Journal of environmental chemical engineering | 2021
Effect of pH, temperature, and use of synergistic oxidative agents on the ultrasonic degradation of tris-2-chloroethyl phosphate, gemfibrozil, and 17β estradiol in water
Abstract
Abstract The degradation of three contaminants: tris-2-chloroethyl phosphate (TCEP), gemfibrozil (GEM), and 17β estradiol (E2) by ultrasonication (US) was investigated in a 0.6\xa0L batch reactor. The effect of power intensity and temperature on degradation kinetics was quantified. The impact of oxygen (O2), hydrogen peroxide (H2O2), and sodium persulfate (Na2S2O8) on US effectiveness was assessed to determine potential synergism with US. The results illustrated that degradation of contaminants by US followed a first order rate expression and achieved their highest rate of degradation at pH 3, the lowest pH evaluated, except for TCEP which had a relatively constant rate of degradation with respect to solution pH. The maximum rate constants were achieved using US combined with Na2S2O8 and were found to be: 0.0070, 0.039, and 0.033\xa0min–1 for degradation of TCEP, GEM, and E2, respectively. Combining US with H2O2 did not show synergism, while a small degree of synergism was observed when amending with O2. A 20% (average) decrease in the kinetic constant values was observed as the reaction temperature increased from 25\xa0°C to 55\xa0°C at pH 3. This study has provided a better understanding of the US process applied to the removal of organic contaminants from water.