Table 1.
Chemical and physical properties of tested compounds [6]
| Property | Value/description | |
|---|---|---|
| BPA | PYR | |
| Molecular formula | C15H16O2 | C6H10 |
| Molecular weight | 228.29 g mol-1 | 202.25 g mol-1 |
| Boiling point | 360°C | 404°C |
| Melting point | 160°C | 151°C |
| Solubility in water at 25°C | 300 mg L-1 | 0.135 mg L-1 |
| Octanol-water partition coefficient Log (Kow) | 3.32 | 5.18 |

Figure 1.
Experimental setup used in the study

Figure 2.
Ultrasound intensity influence on BPA degradation (9, 17, 26 and 43 W/cm2)

Figure 3.
Ultrasound intensity influence on PYR degradation (9, 17, 26 and 43 W/cm2)
Table 2.
Parameters of the ultrasonication process
| Compound (-) | I (W/cm2) | P (W) | Pa (MPa) | k (1/min) | t(1/2) (min) |
|---|---|---|---|---|---|
| BPA | 9 | 12 | 0.52 | 0.053 | 13 |
| 17 | 22 | 0.71 | 0.110 | 6 | |
| 26 | 35 | 1.02 | 0.213 | 3 | |
| 43 | 57 | 1.14 | 0.320 | 2 | |
| PYR | 9 | 12 | 0.52 | 0.018 | 39 |
| 17 | 22 | 0.71 | 0.036 | 19 | |
| 26 | 35 | 1.02 | 0.052 | 13 | |
| 43 | 57 | 1.14 | 0.21 | 3 |

Figure 4.
Ultrasound influence on BPA degradation at pulse ultrasonication modes (R=4:2, R=2:4) and continuous mode (R=cont)

Figure 5.
Ultrasound influence on PYR degradation at pulse ultrasonication modes (R=4:2, R=2:4) and continuous mode (R=cont)

Figure 6.
The degradation rate of BPA in US/UV and US process (intensity of 43 W/cm2)

Figure 7.
The degradation rate of PYR in US/UV and US process (Intensity of 43 W/cm2)
Table 3.
BPA and PRN intermediates identified in samples after ultrasonication
| Compound | Intermediate | Process time, min | ||||
|---|---|---|---|---|---|---|
| 1 | 5 | 10 | 20 | 30 | ||
| BPA | 4-[2-(4-hydroxyphenyl)propan-2-yl]benzene-1,2-diol | - | - | - | + | + |
| 4,4′-isopropylidenebiscatechol | - | - | - | + | + | |
| 4′-hydroxyacetophenone | - | - | - | - | + | |
| 4-hydroxybenzoic acid | - | - | - | - | + | |
| PYR | 1-hydroxypyrene | - | - | + | + | + |
| 3-phenanthrenol | - | - | - | + | + | |
| 9-phenanthrenol | - | - | - | + | + | |
| 1,4-benzoquinone | - | - | - | - | + | |
Table 4.
BPA and PRN intermediates identified in samples after ultrasonication supported by UV light
| Compound | Intermediate | Process time, min | ||||
|---|---|---|---|---|---|---|
| 1 | 5 | 10 | 20 | 30 | ||
| BPA | 4-[2-(4-hydroxyphenyl)propan-2-yl]benzene-1,2-diol | - | + | + | + | + |
| 4,4′-isopropylidenebiscatechol | - | + | + | + | + | |
| 4-(2-hydroxy-2-propanyl) phenol | - | - | + | + | + | |
| 4′-hydroxyacetophenone | - | - | + | + | + | |
| 4-hydroxybenzoic acid | - | - | - | + | + | |
| 1,4-benzoquinone | - | - | + | + | + | |
| PYR | 1-hydroxypyrene | - | - | + | + | + |
| 3-phenanthrenol | - | - | - | - | + | |
| 4-phenanthrenol | - | - | - | - | + | |
| 9-phenanthrenol | - | - | - | + | + | |
| 1,2-benzenediol | - | - | - | - | + | |
| 1,4-benzoquinone | - | - | - | + | + | |

Figure 8.
Pathway of generation of BPA decomposition by-product (where: 1) BPA,
2) 4-[2-(4-hydroxyphenyl)propan-2-yl]benzene-1,2-diol,
3) 4,4’-isopropylidenebiscatechol,
4) 4-(2-hydroxy-2-propanyl) phenol, 5) 4’-hydroxyacetophenone, 6) 1,4-benzoquinone)

Figure 9.
Pathway of generation of PRN decomposition by-product (where: 1) PRN,
2) 1-hydroxypyrene, 3) 3-phenanthrenol,
4) 4-phenanthrenol, 5) 9-phenanthrenol,
6) 1,2-benzenediol, 7) 1,4-benzoquinone)

Figure 10.
Toxicity of the samples after US/UV treatment for BPA removal

Figure 11.
Toxicity of the samples after US/UV treatment for PYR removal