Radiolytic Reduction of Hexachlorobenzene in Surfactant Solutions: A Steady-State and Pulse Radiolysis Study

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• 作者：George Adam Zacheis ; Kimberly A. Gray ; and Prashant V. Kamat
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：August 15, 2000
• 年：2000
• 卷：34
• 期：16
• 页码：3401 - 3407
• 全文大小：146K
• 年卷期：v.34,no.16(August 15, 2000)
• ISSN：1520-5851

文摘

Steady-state and pulse radiolysis experiments have beenperformed to gain insight into the mechanism ofhexachlorobenzene (HCB) degradation in nonionic surfactant(Plurafac RA-40) solutions. This understanding is importantfor the environmental application of radiolysis to remediatesoils contaminated with chlorinated aromatic compounds orto treat surfactant solution wastes from soil washingprocesses. Steady-state experiments showed that, afteran applied dose of 50 kGy, reductive dechlorination of HCBto trichlorobenzene occurs under reducing conditions.Under oxidizing conditions at the same dose, reductivedechlorination proceeds more slowly to yield tetrachlorobenzene. Radiolytic experiments on the surfactant aloneshowed that the reaction rate constant between hydroxylradicals and RA-40 (1.09 × 10⁹ M^-1 s^-1) was nearly 2orders of magnitude higher than that between hydratedelectrons and RA-40 (2.0 × 10⁷ M^-1 s^-1). Reaction kineticsanalysis indicates efficient hydroxyl radical scavengingby surfactant molecules and the production of secondarysurfactant radicals, which are reductive in nature.Thus, we observe HCB dechlorination in surfactant solutionseven under strongly oxidizing conditions.