Photolysis of smoke dyes on soils

Abstract

Photolysis of an azo, a quinophthalone, and several anthraquinone smoke dyes was studied on soil surfaces. Initially, rapid photodegradation of each dye occurred, followed by a period of much slower rate of loss, indicating that the remaining fraction of the dye was photochemicaily protected. The average mean depths of photolysis ranged from 0.33 to 0.68 mm for outdoor studies and from 0.42 to 0.73 mm for lab studies. The magnitude of the mean depths of photolysis suggests that photo‐degradation of the dyes occurs through indirect photochemical processes. Photolysis products for only two of the dyes could be identified. Photolysis of Disperse Red 9 resulted in the formation of 1‐aminoanthraquinone, whereas Solvent Yellow 33 photo‐degraded to give 2‐carboxyquinoline and phthalic anhydride. Reaction mechanisms involving sensitized photo‐oxidation by singlet oxygen are consistent with the formation of these reaction products.

Conceptual Model for the Transport of Energetic Residues from Surface Soil to Groundwater by Range Activities

“…These high K oc values confirm that, once deposited, dyes sorb strongly to soil or sediment particles, even in most coarsegrained, low-organic-matter surface soils, and have very little or no mobility. Dyes also undergo rapid biodegradation and photodegradation Weber 1994, 1991;Adams et al 1993;Hou and Baughman 1992;Hou et al 1991;Yen and Perenich 1991;Yen et al 1989). These research results indicate that dye particles deposited on the surface of soil or vegetation rapidly degrade into by-products subject to greater degradation than the parent dye.…”