Electrochemical oxidation of terbium(III) in aqueous media: influence of supporting electrolyte on oxidation potential and stability

Author(s):  
Meryem Ozge Arman ◽  
Bart Geboes ◽  
Karen Van Hecke ◽  
Koen Binnemans ◽  
Thomas Cardinaels
2015 ◽  
Vol 50 (4) ◽  
pp. 305-313
Author(s):  
Sajjad Khezrianjoo ◽  
Hosakere Doddarevanna Revanasiddappa

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.


2006 ◽  
Vol 61 (10) ◽  
pp. 1254-1260 ◽  
Author(s):  
Durvas S. Bhuvaneshwari ◽  
Kuppanagounder P. Elango

Electrochemical oxidation of fifteen para- and meta-substituted anilines in different mole fractions of acetic acid in water has been investigated in the presence of 0.1 M sulphuric acid as supporting electrolyte. The oxidation potential data of anilines correlates well with Hammett’s and Brown- Okamoto’s substituent constants affording negative reaction constants. The effect of para- and metasubstituents on the oxidation potential conforms to Swain’s F and R parameters, affording negative reaction constants. The oxidation potential values correlate well with macroscopic solvent parameters such as relative permittivity, εr, and polarity, ETN. Multiple correlation analysis also shows an excellent correlation with the oxidation potential values.


1981 ◽  
Vol 36 (3) ◽  
pp. 386-390 ◽  
Author(s):  
G. Abou-Elenien ◽  
J. Rieser ◽  
N. Ismail ◽  
K. Wallenfels

AbstractThe electrochemical oxidation and reduction properties of different dihydropyridines and pyridines have been investigated in non aqueous solvent as benzonitrile and aceto-nitrile with tetra-n-butylammonium perchlorate as supporting electrolyte at platinium electrodes using DC-voltametry, cycl. voltametry and coulometry. Possible redox-mechanisms are discussed.


2019 ◽  
Vol 19 (11) ◽  
pp. 7308-7314
Author(s):  
Jinyan Li ◽  
Qingsong Guan ◽  
Junming Hong ◽  
Chang-Tang Chang

Composite electrodes with different graphene (GN)/TiO2 ratios and nano-activated carbon electrodes were prepared for electrocatalytic performance comparison. The electrodes were loaded with platinum (Pt) by use of chloroplatinic acid to promote their performance. Reactive Black 5 (RBk5) dye wastewater was treated as a challenging pollutant by use of advanced electrochemical oxidation technology. The composite materials were characterized by Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscopy (FE-SEM), and Energy Disperse Spectroscopy (EDS). Results showed that the graphene electrode was prepared successfully and verified because all elements were uniformly loaded on the conductive carbon cloth. The effects of several operating parameters including material types, pH, initial concentration of RBk5, and current density on the removal performance of RBk5 were also assessed. The supporting electrolyte was NaCl solution of 1 g L−1. The concentration of RBk5 was detected using an ultraviolet spectrophotometer with a detection wavelength of 600 nm. The optimum parameters of the experiment were GN/TiO2 ratio of 1:4 and pH of 6.6. The removal efficiency of RBk5 could be higher than 95% under an initial concentration of RBk5 of 5 ppm and a current density of 2.5 mA·cm-2 when reaction time was 30 min.


2019 ◽  
Vol 16 (8) ◽  
pp. 613 ◽  
Author(s):  
Hélène Monteil ◽  
Nihal Oturan ◽  
Yoan Péchaud ◽  
Mehmet A. Oturan

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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