Wet electrolytic oxidation

Wet Electrolytic Oxidation of Organics and Application for Sludge Treatment... 

Serikawa RM, Isaka M, Su Q, Usui T, Nishimura T, Sato H, Hamada S (2000) Wet electrolytic oxidation of organic pollutants in wastewater treatment. J Appl Electrochem 30(7) 875-883... 

Tetravalent lead is obtained when the metal is subjected to strong oxidizing action, such as in the electrolytic oxidation of lead anodes to lead dioxide, Pb02 when bivalent lead compounds are subjected to powerful oxidizing conditions, as in the calcination of lead monoxide to lead tetroxide, Pb O or by wet oxidation of bivalent lead ions to lead dioxide by chlorine water. The inorganic compounds of tetravalent lead are relatively unstable eg, in the presence of water they hydrolyze to give lead dioxide. 

Many methods to destroy these confounds are available including incineration, wet air oxidation, catalytic dehydrochlorination, reaction widi superoxide, photolysis in the presence of hydrogm donors, transition metal-promoted reductive dechlorinations using sodium borohydride or alkoxyborohydrides, electrolytic reductions, hydrogenolyses, " iron-pranoted dechlorination" and thermolysis over solid bases such as CaO/Ca(OH)2. All diese methods have drawback, especially when the toxic pollutants are already distributed in the soil, sludges, ground or surface waters, etc. 

Further improvements in anode performance have been achieved through the inclusion of certain metal salts in the electrolyte, and more recently by dkect incorporation into the anode (92,96,97). Good anode performance has been shown to depend on the formation of carbon—fluorine intercalation compounds at the electrode surface (98). These intercalation compounds resist further oxidation by fluorine to form (CF ), have good electrical conductivity, and are wet by the electrolyte. The presence of certain metals enhance the formation of the intercalation compounds. Lithium, aluminum, or nickel fluoride appear to be the best salts for this purpose (92,98). 

Grove recognized that electrodes above the surface of an electrolyte, (e.g., sulfuric acid) would be wetted by capillary action and so allow the platinum electrodes to catalyze the electrochemical reactions of a fuel and oxidant stich as hydrogen and oxygen. 

The metallic substrate, clean and rinsed, is immersed wet in the plating cell. The base metals which are usually plated present an essentially metallic surface to the electrolyte, and the slight corrosive action of the rinse water in preventing the formation of any substantial oxide film is important. A critical balance of corrosion processes in the initial stages is vital to successful electroplating, and for this reason there is a severe restriction on the composition of the electroplating bath which may be used for a particular substrate. This will be discussed later. The substrate is made the cathode of the cell it may be immersed without applied potential ( dead entry) or may be already part of a circuit which is completed as soon as the substrate touches the electrolyte ( live entry). Live entry reduces the tendency for the plating electrolyte to corrode the substrate in the period before the surface... 

In the more common wet process the frit is milled with water, colloidal clay, opacifier, colouring oxide, refractory and various electrolytes in a bail mill to a closely controlled fineness or coarseness. 

The major differences between polymer and liquid electrolytes result from the physical stiffness of the PE. PEs are either hard-to-soft solids, or a combination of solid and molten in phases equilibrium. As a result, wetting and contact problems are to be expected at the Li/PE interface. In addition, the replacement of the native oxide layer covering the lithium, under the... 

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