UV/ozone system

Combined process constant (k) and radical rate constant (kr) for UV /ozone system. (Data from Benitez, F.J. et al., Chemosphere, 41,1271-1277, 2000.)... 

In AOP such as UV-oxidation, reaction rate with first order with respect to hydroxyl radical increases with the dosage of oxidant such as O3 and H2O2. However, in some systems such as UV/H2O2 there exists an optimum dose of H2O2 beyond which rate declines as H2O2 itself is a scavenger of hydroxyl radical. For UV/ozone system, high ozone concentration in water will result in excess ozone in the off-gas that needs to be disposed. 

---