Environmental catalysis and materials

Stabilization of Fe0 nanoparticles with silica fume for enhanced transport andremediation of hexavalent chromium in water and soil


Yongchao Li , Tielong Li , Zhaohui Jin

DOI:

Received August 26, 2010,Revised October 14, 2010, Accepted , Available online

Volume 23,2011,Pages 1211-1218

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Effective in situ remediation of Cr(VI) in groundwater requires the successful delivery of reactive iron particles to the subsurface. Fe0 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 Fe0 nanoparticles on the commercial available sub-micrometer silica fume prevented them from aggregation while maintaining the particle reactivity. When the Fe0 concentration was 0.4 g/L, 88.00% of 40 mg/L Cr(VI) was removed by silica fume-supported Fe0 nanoparticles (SF-Fe0) in 120 min, 22.55% higher than unsupported Fe0. Furthermore, transport experiments confirmed that almost all unsupported Fe0 was retained, whereas 51.50% and 38.29% of SF-Fe0 were eluted from the vertical and horizontal sand column, respectively. Additionally, the effect of solution ionic strength on the transport ability of SF-Fe0 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+.

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