Search results for "OXIDATION"
showing 10 items of 1913 documents
Electrochemical oxidation of organic pollutants in water at metal oxide electrodes: A simple theoretical model including direct and indirect oxidatio…
2009
Abstract The electrochemical oxidation of organics in water at metal oxide electrodes was investigated with the aim to discuss the correlations between the instantaneous current efficiency ICE and operative conditions by considering both the hypothesis of a direct oxidation process and of an indirect process mediated by adsorbed hydroxyl radicals or chemisorbed “oxygen”, in order to explicit the main differences expected between these cases. Thus, a simple theoretical model was discussed, as an extension of previous studies of Comnnellis and co-workers which were focused on indirect oxidation paths [C. Comninellis, Electrochim. Acta 39 (1994) 1857; O. Simond, V. Schaller, Ch. Comninellis, E…
Electrochemical treatment of paper mill wastewater by electro-Fenton process
2019
Abstract The electrochemical oxidation of organics in paper mill wastewater belonging to Halfa industries (Tunisia) was performed by galvanostatic electrolyses using electro-Fenton (EF) process. The effect of several operating parameters, such as applied current density, electrodes material, air pressure and the presence of sodium chloride (NaCl) was evaluated. In particular, carbon felt (CF), modified carbon felt (MCF) and gas diffusion electrode (GDE) were used as cathode while Ti/IrO2-Ta2O5 and Boron Doped Diamond (BDD) as anode. Total Organic Carbon (TOC) measure was chosen as reference parameter to assess the extent of the treatment. The experimental results show that, by adopting the …
Electrochemistry as an Attractive and Effective Tool for the Synthesis and Immobilization of Porphyrins on an Electrode Surface
2014
Magnesium(II) 10-phenyl-5,15-p-ditolylporphyrin is easily and cleanly transformed by electrolysis. A nitro group is first introduced at the free meso position by anodic substitution. Hydrogenation into the amine is then carried out electrocatalytically under ambient conditions with water as a hydrogen supplier. The synthesized porphyrin under the nickel(II) form can be covalently grafted onto a platinum electrode by electrochemical reduction of the diazonium cation, generated in situ by a reaction of the nickel(II) aminoporphyrin with sodium nitrite and trifluoroacetic acid. The electrosynthesized thin film gives an electrochemical response typical of a porphyrin material. Films grown under…
Electrochemical incineration of oxalic acid at boron doped diamond anodes: Role of operative parameters
2008
The electrochemical incineration of oxalic acid (OA) at boron doped diamond (BDD) anodes was investigated both theoretically and experimentally in order to find the influence of the operative parameters on the performances of the process. Polarization curves and chronoamperometric measurements indicate the probable occurrence of a direct electrochemical oxidation of OA at the surface of the BDD anode at low pH and of a hydroxyl radical-mediated reaction at high pH. When incineration electrolyses are performed at low pH with potentiostatic alimentation, a dramatic influence of the potential is observed. In amperostatic incineration, high CE are obtained when most part of the process was unde…
Increased conductivity of a hole transport layer due to oxidation by a molecular nanomagnet
2008
Thin film transistors based on polyarylamine poly?N,N?-diphenyl-N,N ?bis?4-hexylphenyl?- ?1,1?biphenyl?-4,4?-diamine ?pTPD? were fabricated using spin coating in order to measure the mobility of pTPD upon oxidation. Partially oxidized pTPD with a molecular magnetic cluster showed an increase in mobility of over two orders of magnitude. A transition in the mobility of pTPD upon doping could also be observed by the presence of a maximum obtained for a given oxidant ratio and subsequent decrease for a higher ratio. Such result agrees well with a previously reported model based on the combined effect of dipolar broadening of the density of states and transport manifold filling. Peer Reviewed
Measurement of white wines resistance against oxidation by Electron Paramagnetic Resonance spectroscopy
2018
International audience; Free radical theory of aging hypothesizes that oxygen-derived radicals are responsible for the storage-related flavor instability in wine. In an optimal situation, a balanced-distribution exists between oxidants and antioxidants among wines intrinsic/extrinsic metabolites. Based on the kinetic study of POBN-1-hydroxyethyl spin adduct (POBN-1-HER) formation in wines initiated via the Fenton reaction, a novel tool based on EPR spin trapping methodology was developed to quantify wines resistance against oxidation. Antioxidant capacities of wines were evaluated according to POBN-1-HER maximum signal intensity (Imax POBN-1-HER) and rate formation (r(POBN-1-HER)) kinetic p…
Biomimetic oxidation of pyrene and related aromatic hydrocarbons. Unexpected electron accepting abilities of pyrenequinones
2014
We present a mild catalytic method to oxidize PAHs and, in particular, pyrene. The pyrenediones are much better electron acceptors than benzoquinone in the gas phase and present similar accepting abilities in solution.
Is activated hemocyanin instead of phenoloxidase involved in immune response in woodlice?
2008
In the Common woodlouse Porcellio scaber (Crustacea: Isopoda: Oniscidea), experimental immune challenge did not induce the expression of pro-phenoloxidase that, in most other invertebrates studied thus far, can be activated into phenoloxidase via an activation cascade upon immune challenge. Instead, Porcellio hemocyanin proved to exhibit catecholoxidase activity upon activation. However, none of the activating factors known from other invertebrates other than SDS-treatment resulted in activation of hemocyanin into a functional phenoloxidase in vitro. The distinct characteristics of isopod hemocyanin are reflected by the quaternary structure of the hemocyanin dodecamers that differs from tha…
Confocal microscopy study of the distribution, content and activity of mitochondria during Paracentrotus lividus development
2007
Summary In the present paper we applied confocal microscopy andfluorescence technologies for studying the distribution andthe oxidative activity of sea urchin ( Paracentrotus lividus )mitochondria during development, by in vivo incubating eggsand embryos with cell-permeant MitoTracker probes. Wecalculated, by a mathematical model, the intensity values, the variations of intensity, and the variation index of incorporatedfluorochromes. Data demonstrate that mitochondrial massdoes not change during development, whereas mitochondrialrespirationincreases.Inaddition,startingfrom16blastomeresstage, some regions of the embryo contain organelles moreactive in oxygen consumption. Introduction The con…
Metformin induces lipid changes on sphingolipid species and oxidized lipids in polycystic ovary syndrome women.
2019
Metformin is one of the treatments used for pcoS pathology decreasing body weight, plasma androgen, FSH and glucose levels. Unfortunately, there is little known about metformin’s effects on lipid metabolism, a crucial process in pcoS pathology. We have employed a lipidomic approach to explore alterations in the plasma lipid profile of patients with PCOS following metformin treatment. The aim is to offer new insights about the effect of metformin in PCOS patients. Plasma samples were obtained from 27 subjects prior to and following 12 weeks of metformin treatment. A detailed biochemical characterization and lipidomic profile was performed. Metformin reduces BMI, HOMA-IR, fSH and androstenedi…