Mechanisms of Chlorine Decay in Estuarine Water

摘要

The chemical mechanisms responsible for the decay of chlorine in power plant cooling waters have been investigated. No evidence for a catalytic role of copper, a common constituent of condensers, was observed except at a pH greater than 11. Estuarine waters were found to contain roughly 100,000 M of very fast reacting organic material; second order rate constants for reaction between this material and electrochemically generated bromine were on the order of 10,000,000/M s. Organic sulfur compounds and certain aromatic structures are believed to account for this extremely rapid type of chlorine demand. Chlorine decay curves were obtained for a wide range of estuarine and river water samples under standard conditions. No distinctive geographic or seasonal variations were found, so chlorine decomposition is apparently controlled by ubiquitous components. Production of 20-35 micromolar CO2 from a 140 micromolar chlorine dose was uniformally observed, indicating that oxidation of organic matter is a major chlorine decay pathway.