Arsenic (As) contamination in groundwater is a great environmental health concern and is often the result of contact between groundwater and arsenic-containing rocks or sediments and from variation of pH and redox potentials in the subsurface. In the past decade, magnetite nanoparticles (MNPs) have been shown to have high adsorption activity towards As. Alerted by the reported cytotoxicity of 5–12 nm MNP, we studied the adsorption behavior of 1.15 nm MNP and a MNP composite (MNPC), MNPs interlinked by silane coupling agents. With an initial concentration of As at 25 mg L ？1, MNPs exhibited high adsorption capacity for As(V) and As (III), 206.9 mg·g ？1 and 168.6 mg·g ？1 under anaerobic conditions, respectively, and 109.9 mg·g ？1 and 108.6 mg·g ？1 under aerobic conditions, respectively. Under aerobic conditions, MNPC achieved even higher adsorption capacity than MNP, 165.1 mg·g ？1 on As(V) and 157.9 mg·g ？1 on As(III). For As(V) at 50 mg L ？1, MNPC achieved an adsorption capacity as high as 341.8 mg·g ？1, the highest in the literature. A kinetic study indicated that this adsorption reaction can reach equilibrium within 15 min and the rate constant of As(V) is about 1.9 times higher than that of As(III). These results suggested that MNPC can serve as a highly effective adsorbent for fast removal of As.
References
[1]
Ng, J.C.; Wang, J.; Shraim, A. A global health problem caused by arsenic from natural sources. Chemosphere 2003, 52, 1353–1359, doi:10.1016/S0045-6535(03)00470-3.
[2]
ATSDR. Toxicological Profile for Arsenic. Available online: http://www.atsdr.cdc.gov/toxprofiles/tp2-p.pdf (accessed on 20 August 2011).
[3]
Shalat, S.L.; Walker, D.B.; Finnell, R.H. Role of arsenic as a reproductive toxin with particular attention to neural tube defects. J. Toxicol. Environ. Health 1996, 48, 253–271, doi:10.1080/009841096161320.
[4]
Tseng, W.-P. Effects and dose—Response relationships of skin cancer and blackfoot disease with arsenic. Environ. Health Perspect. 1977, 19, 109–119, doi:10.1289/ehp.7719109.
[5]
Chen, C.-J.; Chuang, Y.-C.; Lin, T.-M.; Wu, H.-Y. Malignant neoplasms among residents of a blackfoot disease-endemic area in Taiwan: High-arsenic artesian well water and cancers. Cancer Res. 1985, 45, 5895–5899.
[6]
Bhaumik, S.; Purkayastha, M.; Basu, S.; Nag Chaudhuri, A.; Das Gupta, S. Apoptosis and necrosis in developing brain cells due to arsenic toxicity and protection with antioxidants. Toxicol. Lett. 2002, 136, 65–76, doi:10.1016/S0378-4274(02)00282-5.
[7]
Ficklin, W.H. Separation of arsenic(III) and arsenic(V) in ground waters by ion-exchange. Talanta 1986, 30, 371–373, doi:10.1016/0039-9140(83)80084-8.
Brandhuber, P.; Amy, G. Alternative methods for membrane filtration of arsenic from drinking water. Desalination 1998, 117, 1–10, doi:10.1016/S0011-9164(98)00061-7.
[10]
Mohan, D.; Pittman, C.U. Arsenic removal from water/wastewater using adsorbents—A critical review. J. Hazard. Mater. 2007, 142, 1–53, doi:10.1016/j.jhazmat.2007.01.006.
[11]
Auffan, M.; Rose, J.; Proux, O.; Borschneck, D.; Masion, A.; Chaurand, P.; Hazemann, J.-L.; Chaneac, C.; Jolivet, J.-P.; Wiesner, M.R.; et al. Enhanced adsorption of arsenic onto maghemites nanoparticles: As(III) as a probe of the surface structure and heterogeneity. Langmuir 2008, 24, 3215–3222.
[12]
Shipley, H.J.; Yean, S.; Kan, A.T.; Tomson, M.B. Adsorption of arsenic to magnetite nanoparticles: Effect of particle concentration, pH, ionic strength, and temperature. Environ. Toxicol. Chem. 2009, 28, 509–515, doi:10.1897/08-155.1.
[13]
Yean, S.; Cong, L.; Yavuz, C.T.; Mayo, J.T.; Yu, W.W.; Kan, A.T.; Colvin, V.L.; Tomson, M.B. Effect of magnetite particle size on adsorption and desorption of arsenite and arsenate. J. Mater. Res. 2005, 20, 3255–3264, doi:10.1557/jmr.2005.0403.
[14]
Yavuz, C.T.; Mayo, J.T.; Yu, W.W.; Prakash, A.; Falkner, J.C.; Yean, S.; Cong, L.; Shipley, H.J.; Kan, A.; Tomson, M.; et al. Low-field magnetic separation of monodisperse Fe3O4 nanocrystals. Science 2006, 314, 964–967.
