ABSTRACT Nanometer-sized iron particles with monodispersity and narrow size distribution were synthesized by modi-fied microemulsion system using environment-friendly non-ionic surfactants Span 80 and Tween 60 as mixed surfactants. The synthesized iron nanoparticles were characterized by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the synthesized particles were mainly composed of α-Fe with an average diameter of 80-90 nm. The chemical activity of the obtained iron nanoparticles was evaluated by the denitrification of nitrate in water. On neutral condition, complete denitri-fication of nitrate was achieved by freshly synthesized nanoiron within 30 min. Ammonia was the main product, with good material balance at the end of the reaction. Two possible reaction pathways for nitrate reduction by nanoiron have been proposed in this study.
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nullT. LI, S. LI, S. WANG, Y. AN and Z. JIN, "Preparation of Nanoiron by Water-in-Oil (W/O) Microemulsion for Reduction of Nitrate in Groundwater," Journal of Water Resource and Protection, Vol. 1 No. 1, 2009, pp. 16-21. doi: 10.4236/jwarp.2009.11003.
 C. P. Zhang, W. Deng, Z. C. Hu, Y. P. Luo, X. Gao, and L. Hu, “Preparation of ultrafine Fe particles by microemulsion method,” Chinese Journal of Applied Chemistry, Vol. 17, No. 3, pp. 248-251, 2000. (in Chinese)
Y. H. Deng, L. Wang, W. L. Yang, S. K. Fu, and E. Abdelhamid, “Synthesis of 30-100 nm nanoscale magnetic polymer particles in inverse microemulsion,” Chemical Journal of Chinese Universities, Vol. 24, No. 5, pp. 920-923, 2003. (in Chinese)
S. X. Zhang, C. P. Zhang, H. Gou, Y. P. Luo, J. Liu, and D. J. Shen, “Preparation of gelatin-nickel-iron composite nanoparticles with gel-microemulsion chemical tailoring (II) effect of relevant parameters on the composition and size of particles and magnetic properties,” Chinese Journal of Rare Metals, Vol. 27 No. 4, pp. 429-433, 2003. (in Chinese)
W. X. Zhang, “Nanoscale iron particles for environmental remediation: An overview,” Journal of Nanoparticle Research, Vol. 5, No. 3-4, pp. 323-332, 2003.
F. Li, C. Vipulanandan, and K. K. Mohanty, “Microemulsion and solution approaches to nanoparticle iron production for degradation of trichloroethylene,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 223, No. 1-3, pp. 103-112, 2003.
C. B. Wang and W. X. Zhang, “Synthesizing nanoscale iron particles for rapid and complete dechlorination of TCE and PCBs,” Environmental Science & Technology, Vol. 31, No. 7, pp. 2154-2156, 1997.
H. L. Lien and W. X. Zhang, “Nanoscale iron particles for complete reduction of chlorinated ethenes,” Colloids and Surface A: Physicochemical and Engineering Aspects, Vol. 191, No. 1-2, pp. 97-105, 2001.
S. R. Kanel, J. M. Greneche., and H. Choi, “Arsenic (V) removal from groundwater using nanoscale zero-valent iron as a colloidal reactive barrier material,” Environmental Science & Technology, Vol. 40, No. 6, pp. 2045-2050, 2006.
S. M. Ponder, J. Darab, and T. E. Mallouk, “Remediation of Cr(VI) and Pb(II) aqueous solutions using supported nanoscale zerovalent iron,” Environmental Science & Technology, Vol. 34, No. 12, pp. 2564-2569, 2000.
L. W. Chen, L. H. Gan, and T. Y. Yue, “Studies on the preparation of aluminium oxide (hydrous) ultrafine particles by the method of microemulsion reaction,” Chemical Journal of Chinese Universities, Vol. 16, No. 1, pp. 13-16, 1995. (in Chinese)
J. Z. Andrey and Y. Y. Jackie, “Reverse microemulsion synthesis of nanostructured complex oxides for catalytic combustion,” Nature, Vol. 403, No. 6, pp. 65-68, 2000.
C. L. Chiang, M. B. Hsu, and L. B. Lai, “Controlled of nucleation and growth of gold nanoparticles in AOT/Span 80/ isooctane mixed reverse micelles,” Journal of Solid State Chemistry, Vol. 177, No. 11, pp. 3891-3895, 2004.
C. Y. Wang, W. Q. Jiang, Y. Zhou, Y. N. Wang, and Z. Y. Chen, “Synthesis of α-Fe ultrafine particles in a saturated salt solution/isopropanol/PVP microemulsion and their structural characterization,” Materials Research Bulletin, Vol. 35, No. 1, pp. 53-58, 2000.
H. L. Lien and W. X. Zhang, “Nanoscale iron particles for complete reduction of chlorinated ethenes,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, Vol. 191, No. 1, pp. 97-105, 2001.
Q. Li, Y. Li, W. H. Li, S. F. Weng, J. G. Wu, and G. X. Xu, “FT-IR study of water structure in water/NaDEHP/n-heptane microemulsion system,” Journal of Peking University (Natural Science), Vol. 33, No. 4, pp. 410-415, 1997. (in Chinese)
G. C. Yang and H. L. Lee, “Chemical reduction of nitrate by nanosized iron: kinetics and pathways [J],” Water Research, Vol. 39, No. 5, pp. 884-894, 2005.