Major products in the photochemistry of perylene adsorbed in models of atmospheric particulate matter

Abstract

The photodegradation of adsorbed perylene is strongly influenced by the environment in which it is found as demonstrated by the nature of the photoproducts characterized on the adsorbed state in comparison to its photochemical behavior in solution. The separation, characterization, and identification of the products were carried out using HPLC equipped with UV-Vis diode array and MS detection. Two of the products were identified as 1,12-perylenedione and 3,10-perylenedione. Three additional products were characterized as a perylenedione and two perylenediols based on their m/z ratio. Based on this information, two possible mechanisms of formation were proposed for the identified diones. The experimental data showed that both the radical cation and singlet oxygen participate in the route of photodegradation of perylene which occurs through a mixed Type I and Type II pathway. These results assist in the understanding of complex processes undergone by perylene and other PAHs in the environment.

Migration of polycyclic aromatic hydrocarbons (PAHs) in urban treatment sludge to the air during PAH removal applications

“…It is known that PAHs in various matrices (such as air, soil, etc.) can convert to PAH-dione compounds with the effects of the radicals and/or oxygen induced at a singlet level (Wang et al, 2009;Sotero and Arce, 2008;Fioressi and Arce, 2005). In the present study, PAH amount in the sludge decreased after the UV application, and PAH amount in the air also decreased by possible convertion of PAHs to various other organic compounds during photodegradation.…”

Heterogeneous Photochemistry in the Atmosphere

“…Sotero and Arce examined 320–580 nm irradiation of perylene adsorbed on silica gel, as a model of particulate matter. 200 The major observed products were 1,12-perylenedione and 3,10-perylenedione. Their results suggested two mechanisms of photodegradation operating in parallel, one involving singlet oxygen ( 1 O 2 ) produced by energy transfer from the photoexcited perylene, and one involving perylene radical-cation.…”

The atmospheric chemistry of indoor environments

“…For example, PAHs, such as perylene, are known to photodegrade when adsorbed onto silica under sunlight conditions. 233 Other surfaces that might experience faster photochemical transformations will be very close to light xtures, such as the backsplash of an illuminated kitchen side wall.…”