The effect of humic acid adsorption on pH-dependent surface charging and aggregation of magnetite nanoparticles

Illés, Erzsébet; Tombácz, Etelka

doi:10.1016/j.jcis.2005.08.003

Cited by 512 publications

(350 citation statements)

References 28 publications

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“…That of SWCNTs was reported to be 20 mmol/L NaCl (Saleh et al, 2010). However, those of pure magnetite sol, C 60 and boron nano-particles reached 120, 160 and 200 mmol/L, respectively (Illés and Tombácz, 2006;Chen and Elimelech, 2007;Liu et al, 2010). Surface modification of colloidal particles can significantly enhance their stability.…”

Section: Aggregation Kineticsmentioning

confidence: 99%

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant

Peng

Yuan

Wang

et al. 2016

Journal of Environmental Sciences

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Surfactant complexation may have significant effects on the environmental behavior of nano-particles. In order to understand the ecological exposure of nano-materials, it is important to determine the stability and mobility of surfactant-complexed nano-materials in aqueous systems. In this study, the aggregation and transport of C 60 complexed by the surfactant sodium dodecyl benzene sulfonate (SDBS) were investigated. It was found that SDBS-complexed C 60 had a ζ-potential of −49.5 mV under near-neutral pH conditions and remained stable during an aging period of 15 days. It had a critical coagulation concentration of 550 mmol/L for NaCl, which was higher than common natural colloids and many kinds of raw nano-materials, and was comparable to those of many kinds of surface-modified nano-materials. SDBS enhanced the stability of C 60 colloid; however, at the same time, it also enhanced the colloidal particle aggregation rate. Much higher mobility was found for SDBS-complexed C 60 than C 60 colloid. Increase in ionic strength, Ca 2+ concentration or Al 3+ concentration decreased the mobility. In general, SDBS-complexed C 60 had high stability and mobility.

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Section: Aggregation Kineticsmentioning

confidence: 99%

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant

Peng

Yuan

Wang

et al. 2016

Journal of Environmental Sciences

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“…HA is able to form appropriate stabilizing layer on metal oxide particles due to its specific affinity to metal ions and polyionic character [4,5]. Besides our several years' experience with aqueous solutions of humic acids, their interaction with magnetite (Fe3O4, magnetic iron oxide) has been also studied [6,7]. The CA, PAA and PAM interactions with magnetite nanoparticles have been recently investigated [8,9,16].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of organic acids on magnetite nanoparticles, pH-dependent colloidal stability and salt tolerance

Tombácz

Tóth

Nesztor

et al. 2013

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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115

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Graphical abstractH-type isotherms HA, PAM, GA, and CA Highlights  Organic acids either stabilize or destabilize oxide nanoparticles in natural waters.  The stabilizing/destabilizing effect depends on pH, salinity and organic concentration.  Specific configuration of carboxylic groups is necessary to surface complexation.  Surface complexation leads to high affinity adsorption isotherms.  Higher molecular weight organic acids provide better stability than smaller ones. AbstractThe adsorption of different organic acids and their influence on the pH-dependent charging, salt tolerance and so the colloidal stability of magnetite nanoparticles are compared. Adsorption isotherms of citric acid -CA, gallic acid -GA, poly(acrylic acid) -PAA, poly(acrylic-co-maleic acid) -PAM and humic acid -HA were measured. The pH-dependent charge state of MNPs was characterized by electrophoretic mobility and their aggregation by dynamic light scattering. The salt tolerance was tested in coagulation kinetic experiments. Although the adsorption capacities, the type of bonding (either H-bonds or metal ioncarboxylate complexes) and so the bond strengths are significantly different, the following general trends have been found. Small amount of organic acids at pH < ~8 (the pH of PZC of magnetite) -relevant condition in natural waters -only neutralizes the positive charges, and so promotes the aggregation and sedimentation of nanoparticles. Greater amounts of organic acid, above the charge neutralization, cause the sign reversal of particle charge, and at high

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“…W is the ratio of the initial slope of the kinetic curve measured at the fast coagulation rate dZave/dt=f (t)fast to that of actual (fast or slow) coagulation. 40 The experiments were performed with five parallel wells.…”

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confidence: 99%

Designed Polyelectrolyte Shell on Magnetite Nanocore for Dilution-Resistant Biocompatible Magnetic Fluids

et al. 2012

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Magnetite nanoparticles (MNPs) coated with poly(acrylic acid-co-maleic acid) polyelectrolyte (PAM) have been prepared with the aim of improving colloidal stability of core-shell nanoparticles for biomedical applications and enhancing the durability of the coating shells. FTIR-ATR measurements reveal two types of interaction of PAM with MNPs: hydrogen bonding and innersphere metal-carboxylate complex formation. The mechanism of the latter is ligand exchange between uncharged -OH groups of the surface and -COO -anionic moieties of the polyelectrolyte as revealed by adsorption and electrokinetic experiments. The aqueous dispersion of PAM@MNP particles (magnetic fluids -MFs) tolerate physiological salt concentration at composition corresponding to the plateau of the high-affinity adsorption isotherm. The plateau is reached at small amount of added PAM and at low concentration of non-adsorbed PAM, making PAM highly efficient for coating MNPs. The adsorbed PAM layer is not desorbed during dilution. The performance of the PAM shell is superior to that of polyacrylic acid (PAA), often used in biocompatible MFs. This is explained by the different adsorption mechanisms, namely metalcarboxylate cannot form in the case of PAA. Molecular-level understanding of the protective shell formation on MNPs presented here improves fundamentally the colloidal techniques used in coreshell nanoparticle production for nanotechnology applications. This is a PDF file of an unedited manuscript that has been accepted for publication. Final edited form is published in Langmuir 2012, 28, 16638−16646. http://dx

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The effect of humic acid adsorption on pH-dependent surface charging and aggregation of magnetite nanoparticles

Cited by 512 publications

References 28 publications

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant

Aqueous stability and mobility of C60 complexed by sodium dodecyl benzene sulfonate surfactant

Adsorption of organic acids on magnetite nanoparticles, pH-dependent colloidal stability and salt tolerance

Designed Polyelectrolyte Shell on Magnetite Nanocore for Dilution-Resistant Biocompatible Magnetic Fluids

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