Hexazinone Adsorption-Desorption Studies with Soil and Organic Adsorbents
1985
Bouchard, D. C. | Lavy, T. L.
Hexazinone [13-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine- 2,4(1H,3H)-dione] adsorption-desorption was studied using soil from different horizons and using organic adsorbents. Hexazinone was adsorbed less than atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] by soil. The Oi horizon (leaf litter) of a forest soil showed the greatest adsorptivity for hexazinone (K = 15.09). Hexazinone was desorbable from all soil horizons with 0.01M CaCl₂. Normalizing for the organic C content of the soil horizons with Kₒc removed differences in the adsorptivity between soils. The octanol-water partition coefficient (Kₒw) estimated the Kₒc for the hexazinone-soil horizon systems within a factor of 2 to 3. Hexazinone was not adsorbed from 0.01M CaCl₂ by purified cellulose, or by anionic (pH = 5.8) or neutral (pH = 2.8) carboxymethyl cellulose. Nonpolar surfaces seem to be important in hexazinone adsorption as polystyrene adsorbed all of the hexazinone from 0.01M CaC₂. The hexazinone adsorbed by polystyrene was not desorbable with 0.01M CaCl₂, but was desorbable with a 3:2 methanol/water (vol/vol) solution. In the absence of competing water molecules, hexazinone was adsorbed from hexane solution on cellulose.
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