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Assessment of the Capability of Magnetic Nanoparticles to Recover Neodymium Ions from Aqueous Solution
Ana Ambrož, Irena Ban, Thomas Luxbacher, 2022, izvirni znanstveni članek

Opis: Magnetic nanoparticles (MNPs) have received increasing attention for various applications due to their fast synthesis, versatile functionalization, and recyclability by the application of a magnetic field. The high surface-to-volume ratio of MNP dispersions has suggested their use as an adsorbent for the removal of heavy metal ions. We investigated the applicability of MNPs composed of a maghemite core surrounded by a silica shell functionalized with aminopropylsilane, γ-Fe2O3-NH4OH@SiO2(APTMS), for the removal of neodymium ions (Nd3+) from aqueous solution. The MNPs were characterized for their size, composition, surface functionality and charge. Despite of the promising properties of MNPs, their removal from the aqueous dispersion with an external magnet was not sufficient to reliably quantify the adsorption of Nd3+ by UV-Vis spectroscopy.
Ključne besede: rare earth elements, maghemite, nanoparticles, UV-Vis spectroscopy, adsorption
Objavljeno v DKUM: 08.08.2023; Ogledov: 320; Prenosov: 20
.pdf Celotno besedilo (829,86 KB)
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5.
Protein-repellent surface coatings made of polycaprolactone-polysaccharide blends : master's thesis
Jan Marko, 2022, magistrsko delo

Opis: This work is focused on surface characterization and fibrinogen adsorption studies of polycaprolactone/chondroitin sulfate (tetrabutylammonium hydroxide) blends. Mixed polymer solutions were spin-coated to form two-phase thin films, which exhibit various patterns depending on the mass ratio of the spin-coating solution. Stability in the aqueous media, however, presents an uncertainty, due to the solubility of chondroitin sulfate (tetrabutylammonium hydroxide) in water. In spite of this, it is observed that the introduction of chondroitin sulfate (tetrabutylammonium hydroxide) in the film increases the repulsion of fibrinogen. Two methods frequently used for polymer characterization, mass determination using Quartz Crystal Microbalance with Dissipation monitoring and the zeta potential measurement, were found to be comparable techniques when studying protein adsorption and complementary techniques when analysing the stability of thin films.
Ključne besede: polycaprolactone, chondroitin sulfate, zeta potential, QCM-D, fibrinogen, adsorption
Objavljeno v DKUM: 15.07.2022; Ogledov: 524; Prenosov: 38
.pdf Celotno besedilo (5,10 MB)

6.
Removal of neodymium ions from aqueous solution by magnetic nanoparticles : magistrsko delo
Ana Ambrož, 2021, magistrsko delo

Opis: This work is focused on the synthesis and characterization of surface-functionalized γ-Fe2O3-NH4OH@SiO2(APTMS) nanoparticles, their applications, and performance for Nd3+ removal from aqueous solutions, with an emphasis on the characterization of MNPs and Nd(NO3)3•6H2O. The γ-Fe2O3 nanoparticles were obtained by the co-precipitation method, stabilized with ammonia solution, and functionalized by SiO2 and APTMS. Neodymium nitrate hexahydrate (Nd(NO3)3•6H2O) used in aqueous solution was synthesised from neodymium oxide (Nd2O3) powder. The thermal behaviour and stability of the magnetic nanoparticles and Nd(NO3)3•6H2O was studied with thermogravimetric analysis (TGA) in O2, N2, and air atmosphere. Transmission electron microscopy (TEM) images were obtained in order to analyse the particle morphology and measure the size distribution of the nanoparticles. The hydrodynamic diameter of particles and the zeta potential were measured to determine the stability of particles in the solution. ATR-FTIR spectroscopy was used to confirm the functionalization of the magnetic nanoparticles and the adsorption of Nd3+ ions. The effect of the REE adsorption on the MNPs was studied by comparing the sample’s UV-Vis absorption spectra. The laboratory testing and analysis of the results indicate promising applications for the removal of the REE from aqueous solutions with magnetic nanoparticles. However, the coating of the MNP core by SiO2(APTMS) is inefficient for the removal of Nd3+ ions.
Ključne besede: Magnetic nanoparticles, Rare earth elements, Neodymium, Adsorption, Zeta potential, UV-Vis spectroscopy
Objavljeno v DKUM: 03.05.2021; Ogledov: 1317; Prenosov: 152
.pdf Celotno besedilo (2,51 MB)

7.
Zeta potential determination of polymeric materials using two differently designed measuring cells of an electrokinetic analyzer
Hermina Bukšek, Thomas Luxbacher, Irena Petrinić, 2010, izvirni znanstveni članek

Opis: The so-called zeta potential can be determined through electrokinetic measurements and indicates the status regarding surface charges along the interface between solids and liquids. Surface charge gives us information about the condition, quality, and characteristics of a macroscopic surface in the polar medium. In our study the zeta potential was determined using a 'SurPASS' electrokinetic analyzer based on the streaming current and streaming potential measurements. The aim of the research was to compare the results of two differently designed measuring cells ('Adjustable Gap Cell' and 'Clamping Cell') but operating on the same principle. In order to investigate this problem, the zeta potential was determined for the three polymeric materials: poly(ethylene terephthalate) foil, thin-film polyamide composite membranes for nanofiltration and reverse osmosis. The results obtained with 'Clamping Cell' versus 'Adjustable Gap Cell' showed differences in zeta potential, where the 'Adjustable Gap Cell' gave more reproducible results. One reason for this behaviour could be the different geometries of the streaming channels. A more likely reason is the design of the 'Clamping Cell', that requires a sample size larger than necessary for zeta potential determination.
Ključne besede: electrical double layer, zeta potential, electrokinetic analyser, streaming current potential, polymeric materials
Objavljeno v DKUM: 31.05.2012; Ogledov: 3124; Prenosov: 123
.pdf Celotno besedilo (202,54 KB)
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