Molecular transformations in hydrotreating and hydrocracking

Sullivan, R.F.; Boduszynski, Mieczyslaw M.; Fetzer, John C.

doi:10.1021/ef00017a013

Cited by 108 publications

(57 citation statements)

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“…This explains the increase in the content of naphthalene in biochars relative to the initial sewage sludge. Higher temperatures are conducive to the formation of larger and larger molecules of PAHs as a result of the "zig-zag addition process" [34]. Therefore a larger amount of organic matter should theoretically favour the formation of a larger amount of PAHs.…”

Section: Pah Contentmentioning

confidence: 99%

The conversion of sewage sludge into biochar reduces polycyclic aromatic hydrocarbon content and ecotoxicity but increases trace metal content

Zielińska

Oleszczuk

2015

Biomass and Bioenergy

172

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Section: Pah Contentmentioning

confidence: 99%

The conversion of sewage sludge into biochar reduces polycyclic aromatic hydrocarbon content and ecotoxicity but increases trace metal content

Zielińska

Oleszczuk

2015

Biomass and Bioenergy

172

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“…It is also possible that some of the new PAHs found in the irradiated samples are products of hydrocarbon fragmentation caused by sunlight. Such fragments are capable of interacting with each other through radical recombination to form higher molecular weight polycyclic aromatic hydrocarbons [20][21][22].…”

Section: Resultsmentioning

confidence: 99%

<b>Aliphatic and polycyclic aromatic hydrocarbons profiles of photomodified natural bitumen of Agbabu, Southwestern Nigeria</b>

Olabemiwo

Adediran

Adekola

et al. 2010

Bull. Chem. Soc. Eth.

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ABSTRACT ABSTRACT. The impact of sunlight on aliphatic and polycyclic aromatic hydrocarbons profiles of Agbabu natural bitumen in Nigeria was investigated. The raw flow type of the bitumen was purified and exposed to sunlight for six consecutive months. Different portions of the bitumen were withdrawn at an interval of one month and were separated into aliphatic and polycyclic aromatic hydrocarbon fractions by column chromatography, followed by the GC analyses of various fractions. The total aliphatic hydrocarbon content was found to be 485, 424, 416 and 392 g/kg for control, one, three and six months solar-irradiated bitumen samples, respectively; while the total polycyclic aromatic hydrocarbons content found in the control, one, three and six months solar-irradiated bitumen samples were 708, 733, 609 and 638 µg/g, respectively. The effects of sunlight on the compositional patterns of bitumen were discussed. KEY WORDS: KEY WORDS: KEY WORDS:

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“…Free radicals, such as acetylene (HC ' C ⅐ ) and 1,3-butadiene (H 2 C ϭ CH-CH ϭ CH ⅐ ), recombine successively to form the unsubstituted PAHs. Once formed, the simple low-molecularweight PAHs (e.g., naphthalene) undergo further synthesis build-up by the "zigzag addition process" (Figure 4) to the thermodynamically most stable PAH series (Stein, 1986;Sullivan et al, 1989). PAHs are generally not biomarkers as defined by various authors (Bernstein et al, 1999a, b;Ehrenfreund, 1999;Ehrenfreund and Charnley, 2000;Blake and Jenniskens, 2001), because they can form from nonbiological carbonaceous matter by free radical build-up (Simoneit and Fetzer, 1996) or by aromatization of biomarker natural products (Simoneit, 1998).…”

Section: Nonbiomarkersmentioning

confidence: 99%

Molecular indicators (biomarkers) of past life

Simoneit

2002

Anat. Rec.

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Biomarkers in geological samples on Earth are products derived from biochemical precursors (i.e., natural products) by reductive and oxidative alteration processes (e.g., cholestanes from cholesterol). Generally, lipids, pigments, and some biomembranes are preserved best over longer geological times, and labile compounds such as amino acids, sugars, etc. are useful biomarkers for recent times. Thus, the detailed characterization of biomarker composition permits the assessment of the major contributing species of extinct and/or extant life. Nonbiomarkers and abiogenic organic compounds are also discussed. In the case of the early Earth, work has progressed to elucidate biomarker structures and carbon isotopic signals preserved in ancient sedimentary rocks. In addition, the combination of bacterial biochemistry with the organic geochemistry of contemporary and ancient hydrothermal ecosystems permits the modeling of the nature, behavior, and preservation potential of primitive microbial communities. This approach entails combined molecular and isotopic analyses to characterize lipids and biopolymers produced by cultured bacteria (representative of ancient strains) and to test a variety of culture conditions that affect their biosynthesis processes. In regards to Mars, the biomarkers from lipids and biopolymers would be expected to be preserved best if life flourished there during its early history (3.5-4 ϫ 10 9 years ago). Both oxidized and reduced products would be expected. This is based on the inference that hydrothermal activity occurred during that time, with the concomitant preservation of biochemically-derived carbonaceous matter. Known biomarkers (i.e., as elucidated for early terrestrial samples and for primitive terrestrial microbiota) as well as novel, potentially unknown compounds, should be characterized. Anat

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Molecular transformations in hydrotreating and hydrocracking

Cited by 108 publications

References 0 publications

The conversion of sewage sludge into biochar reduces polycyclic aromatic hydrocarbon content and ecotoxicity but increases trace metal content

The conversion of sewage sludge into biochar reduces polycyclic aromatic hydrocarbon content and ecotoxicity but increases trace metal content

<b>Aliphatic and polycyclic aromatic hydrocarbons profiles of photomodified natural bitumen of Agbabu, Southwestern Nigeria</b>

Molecular indicators (biomarkers) of past life

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