ATRAZINE IN ORGANIC SOIL - CHEMICAL SPECIATION DURING HETEROGENEOUS CATALYSIS

Two Brönsted acid catalysts are known to cause the hydrolysis of atrazine. They are H+ and un-ionized carboxyl groups, both of which can exist in organic soils. When hydroxyatrazine is the only reaction product, there are four chemical species. These are the reactant and product in both free and sorbed states. A typical heterogeneous kinetics experiment would monitor only one or two of these. An HPLC technique has now been demonstrated however, which monitors five chemical species during the course of heterogeneous catalysis experiments. These are solution-phase reactant and product, reversibly sorbed reactant and product, and material balance loss. A 2-week experiment can produce equilibrium and rate constants for sorption and the reaction rate constant. These are relevant to the persistence and movement of atrazine in soils. The constants are consistent with those previously found for a humic acid. © 1990, American Chemical Society. All rights reserved.