To quantitatively analyze the sonochemical oxidation process, the degradation of rhodamine B was evaluated using a spectrophotometric method measured at 554 nm (Vibra S60, Biochrom Ltd., UK). The initial concentration of the rhodamine B solution was 5 mg L–1, where the solution was prepared with tap water. No significant difference in water quality was observed during the experiments. The ultrasound irradiation time was 180 min and the concentration of rhodamine B was monitored at 20 min intervals. All measurements were repeated three times; the average values are reported herein.
The sonochemically active zone was visualized using luminol solution (0.1 g L–1 luminol and 1 g L–1 NaOH) in a completely dark room [14] , [26] (link). SCL images were acquired using an exposure-controlled digital camera (α58; Sony Corp., JPN).
The sonochemically active zone was visualized using luminol solution (0.1 g L–1 luminol and 1 g L–1 NaOH) in a completely dark room [14] , [26] (link). SCL images were acquired using an exposure-controlled digital camera (α58; Sony Corp., JPN).