Instantaneous Current Efficiency Research Articles

Electrochemical Oxidation of Aqueous Phenol Wastes on Synthetic Diamond Thin-Film Electrodes

The electrochemical oxidation of phenol in basic media using a diamond thin-film electrode has been studied. Within the parameter ranges used (temperature: 15−60 °C, initial total carbon concentration: 360−1450 mg of C dm-3; current density: 15−60 mA cm-2), almost complete mineralization of the organic waste is obtained. The mineralization rate increases with current density and temperature. Current efficiency depends mainly on mass transfer limitations: in the absence of mass transfer limitations, instantaneous current efficiencies of 1 are obtained. The main intermediates formed are maleic, fumaric, and oxalic acids. A simple model based on mass transfer and kinetic considerations, which involves four species (phenol, maleic/fumaric acid, oxalic acid, and carbon dioxide), can be used to explain the experimental behavior of the system, regardless of the conditions applied.

Electro-combustion of polyacrylates with boron-doped diamond anodes

The electro-combustion of water soluble polymeric contaminants like polyacrylates (PA) in aqueous acid solution using a boron-doped diamond (BDD) anode has been investigated by bulk electrolysis in 1 mol dm −3 HClO 4 under galvanostatic conditions in a wide range of PA concentrations and current densities. In all cases complete electro-combustion of PA has been achieved and this is the first successful report for the electro-combustion of soluble organic polymers. The experimental chemical oxygen demand (COD) and instantaneous current efficiency (ICE) values are well predicted from a theoretical model which suppose that the rate of electro-combustion of PA with electrogenerated active intermediates (probably hydroxyl radicals) is a fast reaction and is controlled by mass transport of PA towards the anode (concept of the “ideal anode” for electro-combustion).

Electrochemical Treatment of Simulated Textile Effluent

Electrooxidation of simulated Acid Blue 113 dye effluent has been carried out using a RuO 2 /Ti electrode. The influence of the initial concentration of dye, supporting electrolyte, current densities and pH on COD reduction has been critically studied. Electrochemical analysis such as Instantaneous Current Efficiency (ICE) and Electrochemical Oxygen Demand (EOD) were used.

Partial degradation of phenol by advanced electrochemical oxidation process.

The partial electrocatalytic degradation of phenol to organic acids has been investigated using an undivided electrolytic reactor with a beta-PbO2 anode containing fluorine resin. It was found that the decrease of benzoquinone (BQ) formed during phenol degradation and the acceleration of the process from phenol to organic acids are possible under an optimized operating condition. A possible pathway for phenol degradation was proposed, and a mathematical model for phenol and BQ evolution was developed. Operating parameters such as initial pH, current density, and temperature of the reaction were found to greatly impact the degradation rate of the phenol and even the pathway. Higher removal rate of phenol and BQ can be achieved at an appropriate temperature and higher current density in acidic medium preferably at pH 4. Under these conditions, phenol would be more likely degraded in the pathway from phenol to organic acids rather than through the BQ. When phenol is completely removed, the toxicity of the wastewater would be lessened suitable for biological process treatment. Accounting for the decrease of instantaneous current efficiency (ICE) during degradation, partial degradation would be highly economical for wastewater treatment, which would be an alternative process in practical application.

Electrochemical Oxidation of Benzoic Acid on Boron Doped Diamond Electrodes

The oxidn. of benzoic acid has been performed on boron doped diamond electrodes supported on silicon substrate. The voltammetric behavior has shown that during the oxidn. of benzoic acid at 2.7V (RHE), a polymeric film is formed on the electrode surface that is oxidized at higher potential values. Bulk electrolysis of benzoic acid in HClO4, under galvanostatic conditions results in an instantaneous current efficiency(ICE) near 100% at low current densities and high benzoic acid concns. Electrolysis at high current densities and low benzoic acid concns. results in a decrease of ICE due to mass transport limitations. [on SciFinder (R)]