Synthesis, surface characterization and electrokinetic properties of colloidal silica nanoparticles with magnetic core

Abstract

In order to obtain functionalized silica colloids with magnetic properties, the three-step reaction, was carried out. The aqueous suspension of iron oxide nanoparticles as magnetic core (maghemite-c-Fe 2 O 3 ) was synthesized according to the Massart's method (Massart in IEEE Trans Magn 17:1247-1248, 1981. A silica shell was obtained onto maghemite employing a modified sol-gel method by Salgueirino (Salgueirino-Maceira et al. in Adv Mater 19:4131-4144, 2006). As-synthesized magnetic silica core/shell nanocomposites were further functionalized by the post-grafting approach, using (3-Aminopropyl)-trimethoxysilane (APTMS) (Pham et al. in Langmuir 18:4915-4920, 2002). The obtained materials were characterized by nitrogen adsorption/desorption measurements, X-ray powder diffractometry (XRD), transmission electron microscopy (TEM). Particle sizes were measured by diffraction laser (DL). In order to establish colloidal stability of the system, zeta potential were measured. The syntheses routes led to obtain both, good purity of maghemite particles (more than 90 %) and their good coverage by outer silica shell. Thanks to their nanometer size and surface properties (especially, presence of amino groups which can ensure the electrostatic interaction between surface of adsorbent and adsorbate molecules), asprepared nanocomposites can be considered as promising

Amine-functionalized silica particles with magnetic core as magnetically removable adsorbents of Ag(I) ions

“…NaOH and HNO 3 were employed to adjust the pH values of the suspensions. In order to determine the zeta potential, three equations were used: Huckel’s, Henry’s and Smoluchowski’s (Gdula et al., 2016). The previous experiments have shown that in any case κ·a relation was higher than 100.…”

Microwave-Assisted Sol–Gel Preparation of the Nanostructured Magnetic System for Solid-Phase Synthesis

“…The shell contributes to the improvement of their chemical and physical properties and ensures increased biocompatibility and biodegradability. Silica is the most widely used to functionalize the surface of nanoparticles [2], because it provides a steric barrier against core agglomeration preventing interactions between nanoparticles [3,4], good hydrophilicity (due to Si-OH), an increase in the stability of the dispersions over a wide pH range, and biocompatibility of the nanoparticles; it also allows the attachment of other functional groups for further application [5,6].…”

Ultrasound Assisted Green Synthesis of Silver and Iron Oxide Nanoparticles Using Fenugreek Seed Extract and Their Enhanced Antibacterial and Antioxidant Activities

“…Magnetic nanoparticles used for the diagnosis should be free of agglomerates, be super-magnetic at room temperature, and be biocompatible and nontoxic. [22]. Therefore, it is necessary to enhance the synthesis method to improve the physicochemical properties of magnetic nanoparticles.…”