title: Stabilization of Fe(0) nanoparticles with silica fume for enhanced transport and remediation of hexavalent chromium in water and soil.
abstract: Effective in situ remediation of Cr(VI) in groundwater requires the successful delivery of reactive iron particles to the subsurface. Fe(0) nanoparticles (20-110 nm diameter) supported on silica fume were synthesized by borohydride reduction of an aqueous iron salt in the presence of a support material. The experimental result showed that attachment of Fe(0) nanoparticles on the commercial available sub-micrometer silica fume prevented them from aggregation while maintaining the particle reactivity. When the Fe(0) concentration was 0.4 g/L, 88.00% of 40 mg/L Cr(VI) was removed by silica fume-supported Fe(0) nanoparticles (SF-Fe(0) in 120 min, 22.55% higher than unsupported Fe(0). Furthermore, transport experiments confirmed that almost all unsupported Fe(0) was retained, whereas 51.50% and 38.29% of SF-Fe(0) were eluted from the vertical and horizontal sand column, respectively. Additionally, the effect of solution ionic strength on the transport ability of SF-Fe(0) was evaluated. The result showed that increase in the salt concentration led to a decrease in the mobility and also the divalent ion Ca2+ had a greater effect than that of monovalent ion Na+.
authors: College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China. liyongchao@mail.nankai.edu.cn
authors: Yongchao
authors: Y
authors: Li
authors: Tielong
authors: T
authors: Li
authors: Zhaohui
authors: Z
authors: Jini
mesh_terms: D002857:Chromium / Q000737:chemistry* / Q000302:isolation & purification; D007501:Iron / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry* / Q000302:isolation & purification; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D002857:Chromium; C074702:chromium hexavalent ion; D012822:Silicon Dioxide; D007501:Iron