期刊
ENVIRONMENTAL SCIENCE & TECHNOLOGY
卷 45, 期 14, 页码 6102-6109出版社
AMER CHEMICAL SOC
DOI: 10.1021/es200577n
关键词
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资金
- U.S. EPA [R833326]
- NSF [BES-068646, EF-0830093]
- Department of Defense [W912HQ-06-C-0038]
- Environmental Research and Training Centre (ERTC), Department of Environmental Quality Promotion (DQEP), Ministry of Natural Resources and Environment, Thailand
- Div Of Biological Infrastructure
- Direct For Biological Sciences [830093] Funding Source: National Science Foundation
Polymer-modified nanoscale zerovalent iron (NZVI) particles are delivered into porous media for in situ remediation of nonaqueous phase liquid (NAPL) source zones. A systematic and quantitative evaluation of NAPL targeting by polymer-modified NZVI in two-dimensional (2-D) porous media under field-relevant conditions has not been reported. This work evaluated the importance of NZVI particle concentration, NAPL saturation, and injection strategy on the ability of polymer-modified NZVI (MRNIP2) to target the NAPL/water interface in situ in a 2-D porous media model. Dodecane was used as a NAPL model compound for this first demonstration of source zone targeting in 2-D. A driving force for NAPL targeting, the surface activity of MRNIP2 at the NAPL/water interface was verified ex situ by its ability to emulsify NAPL in water. MRNIP2 at low particle concentration (0.5 g/L) did not accumulate in or near entrapped NAPL, however, MRNIP2 at moderate and high particle concentrations (3 and 15 g/L) did accumulate preferentially at entrapped NAPL, i.e., it was capable of in situ targeting. The amount of MRNIP2 that targets a NAPL source depends on NAPL saturation (S-n), presumably because the saturation controls the available NAPL/water interfacial area and the flow field through the NAPL source. At effective S-n close or equal to 100%, MRNIP2 bypassed NAPL and accumulated only at the periphery of the entrapped NAPL region. At lower S-n, flow also carries MRNIP2 to NAPL/water interfaces internal to the entrapped NAPL region. However, the mass of accumulated MRNIP2 per unit available NAPL/water interfacial area is relatively constant (similar to 0.8 g/m(2) for MRNIP2 = 3 g/L) from S-n = 13 to similar to 100%, suggesting that NAPL targeting is mostly controlled by MRNIP2 sorption onto the NAPL/water interface.
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