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Instantaneous current efficiency

Current-potential curves obtained under steady state conditions are called polarization curves. If two or more faradaic processes occur at the electrode, the fraction of current (ir) driving the rth process is the instantaneous current efficiency. Over a period of operating time the fraction of the total number of coulombs used in the rth process ( r) is related to the overall current efficiency of that process (OCE), i.e. [Pg.4]

On the other hand, several experimental parameters have been defined to quantify the destruction of an organic species in aqueous medium by anodic oxidation (38-44). Because the main side reaction is 02 evolution due to water decomposition, the instantaneous current efficiency (ICE) at a given time t for its oxidation can be determined from the 02 flow rate during electrolysis in the absence (V0) and the presence (F,>org) of the selected pollutant as follows ... [Pg.255]

In the basis of this simplified reaction scheme, two techniques have been proposed for the estimation of the instantaneous current efficiency (ICE) during electrolysis the chemical oxygen demand (COD) and the oxygen flow rate (OFR) techniques. [Pg.11]

In this technique, the COD of the electrolyte is measured at regular intervals (At) during constant current (galvanostatic) electrolysis and the instantaneous current efficiency (ICEcod) is calculated using the relation ... [Pg.11]

The instantaneous current efficiency (ICE) of the electrooxidation is determined by chemical oxygen demand (COD) measurements, using the relationship (Comninellis and Pulgarin 1991) ... [Pg.26]

In these equations, COD (t) is the chemical oxygen demand at time t (mol 02 m-3), I is the current intensity (A), F is the Faraday constant (96,487C mol-1), apPi is the applied current density (Am-2), km the mass-transfer coefficient (ms-1), and ICE is the instantaneous current efficiency. For a typical-batch electrochemical... [Pg.112]

Under conditions of high current density and low phenol concentration, the complete combustion to C02 was obtained. In this case, due to the high local concentration of OH radicals, the anodic oxidation was a fast reaction under diffusion control, so that the instantaneous current efficiency decreased during the electrolysis as phenol was oxidised. [Pg.208]

No strong differences were observed when multicomponent mixtures of phenols (phenol, benzyl alcohol, 1-phenyl-ethanol and m-cresol) were treated (Morao et al. 2004) the experimental results were interpreted well by assuming that all the components in the mixture were degraded in the same time and that the combustion of the compounds to C02 occurred at the anode surface by means of hydroxyl radicals electrogenerated. The instantaneous current efficiency was unity, until the reaction became diffusion controlled. [Pg.212]

Fig. 8.5 Influence of the current density in the efficiency of the process (Na2SC>4, 500 mg dm 3, natural pH T = 25°C). Changes in the instantaneous current efficiency (ICE) with the residual COD during electrolyses (triangles) 600 and (squaresa) 300 A nW2 of current density (Cafiizares et al. 2006a)... Fig. 8.5 Influence of the current density in the efficiency of the process (Na2SC>4, 500 mg dm 3, natural pH T = 25°C). Changes in the instantaneous current efficiency (ICE) with the residual COD during electrolyses (triangles) 600 and (squaresa) 300 A nW2 of current density (Cafiizares et al. 2006a)...
Jiang et al. studied the electrodeposition and surface morphology of aluminum on tungsten (W) and aluminum (Al) electrodes from 1 2 M ratio of [Emim]CI/AlCl3 ionic liquids [165,166]. They found that the deposition process of aluminum on W substrates was controlled by instantaneous nucleation with diffusion-controlled growth. It was shown that the electrodeposits obtained on both W and Al electrodes between -0.10 and -0.40 V (vs. AI(III)/A1) are dense, continuous, and well adherent. Dense aluminum deposits were also obtained on Al substrates using constant current deposition between 10 and 70 mA/cm. The current efficiency was found to be dependent on the current density varying from 85% to 100%. Liu et al. showed in similar work that the 20-pm-thick dense smooth aluminum deposition was obtained with current density 200 A/m for 2 h electrolysis [167],... [Pg.133]

When two or more faradaic reactions can occur simultaneously at an electrode, the fraction of the total current (/total) going to the rth process is called the instantaneous current efficiency ... [Pg.421]

In the oxygen flow rate method the oxygen flow rate was measured during electrolysis and the Instantaneous Current Efficiency (ICE) for oxidation of the OP at given experimental conditions was calculated using the relation... [Pg.78]

Figure 2. Equipment used for the determination of the Instantaneous Current Efficiency (ICE) during the electrochemical treatment of wastewater. Figure 2. Equipment used for the determination of the Instantaneous Current Efficiency (ICE) during the electrochemical treatment of wastewater.
From the Instantaneous Current Efficiency (ICE) - time curve (Fig. 1) an average value can be calculated and defined as the Electrochemical oxidation Index (EOI)... [Pg.84]

Instantaneous current efficiency (ICE) Chemical oxygen demand COD (mol O m... [Pg.581]

In the Oxygen Flow Rate technique (ICEofr)> a two compartment electrochemical cell is used, and the oxygen flow rate is measured continuously in the anodic compartment during constant current (galvanostatic) electrolysis. The instantaneous current efficiency is then calculated using the relationship ... [Pg.944]

When the applied current exceeds the limiting one (i > iiim), secondary reactions (such as oxygen evolution) commence, resulting in a decrease of the instantaneous current efficiency (ICE). In this case, the temporal evolution of COD(t) is given by ... [Pg.1433]

The instantaneous current efficiency (ICE has been obtained through the measurement of COD using relation (20.21) ... [Pg.473]

This reaction is subject to a number of errors (1) the hydriodic acid (from excess of iodide and acid) is readily oxidised by air, especially in the presence of chromium(III) salts, and (2) it is not instantaneous. It is accordingly best to pass a current of carbon dioxide through the reaction flask before and during the titration (a more convenient but less efficient method is to add some solid sodium hydrogencarbonate to the acid solution, and to keep the flask covered as much as possible), and to allow 5 minutes for its completion. [Pg.392]

See other pages where Instantaneous current efficiency is mentioned: [Pg.439]    [Pg.330]    [Pg.294]    [Pg.335]    [Pg.367]    [Pg.20]    [Pg.208]    [Pg.421]    [Pg.204]    [Pg.125]    [Pg.204]    [Pg.944]    [Pg.1433]    [Pg.1439]    [Pg.557]    [Pg.266]    [Pg.7]    [Pg.474]    [Pg.607]    [Pg.158]    [Pg.821]    [Pg.455]   
See also in sourсe #XX -- [ Pg.10 , Pg.11 , Pg.19 , Pg.26 , Pg.112 , Pg.208 , Pg.212 , Pg.215 ]



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