CHED 214

Determination of the wavelength dependence on the metal-catalyzed degradation rate of the herbicides 2,4-dichlorophenoxyacetic acid and atrazine

Charles Langelier, Timothy Bertram, and D. Whitney King. Chemistry, Colby College, 5700 Mayflower Hill, Colby College, Waterville, ME 04901, fax: 207-872-3804, crlangel@colby.edu

A series of photochemical experiments have been conducted to determine the wavelength dependence on the degradation rate of the herbicides 2,4-dichlorophenoxyacetic acid and atrazine in aqueous Fe(III)/H2O2 solutions. The mixed solution was illuminated with a high-energy lamp coupled to a high-throughput monochromater. Product analysis was performed using HPLC. Degradation rates were correlated with OH production associated with iron redox cycling. Production of oxalate in the degradation of 2,4-dichlorophenoxyacetic acid enhanced the degradation rates by further reducing Fe(III).