On the rest potential of pyrite electrode in oxygen-free solutions of iron (II) sulfate

• Autorzy: Nowak P. , Kozioł B.

Warianty tytułu

PL

Potencjał spoczynkowy elektrody pirytowej w odtlenionym roztworze siarczanu żelaza(II)

• Języki publikacji: EN

Abstrakty

EN

The exchange current density (ECD) for the reaction: [wzór] was estimated measuring the impedance of pyrite electrodes in the solutions of iron (II) sulfate. For five different pyrite electrodes, 0.5 mol dm-3 FeSO4 solution and potentials close to the potential of the reaction .[wzór] the ECD was found to be between 8 and 15 µA cm2. Low value of the ECD causes that the potential of pyrite electrode in solutions of iron (II) sulfate does not attain the equilibrium value (i.e. the value within the range of pyrite thermodynamic stability) except the most concentrated and very well deoxidized solutions. For the concentrations of FeSO4 solution lower than 0.5 mol dm-3 pyrite electrode shows the rest potential outside the limits of thermodynamic stability, which means that the measured potential is a mixed (corrosion), not equilibrium potential.

PL

Na podstawie pomiarów impedancji elektrod pirytowych w roztworach sirczanu żeleza (II) oceniono wartość gęstości prądu wymiany dla reakcji: [wzór]. Dla pięciu elektrod pirytowych w roztworze siarczanu żelaza (II) o stężeniu 0,5 mol dm-3, przy potencjale zbliżonym do potencjału równowagowego reakcji: [wzór] wyznaczono prąd wymiany pomiędzy 8 i 15 žA cm2. Niska wartość prądu wymiany powoduje, że elektroda pirytowa w roztworach siarczanu żelaza (II) nie osiąga warości równowagowych, to znaczy wartości w obszarze termodynamicznej stabilności elektrody, z wyjątkiem najbardziej stężonych i dobrze odtlenionych roztworów. W przypadku roztworów siarczanu żelaza (II) o stężeniu mniejszym niż 0,5 mol dm-3 potencjał spoczynkowy elektrody przyjmuje wartości poza zakresem termodynamicznej stabilności, co oznacza że mierzony potencjał jest potencjałem korozyjnym (mieszanym) a nie potencjałem równowagowym.

Słowa kluczowe

EN

pyrite; pyrite electrochemistry; impedance spectroscopy

PL

potencjał spoczynkowy; elektroda pirytowa; siarczan żelaza; impedancja

• Wydawca: Oficyna Wydawnicza Politechniki Wrocławskiej
• Czasopismo: Physicochemical Problems of Mineral Processing
• Rocznik: 2002
• Tom: Vol. 36
• Strony: 77--88
• Opis fizyczny: Bibliogr. 28 poz., tab., wykr.

Twórcy

autor

Nowak P.

autor

Kozioł B.

• Polish Academy of Sciences, Institute of Catalysis and Surface Chemistry, ul. Niezapominajek 8, 30239, Kraków, Poland

Bibliografia

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