Bare and polymer coated iron oxide superparamagnetic nanoparticles for effective removal of U (VI) from acidic and neutral aqueous medium

Abstract

Superparamagnetic γ-Fe 2 O 3 nanoparticles (5 nm diameter) were synthesized in water. The bare particles exhibit good colloidal stability at ~ pH 2 because of the strong electrostatic repulsion with a surface charge of +25 mV. The polyacrylic acid (PAA)-coated particles exhibit remarkable colloidal stability at ~ pH 7 with abundant free carboxyl groups as reactive sites for subsequent functionalization. In this work, we used zeta potential analysis, transmission electron microscopy, small angle X-ray scattering, and Inductively coupled plasma mass spectrometry to investigate the adsorption behavior of U (VI) on bare and coated colloidal superparamagnetic nanoparticles at pH 2 and pH 7. At pH 2, uranyl ion (UO 2 2+ ) absorbed on the surface of the bare particles with decreasing particle surface charge. This induced particle agglomeration. At pH 7, uranyl ion (UO 2 2+ ) hydrolyzed and formed plate-like particles of uranium hydroxide that were ~ 50 nm in diameter. The PAA-coated iron oxide nanoparticles absorbed on the surface of these U (VI) hydroxide plates to form large aggregates that precipitate to the bottom of the dispersion. At both pH 2 and pH 7, the resulting U (VI)/nanoparticle complex can be easily collected and extracted from the aqueous environment via an external magnetic field. The results show that both bare and polymer-coated superparamagnetic γ-Fe 2 O 3 nanoparticles are potential absorbents for removing U (VI) from water.

Comparison of Structure and Adsorption Properties of Mesoporous Silica Functionalized with Aminopropyl Groups by the Co-Condensation and the Post Grafting Methods

“…Small-angle X-ray scattering measurements were performed with an Anton Paar SAXSpace instrument (Anton Paar GmbH, Graz, Austria), equipped with a MYTHEN2 R 1 K one-dimensional detector (Dectris Ltd., Baden-Daettwil, Switzerland) [ 28 , 29 ]. The X-ray generator was operated at 40 kV and 50 mA using Cu K α radiation (λ = 0.1542 nm) and a line source with a Kratky block-collimation system.…”

Fast and High Amount of U(VI) Uptake by Functional Magnetic Carbon Nanotubes with Phosphate Group

“…Among the different methods for removing uranium from wastewater, the sorption method has been proven to be the most effective . Numerous sorbents have been reported in the literature, for example, graphene oxide, − metal–organic frameworks (MOFs), − mesoporous silica nanospheres, polymers, , magnesium oxide foam, and chitosan …”

“…4 Among the different methods for removing uranium from wastewater, the sorption method has been proven to be the most effective. 5 Numerous sorbents have been reported in the literature, for example, graphene oxide, 6−9 metal−organic frameworks (MOFs), 10−16 mesoporous silica nanospheres, 17 polymers, 18,19 magnesium oxide foam, 20 and chitosan. 21 In addition to these adsorbents, different carbonaceous materials such as carbon nanotubes (CNTs), graphene, and others have displayed amazing latent capacity while removing the uranium via adsorption because of increased specific surface area and functional groups.…”

Synthesis and Characterization of Citric Acid-Modified Iron Oxide Nanoparticles Prepared with Electrohydraulic Discharge Treatment

“…Nanosystems consisting of superparamagnetic magnetite (Fe 3 O 4 ) NPs modified and stabilized with different kind of surfactant molecules and suspended in aqueous medium represent a versatile platform for both in vitro and in vivo applications such as drug delivery systems [ 9 , 10 , 11 ], hyperthermia [ 12 , 13 , 14 ], magnetic resonance imaging (MRI) [ 2 , 15 , 16 ] and magnetic labels for biosensing [ 17 , 18 ]. Besides biomedical applications, iron-based magnetic nanoparticles (MNPs) can be used in the fields of data storage [ 19 ], catalysis [ 20 , 21 ] and environmental remediation [ 22 , 23 , 24 , 25 , 26 ], and as plant protective agents [ 27 , 28 ] or plant growth stimulators [ 29 , 30 ]. Concerning their magnetic properties, iron oxide nanoparticles, in contrast to nanoparticles composed of transition metals such as Co, Ni and Mn, are favoured in biomedical applications because of the high toxicity of the latter compounds [ 31 ].…”