Mechanism and kinetics of reductive dehalogenation of PBB (polybrominated biphenyl) in the sonolytic and ketyl radical system.

Daeik Kim, Jau Ren Chen, Teh Fu Yen

City of Los Angeles, Department of Public Works, Bureau of Engineering, Los Angeles, CA 90015, USA.

Journal of hazardous materials 2009 Apr 15

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The kinetics and mechanism of reductive destruction of aqueous polybrominated biphenyl (PBB) were studied. Complete degradation was achieved within 30 min of ultrasound-assisted chemical process (UACP), which involved sonication, ketyl radical and its anion, and metal catalyst (ferrous ion). Reductive dehalogenation of PBB is a first-order reaction between PBB concentration and UACP reaction time. The kinetic condition of PBB degradation was optimized in terms of temperature, dosage of radical initiator, and metal catalyst. Mechanism of reductive debromination was also proposed to explain the function of ketyl and aryl radicals on the debromination of bromobiphenyl. Two kinetic models were studied to elucidate the debromination mechanism pathway. Laboratory observed data were found to fit model predicted values obtained from equilibrium and differential equations.

Citation

Daeik Kim, Jau Ren Chen, Teh Fu Yen. Mechanism and kinetics of reductive dehalogenation of PBB (polybrominated biphenyl) in the sonolytic and ketyl radical system. Journal of hazardous materials. 2009 Apr 15;163(1):231-8