Radicals and radical anions such as OH, NO(3) and SO(4)(-) can act as important oxidants in aqueous solutions, e.g. as a part of the tropospheric multiphase system. In the present study the aqueous phase kinetics of OH, NO(3) and SO(4)(-) radical reactions with the following ten aliphatic poly-alcohols 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, (2R,3S)-butane-1,2,3,4-tetraol (meso-erythritol), (2R,4R)-pentane-1,2,3,4,5-pentol (arabitol) and (2R,3R,4R,5R)-hexane-1,2,3,4,5,6-hexol (mannitol) were investigated. These alcohols are both of anthropogenic and of biogenic origin and all are highly water soluble. All rate constants throughout this study were determined as a function of the temperature between 278 < or = T [K] < or = 328. OH radical reactions with poly-alcohols (k(2nd) = 1.6-4.7 x 10(9) L mol(-1) s(-1)) are the fastest among the three investigated radicals. The corresponding NO(3) radical (k(2nd) = 0.66-1.5 x 10(7) L mol(-1) s(-1)) and SO(4)(-) radical (k(2nd) = 2.7-5.3 x 10(7) L mol(-1) s(-1)) reactions are on average two orders of magnitude slower. All three radicals react by an H-abstraction mechanism preferably at the alpha-carbon atom of the investigated alcohols. Kinetic measurements were performed using laser flash photolysis-long path absorption (LFP-LPA). Rate constants were measured either directly following the NO(3) and SO(4)(-) concentration-time profile or by a competition kinetics method using a well characterized reference reaction (SCN(-)) for OH radicals. Furthermore, obtained kinetic data are used to extend existing reactivity correlations for H-abstraction reactions with bond dissociation energies in aqueous solution and to calculate the tropospheric lifetimes of the alcohols.
Zusammenfassung: Eine einstufige Labor-Klaranlage, bestehend aus einem Blasensaulenreaktor mi! Nachklarung und Schlammriickfuhrung, wird mit einer OITWasser-Emulsion als Substrat beschickt, die von einem Altlastenstandort stammt und in ihrer Olphase in erheblichem Umfang mit polycyclischen aromatischen Kohlenwasserstoffen (PAK) kontaminiert ist. Die Beprobung erfolgt regelmaljig im Zulauf, Reaktor, Riicklauf und Klarlauf und die Messung der PAK mit Hilfe einer HPLC. Es kann gezeigt werden, daD neben den niedrig kondensierten PAK auch die als besonders schwer biologisch abbaubar geltenden hoher kondensierten PAK wie z. B. Benzo[n]pyren biologisch umgesetzt werden. Zusatzlich durchgefuhrte Messungen zum toxischen und mutagenen Potential des Abwassers ergeben, dal3 in der Labor-Klaranlage eine vollstandige Detoxifizierung der vorhandenen Schadstoffe erreicht wird. Allerdings kann im Klarlauf noch mutagenes Potential nachgewiesen werden. Dies laat sich darauf zuruckfiihren, da13 bei der biologischen Umsetzung von hoherkernigen PAK mutagene Dead-End-Metaboliten gebildet werden. Acta hydrochim. hydrobiol. 23 (1995) 4 mm 0 VCH Verlagsgesellschaft mbH, D-69451 Weinheim, 1995 0323-4320/95/0407-0149 $05.00+.25/0
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