Table 5.
The effect of water matrix (CO32– and humic acid as •OH scavengers) on the rate of caffeine decay (C0 = 5.0 mg L−1) by US and US-assisted photocatalysis. Control1 and Control2 refer respectively to single ultrasound and ultrasound-assisted photocatalysis with 0.1 g L−1 TiO2.
| Process | k′ × 10−3 s−1 |
|---|---|
| Control1 | 1.05 ± 0.09 |
| Control1 + CO3 | 0.63 ± 0.03 |
| Control1 + HA | 0.62 ± 0.01 |
| Control1 + CO3 + HA | 0.55 ± 0.01 |
| Control2 | 6 0.11 ± 0.20 |
| Control2 + CO3 | 2.33 ± 0.11 |
| Control2 + HA | 1.42 ± 0.13 |
| Control2 + CO3 + HA | 1.07 ± 0.09 |