The electrochemical oxidation of 1,3-dimethyl-2-imidazolidinethione in aqueous media

The present investigation showed that the indicator dye m-cresol purple (mCP) was degraded in a laboratory scale, undivided electrolysis cell system. A platinum anode was used for generation of chlorine in the dye solution. The influence of supporting electrolyte, applied voltage, pH, initial dye concentration and temperature were studied. The ultraviolet-visible spectra of samples during the electrochemical oxidation showed rapid decolorization of the dye solution. During the electrochemical degradation process, dye concentration and current were measured to evaluate the energy consumption and current efficiency. After 10 minutes of electrolysis, a solution containing 20 mg/L mCP showed complete color removal at a supporting electrolyte concentration of 1 g/L NaCl, initial pH 6.7, temperature 25 °C and applied voltage 5 V; however, when pH was kept at 6.7, a higher rate constant was observed. There was good fit of the data to pseudo-first-order kinetics for dye removal in all experiments. Dependence of the decolorization rate on the initial mCP concentration can be described as roα[mCP]o−0.98. The apparent activation energy for the electrochemical decolorization of mCP was determined to be −6.29 kJ/mol.

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Efficient removal of diuretic hydrochlorothiazide from water by electro-Fenton process using BDD anode: a kinetic and degradation pathway study

Environmental Chemistry ◽

10.1071/en19121 ◽

2019 ◽

Vol 16 (8) ◽

pp. 613 ◽

Cited By ~ 1

Author(s):

Hélène Monteil ◽

Nihal Oturan ◽

Yoan Péchaud ◽

Mehmet A. Oturan

Keyword(s):

Electrochemical Oxidation ◽

Oxidation Reaction ◽

Oxidation Process ◽

Aqueous Media ◽

Degradation Pathway ◽

Constant Current ◽

Gas Chromatography Mass Spectrometry ◽

Aqueous Environment ◽

Fenton Process ◽

Kinetic Rate Constant

Environmental contextHydrochlorothiazide, a common diuretic pharmaceutical, occurs in environmental waters because current treatment technologies are unable to eliminate it from wastewater. To remove this environmentally hazardous chemical from water, we developed an advanced electrochemical oxidation process to efficiently degrade and mineralise the compound. Wider application of the process holds the promise of general, efficient destruction of pharmaceuticals in aqueous media. AbstractThe degradation and the mineralisation of the diuretic hydrochlorothiazide were studied by an advanced electrochemical oxidation process, ‘electro-Fenton’, which generates in situ hydroxyl radicals that are able to successfully oxidise or mineralise organic pollutants. In this study, a 0.1mM (29.8mgL−1) hydrochlorothiazide solution was completely oxidatively degraded in 15min under constant current electrolysis at 500 mA. The absolute kinetic rate constant of the oxidation reaction was also determined as (4.37±0.04)×109M−1s−1. The quasi-complete mineralisation of the solution was obtained with electrolysis for 6h under the same applied current. Several oxidation reaction intermediates were identified using gas chromatography-mass spectrometry (GC-MS). The formed carboxylic acids during the mineralisation process were also studied; oxamic, oxalic, acetic and maleic acids were identified and their concentrations were monitored throughout the electrolysis. The ions released during the treatment were also considered. Based on these data and the total organic carbon (TOC) removal results, a possible mineralisation pathway was proposed. These findings enable the conclusion that the electro-Fenton process is an efficient and environmentally-friendly method to eliminate the hazardous drug hydrochlorothiazide from an aqueous environment.

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Rational Design of Amphiphilic Diblock Copolymer/MWCNT Surface Modifiers and Their Application for Direct Electrochemical Sensing of DNA

Polymers ◽

10.3390/polym12071514 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1514

Author(s):

Larisa V. Sigolaeva ◽

Tatiana V. Bulko ◽

Apollinariya Yu. Konyakhina ◽

Alexey V. Kuzikov ◽

Rami A. Masamrekh ◽

...

Keyword(s):

