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11.
Separation of mercuric ions using 2-thienylbenzimidazole/cucurbit[7] uril/iron-oxide nanoparticles by pH control
Falguni Chandra, Paltan Laha, Farah Benyettou, Tina Škorjanc, Naʹil Saleh, 2023, izvirni znanstveni članek

Opis: 2-Thienylbenzimidazole (TBI)/cucurbit[7]uril (CB7) host–guest complex was used as a motif to significantly improve the turnover of γ-Fe3O4 magnetic nanoparticles for potential application in the separation of toxic mercuric ions in polluted water samples. The mechanism of restoring the original solid materials is based on applying the pH-controlled preferential binding of the CB7 host to the TBI guest. The analytical application of this concept has not been realized in the literature. The pH-controlled stimuli-responsive abilities were confirmed in aqueous solution by the three-order of magnitudes higher stability constant of the protonated TBIH+/CB7 complex (e.g., K = 4.8 × 108 M−1) when compared to neutral TBI/CB7 complex (e.g., K = 2.4 × 105 M−1), also manifested in an increase in pKa values by ~ 3.3 units in the ground state. The supramolecular interaction and adsorption on iron oxide nanoparticles (NPs) were also spectroscopically confirmed in the solid state. The excited-state lifetime values of TBI/CB7NPs increased upon lowering the pH values (e.g., from 0.6 to 1.3 ns) with a concomitant blue shift of ~ 25 nm because of polarity effects. The time-resolved photoluminescent behaviors of the final solids in the presence of CB7 ensured pH-driven reusable systems for capturing toxic mercuric ions. The study offers a unique approach for the controllable separation of mercury ions using an external magnet and in response to pH through preferential binding of the host to guest molecules on the top of magnetic surfaces.
Ključne besede: iron oxide nanoparticles (IONPs), mercury, thienylbenzimidazole, cucurbit[n]uril
Objavljeno v RUNG: 13.07.2023; Ogledov: 821; Prenosov: 3
.pdf Celotno besedilo (2,41 MB)
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12.
Saturation magnetisation as an indicator of the disintegration of barium hexaferrite nanoplatelets during the surface functionalisation
Darja Lisjak, Iztok Arčon, Matic Poberžnik, Gabriela Herrero‑Saboya, Ali Tufani, Andraž Mavrič, Matjaž Valant, Patricija Hribar Boštjančič, Alenka Mertelj, Darko Makovec, Layla Martin‑Samos, 2023, izvirni znanstveni članek

Opis: Barium hexaferrite nanoplatelets (BHF NPLs) are permanent nanomagnets with the magnetic easy axis aligned perpendicular to their basal plane. By combining this specific property with optimised surface chemistry, novel functional materials were developed, e.g., ferromagnetic ferrofluids and porous nanomagnets. We compared the interaction of chemically different phosphonic acids, hydrophobic and hydrophilic with 1–4 phosphonic groups, with BHF NPLs. A decrease in the saturation magnetisation after functionalising the BHF NPLs was correlated with the mass fraction of the nonmagnetic coating, whereas the saturation magnetisation of the NPLs coated with a tetraphosphonic acid at 80 °C was significantly lower than expected. We showed that such a substantial decrease in the saturation magnetisation originates from the disintegration of BHF NPLs, which was observed with atomic-resolution scanning transmission electron microscopy and confirmed by a computational study based on state-of-the-art first-principles calculations. Fe K-edge XANES (X-ray absorption near-edge structure) and EXAFS (Extended X-ray absorption fine structure) combined with Fourier-transformed infrared (FTIR) spectroscopy confirmed the formation of an Fe–phosphonate complex on the partly decomposed NPLs. Comparing our results with other functionalised magnetic nanoparticles confirmed that saturation magnetisation can be exploited to identify the disintegration of magnetic nanoparticles when insoluble disintegration products are formed.
Ključne besede: barium hexaferrite, Fe XANES, EXAFS, magnetic nanoparticles
Objavljeno v RUNG: 06.07.2023; Ogledov: 1007; Prenosov: 4
.pdf Celotno besedilo (3,60 MB)
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Composites of transition metal dichalcogenides and topological insulators as a new class of catalytic materials
Jelena Rmuš, Blaž Belec, Igor Milanović, Mattia Fanetti, Sandra Gardonio, Matjaž Valant, Sandra V. Kurko, 2022, objavljeni povzetek znanstvenega prispevka na konferenci

Ključne besede: composites, topological insulators
Objavljeno v RUNG: 13.02.2023; Ogledov: 904; Prenosov: 0
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18.
Colloidal nanoparticles for photo(electro)catalytic water splitting studies
Saim Emin, Manel Machreki, Takwa Chouki, 2022, objavljeni povzetek znanstvenega prispevka na konferenci

Ključne besede: nanoparticles, electrocatalysis, water splitting
Objavljeno v RUNG: 10.02.2023; Ogledov: 1164; Prenosov: 0
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