444 results match your criteria: "Institute of Surface Chemistry[Affiliation]"

The phase state of heterogeneous systems prepared on the basis of mixtures of hydrophobic and hydrophilic silica and water, depending on the ratio of component concentrations, and their using as thixotropic agents has been studied. It was found that the dependence of the interfacial energy of water with the surface of the particles of the composite system made on the basis of hydrophilic and hydrophobic silica taken in the proportion of 1:1 as for the individually taken AM-1 has a bell-shaped form with peaks at  = 3 and 1.5 g/g, respectively.

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Silica materials, natural and synthetic variants, represent a promising material for the application in heterogeneous organocatalysis due to their readily modifiable surface and chemical inertness. To achieve high catalyst loadings, usually, porous carriers with high surface areas are used, such as silica monoliths or spherical particles for packed bed reactors. While these commercial materials were shown to be efficient supports, their synthesis is elaborate, and thus less complex and cheaper alternatives are of interest, especially considering scaling up for potential applications.

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First-passage and first-arrival problems in continuous-time random walks: Beyond the diffusion approximation.

Phys Rev E

August 2024

Chuiko Institute of Surface Chemistry, National Academy of Sciences of Ukraine, General Naumov Street 17, 03164 Kyiv, Ukraine.

Some exact solutions of the first-passage and first-arrival problems for the continuous-time random-walk model are obtained. On the basis of these exact solutions, the following has been revealed. First, for some jump-length distributions with a finite variance, the approximate solutions obtained in the diffusion approximation can differ significantly from the exact solutions.

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The interaction of CO with copper oxide clusters of different size, composition, and charge is investigated infrared multiple-photon dissociation (IR-MPD) spectroscopy and density functional theory (DFT) calculations. Laser ablation of a copper target in the presence of an O/He mixture leads to the preferred formation of oxygen-rich copper oxide cluster cations, CuO ( > ; ≤ 8), while the anionic cluster distribution is dominated by stoichiometric ( = ) and oxygen-deficient ( < ; ≤ 8) species. Subsequent reaction of the clusters with CO in a flow tube reactor results in the preferred formation of near-stoichiometric CuO(CO) complexes.

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New hybrid hydrogel composites based on a mixture of natural polysaccharides (sodium alginate, κ-carrageenan, and chitosan) filled with the clay mineral of natural origin, montmorillonite (MMT), were studied. The structure of intercalated/flocculated MMT distribution in the interpenetrating network of polysaccharide matrix was characterized using FTIR, X-ray diffraction, and SEM techniques. Swelling kinetics was investigated using the weight analysis, whereas the phase transition of water in the composition of hybrid hydrogels, by DSC method.

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Due to the extensive application of pesticides and their hazardous effects on organisms, there is an urgent need to remove them effectively from wastewater. Metal-incorporated carbon-mineral composites (Ni/Mn-CMC and Ni/Fe-CMC) described in this paper can certainly be applied for this purpose. They were synthesized by combining mechanochemical and pyrolytic processes and their physicochemical properties were investigated using numerous methods (SEM-EDS, N adsorption/desorption, XRD, surface charge, FTIR).

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In this study, the adsorption characteristics of novel activated biocarbons prepared from horsetail herb (a popular and troublesome weed) by physical activation (using carbon dioxide) and chemical one (using phosphoric(V) acid) in the process of simultaneous proteins immobilization in multicomponent solutions were examined. The carbon materials were characterized in terms of their porous structure, acidic-basic properties, and surface morphology. The binding mechanisms of such proteins as bovine serum albumin (BSA) and lysozyme (LSZ), differing in internal stability, were determined alone and in their blends.

