Degradation and Transformation of Trichloroethylene in Miscible-Displacement Experiments through Zerovalent Metals

详细信息    查看全文

• 作者：Francis X. M. Casey ; Say Kee Ong ; and Robert Horton
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：December 1, 2000
• 年：2000
• 卷：34
• 期：23
• 页码：5023 - 5029
• 全文大小：100K
• 年卷期：v.34,no.23(December 1, 2000)
• ISSN：1520-5851

文摘

Fate and transport of chlorinated solvents flowing throughreactive barriers containing zerovalent metals areinfluenced by advection, dispersion, adsorption, andtransformation reactions. Batch experiments or residentconcentration column experiments have been usedextensively to study reactions of zerovalent metals andfor the design of in situ flow-through reactive barriers.However, extending results from batch or residentconcentration column experiments to zerovalent metal flow-through systems may be challenging because sorptionand degradation are indistinguishable, and nonequilibriumadsorption-desorption may occur. This study presentsthe first reported miscible-displacement experiments tostudy the fate and transport of chlorinated solvents flowingthrough zerovalent metals. The miscible-displacementexperiments resulted in simultaneous breakthrough curvesof trichloroethylene (TCE) and its reduction daughterproduct, ethylene. Pulses of dissolved TCE were introduced,at three different flow rates, into columns filled withsand, iron filings, or copper-plated iron filings (Cu-Fe).Column effluent was directed through a high performanceliquid chromatography diode-array detector that determinedconcentrations of TCE and its degradation daughter products.Trichloroethylene did not degrade in the presence ofsand. Slightly less TCE was observed with the Cu-Febreakthrough curve than for the iron breakthrough curve.The simultaneous TCE and ethylene breakthrough curveswere described with an equilibrium sorption/degradationmodel and a two-site partial nonequilibrium sorption modelwith degradation and production. Results of the experimentsindicate that sorption is an important process to beconsidered when TCE is flowing through zerovalent metalsystems.