Influence of Sorption to Dissolved Humic Substances on Transformation Reactions of Hydrophobic Organic Compounds in Water. I. Chlorination of PAHs

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• 作者：Anett Georgi ; Annett Reichl ; Ulf Trommler ; Frank-Dieter Kopinke
• 刊名：Environmental Science & Technology
• 出版年：2007
• 出版时间：October 15, 2007
• 年：2007
• 卷：41
• 期：20
• 页码：7003 - 7009
• 全文大小：137K
• 年卷期：v.41,no.20(October 15, 2007)
• ISSN：1520-5851

文摘

The effect of sorption to dissolved humic acids (HAs) onthe chlorination of PAHs in aqueous solution was studied.The addition of HA accelerated the chlorination offluoranthene and naphthalene in hypochlorite solutions atpH 5, the stronger effect being observed for fluoranthenethat is sorbed to a higher extent than naphthalene. Sorptioncoefficients (K_DOC) of the analytes were determined by solid-phase microextraction (SPME). The observed rate constantfor fluoranthene chlorination is, for example, larger by afactor of 5 in the presence of 10 mg L^-1 of an aquaticHA as compared to HA-free solution (k' = 0.02 h^-1at 60 mg L^-1 active chlorine, pH 5, without HA). While Cl₂is the dominant reactive species in pure aqueous solutionfor both PAHs, the reaction of fluoranthene seems to involvean additional pathway of chlorination by HOCl in thepresence of HA. It was found that not only did HA notprotect PAHs from the electrophilic attack of the chlorinatingspecies, but the sorption of PAHs on the hydrophobicdomains of the HA favored instead the extent of thechlorination reaction.