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Article Synopsis
  • The study explores the use of FeO and FeO Au nanoparticles as hyperthermic agents to treat breast cancer by increasing temperatures beyond normal levels, focusing on their cytotoxic effects on cancer cells compared to normal cells.
  • Researchers tested these nanoparticles on the SK-BR-1 breast cancer cell line and assessed toxicity and the expression of proliferation markers (Ki-67, TOP2A, TPX2) using real-time PCR.
  • Results indicated that FeO Au nanoparticles were more toxic to cancer cells than FeO, reducing the expression of proliferation markers in the cancer cells, suggesting that surviving cells were not actively dividing, highlighting the potential of these nanoparticles in cancer treatment.
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The interaction of free cationic silicon oxide clusters, Si O ( = 2-5, ≥ ), with dilute water vapor, was investigated in a flow tube reactor. Product mass distributions indicate cluster size-dependent dissociative water adsorption. To probe the structure and vibrational spectra of the resulting Si O H ( = 2-4) clusters, we employed infrared multiple photon dissociation spectroscopy and density functional theory calculations.

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The objective of this study was to investigate the modification of glass surfaces by the synergistic combination of cold plasma and chemical surface modification techniques. Glass surface hydrophobicity was obtained as a result of various plasma and deposition operational conditions. The mechanisms governing the hydrophobization process were also studied.

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Spherical particles with tunable anisotropic structures enabled by multiple surface functionalities have garnered interest for their potential applications in adsorption technologies. The presence of diverse functional groups in the surface layer, exhibiting varying acidity and hydrophilicity, can lead to unique characteristics in terms of surface structure and behaviour. In this study, the particles were synthesised using a two-step approach involving surface functionalisation of previously synthesised SiO Stöber particles.

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This research focuses on the synthesis of novel low-cost granular sorbents based on bentonite clay of the Navbahor deposit, dust fraction of Angren brown coal, and agricultural wastes such as straw and sawdust to meet the internal needs of the Republic of Uzbekistan. The impact of the initial mixture ingredients on the structural and textural properties of bentonite-coal sorbents (BCSs) has been studied using X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, optical microscopy, and nitrogen adsorption-desorption analysis. For determining the sorption capacity of BCSs, a standard model substance methylene blue (MB), was applied.

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The hydrogenation of CO to CH has gained considerable interest in terms of sustainable energy and environmental mitigation. In this regard, the present work aims to investigate the adsorptive concentration and CO methanation performance over CoFe and NiFe bimetallic catalysts supported on fumed alumina-silica SA96 support at 170-450 °C and under atmospheric pressure. The catalysts were prepared by wet impregnation method, subjected to calcination and further reduced with hydrogen, and their performance in CO methanation was investigated in a hydrogen-rich 2%CO-55%H-43%He gas mixture.

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Article Synopsis
  • A series of carbon-based nanocomposites were created by heating a resorcinol-formaldehyde polymer with metal oxide/silica nanocomposites, leading to different structural properties depending on the metal used (Mg, Mn, Ni, Cu, Zn).
  • The synthesized materials exhibited mesoporous structures and showed significant variations in porosity and surface area based on the metal fillers, with nickel and copper enhancing graphitization and order.
  • The resulting composites demonstrated effective adsorption capabilities for pollutants like p-chlorophenol and p-nitrophenol from water, highlighting their potential applications in environmental remediation.
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Sustainable composite materials, including carnauba wax, can store energy in the form of latent heat, and containing the wax may allow form-stable melting and crystallization cycles to be performed. Here, it is shown that carnauba wax in the molten state and the abundant nanoclay montmorillonite form stable composites with mass ratios of 50-70% (/). Transmission electron microscopy analysis reveals the inhomogeneous distribution of the nanoclay in the wax matrix.

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The use of plant gum-based biodegradable bioplastic films as a packaging material is limited due to their poor physicochemical properties. However, combining plant gum with synthetic degradable polymer and some additives can improve these properties. Keeping in view, the present study aimed to synthesize a series of bioplastic films using Moringa oleifera gum, polyvinyl alcohol, glycerol, and citric acid via thermal treatment followed by a solution casting method.

