Ozonation of endocrine disrupting chemical BHA under the suppression effect by salt additive-With and without H2O2

The oxidation of fresh and saline wastewater containing an endocrine disrupting chemical (butylated hydroxyanisole, BHA) under different reaction conditions by ozonation and O3/H2O2 was investigated at various pH levels. The observed pseudo-first-order reaction kinetics was justified through a combined direct ozone and indirect radical oxidation approach for the ozonation process. The BHA decay rates increased with the increase of the solution pH, but decreased as the NaCl concentration increased because of the consumption of ozone by chloride. A kinetic model was therefore derived for predicting BHA degradation at various initial pH levels and NaCl concentrations. For the O3/H2O2 and O3/H2O2/Cl− processes, the rate of BHA removal was investigated at hydrogen peroxide concentration ranged from 0.5 to 5 mM at pH 7. Different optimal H2O2 dosages and decay rates were found for both processes due to the participation of reactions among O3, H2O2, OH and Cl− as discussed in the paper.