Electrokinetic Delivery of Nanoscale Iron Particles for In-Situ Remediation of Pentachlorophenol-Contaminated Soils
This paper investigates the potential in-situ remediation of low permeability soils contaminated with pentachlorophenol (PCP) by electrokinetic delivery of nanoscale iron particles (NIPs). Kaolin soil was used as a model low permeability soil and it was artificially spiked with PCP (1000 mg per Kg of dry soil). Laboratory electrokinetic experiments were conducted using deionized water or NIPs of 50-300 nm particle size at slurry concentrations of 5 g/L and 10 g/L at the anode. All experiments were conducted for 427 hours at a constant voltage gradient of 1 VDC/cm. The experimental results showed that the soil pH decreased near the anode and increased near the cathode. Substantial electroosmotic flow was induced initially and then it decreased, but the flow was not hindered by the NIPs. The total iron in the soil increased from the anode to the cathode, indicating that NIPs may have transported towards the cathode.However, the transport of NIPs in the soil was limited by aggregation and settling of NIPs in the anode. In addition, NIPs may have transformed into Fe3+ ions under the oxygenated and low pH conditions that existed at the anode. It appears that NIPs may not have contributed to PCP degradation. Instead, 47 to 55％ of PCP was degraded in the cathode by reductive dechlorination in all tests. Complete PCP degradation did not occur in any of the tests because of limited transport of PCP into the cathode as a result of low solubility of PCP under the low pH conditions induced near the anode and low electroosmotic flow. An electrokinetic system without NIPs may be effective for remediation of PCP provided enhanced transport of PCP into the cathode and high electroosmotic flow are achieved.
electrokinetics nanoscale iron particles organic contaminants chemical reduction
Krishna R.Reddy Madhusudhana R.Karri
Department of Civil and Materials Engineering, University of Illinois at Chicago,842 West Taylor Steet,Chicago,Illinois 60607,USA
国际会议
徐州
英文
74-79
2007-10-22（万方平台首次上网日期，不代表论文的发表时间）