Oxidation of the mercurous ion by peroxidase

The kinetics of oxidation of the mercurous ion by peroxidase have been measured by following the disappearance of mercurous ion using cold-vapour atomic absorption spectroscopy. Pseudo-first-order kinetics are observed with respect to mercurous ion, and the pseudo-first-order rate constants are linearly related to peroxidase concentration, showing first-order dependence on peroxidase. This behaviour is identical to oxidation of elemental mercury, and the second-order rate constant, 1.44 × 104 M−1 s−1 at 23 °C, is also, within experimental error, the same as that for elemental mercury oxidation. The data are interpreted in terms of peroxidase-induced disproportionation of the mercurous dimer, followed by two-electron oxidation of zero-valent mercury.

A convection-free electrolysis cell in which a steady state is attainable

Studies of a cell consisting of a sheet of a porous medium soaked with an aqueous electrolyte solution containing the mercurous ion and sandwiched between mercury pools show that steady-state electrolysis may be attained in the absence of convection. Several different porous matrices have been studied and, in some cases, a very simple model of the pore structure predicts behaviour close to that observed experimentally.