In this study, a series of experiments were carried out to determine the effects of ultrasound frequency at 28, 580, and 1000kHz on H2O2 production in the presence of both inert and TiO2-coated glass beads. Several different sizes (no addition, 0.05, 0.1, 1, 2, 3, and 5mm) and amounts (no addition, 10, 25, 50, 100, and 200gL-1) of inert glass beads were tested at a power density of 0.2WmL-1. The production of H2O2 with a contact time of 60min at different frequencies follows the order: 580kHz (339μM/no addition-105μM/2mm)>1000kHz (208μM/no addition-4.0μM/1mm)>28kHz (71.2μM/0.1mm-18.5μM/no addition). For a constant glass-bead size of 0.1mm and at a frequency of 28kHz, the zero-order rate constant is highest in the presence of glass beads of the amount 10gL-1 (3.3μM-1min-1), and it decreases significantly with increasing inert glass-bead amounts (2.7μM-1min-1/25gL-1 to 0.45μM-1min-1/200gL-1). The zero-order rate constant is the lowest (0.31μM-1min-1) with no addition of glass beads. Sonocatalysis at a low frequency of 28kHz with the addition of TiO2-coated glass beads (5mm) of amount 100gL-1 was significantly more effective (1540μM) than sonocatalysis carried out with no addition and inert glass beads (12-18μM) and those carried out at the high frequencies of 580kHz (33.4μM) and 1000kHz (8.77μM), with the other conditions remaining the same.
Bibliographical noteFunding Information:
This research was supported by the Korea Ministry of Environment , “GAIA Project, 02-141-081-021”.
- Glass bead
- Hydrogen peroxide
- Titanium dioxide