Gasoline Weathering by Evaporation MTBE Fresh Gasoline Toluene
Gasoline - Weathering by Evaporation MTBE Fresh Gasoline Toluene C 2 -benzenes C 3 -benzenes C 4 - and C 5 -benzenes Mildly Weathered Moderately Weathered Severely Weathered
Weathering by Biodegradation Normal Alkanes: Readily biodegraded aerobically Fresh Crude Oil N-heptadecane Isoprenoids (Isoalkanes) Relatively more resistant to biodegradation 2, 6, 10 -Trimethyldodecane Farnesane Weathered Crude Oil 2, 6, 10, 14 -Tetramethylpentadecane Pristane 2, 6, 10, 14 -Tetramethylhexadecane Phytane Can use ratios of isoprenoids for potential source identification and ratios of n-alkanes to isoprenoids as biodegradation indicators
Diesel Biodegraded
SVE System Weathered gasoline C 3 Substituted Benzenes 12 13 9 MTBE 5 10 * ** 1 4 * 11 * 8 3 C 4 Substituted Benzenes 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. * Isobutane n-Butane Isopentane (2 -methylbutane) n-Pentane MTBE 2 -Methylpentane 3 -Methylpentane Benzene Isooctane (2, 2, 4 -Trimethylpentane) Toluene Ethylbenzene m+p-Xylenes o-Xylene 1, 2, 4 -Trimethylbenzene Internal Standards added for analysis Fresh gasoline 2 1 4 6 7 n-Hexane TPHg Method: TO-3 Target Compounds: TO-15
Vapors from 3 gasolines – Reported Compounds in API Study Isobutane (C 4) to Xylenes (C 8) 3 2 1 4 Influent to SVE System 6 n-Hexane 7 * 8 1 2 3 4 * 9 *10 * Influent is similar in distribution of light ends of fresh gasoline vapors * Data Source: API Publication Number 4646 December 1996
Class separation - diesel Whole Diesel Direct Analysis TPH Method Normalized Results, ~82% Recovery Aliphatics Aromatics Fraction Whole Diesel % >C 6 -C 8 >C 8 -C 10 >C 10 -C 12 >C 12 -C 16 >C 16 -C 21 >C 21 -C 35 0. 8 2. 5 5. 9 31 56 17 Aliphatic Aromatic % % 0. 3 1. 7 3. 3 16 33 8. 4 0. 6 0. 5 11 16 5. 7
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