Electrochemical Oxidation ◽

Diblock Copolymer ◽

Rational Design ◽

Diblock Copolymers ◽

Aqueous Media ◽

Electrochemical Sensing ◽

Multiwalled Carbon ◽

Surface Areas ◽

Copolymer Structure ◽

Great Acceleration

We demonstrate the application of amphiphilic ionic poly(n-butylmethacrylate)-block- poly(2-(dimethylamino)ethyl methacrylate) diblock copolymers (PnBMA40-b-PDMAEMA40, PnBMA40-b-PDMAEMA120, PnBMA70-b-PDMAEMA120) for dispersing multiwalled carbon nanotubes (MWCNTs) in aqueous media, a subsequent efficient surface modification of screen-printed electrodes (SPEs), and the application of the modified SPEs for DNA electrochemistry. Stable and fine aqueous dispersions of MWCNTs were obtained with PnBMAx-b-PDMAEMAy diblock copolymers, regardless of the structure of the copolymer and the amount of MWCNTs in the dispersions. The effect of the diblock copolymer structure was important when the dispersions of MWCNTs were deposited as modifying layers on surfaces of SPEs, resulting in considerable increases of the electroactive surface areas and great acceleration of the electron transfer rate. The SPE/(PnBMAx-b-PDMAEMAy + MWCNT) constructs were further exploited for direct electrochemical oxidation of the guanine (G) and adenine (A) residues in a model salmon sperm double-stranded DNA (dsDNA). Two well-defined irreversible oxidation peaks were observed at about +600 and +900 mV, corresponding to the electrochemical oxidation of G and A residues, respectively. A multi-parametric optimization of dsDNA electrochemistry enables one to get the limits of detection (LOD) as low as 5 μg/mL (0.25 μM) and 1 μg/mL (0.05 μM) for G and A residues, respectively. The achieved sensitivity of DNA assay enables quantification of the A and G residues of dsDNA in the presence of human serum and DNA in isolated human leukocytes.

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Solid State Electrochemical Oxidation Mechanisms Of Morin in Aqueous Media

Electroanalysis ◽

10.1002/elan.200403155 ◽

2005 ◽

Vol 17 (9) ◽

pp. 733-738 ◽

Cited By ~ 62

Author(s):

Patricia Janeiro ◽

Ana?Maria?Oliveira Brett

Keyword(s):

Solid State ◽

Electrochemical Oxidation ◽

Aqueous Media ◽

Oxidation Mechanisms

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Electron transfer reactions of nickel complexes of 1,4,7-triazacyclodecane

Canadian Journal of Chemistry ◽

10.1139/v85-495 ◽

1985 ◽

Vol 63 (11) ◽

pp. 2983-2989 ◽

Cited By ~ 8

Author(s):

M. G. Fairbank ◽

A. McAuley ◽

P. R. Norman ◽

O. Olubuyide

Keyword(s):

Electron Transfer ◽

Exchange Rate ◽

Proton Transfer ◽

Electrochemical Oxidation ◽

Rate Constant ◽

Aqueous Media ◽

Nickel Complexes ◽

Outer Sphere ◽

The Self ◽

Transfer Reactions

The preparation of [Ni(1,4,7-triazacyciodecane)2]3+, (Ni(10-aneN3)23+) is described. The existing procedure has been modified leading to good yields of the ligand trihydrochloride. The nickel(II) analogue (reported previously) is oxidised in a facile manner, either by Co3+aq in acidic aqueous media or by NO+ in CH3CN. Since the octahedral NiN6, chromophore is retained upon electron transfer, outer sphere reactions both of the Ni(II) and Ni(III) species have been studied. Rates of oxidation by various nickel(III) macrocycles have been measured and details are provided. Electrochemical oxidation of the Ni(II) complex is consistent with E0(Ni(10-aneN3)23+/2+) = 0.997 V (vs. NHE). The data have been used in a Marcus correlation, leading to the self-exchange rate k11 for the couple (Ni(10-aneN3)23+/2+) = (2 ± 1) × 104 M−1 s−1. This value is compared with other data derived using octahedral Ni(II)/Ni(III) centres. The oxidation of the Ni(II) complex by Co(III)aq has been studied in both protonated and deuterated media. There is no evidence for any proton transfer (from the N—H) being coupled to the electron transfer step. The observed rate constant for the reaction of Co3+ with Ni(II)(10-aneN3)22+ (550 M−1 s−1) may be compared with the calculated outer sphere rate (270 M−1 s−1). An estimate of k11 (CoOH2+/+) ~ 3 M−1 s−1 for the CoOH2+/+ exchange is discussed.

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A photo-oxidation of croconic acid into oxalic acid

Canadian Journal of Chemistry ◽

10.1139/v95-160 ◽

1995 ◽

Vol 73 (8) ◽

pp. 1298-1304 ◽

Cited By ~ 6

Author(s):

Paul-Louis Fabre ◽

Paule Castan ◽

Diane Deguenon ◽

Nicole Paillous

Keyword(s):

Nmr Spectroscopy ◽

Oxalic Acid ◽

Electrochemical Oxidation ◽

Oxidation Process ◽

Aqueous Media ◽

Oxidation Products ◽

Acid Oxidation ◽

Experimental Conditions ◽

Photo Oxidation ◽

C Nmr

Croconic acid, H2C5O5, is readily oxidized. This may be attested by decolorization of the solutions and by observation of oxalic acid complexes. The oxidation products are identified by 13C NMR spectroscopy as oxalic and mesoxalic acids, and experimental conditions are specified. The oxidation process requires dioxygen and photons. In parallel, the electrochemical oxidation of croconic acid is studied in aqueous media and in acetonitrile. A potential–pH diagram is drawn. Keywords: croconic acid, oxalic acid, oxidation, electrochemistry, photochemistry.

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