Photodegradation of crude oil on a solid support.

The modifications of crude oil after absorption on silica, montmorillonite, and zeolite were studied. Solid-phase microextraction gas chromatography-mass spectrometry analysis showed that some compounds are kept better by the solid support than other ones. The modifications that occurred were studied considering the relative amount of different classes of compounds, the number of compounds in function of the number of carbon atoms, and the relative amount in function of the number of carbon atoms for different classes of compounds (linear alkanes, branched alkanes, cyclic alkanes, aromatic hydrocarbons, and alkenes). The modifications which occurred after irradiation with a 125 W high pressure mercury arc towards Pyrex were studied. A global index of the modifications which occurred was proposed. All of the solids prevent photodegradation. Zeolite was the worst, while the most preservative effect was showed by montmorillonite.