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The thermal degradation of kerogen during pyrolysis in the presence and absence of pyrite as an additive was investigated and discussed from a free-radical chemistry standpoint using in situ ESR techniques. The added pyrite has pronounced effects on the activity of free radicals of kerogen samples representing the diagenesis stage. In this stage, pyrite enhances and accelerates the process of free-radical formation, where the generation of free radicals in kerogen, in the presence of added pyrite, starta at temperature lower than those observed in its absence. On the contrary, pyrite has negligible effects on the formation of free radicals in kerogen samples representing the catagenesis stage. The overall increase of free-radical activity in the presence of pyrite is consistent with the conversion of pyrite to pyrrhotite. It is suggested that pyrite acts indirectly as a catalyst through the nascent sulfur produced from the pyrite to pyrrhotite conversion process.

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The review tackles common diatomite, its characterization, modifications and its composites, heavy metal toxicity and its immobilization techniques using diatomite, other important applications of diatomite.

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Eight crude oil samples recovered from eight fields located in Abu Gharadig and Shushan basins in the north Western Desert, Egypt, were geochemically assessed in order to understand their genetic relationships. Two genetic families of oil are identified in this study, namely Abu Gharadig and Shushan oil families. Bulk (API and sulphur contents), n-alkanes, isoprenoids, biomarkers terpanes and steranes, and dibenzothiophene and phenanthrene parameters of the oils of the two families suggest regional variations of organic facies in their source rocks. Shushan samples represent oil typically generated from clay-rich terrigenous source rocks with great higher plant input, deposited under oxic conditions. Contrary, Abu Gharadig oil samples are of marine origin, their source rocks are rich in clay content and were deposited under suboxic environment. Biomarker maturity parameters Ts/Ts+Tm, ββ/αα and 20S/(20S+20R) C 29 sterane ratios indicate that the studied samples had reached the peak of the oil window, with high maturity level biased towards Abu Gharadig oil. None of the studied oils have undergone biodegradation or water washing. This explains much of the chemical and physical properties uniformity observed across individual oil samples in each basin.