Effects of derivatization on solar-induced decomposition of polycyclic aromatic hydrocarbons in aqueous media

Abstract

The solar-induced decomposition of 10 polycyclic aromatic hydrocarbons (PAHs) was observed in aqueous media. All 10 PAHs observed were half-decomposed within 120 min. Among anthracene derivatives, the decomposition rates were: anthracene = 1-methylanthracene < 2-methylanthracene < 9-methylanthracene < 9,10-dimethylanthracene ∼ 2-aminoanthracene. The addition of commercial humic acid had no effect on the decomposition rates of these PAHs. Deuterium water also hastened the decomposition of PAH. The products obtained by the solar radiation of PAH after extraction to DCM were mainly ketone and hydroxyl derivatives. To explaine these results, reactivities and electron charges at the constituent carbon atoms in each anthracene derivative were examined by an ab initio molecular orbital calculation method.

Keywords:

• Solar radiation
• photodecomposition
• derivatization effect
• anthracene
• polycyclic aromatic hydrocarbons
• deuterium water

Acknowledgments

We are grateful to Prof. Kazuhisa Sakakibara, Yokohama National University, Japan for advising us on the ab initio calculation of the frontier electron distribution with win-MOPAC. This research was supported by a Grant in Aid # 14340235 from the Ministry of Education, Science, and Culture, Japan, a Grant (No. 2003-03) from the Tokyu Environmental Science Foundation, and the Global Environmental Research Fund of Ministry of the Environment, Japan.