Photodegradation of alachlor by H2O2/UV process in aqueous media: kinetic modeling

Abstract

A kinetic model, which predicts Alachlor degradation by hydrogen peroxide-ultraviolet irradiation (H2O2/UV) process in
synthetic and natural water matrices is developed, and validated with experimental results issued from the literature. The
developed model is based on the elementary (photo)chemical reactions known to occur during the H2O2/UV process and
their rate constants reported in the literature. The model does not employ the pseudo-steady-state assumption. It takes into
account the pH decrease during the degradation and considers the presence of carbonate species and natural organic matter
(NOM) in the system. Model verification was done by predicting Alachlor degradation under different process parameters:
H2O2 concentration, solution pH and UV light intensity. Predicted results have shown good agreement with experimental
data. Therefore, the model is considered to be valid and can be used for optimization purposes.