Influence of synthesis parameters on iron nanoparticle size and zeta potential
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Zero valent iron nanoparticles are of increasing interest in clean water treatment applications due to their reactivity toward organic contaminants and their potential to degrade a variety of compounds. This study focuses on the effect of organophosphate stabilizers on nanoparticle characteristics, including particle size distribution and zeta potential, when the stabilizer is present during nanoparticle synthesis. Particle size distributions from DLS were obtained as a function of stabilizer type and iron precursor (FeSO4·7H2O or FeCl3), and nanoparticles from 2 to 200 nm were produced. Three different organophosphate stabilizer compounds were compared in their ability to control nanoparticle size, and the size distributions obtained for particle volume demonstrated differences caused by the three stabilizers. A range of stabilizer-to-iron (0.05–0.9) and borohydride-to-iron (0.5–8) molar ratios were tested to determine the effect of concentration on nanoparticle size distribution and zeta potential. The combination of ferrous sulfate and ATMP or DTPMP phosphonate stabilizer produced stabilized nanoparticle suspensions, and the stabilizers tested resulted in varying particle size distributions. In general, higher stabilizer concentrations resulted in smaller nanoparticles, and excess borohydride did not decrease nanoparticle size. Zeta potential measurements were largely consistent with particle size distribution data and indicated the stability of the suspensions. Probe sonication, as a nanoparticle resuspension method, was minimally successful in several different organic solvents.
KeywordsNanoparticles Zero valent iron Particle size distribution Stabilizer Organophosphate Carboxymethyl cellulose Water treatment Environmental effects
The authors acknowledge Roy H. Geiss for obtaining TEM images (Online resource 1). LF Greenlee acknowledges the National Research Council and NIST for a postdoctoral fellowship.
- Greenlee LF, Hooker S (2011) Characterization of stabilized zero valent iron nanoparticles. In: Boellinghaus T, Lexow J, Kishi T, Kitagawa M (eds) Materials challenges and testing for supply of energy and resources, pp 173–188Google Scholar
- Martell AE, Smith RM, Motekaitis RJ (2004) NIST critically selected stability constants of metal complexes, version 8. Texas A and M University, TexasGoogle Scholar
- Ponder SM, Darab JG, Bucher J, Caulder D, Craig I, Davis L, Edelstein N, Lukens W, Nitsche H, Rao LF, Shuh DK, Mallouk TE (2001) Surface chemistry and electrochemistry of supported zerovalent iron nanoparticles in the remediation of aqueous metal contaminants. Chem Mater 13(2):479–486. doi: 10.1021/cm000288r CrossRefGoogle Scholar
- Sawada K, Miyagawa T, Sakaguchi T, Doi K (1993) Structure and thermodynamic properties of aminopolyphosphate complexes of the alkaline-earth metal ions. J Chem Soc Dalton Trans 3777–3784Google Scholar
- Tratnyek PG, Salter-Blanc AJ, Nurmi JT, Amonette JE, Liu J, Wang C, Dohnalkova A, Baer DR (2011) Reactivity of zero valent metals in aquatic media: effects of organic surface coatings in aquatic redox chemistry (ed) American Chemical Society, vol 1071, 381–406Google Scholar