Figure 1
Figure 2
The conditions for the Abyssinian oil modification process with scCO2 (Oil 2) or without scCO2 (Oil 1) and their analytical properties
| Oil 1 | Oil 2 | |
|---|---|---|
| Temperature, °C | 120 | 120 |
| Pressure O2/Σ, MPa | 0.4 | 10 |
| Catalyst, % (w/w) | 0.05 | 0.05 |
| Kinematic viscosity at 40°C, mm2/s | 156.9 | 143.4 |
| Peroxide number, meq O2/kg | 15.16 | 13.10 |
| Iodine number, g I2/100 g | 54.10 | 63.70 |
| Saponification number, mg KOH/g | 214.23 | 248.70 |
| Acid number, mg KOH/g | 25.70 | 28.05 |
Oxygen uptake and the biodegradation degree of modified vegetable oils during 28 days
| Time, days | ||||||
|---|---|---|---|---|---|---|
| 0 | 7 | 14 | 21 | 28 | ||
| Average O2uptake by test sample, mg/l | Oil 1 | 0.0 ± 0.0 | 83.9 ± 0.0 | 138.8 ± 0.0 | 174.0 ± 0.0 | 202.5 ± 2.0 |
| Oil 2 | 0.0 ± 0.0 | 91.4 ± 2.0 | 144.0 ± 2.0 | 180.0 ± 2.0 | 208.5 ± 6.0 | |
| Average O2 uptake in the blank test, mg/l | Blank test (b.1.) | 0.0 ± 0.0 | 9.0 ± 2.1 | 10.5 ± 2.1 | 13.5 ± 2.1 | 13.5 ± 2.1 |
| Average O2 intake in the reference material, mg/l | Reference material (w.1.) | 0.0 ± 0.0 | 85.4 ± 2.1 | 112.5 ± 2.1 | 123.0 ± 0.0 | 126.0 ± 4.2 |
| Degree of decomposition, % (BOD/ThOD*C)*100 | Oil 1 | - | 26.9 ± 0.0 | 45.9 ± 0.0 | 57.7 ± 0.0 | 68.0 ± 0.8 |
| Oil 2 | - | 29.3 ± 0.8 | 47.5 ± 1.5 | 59.3 ± 0.8 | 69.4 ± 2.3 | |
| Reference material (w.1.) | - | 59.2 ± 1.6 | 79.1 ± 1.6 | 84.9 ± 0.0 | 87.2 ± 3.3 | |
Chemical shifts and vibrational modes present in the Raman spectra of oils
| Raman Shift, cm−1 | Bond | Group | Vibrational Mode |
|---|---|---|---|
| 3100–2800 | =C−H, C−H | −CH3, −CH2 | stretching |
| 1656 | C=C | cis RCH=CHR | stretching |
| 1444 | C−H | −CH2 | stretching |
| 1300 | −C−H | −CH2 | scissoring |
| 1266 | =C−H | −CH2 | twisting |
| 1087 | C−C | −(CH2)n | stretching |
Characterization of activated sludge
| Parameter | Value |
|---|---|
| Activated sludge suspension, g/l | 9.229 |
| pH | 6.93 |
| Dissolved oxygen content, mg/l | 3.02 |
| Sedimentation after 0.5 h, ml/100 ml | 89 |