Résumé:
The photodeamination of the herbicide metamitron (M
T) was studied in pure water by
irradiation with continuous and pulsed light. This
study leads to understand the mechanism of
this photochemical reaction and to demonstrate the
formation of nitrous acid and
desaminometamitron (DAM) as main product. Two origi
nal transients resulting from the
photolysis of MT and leading to deamination were de
tected and characterized.
We also studied the influence of humic substances (
HS) from various sources (humic and
fulvic acids, soil or peat) on the degradation of t
rimethylphenol (TMP) photosensitized by
riboflavin (Ri). Humic acids (HA) have a prooxidant
effect on the phototransformation for
low concentrations and antioxidant for high ones. A
reactional mechanism was proposed in
both cases. Fulvic acids (FA) have almost no effect
