Predicting pharmaceutical degradation by UV (LP)/H2O2 processes: A kinetic model

“Pharmaceuticals and other organic micropollutants are increasingly found in water sources. The UV/H2O2
process is a suitable technology to degrade these pharmaceuticals. A kinetic model is presented to predict
pharmaceutical degradation during UV/H2O2 treatment. Reactions with background constituents in the
water matrix, such as (bi)carbonate, nitrate and NOM were considered as well as hydroxyl radical and
carbonate radical reactions with the pharmaceuticals. The kinetic model is validated by collimated beam
experiments. In several water matrices a good agreement between measured and modelled degradation
was found, for direct photolysis as well as advanced oxidation. For only 5 of the 36 compounds, the model
over or under predicted the measured results. Possible explanations are: pH effects during photolysis and
radical scavenging by NOM. The influence of each reaction incorporated in the kinetic model was studied
by a sensitivity analysis. The sensitivity study showed that nitrate reactions can also be relevant in UV
(LP) applications when there is no hydrogen peroxide and low concentrations of NOM.”

Copyright © 2014 Elsevier B.V. All rights reserved.

(Citaat: Wols, B.A., Harmsen, D.J.H., et al. – Predicting pharmaceutical degradation by UV (LP)/H2O2 processes: A kinetic model – Chemical Engineering Journal 263(2015), p.336-345)