Overview of main research works on sonochemical oxidation of phenolic compounds in recent years
| Phenols . | Experimental conditions . | Main results . | References . |
|---|---|---|---|
| p-nitrophenol | Power = 84 W frequency = 20 kHz T = 30 °C, pH = 5 | The p-nitrophenol reduction fit the first order kinetics model with current-dependent parameters The reaction products are: NO2-,NO3-, benzoquinone hydroquinone, 4nitrocatecho1, formate, and oxalate | Kotronarou et al. (1991) |
| Phenol | Power = 30 W frequency = 20, 487 kHz T = 25 °C | After 300 min sonication, the degradation rate of phenolic pollutants is higher at 487 kHz than at 20 kHz | Petrier et al. (1994) |
| p-nitrophenol | Frequency = 321 kHz T = 25 °C, pH 4–10 Water-absorbed power = 170 W/kg | A detailed study on the sonolysis of 4-nitrophenol in argon-saturated solution The reaction products are: NO2-,NO3-, 4-Nitrocatechol, hydroquinone, benzoquinone, 4-aminophenol | Tauber et al. (2000) |
| 2-, 3- and 4-chlorophenol and pentachlorophenol | Power = 200 W Frequency = 200 kHz Under air and argon atmosphere | A total degradation rate under argon and 80–90% after one-hour of sonolysis | Nagata et al. (2000) |
| p-chlorophenol | Three different ultrasonic devices used: Probe and cup-horn system: Power = 475 W, frequency = 20 kHz Beaker system: Power = 850 W, frequency = 850 kHz T = 35–39 °C, atmospheric pressure | After 20 min sonication, over 2, 25 and 50% degradation was achieved in cup-horn, beaker and probe respectively. The degradation of intermediate products follow a first-order kinetic rate The reaction products are: hydroquinone, 1, 4-benzoquinone, 4-chlorocatechol, 4-chlororesorcinol | Teo et al. (2001) |
| p-coumaric and p-hydroxybenzaldehyde | Power = 150 W Frequency = 80 kHz T = 25–70 °C | After 150 min sonication, 56 and 60% of COD and polyphenols have been removed | Vassilakis et al. (2004) |
| Phenol, 4-chlorophenol (4-CP), 2,6-dichlorophenol (2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP) | Power = 200 W Frequency = 580 kHz T = 20 °C | After 40 min sonication, the degradation rate of chlorinated phenolic pollutants followed the order: 580 kHz (91–93%) >1,000 kHz (84–86%) >28 kHz (17–34%) The degradation rate followed the order: PCP > 2,3,4,6-TeCP >2,4,6-TCP > 2,6- DCP >4-CP > phenol at various frequencies | Park et al. (2011) |
| Phenols . | Experimental conditions . | Main results . | References . |
|---|---|---|---|
| p-nitrophenol | Power = 84 W frequency = 20 kHz T = 30 °C, pH = 5 | The p-nitrophenol reduction fit the first order kinetics model with current-dependent parameters The reaction products are: NO2-,NO3-, benzoquinone hydroquinone, 4nitrocatecho1, formate, and oxalate | Kotronarou et al. (1991) |
| Phenol | Power = 30 W frequency = 20, 487 kHz T = 25 °C | After 300 min sonication, the degradation rate of phenolic pollutants is higher at 487 kHz than at 20 kHz | Petrier et al. (1994) |
| p-nitrophenol | Frequency = 321 kHz T = 25 °C, pH 4–10 Water-absorbed power = 170 W/kg | A detailed study on the sonolysis of 4-nitrophenol in argon-saturated solution The reaction products are: NO2-,NO3-, 4-Nitrocatechol, hydroquinone, benzoquinone, 4-aminophenol | Tauber et al. (2000) |
| 2-, 3- and 4-chlorophenol and pentachlorophenol | Power = 200 W Frequency = 200 kHz Under air and argon atmosphere | A total degradation rate under argon and 80–90% after one-hour of sonolysis | Nagata et al. (2000) |
| p-chlorophenol | Three different ultrasonic devices used: Probe and cup-horn system: Power = 475 W, frequency = 20 kHz Beaker system: Power = 850 W, frequency = 850 kHz T = 35–39 °C, atmospheric pressure | After 20 min sonication, over 2, 25 and 50% degradation was achieved in cup-horn, beaker and probe respectively. The degradation of intermediate products follow a first-order kinetic rate The reaction products are: hydroquinone, 1, 4-benzoquinone, 4-chlorocatechol, 4-chlororesorcinol | Teo et al. (2001) |
| p-coumaric and p-hydroxybenzaldehyde | Power = 150 W Frequency = 80 kHz T = 25–70 °C | After 150 min sonication, 56 and 60% of COD and polyphenols have been removed | Vassilakis et al. (2004) |
| Phenol, 4-chlorophenol (4-CP), 2,6-dichlorophenol (2,6-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP), and pentachlorophenol (PCP) | Power = 200 W Frequency = 580 kHz T = 20 °C | After 40 min sonication, the degradation rate of chlorinated phenolic pollutants followed the order: 580 kHz (91–93%) >1,000 kHz (84–86%) >28 kHz (17–34%) The degradation rate followed the order: PCP > 2,3,4,6-TeCP >2,4,6-TCP > 2,6- DCP >4-CP > phenol at various frequencies | Park et al. (2011) |