Electrolyte nitric-acid-containing

Properties. Only plattnerite has attractive features for electrochemical applications such as a low electrical resistivity (40 to 50 p 2.cm), a good chemical and electrochemical corrosion resistance in sulfates media even at low pH, and a high overvoltage for the evolution of oxygen in suhuric- and nitric-acid-containing electrolytes while it withstands chlorine evolution in hydrochloric acid. In fact, the more electrochemically active phase consists... 

The experimental results for the basic model of the system indicated in Fig. 3.17 were obtained with a titanium RDE. The electrolyte was aqueous nitric acid containing hydrazine, which stabilizes the U(IV) ion. 

Oxidative surface treatment processes can be gaseous, ie, air, carbon dioxide, and ozone Hquid, ie, sodium hypochlorite, and nitric acid or electrolytic with the fiber serving as the anode within an electrolytic bath containing sodium carbonate, nitric acid, ammonium nitrate, ammonium sulfate, or other electrolyte. Examples of electrolytic processes are described in the patent Hterature (39,40)... 

Takahashi et al. [220] first reported the formation of Bi-Te alloy films with varying chemical composition by means of cathodic electrodeposition from aqueous nitric acid solutions (pH 1.0-0.7) containing Bi(N03)3 and Te02. The electrodeposition took place on Ti sheets at room temperature under diffusion-limited conditions for both components. In a subsequent work [221], it was noted that the use of the Bi-EDTA complex in the electrolyte would improve the results, since Bi " is easily converted into the hydrolysis product, Bi(OH)3, a hydrous polymer, thus impairing the reproducibility of electrodeposition. The as-produced films were found to consist of mixtures of Te and several Bi-Te alloy compounds, such as Bi2Tc3, Bi2+xTe3 x, Bi Tee, and BiTe. Preparation of both n- and p-type Bi2Te3 was reported in this and related works [222]. 

Production. In large-scale production, lead or lead oxide is reacted with nitric acid to give lead nitrate solutions, which are then mixed with sodium dichromate solution. If the precipitation solutions contain sulfate, lead sulfochromate is formed as a mixed-phase pigment. After stabilization the pigment is filtered off, washed until free of electrolyte, dried, and ground. 

Of the older methods for the preparation of periodic acid, the most satisfactory for obtaining large quantities is the electrolytic oxidation of iodic acid at an anode of platinum plated with lead dioxide, the cathode solution being dilute nitric acid.1 The iodic acid for this preparation is conveniently prepared by the electrolytic oxidation of iodine.1 However, periodic acid prepared in this way often contains... 

The electrolyte may also contain species such as Fe3+ ions or nitric acid, in which case there can be additional electronation reactions of the type... 

The 2.54-cm diameter Electropulse Column shown in Figure 1, after completion of uranium runs, was installed at Battelle Memorial Institute (Columbus, Ohio) for uranium-plutonium partition tests. Six electrolytic runs were made under conditions corresponding to partitioning in the first process cycle to determine the effect of uranium reduction efficiency R(u) on t le separation process. The organic feed contained 80 to 83 grams/L of uranium and 0.71 to 0.82 grams/L of plutonium. The nitric acid concentration in the aqueous feed was 2.5 to 2.8 M and in the organic feed 0.2 to 0.3 M. 

In practice, electrolysis at a constant cell potential is limited to the separation of easily reduced cations from those that are more difficult to reduce than hydrogen ion or nitrate ion. The reason for this limitation is illustrated in Figure 22-7, which shows the changes of current, IR drop, and cathode potential during electrolysis in the cell in Figure 22-6. The analyte here is copper(II) ions in a solution containing an excess of sulfuric or nitric acid. Initially, R is adjusted so that the potential applied to the cell is about — 2.5 V, which, as shown in Figure 22-7a, leads to a current of about 1.5 A. The electrolytic deposition of copper is then completed at this applied potential. 

In contrast, when a sample of sodium acetate, NaCH3COO, is dissolved in H2O and mixed with nitric acid, the resulting solution initially contains Na, CH3COO , H+, and N03 ions. But most of the H+ and CHjCOO" ions combine to produce nonionized molecules of acetic acid, the reverse of the ionization of the acid. Thus, the ionization of acetic acid, like that of any other weak electrolyte, is reversible. 

A common method for the electrodeposition of Am is from isopropanol solutions containing small quantities of dilute acid stock solutions of Am ions. Aqueous deposition methods have also been employed, but the organic electrolyte medium is more advantageous in that it tends to produce more uniform coatings [151[. Zhi etal. prepared relatively thick targets of Am from a mixture of isopropanol and dilute (0.1 N) nitric acid stock solutions pf [152]. The electrolysis... 

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