Dissertation - Open Access
Doctor of Philosophy (PhD)
Chemistry and Biochemistry
Degradation, Emission, Ethanol-blended gasoline, Gas Chromatography, Petroleum hydrocarbons, Solid-phase microextraction
Volatile organic compounds (VOCs) are abundant in nature and can occur in various forms in a wide variety of sources. Petroleum is one of the major sources of VOCs. Petroleum being the most widely used energy resources of the world, often released to the environment due to emission and leakage or accidental spillage during exploration, transportation and manufacturing. Once released to the environment, petroleum poses a serious threat to the environment due to some of its toxic organic components. Therefore, the analysis of petroleum is critical to understand its effect on the environment and remediation. This dissertation is focused on the analysis of VOCs from petroleum to understand their emission characteristics and microbial degradation. In Chapter 2, the effect of ethanol on the evaporative emission characteristics of ethanol-blended medium and high-density gasoline was studied by measuring the vapor phase composition at different temperatures (room temperature, 38, and 49 °C) using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatographymass spectrometry (GC-MS). A standard mixture of gasoline was prepared based on the detailed hydrocarbon analysis of high-density gasoline by mixing 16 selected compounds and tested. Ethanol was added in different percentages to prepare E0, E10, and E20 (0, 10 and 20 v/v % ethanol) fuel samples. The results obtained from GC-MS were calculated in terms of percentage compositions of compounds separated into four groups (paraffins, iparaffins, monoaromatics, and mononaphthene). The results showed the decrease of vapor phase composition of monoaromatics with the increasing ethanol percentages for most of the tested fuels at all tested temperatures. Similar results were also obtained in paraffin and i-paraffins except for i-paraffins in standard and high-density gasoline and paraffins in medium-density gasoline at room temperature. The percentage decrease is much higher from 0 % to 20 v/v % ethanol containing fuel. In Chapter 3, we investigated the biodegradation ability of petroleum hydrocarbons from kerosene in tryptic soy broth (TSB) and minimal culture media by Bacillus amyloliquefaciens. Two isolates (1BA and 1D3) of B. amyloliquefaciens were grown in TSB and minimal media supplemented with 1% kerosene to understand if the isolates could co-metabolize (or metabolize in case of minimal media) the petroleum hydrocarbons from kerosene by utilizing them. The degradation was measured using GCMS. The result showed the decrease of residual kerosene to below 50% after 4 and 6 days by 1BA and 1D3 respectively. However, beyond this period, the results for control showed more degradation compared to media containing isolates. Although the residual percentage kerosene was comparatively less, meaning more degradation by 1BA and 1D3 compared to control in minimal media, the difference was comparatively low to determine whether the degradation was due to bacterial isolates or not. Further studies were done in terms of iturin A and surfactin biosurfactant production using UHPLC with diode array detection to find out the degradation of petroleum hydrocarbons if a correlation between biosurfactant production and hydrocarbon utilization could be established or not. The UHPLC results confirmed the production of surfactin by only 1D3, but no iturin A by any isolates. Based on the results, 1D3 produced surfactin both in the presence and absence of kerosene in TSB media. However, the concentration in absence of kerosene was much higher (more than double) than in presence of kerosene. Although no surfactin isoform peaks were produced by 1D3 in the presence of kerosene in minimal culture media, it gave some peaks, but very low in intensity in the absence of kerosene, hence concentration was seemed to be very low when compared to 100 ppm standard solution. Since UHPLC results did not find any correlation between surfactin production and kerosene utilization, based on the result, it is less likely that the studied bacteria isolates were utilizing the kerosene to grow and producing lipopeptide surfactants. In Chapter 4, we developed an analytical technique using a commercial dry herb vaporizer (vape) to be used for sample heating and direct extraction of analyte compounds from the headspace of the vape using headspace solid-phase microextraction (HS-SPME) coupled with GC-MS. VOCs from three samples (horseradish, cinnamon, and gasoline spiked soil) were analyzed, and the results were compared with the traditional headspace method. Although comparable results were obtained in term of relative area percentage for both methods, the vape method was found to be more concentrated, since the abundance in the total ion chromatogram obtained for identified peaks were much higher than traditional headspace method.
Number of Pages
South Dakota State University
Copyright © 2021 the Author
Ahmed, A K M Ahsan, "Analysis of Volatile Organic Compounds: Petroleum Emissions and Microbial Degradation" (2021). Electronic Theses and Dissertations. 5251.