Electrodeposition sulfuric acid electrolytes

Suppose that a 0.5 M sulfuric acid electrolyte contains a small concentration, say 10 mol L , of copper sulfate. In this multicomponent solution, different cationic and anionic species are present such as cupric ions, protons, hisuUate, and sulfate ions. Equation (17) indicates that, because of its small concentration, the transport number of cupric ion will be extremely small, somewhere around 0.001. So, only a very small fraction of the current in the solution will be carried by cupric ion. Consider now the electrodeposition of copper on a cathode from such a solution. Assuming copper deposits with 100% current efficiency, the cathodic current passing the interface (faradaic current) will be entirely due to cupric ion discharge ... 

Electrodeposition of copper-tin alloy of sulfuric acid electrolyte in the presence of DS-10 sintanol. Zashchita Metallov, 20 (3), 392-394. 

The anodic oxidation of phenol (dissolved in sodium sulfate) was studied by De Sucre and Watkinson using two types of lead dioxide anodes [26]. The first was made of 2 mm lead shot that was oxidized for 12 h at 526mA/cm in 20% sulfuric acid while the second anode, electrodeposited lead dioxide flakes, was supplied by a commercial manufacturer. The phenol oxidized faster on the electrodeposited Pb02, which also turned out to be more corrosion-resistant than the oxidized lead shot. While all of the phenol oxidized rapidly (1.5 h) on the electrodeposited anode, not all of it formed CO2. It was found that 80% of the total organic carbon remained in solution after the phenol was completely oxidized. Phenol destruction increased with an increase in current density, and decreased as electrolyte flowrate, pH, and anode particle size were increased. 

The electrolyte composition was 0.24 M copper sulfate for the second part of the experiments, we added sulfuric acid. Tests were performed with 0.5-1.5 M of sulfuric acid obtaining the same type of morphology. The solutions were deaerated with bubbling nitrogen before experiments. The depositions were performed at ambient temperature without stirring. The rest of the procedure was similar to that used for Zn electrodeposition, with the necessary modifications. 

The mined zinc ores retrieved from the mines are too low in zinc content for direct reduction to refined metal thus, they are first concentrated. Production of concentrates requires crushing and grinding followed by gravity or magnetic methods of separation or flotation. These processes may be combined, depending on the complexity of the ore. A caustic-leach process is used to decrease the extent of metal loss during the concentration process. In this process, the metal is leached by caustic soda, the resulting electrolyte is purified with zinc dust and lime, and the zinc is electrodeposited. The crude zinc may be dissolved in sulfuric acid and purified by electrodeposition. 

Essentially, the new approach (Fig. 43) consists in the dipping of the nanotube electrodes in the precursor electrolytes (0.1 M CdS04 and 0.1 mM Te02 in dilute sulfuric acid at pH 1.4), where the capillary forces draw the electrolyte inside the pores. The electrode is then transferred in an inert supporting electrolyte where the electrodeposition is carried out at constant cathodic potential (—0.4 V). The procedure can be repeated imtil a desired amount of CdTe is deposited into the pores (Fig. 44). 

The most often employed electrolytes for the electrodeposition of copper are those based on aqueous solutions of cupric sulfate (CUSO4) and sulfuric acid (H2SO4) [33]. There is an ionic equilibrium of a... 

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