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Title

Formation of complexes between hematite nanoparticles and a non-conventional galactomannan gum. Toward a better understanding on interaction processes

Authors
Busch, Verónica M.
Santagapita, Patricio R.
Buera, M. Pilar
Published in Science of the Total Environment. 2015, vol. 532, p. 556-563
Abstract The physicochemical characteristics of hematite nanoparticles related to their size, surface area and reactivity make them useful for many applications, as well as suitable models to study aggregation kinetics. For several applications (such as remediation of contaminated groundwater) it is crucial to maintain the stability of hematite nanoparticle suspensions in order to assure their arrival to the target place. The use of biopolymers has been proposed as a suitable environmentally friendly option to avoid nanoparticle aggregation and assure their stability. The aim of the present work was to investigate the formation of complexes between hematite nanoparticles and a non-conventional galactomannan (vinal gum — VG) obtained from Prosopis ruscifolia in order to promote hematite nanoparticle coating with a green biopolymer. Zeta potential and size of hematite nanoparticles, VG dispersions and the stability of their mixtures were investigated, as well as the influence of the biopolymer concentration and preparation method. DLS and nanoparticle tracking analysis techniques were used for determining the size and the zeta-potential of the suspensions. VG showed a polydispersed size distribution (300–475 nm Z-average diameter, 0.65 Pdi) and a negative zeta potential (between − 1 and − 12 mV for pH 2 and 12, respectively). The aggregation of hematite nanoparticles (3.3 mg/L) was induced by the addition of VG at lower concentrations than 2 mg/L (pH 5.5). On the other hand, hematite nanoparticles were stabilized at concentrations of VG higher than 2 mg/L. Several phenomena between hematite nanoparticles and VG were involved: steric effects, electrostatic interactions, charge neutralization, charge inversion and polymer bridging. The process of complexation between hematite nanoparticles and the biopolymer was strongly influenced by the preparation protocols. It was concluded that the aggregation, dispersion, and stability of hematite nanoparticles depended on biopolymer concentration and also on the way of preparation and initial physicochemical properties of the aqueous system.
Keywords Hematite nanoparticlesVinal gumPolymer–nanoparticle interactionAggregation kineticsIron oxides
Identifiers
Full text
Structures
Research groups Environmental Physical Chemistry
ISE Pôle Sciences
ISE Eau
Project CONICET (PIP 100846), UBACyT (20020100100397), and ANPCyT (PICT 2008–0928),
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BUSCH, Verónica M. et al. Formation of complexes between hematite nanoparticles and a non-conventional galactomannan gum. Toward a better understanding on interaction processes. In: Science of the Total Environment, 2015, vol. 532, p. 556-563. https://archive-ouverte.unige.ch/unige:73331

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Deposited on : 2015-06-23

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