title: Degradation of Trichloroethene with a Novel Ball Milled Fe-C Nanocomposite.
abstract: Nanoscale zero-valent iron (NZVI) is effective in reductively degrading dense non-aqueous phase liquids (DNAPLs), such as trichloroethene (TCE), in groundwater (i.e., dechlorination) although the NZVI technology itself still suffers from high material costs and inability to target hydrophobic contaminants in source zones. To address these problems, we developed a novel, inexpensive iron-carbon (Fe-C) nanocomposite material by simultaneously milling micron-size iron and activated carbon powder. Microscopic and X-ray diffraction (XRD) characterization of the composite material revealed that nanoparticles of Fe were dispersed in activated carbon and a new iron carbide phase was formed. Bench-scale studies showed that this material instantaneously sorbed >90% of TCE from aqueous solutions and subsequently decomposed TCE into non-chlorinated products. Compared to milled Fe, Fe-C nanocomposite dechlorinated TCE at a slightly slower rate and favored the production of ethene over other TCE degradation products such as C3--C6 compounds. When placed in hexane-water mixture, the Fe-C nanocomposite materials are preferentially partitioned into the organic phase, indicating the ability of the composite materials to target DNAPL during remediation.
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Rondinone
authors.affiliation: College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, Zhejiang 310032, China. Electronic address: fenghe@zjut.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: He
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States.
authors.forename: Liyuan
authors.initials: L
authors.lastname: Liang
keywords: Activated carbon; ball mill; dechlorination; groundwater remediation; zero-valent iron nanoparticles