Molecular iodine reduction in seawater, an improved rate equation considering organic compounds

The earlier modelling of the reduction of micro-molar amounts of molecular iodine added to seawater by means of linked first-order reactions considering only iodine species is shown to be inappropriate. Reasons are given for believing that the characteristic of a rapid initial phase followed by a much slower one results from speciation of the reducing organic compounds, not the iodine. An alternative approach using two competing reductions, one fast the other much slower, is explored. Both reactions are first order with respect to concentrations of iodine and organics, with the rapidly reduced material being consumed fully. The similarity between iodineʹs reaction with reducing species in seawater and that of chlorine and ozone is considered.