Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly

2009   Vol. 10   No. 1   p. 121~126

Dechlorination mechanism of 2,4-dichlorophenol by Ni/Fe nanoparticles in the presence of humic acid

Jing-jing WO¹, Zhen ZHANG^1,2, Xin-hua XU^†‡1

(¹Department of Environmental Engineering, Zhejiang University, Hangzhou 310027, China)
(²School of Bioscience, Taizhou University, Linhai 317000, China)
^‡ Corresponding Author
^†E-mail: xuxinhua@zju.edu.cn
Received Apr. 12, 2008; revision accepted July 7, 2008

Abstract: To understand the feasibility of its application to the in situ remediation of contaminated groundwater, the dechlorination of 2,4-dichlorophenol (2,4-DCP) by Ni/Fe nanoparticles in the presence of humic acid (HA) was investigated. We found that, as high performance liquid chromatography (HPLC) was used, the 2,4-DCP was first quickly reduced to o-chlorophenol (o-CP) and p-chlorophenol (p-CP), and then reduced to phenol as the final product. Our experimental results indicated that HA had an adverse effect on the dechlorination of 2,4-DCP by Ni/Fe nanoparticles, as the HA concentration increased, the removal rate decreased evidently. It also demonstrated that 2,4-DCP was reduced more easily to o-CP than to p-CP, and that the sequence of the tendency in dechlorination of intermediates was p-CP>o-CP. Transmission electron microscope (TEM) showed that HA could act as an adsorbate to compete reactive sites on the surface of Ni/Fe nanoparticles to decrease the dechlorination rate. Also we concluded that the dechlorination reaction of 2,4-DCP over Ni/Fe nanoparticles progressed through catalytic reductive dechlorination.

Key words: Dechlorination, Ni/Fe nanoparticles, 2,4-dichlorophenol (2,4-DCP), Humic acid (HA)
doi:10.1631/jzus.A0820277             CLC number: X52

References:

[1] Burris, D.R., Campbell, T.J., Manoranjan, V.S., 1995. Sorption of trichloroethylene and etrachloroethylene in a batch reactive metallic iron-water system. Environmental Science & Technology, 29(11):2850-2855.

[2] Cheng, S.F., Wu, S.C., 2001. Feasibility of using metals to remediate water containing TCE. Chemosphere, 43(8):1023-1028.

[3] Coq, B., Figueras, F., 2001. Bimetallic palladium catalysts: influence of the co-metal on the catalyst performance. Journal of Molecular Catalysis A Chemical, 173(1-2): 117-134.

[4] Dolfing, J., Harrison, B.K., 1992. Gibbs free energy of formation of halogenated aromatic compounds and their potential role as electron acceptor in anaerobic environments. Environmental Science & Technology, 26(11):2213-2216.

[5] Doong, R.A., Lai, Y.L., 2005. Dechlorination of tetrachloroethylene by palladized iron in the presence of humic acid. Water Research, 39(11):2309-2318.

[6] Doong, R.A., Lai, Y.L., 2006. Effect of metal ions and humic acid on the dechlorination of tetrachloroethylene by zerovalent iron. Chemosphere, 64(3):371-378.

[7] He, F., Zhao, D., 2005. Preparation and characterization of a new class of starch-stabilized bimetallic nanoparticles for degradation of chlorinated hydrocarbons in water. Environmental Science & Technology, 39(9):3314-3320.

[8] Johnson, T.L., Fish, W., Gorby, Y.A., Tratnyek, P.G., 1998. Degradation of carbon tetrachloride by iron metal: complexation effects on the oxide surface. Journal of Contaminant Hydrology, 29(4):379-398.

[9] Lien, H.L., Zhang, W.X., 2001. Nanoscale iron particles for complete reduction of chlorinated ethenes. Colloids and Surfaces A Physicochemical and Engineering Aspects, 191(1-2):97-105.

[10] Matheson, L.J., Tratnyek, P.G., 1994. Reductive dehalogenation of chlorinated methanes by iron metal. Environmental Science & Technology, 28(12):2045-2053.

[11] Niu, S.F., Zhou, H.Y., Ao, X.P., Xu, X.H., Lou, Z.H., 2006. Structure relationship of nitrochlorobenzene catalytic degradation process in water over palladium-iron bimetallic catalyst. Journal of Zhejiang University SCIENCE B, 7(7):548-552.

[12] Oliver, B.G., Nicol, K.D., 1982. Chlorobenzenes in sediments, water, and selected fish from Lakes Superior, Huron, Erie, and Ontario. Environmental Science & Technology, 16(8):532-536.

[13] Schrick, B., Blough, J.L., Jones, A.D., Mallouk, T.E., 2002. Hydrodechlorination of trichloroethylene to hydrocarbons using bimetallic nickel-iron nanoscales. Chemistry of Materials, 14(12):5140-5147.

[14] Schwarzenbach, R.P., Molnar-Kubica, E., Giger, W., Wakeham, S.G., 1979. Distribution, residence time, and fluxes of tetrachloroethylene and 1,4-dichlorobenzene in Lake Zurich, Switzerland. Environmental Science & Technology, 13(11):2154-2156.

[15] US EPA (US Environmental Protection Agency), 1988. National Pollutant Discharge Elimination System, Code of Federal Regulations. US Government Printing Office, Washington, DC.

[16] Wei, J.J., Xu X.H., Liu, Y., Wang, D.H., 2006. Catalytic hydrodechlorination of 2,4-dichlorophenol over nanoscale Pd/Fe: reaction pathway and some experimental parameters. Water Research, 40(2):348-354.

[17] Wu, L.F., Stephen, M.C., 2006. Removal of trichloroethylene from water by cellulose acetate supported bimemetallic Ni/Fe nanoscales. Chemosphere, 63(2):285-292.

[18] Xu, X.H., Zhou, H.Y., He, P., Wang, D.H., 2005a. Catalytic dechlorination kinetics of p-dichlorobenzene over Pd/Fe catalysts. Chemosphere, 58:1135-1140.

[19] Xu, X.H., Zhou, H.Y., Wang, D.H., 2005b. Structure relationship for catalytic dechlorination rate of dichlorobenzenes in water. Chemosphere, 58(8):1497-1502.

[20] Xu, X.H., Zhou, H.Y., Zhou, M., 2006. Catalytic amination and dechlorination of para-nitrochlorobenzene (p-NCB) in water over palladium-iron bimetallic catalyst. Chemosphere, 62(5):847-852.

[21] Zhang, W.X., Wang, C.B., Lien, H.L., 1998. Treatment of chlorinated organic contaminants with nanoscale bimetallic particles. Catalysis Today, 40(4):387-395.

[22] Zhu, B.W., Lim, T.T., Feng, J., 2006. Reductive dechlorination of 1,2,4-trichlorobenzene with palladized nanoscale Fe⁰ particles supported on chitosan and silica. Chemosphere, 65(7):1137-1146.