anodic thiocyanation of various aromatic substrates under mild conditions.

[reaction: see text] A new method of deprotection of N-p-methoxyphenylamines using anodic oxidation in acidic medium is presented. The process furnishes a high yield of amine and is compatible with several oxidable functional groups.

In this paper nanotube TiO2 coating as an interlayer was produced on Ti substrate and the performances of the Ti/nanotube TiO2/Sb-SnO2 electrodes were investigated. It is shown that the microstructure of the nanotubes changes with the anodic oxidation voltage and time, and the introduction of the nanotube TiO2 in the electrodes gives rise to both the oxygen evolution potential and the accelerated life of the electrodes.

目的: 放電陽極酸化と水熱処理により, 純チタン表面に結晶性の高いハイドロキシアパタイト (HAP) を析出させる方法 (SA処理) を開発し, 優れた骨伝導能を有することを報告してきた. 埋入後のSA処理インプラントが恒常的に維持・機能するためには, HAP結晶変化について検討しておく必要がある. 本研究では, 浸漬試験を行い, HAP結晶変化について走査型電子顕微鏡 (SEM), X線回折装置 (XRD), X線光電子分光分析装置 (XPS) にて解析した.方法: SA処理を施した純チタンディスクを試料として用いた. 緩衝液を使用して調整した0.9%NaCl溶液 (pH6.0), 1M Tris-HCl溶液 (pH7.4) それぞれに試料を1, 7, 14日間浸漬後, SEM, XRD, XPSにてHAP結晶変化を解析した.結果: 0.9%NaCl溶液に浸漬後14日目のSEM像でのHAP結晶の一部に形態変化が認められた. しかし, XRD解析では同定物質 (Ti, TiO2, Calcium acetate monohydrate, α-tricalcium phosphate, HAP, CaTiO) の浸漬前後における変化は認められなかった. XPS解析では, 浸漬後1日目よりHAP結晶中のPとCaの結合エネルギーが変化し, 活性化状態になっていることがわかった.結論: 0.9%NaCl溶液を用いて酸性化の環境を想定した場合では, HAP結晶内部エネルギーとHAP結晶の形状に変化が認められたが, 性状は影響を受けていなかった. 一方, Tris-HCl液中においては, HAP結晶内部エネルギーの変化は認められるものの, HAP結晶の形状や性状は影響を受けていなかった. したがって, SA処理により析出したHAP結晶は, 生体内環境下で安定した状態であることが考えられた.

Perfluoroallylbenzene ( I ) can be isomerized under the action of HSO 3 F to form perfluoropropenylbenzene (in the form of a mixture of cis - and trans -isomers) which undergoes anodic oxidation in HSO 3 F to give α,β-bis(fluorosulfonyloxy)perfluoropropylbenzene ( III ). Reaction of III with CsF in tetraglyme gives perfluoro-2-methylbenzoxolene ( XII ), whereas III is converted to perfluoromethylphenyl-α-dione ( IX ) by reacting with AcONa/AcOH. Cyclization of ( IX ) catalyzed by CsF occurs to form perfluoro-2-methyl-3-oxobenzoxolene ( XIII ).

The new and efficient electrochemical synthesis of nitriles (II) (14 examples) is more environmentally friendly and easier to handle compared to conventional synthetic methods.

A direct coupling of aldehydes and mercaptans to thioesters is demonstrated by integration of NHC-organocatalyst into electrophilic anodic oxidation.

International audience; Boron-doped diamond (BDD) is playing an important role in environmental electrochemistry and has been successfully applied to the degradation of various bio-refractory organic pollutants. However, the review concerning recent progress in this research area is still very limited. This mini-review updated recent advances on the removal of three kinds of bio-refractory wastewaters including pharmaceuticals, pesticides, and dyes using BDD electrode. It summarized the important parameters in three electrochemical oxidation processes, i.e., anodic oxidation (AO), electro-Fenton (EF), and photoelectro-Fenton (PEF) and compared their different degradation mechanisms and behaviors. As an attractive improvement of PEF, solar photoelectro-Fenton using sunlight as UV/vis source presented cost-effectiveness, in which the energy consumption for enrofloxacin removal was 0.246 kWh/(g TOC), which was much lower than that of 0.743 and 0.467 kWh/(g TOC) by AO and EF under similar conditions. Finally the existing problems and future prospects in research were suggested.