3. Results and discussion
3.1. Effect of BPA concentration
Fig. 1a shows BPA profiles as a function of irradiation time and initial concentration at 20 W/L power density, constant temperature of 30 °C, inherent pH = 6, with or without 10 mg/L SPS. Complete conversion can be achieved at treatment times no longer than 180 min for the run at 450 μg/L BPA and this MPC-3100 decreases to 45–60 min as BPA concentration decreases.
Fig. 1. Effect of initial BPA concentration on its sonodegradation with and without 10 mg/L SPS at 20 W/L power density and constant temperature of 30 °C. (a) Concentration–time profiles; (b) Apparent rate constants and 20-min conversion.Figure optionsDownload full-size imageDownload as PowerPoint slide
The addition of SPS has a positive effect on BPA degradation as evidenced by the increased rate constants, whose values are nearly double those without SPS. Water sonolysis (R1) generates hydroxyl radicals systolic pressure attack BPA and its TBPs in the vicinity of the cavitation bubble–liquid interphase, as well as in the liquid bulk (R2):equation(R1)H2O+)))→H+HOH2O+)))→H+HOequation(R2)BPA+HO→TBPs+HO→end-productsBPA+HO→TBPs+HO→end-products