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Magnetic nanocomposites (MNC) are promising theranostic platforms with tunable physicochemical properties allowing for remote drug delivery and multimodal imaging. Here, we developed doxorubicin-loaded FeO-Au MNC (DOX-MNC) using electron beam physical vapor deposition (EB-PVD) in combination with magneto-mechanochemical synthesis to assess their antitumor effect on Walker-256 carcinosarcoma under the influence of a constant magnetic (CMF) and electromagnetic field (EMF) by comparing tumor growth kinetics, magnetic resonance imaging (MRI) scans and electron spin resonance (ESR) spectra. Transmission (TEM) and scanning electron microscopy (SEM) confirmed the formation of spherical magnetite nanoparticles with a discontinuous gold coating that did not significantly affect the ferromagnetic properties of MNC, as measured by vibrating-sample magnetometry (VSM).

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Composites with Immobilized Bioactive Spirulina on an Inorganic Substrate (Yellow Clay, Hydroxyapatite, SiO, TiO, ZnO).

Chemphyschem

August 2024

Department of Radiochemistry and Environmental Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Skłodowska University, 3 Maria Curie-Skłodowska Sq., 20-031, Lublin, Poland.

In order to improve the structural properties of clays and composites of powdered spirulina, clay, nanosilica, hydroxyapatite, TiO and ZnO were used as an additive for mechanical processing. As a result, composites with natural nanostructured materials (NNM) are prepared with improved structural properties and bioactivity. The mixtures based on NNM with crystalline kaolinite, clays and admixtures were processed in a knife mill.

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Silver nanoparticles (AgNPs) conjugated with polymers are well-known for their powerful and effective antimicrobial properties. In particular, the incorporation of AgNPs in biocompatible catecholamine-based polymers, such as polydopamine (PDA), has recently shown promising antimicrobial activity, due to the synergistic effects of the AgNPs, silver(I) ions released and PDA. In this study, we generated AgNPs-PDA-patterned surfaces by localised electrochemical depositions, using a double potentiostatic method scanning electrochemical cell microscopy (SECCM).

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To create materials that interact effectively with electromagnetic (EM) radiation, new nanosized substituted ferrites (NiZn)MnFeO (x = 0, 0.5, and 1) anchored on the surface of multi-walled carbon nanotubes (CNTs) have been synthesized. The concentration of CNTs in the (NiZn)MnFeO/CNT system was from 0.

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Emerging photoelectrochemical (PEC) photodetectors (PDs) have notable advantages over conventional PDs and have attracted extensive attention. However, harsh liquid environments, such as those with high corrosivity and attenuation, substantially restrict their widespread application. Moreover, most PEC PDs are constructed by assembling numerous nanostructures on current collector substrates, which inevitably contain abundant interfaces and defects, thus greatly weakening the properties of PDs.

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Diclofenac is one of the most popular over-the-counter non-steroidal anti-inflammatory drug and poly(acrylic acid) is a frequently used as thickener, filler or stabilizer. For these reasons, they are common organic contaminants in raw wastewater. The purpose of the presented studies was to compare the adsorption capacity of three carbon-silica composites - metal-free C/SiO, iron-enriched C/Fe/SiO and manganese-enriched C/Mn/SiO towards diclofenac.

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Green Synthesis and Efficient Adsorption: Na-X Zeolite vs. C/Mn/SiO Composite for Heavy Metals Removal.

Materials (Basel)

February 2024

Department of Building Materials Engineering and Geoengineering, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland.

The studies aimed to test the adsorption capacity of two silica-enriched porous materials, synthetic Na-X zeolite and Mn-containing carbon composite, towards Pb(II) and Zn(II) ions in single and mixed systems and in the presence of diclofenac (DCF) and (or) poly(acrylic acid) (PAA). The synthetic zeolite was characterized by a well-developed surface area of 728 m/g and a pore diameter of 1.73 nm, while the carbon composite exhibited 268 m/g and 7.

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Article Synopsis
  • The study examines how the structure of carbon materials affects their ability to adsorb certain cationic dyes, including Basic Violet 3, Basic Red 1, and Basic Blue 9.
  • Various techniques, such as scanning electron microscopy and nitrogen adsorption, were used to analyze the carbon's structure and surface properties.
  • The results suggest that these carbons are effective adsorbents due to their uniform spherical shape and diverse pore sizes suitable for trapping larger dye molecules.
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