[15]
Pisanic, T.R.; Blackwell, J.D.; Shubayev, V.I.; Fi？ones, R.R.; Jin, S. Nanotoxicity of iron oxide nanoparticle internalization in growing neurons. Biomaterials 2007, 28, 2572–2581.
[16]
Elias, A.; Tsourkas, A. Imaging circulating cells and lymphoid tissues with iron oxide nanoparticles. Hematol. Am. Soc. Hematol. Educ. Program. 2009, 184, 5935–5945.
[17]
Shipley, H.; Yean, S.; Kan, A.; Tomson, M. A sorption kinetics model for arsenic adsorption to magnetite nanoparticles. Environ. Sci. Pollut. Res. 2010, 17, 1053–1062, doi:10.1007/s11356-009-0259-5.
[18]
Ko, S.P.; Liu, H.-L.; Kim, S.; Ju, J.-S.; Kim, Y.K. Sub 5 nm magnetite nanoparticles: Synthesis, microstructure, and magnetic properties. Mater. Lett. 2007, 61, 3124–3129, doi:10.1016/j.matlet.2006.11.032.
[19]
Liu, Z.L.; Wang, X.; Yao, K.L.; Du, G.H.; Lu, Q.H.; Ding, Z.H.; Tao, J.; Ning, Q.; Luo, X.P.; Tian, D.Y.; et al. Synthesis of magnetite nanoparticles in w/o microemulsion. J. Mate. Sci. 2004, 39, 2633–2636, doi:10.1023/B:JMSC.0000020046.68106.22.
[20]
Yokoi, H.; Kinoshita, T.; Zhang, S. Dynamic reassembly of peptide rada16 nanofiber scaffold. Proc. Nati. Acad. Sci.U.S. Amer. 2004.
[21]
Sen, T.; Magdassi, S.; Nizri, G.; Bruce, I.J. Dispersion of magnetic nanoparticles in suspension. Micro. Nano Lett. 2006, 1, 39–42, doi:10.1049/mnl:20065033.
[22]
Tuutij？rvi, T.; Lu, J.; Sillanp？？, M.; Chen, G. As(V) adsorption on maghemite nanoparticles. J. Hazard. Mater. 2009, 166, 1415–1420.
[23]
Wang, Y.; Morin, G.; Ona-Nguema, G.; Juillot, F.; Calas, G.; Brown, G.E. Distinctive arsenic(V) trapping modes by magnetite nanoparticles induced by different sorption processes. Environ. Sci. Technol. 2011, 45, 7258–7266.
[24]
Wang, Y.; Morin, G.; Ona-Nguema, G.; Menguy, N.; Juillot, F.; Aubry, E.; Guyot, F.; Calas, G.; Brown, G.E., Jr. Arsenite sorption at the magnetite–water interface during aqueous precipitation of magnetite: EXAFS evidence for a new arsenite surface complex. Geochim. Cosmochim. Acta 2008, 72, 2573–2586, doi:10.1016/j.gca.2008.03.011.
[25]
Morin, G.; Wang, Y.; Ona-Nguema, G.; Juillot, F.; Calas, G.; Menguy, N.; Aubry, E.; Bargar, J.R.; Brown, G.E. Exafs and hrtem evidence for as(III)-containing surface precipitates on nanocrystalline magnetite: Implications for as sequestration. Langmuir 2009, 25, 9119–9128.
[26]
Dixit, S.; Hering, J.G. Comparison of arsenic(V) and arsenic(III) sorption onto iron oxide minerals: Implications for arsenic mobility. Environ. Sci. Technol. 2003, 37, 4182–4189, doi:10.1021/es030309t.
[27]
Cornell, R.M.; Schwertmann, U. The Iron Oxides; WILEY-VCH Verlag GmbH & Co: Weinheim, Germany, 2003; pp. 536–537.
[28]
Herbel, M.; Fendorf, S. Biogeochemical processes controlling the speciation and transport of arsenic within iron coated sands. Chem. Geol. 2006, 228, 16–32, doi:10.1016/j.chemgeo.2005.11.016.
[29]
Zhang, Q.L.; Lin, Y.C.; Chen, X.; Gao, N.Y. A method for preparing ferric activated carbon composites adsorbents to remove arsenic from drinking water. J. Hazard. Mater. 2007, 148, 671–678, doi:10.1016/j.jhazmat.2007.03.026.
[30]
Gupta, A.K.; Gupta, M. Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications. Biomaterials 2005, 26, 3995–4021, doi:10.1016/j.biomaterials.2004.10.012.
[31]
Vayssières, L.; Chanéac, C.; Tronc, E.; Jolivet, J.P. Size tailoring of magnetite particles formed by aqueous precipitation: An example of thermodynamic stability of nanometric oxide particles. J. Colloid Interface Sci. 1998, 205, 205–212, doi:10.1006/jcis.1998.5614.
[32]
Iler, R.K. The Chemistry of Silica; Wiley: New York, NY, USA, 1979; pp. 172–177.
