Electrode, antimony bismuth

Ashrafi, A.M. and Vytfas, K. (2013) Codeposited antimony-bismuth film carbon paste electrodes for electrochemical stripping determination of trace heavy metals. Int. J. Electrochem. Sci., 8, 2095 - 2103. 

Exploring the excellent combination between SIA and anodic stripping voltammetry for quantification of metals in river sediment extracts and water samples, different detectors were used as well as the preconcentration step was carried out by deposition of analytes on mercury electrode and bismuth or antimony film electrode [115-117]. Reliable voltammetric signals were obtained since it was possible to reproduce the conditions of charge and mass transport with high precision by reproducible electrode area, stirring, and time control. 

Arsenic and antimony are metalloids. They have been known in the pure state since ancient times because they are easily obtained from their ores (Fig. 15.3). In the elemental state, they are used primarily in the semiconductor industry and in the lead alloys used as electrodes in storage batteries. Gallium arsenide is used in lasers, including the lasers used in CD players. Metallic bismuth, with its large, weakly bonded atoms, has a low melting point and is used in alloys that serve as fire detectors in sprinkler systems the alloy melts when a fire breaks out nearby, and the sprinkler system is activated. Like ice, solid bismuth is less dense than the liquid. As a result, molten bismuth does not shrink when it solidifies in molds, and so it is used to make low-temperature castings. 

Herteto E, Febu JM, Aldaz A. 1994. Poison formation reaction from formic-acid on Pt(lOO) electrodes modified by irreversibly adsorbed bismuth and antimony. J Electroanal Chem 368 101-108. 

Metal oxide electrodes are also of the second type. A well known example is a rod of antimony coated with Sb203 (or bismuth with Bi203), which can function as a pH electrode33 ... 

Wang et al. [475] have proposed a similar analytical method as that for bismuth for antimony determination based on Sb UPD on gold electrode. In the proposed procedure, Sb was accumulated at the gold surface, and this step was followed by anodic stripping. A detection limit 2.1 X 10 M was reported for a 120 s electrochemical deposition. 

The influence of antimony, arsenic and bismuth on the reversibility of the PAM structure has been studied via cycling of cylindrical tubular electrodes filled with PAM powder to a density of 4.15 g cm [47,48]. Current collectors (spines) of Pb or Pb—6.0 wt% Sb alloy are used. Figure 4.22 illustrates the effect of Sb , As and Bi ions in the electrolyte on the specific capacity of the tubular electrodes during the first 20 cycles. 

Our samples were prepared by the fusion of the components in evacuated and sealed quartz ampoules. We used bismuth of the V-000 grade, antimony of the Su-000 grade, and selenium and tellurium containing at least 99.99% of the element. The samples prepared in this way were ground and compacted into cylindrical pellets <5 mm in diameter and 7—9 mm high), which were used as the electrodes. Tungsten wires, embedded in the pellets, were used as the current leads. 

ASV can be used for trace measurements of more than 20 elements that can be readily reduced to the metallic state and reoxidized. Most successful are ASV measurements of amalgam-forming elements, such as lead, cadmium, copper, zinc, thallium, bismuth, tin, or antimony, at a mercury working electrode. The amalgam-forming preconcentration step is given by... 

Fig. 3.7 Adatom coverage-dependent current densities acquired at 0.5 V versus RHE from cyclic voltammograms anodic scan (50 mV s ) on Pt single-crystal electrodes in 0.25 M formic acid and 0.5 M H2SO4. The experimental results (filled circle) are compared to the theoretically (continuous line) predicted activity. (A) Pt(l 1 l)/bismuth and (B) Pt(100)/antimony [56]...

Anodic stripping voltammetry was in use already in 1972 to determine Bi in plasma [120]. Bismuth is one of the elements most easily determined with this method. It can be deposited on electrodes at potentials at which most other elements ate in solution. Glassy carbon electrodes coated with films of mercury [100,121-124], but also of gold [101,125], are used. As reference served calomel or silver/silver chloride electrodes [121]. Platinum foils or wires were used as counterelectrodes. At -0.7 V carbon electrodes are precoated with mercury from acid Hg(II) or gold from acid Au(III) solutions. To deposit Bi on the electrode -0.2 to -0.3 V is a sufficient potential for preelectrolysis, but mostly higher voltages are chosen to determine other metals as well. Bi is stripped fiom the electrode at potentials of about -0.10 to -0.16 V. Only some elements interfere with Bi, such as arsenic, mercury, copper, and antimony. Copper interferes at high concentrations and is separated by extraction [101]. Arsenic or antimony in urine are oxidized to their pentavalent states [125]. 

Precipitation of lead dioxide by anodic deposition on a platinum gauze electrode Is a standard method of separation and determination for lead (H3) In the standard procedure the presence of chloride Ion, mercury, arsenic, tellurium, selenium and phosphorus prevent the complete deposition of lead, while bismuth, tin, antimony, and manganese co-deposit. The use of controlled potential deposition and com-plexlng agents make this separation method much more selective (l4). The eleotroanalytical method has been Important for lead analysis and is discussed In detail In section IV-10,... 

Quite similarly and in the same spirit, Svetlicic and coworkers showed that mercury is not the lone electrode material that could electrochemically react in this way with quaternary ammonium salts [17]. Indeed, some posttransition metals also react with quaternary ammonium salts in a similar way [18], In particular, lead, tin, antimony, and bismuth were reported to produce thin organic layers under electrochemical reduction. From coulometric measurements, the stoichiometries of these electroformed materials were established. Under the experimental conditions chosen by Kariv-Miller, the cathodic material M was deeply changed each ammonium is associated with a homopolyanion derived from reduction of the metal M according to the following general equation ... 

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