Leipzig 2002 – scientific programme

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UP: Umweltphysik

UP 15: Bodenphysik II

UP 15.3: Talk

Tuesday, March 19, 2002, 17:00–17:15, HS 11

Electric potential and reaction rates at charged surfaces in asymmetric electrolytes - an analytic approach — •H. Lustfeld¹ and A. Pohlmeier² — ¹Forschungszentrum Jülich, IFF, 52425 Jülich — ²Forschungszentrum Jülich, ICG IV, 52425 Jülich

The electric potential and reaction rates of ions hitting the chemically active surface of microcrystals in an asymmetric electrolyte are computed analytically. Following ideas of Debye we start this by solving the Poisson-Boltzmann equations and by determining the electric potential of the transport equations. We find distinct deviations when comparing our result with the Gouy Chapman formula. In a simple model approximating a situation in which lead and hydrogen ions can react at goethite surfaces we compute analytically the currents of ions diffusing to the surface of microcrystals where they undergo a chemical reaction. We compute the reaction rates that can be controlled either by chemical reactions at the surface of the microcrystals or by diffusional transport.