In Situ Stabilization of Metal-Contaminated Groundwater by Hydrous Ferric Oxide: An Experimental and Modeling Investigation

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• 作者：Todd A. Martin and J. Houston Kempton
• 刊名：Environmental Science & Technology
• 出版年：2000
• 出版时间：August 1, 2000
• 年：2000
• 卷：34
• 期：15
• 页码：3229 - 3234
• 全文大小：74K
• 年卷期：v.34,no.15(August 1, 2000)
• ISSN：1520-5851

文摘

A potential method is investigated for remediation ofmetal-contaminated groundwater by in-situ emplacementof an adsorptive coating on the aquifer matrix. The coatingis emplaced by sequentially injecting solutes that reactas they mix in the aquifer to form a sparingly soluble solidwith a high metal-adsorption capacity. Dissolved metalsare removed passively as groundwater flows through thetreated aquifer. The potential effectiveness of thismethod was demonstrated by sequentially injecting firstferrous sulfate and then oxygen solutions into a column ofunconsolidated sand, producing a coating of hydrousferric oxide (HFO) as the unretarded oxygen reacted withFe(II) bound to the sand. The HFO delayed the breakthroughof Cr(VI) and As(V) by 8 and 30 pore volumes, respectively,relative to the unamended material. Attenuation ofsolutes by the unamended sand was reaction-rate limited,but coupled transport/equilibrium geochemical modelingmatched well with the increased metal attenuation by thecoating. Potential advantages of this method include thefollowing: (1) coatings are emplaced preferentially in high-conductivity zones, reducing problems caused by aquiferheterogeneity; (2) surface disturbance is minimal; (3)regeneration of the coating is straightforward; (4) nohazardous material is generated; and (5) existing geochemicalmodels can help extrapolate to larger scales.