Photochemistry heterogeneous

With this chapter we would like to convince the reader that heterogeneous photochemistry is an exciting field of surface science and that heterogeneous photoredox reactions are of importance in many naturally occurring processes. 

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Photochemical reactions occur when a gas, a solution, or a solid mixture of chemicals absorbs light to produce an excited state, which further reacts generating different reaction products. Part of the excited-state particles might not convert into new species, but rather revert to the ground-state species. The research field of heterogeneous photochemistry is focused toward the investigation of each of the above-mentioned steps and elucidation of their mechanism and kinetics. 

Keywords Aerosols Heterogeneous photochemistry Hydrosphere Particulate matter Soils... 

A further interesting aspect of heterogeneous photochemistry concerns oil spilled at sea near land, which is subjected to environmental effects such as evaporation, dissolution, photo oxidation, dispersion into the water column and biodegradation. The fate of heavy fuel oil stranded on rock was studied under different environmental conditions [87]. Samples exposed to full or reflected sunlight showed depletion of the larger and more alkylated aromatic hydrocarbons and formation of resins, in agreement with reported laboratory studies on thin films of oil. 

In heterogeneous photochemistry, an increasing effort is going into the study of the photocatalytic degradation of organic pollutants with Ti02 as a photocatalyst. In these oxidation processes either the organic compound is directly oxidized by the valence band holes (hvli+)... 

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