References
[1] Albert, A., Rees, C.W., 1956. Avidity of the tetracycline for the cations of metals.
Nature, 177(4505):433-434.

[2] ATSDR (Agency for Toxic Substances and Disease Registry), 2013. CERCLA Priority List of Hazardous Substances.
, Available from
http://www.atsdr.cdc.gov/SPL/index.html,[Accessed on May 07, 2013],:
[3] Baker, W.A., Brown, P.M., 1966. Metal binding in tetracyclines. Cobalt(II) and nickel(II) complexes.
Journal of the American Chemical Society, 88(6):1314-1317.

[4] Balasubramanian, K., Burghard, M., 2005. Chemically functionalized carbon nanotubes.
Small, 1(2):180-192.

[5] Chen, J.Y., Zhu, D.Q., Sun, C., 2007. Effect of heavy metals on the sorption of hydrophobic organic compounds to wood charcoal.
Environmental Science and Technology, 41(7):2536-2541.

[6] Chen, W., Duan, L., Zhu, D.Q., 2007. Adsorption of polar and nonpolar organic chemicals to carbon nanotubes.
Environmental Science and Technology, 41(24):8295-8300.

[7] Chen, W., Duan, L., Wang, L.L., 2008. Adsorption of hydroxyl- and amino-substituted aromatics to carbon nanotubes.
Environmental Science and Technology, 42(18):6862-6868.

[8] Chen, W.F., Zhu, D.Q., Zheng, S.R., 2014. Catalytic effects of functionalized carbon nanotubes on dehydrochlorination of 1,1,2,2-tetrachloroethane.
Environmental Science and Technology, 48(7):3856-3863.

[9] Doluisio, J.T., Martin, A.N., 1963. Metal complexation of the tetracycline hydrochlorides.
Journal of Medicinal Chemistry, 6(1):16-20.

[10] Gao, Y., Li, Y., Zhang, L., 2012. Adsorption and removal of tetracycline antibiotics from aqueous solution by graphene oxide.
Journal of Colloid and Interface Science, 368(1):540-546.

[11] Gu, C., Karthikeyan, K.G., 2005. Interaction of tetracycline with aluminum and iron hydrous oxides.
Environmental Science and Technology, 39(8):2660-2667.

[12] Halling-Srensen, B., Nors Nielsen, S., Lanzky, P.F., 1998. Occurrence, fate, and effects of pharmaceutical substances in the environment—A review.
Chemosphere, 36(2):357-393.

[13] Hirsch, R., Ternes, T.A., Haberer, K., 1999. Occurrence of antibiotics in the aquatic environment.
Science of the Total Environment, 225(1-2):109-118.

[14] Jezowska-Bojczuk, M., Lambs, L., Kozlowski, H., 1993. Metal ion-tetracycline interactions in biological fluids. 10. Structural investigations on copper(II) complexes of tetracycline, oxytetracycline, chlortetracycline, 4-(dedimethylamino)tetracycline, and 6-desoxy-6-demethyltetracycline and discussion of their binding modes.
Inorganic Chemistry, 32(4):428-437.

[15] Ji, L.L., Chen, W., Duan, L., 2009. Mechanisms for strong adsorption of tetracycline to carbon nanotubes: a comparative study using activated carbon and graphite as adsorbents.
Environmental Science and Technology, 43(7):2322-2327.

[16] Ji, L.L., Liu, F., Xu, Z., 2010. Adsorption of pharmaceutical antibiotics on template-synthesized ordered micro- and mesoporous carbons.
Environmental Science and Technology, 44(8):3116-3122.

[17] Ji, L.L., Chen, W., Bi, J., 2010. Adsorption of tetracycline on single-walled and multi-walled carbon nanotubes as affected by aqueous solution chemistry.
Environmental Toxicology and Chemistry, 29(12):2713-2719.

[18] Kandah, M.I., Meunier, J., 2007. Removal of nickel ions from water by multi-walled carbon nanotubes.
Journal of Hazardous Materials, 146(1-2):283-288.

[19] Karousis, N., Tagmatarchis, N., 2010. Current progress on the chemical modification of carbon nanotubes.
Chemical Reviews, 110(9):5366-5397.

[20] Lambs, L., Berthon, G., 1988. Metal ion-tetracycline interactions in biological fluids. Part 7. Quantitative investigation of methacycline complexes with Ca(II), Mg(II), Cu(II) and Zn(II) ions and assessment of their biological significance.
Inorganica Chimica Acta, 151(1):33-43.

[21] Li, Z., Chang, P.H., Jean, J.S., 2010. Interaction between tetracycline and smectite in aqueous solution.
Journal of Colloid and Interface Science, 341(2):311-319.

[22] Lu, C.Y., Liu, C.T., 2006. Removal of nickel(II) from aqueous solution by carbon nanotubes.
Journal of Chemical Technology and Biotechnology, 81(12):932-940.

[23] Luo, Y., Xu, L., Rysz, M., 2011. Occurrence and transport of tetracycline, sulfonamide, quinolone, and macrolide antibiotics in the Haihe River basin, China.
Environmental Science and Technology, 45(5):1827-1833.

[24] Mauter, M.S., Elimelech, M., 2008. Environmental applications of carbonbased nanomaterials.
Environmental Science and Technology, 42(16):5843-5859.

[25] Pan, B., Xing, B.S., 2008. Adsorption mechanisms of organic chemicals on carbon nanotubes.
Environmental Science and Technology, 42(24):9005-9013.

[26] Rao, G.P., Lu, C., Su, F.S., 2007. Sorption of divalent metal ions from aqueous solution by carbon nanotubes: a review.
Separation and Purification Technology, 58(1):224-231.

[27] Saito, T., Matsushige, K., Tanaka, K., 2002. Chemical treatment and modification of multi-walled carbon nanotubes.
Physica B: Condensed Matter, 323(1-4):280-283.

[28] Sun, H.Y., Shi, X., Mao, J.D., 2010. Tetracycline sorption to coal and soil humic acids: an examination of humic structural heterogeneity.
Environmental Toxicology and Chemistry, 29(9):1934-1942.

[29] Sun, Y.P., Fu, K., Lin, Y., 2002. Functionalized carbon nanotubes: properties and applications.
Accounts of Chemical Research, 35(12):1096-1104.

[30] Tasis, D., Tagmatarchis, N., Bianco, A., 2006. Chemistry of carbon nanotubes.
Chemical Reviews, 106(3):1105-1136.

[31] Wang, F., Zhu, D.Q., Chen, W., 2012. Effect of copper ion on adsorption of chlorinated phenols and 1-naphthylamine to surface-modified carbon nanotubes.
Environmental Toxicology and Chemistry, 31(1):100-107.

[32] Wang, Y.J., Jia, D.A., Sun, R.J., 2008. Adsorption and cosorption of tetracycline and copper(II) on montmorillonite as affected by solution pH.
Environmental Science and Technology, 42(9):3254-3259.

[33] Yang, K., Xing, B.S., 2010. Adsorption of organic compounds by carbon nanomaterials in aqueous phase: Polanyi theory and its application.
Chemical Reviews, 110(10):5989-6008.

[34] Zhang, Z.Y., Sun, K., Gao, B., 2011. Adsorption of tetracycline on soil and sediment: effects of pH and the presence of Cu(II).
Journal of Hazardous Materials, 190(1-3):856-862.

[35] Zhao, Y., Geng, J., Wang, X., 2011. Adsorption of tetracycline onto goethite in the presence of metal cations and humic substances.
Journal of Colloid and Interface Science, 361(1):247-251.

Open peer comments: Debate/Discuss/Question/Opinion
<1>