Voltammetry, linear potential sweeps

Hamilton IC, Woods R (1981) An investigation of surface oxidation of pyrite and pyrrhotite by linear potential sweep voltammetry. J Electroanal Chem 118 327-343... 

Since the 1960s , various electrochemical methods such as linear potential sweep voltammetry, cyclic voltammetry etc. and various surface analysis apparatuses such as infrared spectra, X-ray photoelecfron spectroscopy etc. have been developed to investigate the electrochemical reaction mechanism involved in the flotation of sulphide minerals (Fuerstenau et al., 1968 Woods, 1976 Ahmed, 1978 Stm, 1990 Feng, 1989 Buckley, 1995 Arce and Gonzalez, 2002 Bulut and Atak, 2002 Costa et al., 2002). 

Abstract This chapter first explains the natural flotability of some minerals in the aspect of the crystal structure and demonstates the collectorless flotaiton of some minerals and its dependence on the h and pH of pulp. And then the surface oxidation is analysed eletrochemically and the relations of E to the composition of the solutions are calculated in accordance with Nemst Equation. The E h-pH diagrams of several minerals are obtained. Thereafter, electrochemical determination such as linear potential sweep voltammetry (LPSV) and cyclic voltammetry (CV) and surface analysis of surface oxidation applied to the sulphide minerals are introduced. And recent researches have proved that elemental sulfur is the main hydrophobic entity which causes the collectorless flotability and also revealed the relation of the amount of sulfur formed on the mineral surfaces to the recoveries of minerals, which is always that the higher the concentration of surface sulphur, the quicker the collectorless flotation rate and thus the higher the recovery. 

Keywords natural flotability collectorless flotation h pH diagram linear potential sweep voltammetry cyclic voltammetry XPS UV... 

Many investigators have used different techniques to study the electrochemical behavior of different sulphide mineral electrodes in solutions of different compositions. Linear potential sweep voltammetry (LPSV), and cyclic voltammetry (CV) have been perhaps, used most extensively and applied successfully to the investigation of reactions of sulphide minerals with aqueous systems. These techniques have provided valuable information on the extent of oxidation as a function of potential for various solution conditions and have allowed the identity of the surface products to be deduced. 

Figure 6.23. Linear potential sweep voltammetry (a) input function (b) response function.

When the transport of reactants is controlled by linear diffusion, the kinetic analysis can be performed using convolution potential sweep voltammetry [182]. Here it is more convenient to choose one of the reactant concentrations to be equal to zero, i.e., the initial conditions are recovered at sufficiently negative or positive potentials as in linear potential sweep voltammetry. By using the Laplace transform and the convolution theorem in solving the second Fick equation for each reactant, the convolution current m. 

The two types of electrochemically formed chemisorbed oxygen on Pt films interfaced with YSZ are also clearly manifest via solid state linear potential sweep voltammetry (Fig. 9 bottom, Ref. [39]) The first oxygenX reduction peak corresponds to normally chemisorbed oxygen (y-state) and the second reduction peak which appears only after prolonged positive current application [39] corresponds to the 5-state of oxygen, i.e. backspillover oxidic oxygen, which is significantly less reactive than the y-state. 

Methanol oxidation on CNF- and CNT-supported Pt-Ru particles in liquid electrolytes has been studied using cyclic voltammetry, chronoamperometry [13,231-237], and electrochemical impedance spectroscopy [236]. Rotating disk electrode and linear potential sweep voltammetry in liquid electrolytes were used to study the oxygen reduction reaction on Pt supported on CNTs and CNFs (see,... 

Hubbard, A. T. and E C. Anson. 1966. Linear potential sweep voltammetry in thin layers of solution. Analytical Chemistry, 38,58-61. 

Linear potential sweep voltammetry with a wax-impregnated carbon electrode could be used for the determination of free chlorine in the ng/dm level. The pH change does not affect the results since during determination, the equilibrium between free and bound chlorine is not disturbed and the sum of the HCIO and CIO is measured [5]. 

Kanapeckaite, S. (1998) Concept of Nernst-type diffusion layer in linear potential sweep voltammetry. Chemija,... 

Linear potential sweep voltammetry of electroreduction of labile metal complexes. I. Back-ground model. Electrochim. Acta, 42 (7), 1113-1119. 

Laviron E (1974) Adsorption, autoinhibition and autocatalysis in polarography and in linear potential sweep voltammetry. Electroanal Chem Interracial Electrochem 52 355-393... 

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