2.3. Ozonation Process
Ozone was generated from pure oxygen using an OZOCAV ZT-2 generator (Inter Ozone Ingeneria
Ecologica, Santiago, Chile). The amount of ozone produced was determined spectrophotometrically at
258 nm (ε =3.000 L mol−1cm−1) in the gas phase by passing the mixture of oxygen and ozone through a
flow cell. The system reached a steady-state production of ozone in 10 min [33,34]. An ozone
concentration of 14 mg L−1 was applied for 1 hour in a batch reactor. Lab-scale investigations were
done with paper mill wastewater. Samples of this effluent (400 mL) were submitted to the ozonation
process (at pH from activated sludge 8.3 and adjusted to pH 10) at room temperature, using a tubular
500 mL reactor fitted with a sintered glass dispenser that released the gas from the bottom of the
reactor. Ozonation was continued until the consumption of ozone had ceased. For subsequent
experiments, an excess of ozone gas was passed from the reactor into a glass flask containing a 2%
solution of KI.