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Wyniki wyszukiwania dla: chemical modification
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Characteristics, Chemical Modification Processes as well as the Application of Silica and its Modified Forms
PublikacjaThe variety of chemical modifications of the surface of silica and its modified forms cause thesematerials to find a consistently wider scope of application. In the publication, the characteristicsof silica, silica gel, aerogel and xerogel are presented. The obtainment, application and propertiesof these materials are discussed. Methods of chemical modifications of surface structures withthe use of different chemical compounds...
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Chemical modification of tannins from Acacia mearnsii to produce formaldehyde free flocculant
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Chemical modification of natural immunomodulators tuftsin and muramyl dipeptide significantly influence their biological activity
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Does the chemical modification of Nystatin A1 affect the drug's ability to overcome the multidrug resistance of fungi?
PublikacjaAlthough the contemporary medicine keeps moving forward, disseminated infections caused by fungal pathogens are an emerging challenge. The dramatic rise of fungal diseases, especially the most life-threatening systemic mycoses is associated with a permanently growing number of immunodeficient patients. Undoubted difficulties in the treatment of fungal infections are caused by lack of highly effective and selective antifungal drugs,...
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Tribo-Environment Dependent Chemical Modification of Sliding Interfaces in Ultrananocrystalline Diamond Nanowall Film: A Correlation with Friction and Wear
PublikacjaTribological properties of ultrananocrystalline diamond nanowall (UNCD NW) films were investigated quantitatively in three different and controlled tribo-environmental conditions, proposing the passivation and graphitization mechanisms. However, these mechanisms are rather complicated and possibly can be understood in well-controlled tribological conditions. It was shown that the friction and wear of these films were high in highPage 1...
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Designing high-performance quasi-symmetrical solid oxide cells with a facile chemical modification strategy for Sr2Fe2−xWxO6−δ ferrites electrodes with in situ exsolution of nanoparticles
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Charakterystyka, procesy chemicznej modyfikacji oraz zastosowanie krzemionki i jej zmodyfikowanych postaci = Characteristics, processes of chemical modification as ell as the application of silica and its modified forms
PublikacjaRóżnorodność chemicznych modyfikacji krzemionki i jej zmodyfikowanych postaci powodują, iż materiały te znajdują coraz szerszy zakres wykorzystania. W artykule przedstawiono charakterystykę krzemionki, żelu krzemionkowego, aerożelu oraz kserożelu. Omówiono otrzymywanie, zastosowanie, a także właściwości tych materiałów. Przedstawiono sposoby chemicznej modyfikacji struktur powierzchniowych z użyciem różnych związków chemicznych....
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Surface characteristics of glass fibres covered with an aluminum layer after a chemical modification process using secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM)
PublikacjaPrzedstawiono wyniki z badań powierzchni modyfikowanych włókien szklanych (przed i po procesie chemicznej modyfikacji ich powierzchni), które są kandydatem na przyszły oryginalny bezmatrycowy materiał odniesienia lotnych analitów etenu (C2H4) metodami spektrometrii mas jonów wtórnych oraz mikroskopii sił atomowych. Badania miały na celu obserwację zmian oraz procesów, jakie zaszły na powierzchni włókien szklanych pokrytych...
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Bacterial presence in polar regions associated with environment modification by chemical compounds including contaminants
PublikacjaMicrobes are omnipresent and diverse members of all biological communities. In marine and freshwater ecosystems, microorganisms form the base of the food chain supporting higher trophic levels. Even though, microbes generally are thought to live in warm regions of Earth, many of them develop in cold climates. Polar regions remain relatively protected from widespread anthropogenic disturbances, which is a consequence of its remoteness...
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Modification of cellulosic filler with diisocyanates – volatile organic compounds emission assessment and stability of chemical structure over time
PublikacjaThis paper investigated the impact of type and content of diisocyanate on the structure of modified cellulose fillers. Four the most popular isocyanates were applied – isophorone, hexamethylene, toluene and methylene diphenyl diisocyanate – at loadings of 1–15 wt%. Chemical structure, and its short-term storage stability, were investigated for eight weeks. Moreover, the main volatile organic compounds detected during modification,...
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Influence of modification of the amino acids ionic liquids on their physico-chemical properties: Ionic liquids versus ionic liquids-supported Schiff bases
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Chemical modifications of natural oils and examples of their usage for polyurethane synthesis
PublikacjaNatural oils have been used in the production of plastics for a long time. However, the number of studies dedicated to polyurethane research has shown an increase only recently. Usually, petrochemical components are used in polyurethane synthesis. Nowadays, there have been attemptsmade to replace polyols in polyurethanes with the modified oils and other natural raw materials. It is a promising and important scenario because the...
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Chemical modifications of graphene and their influence on properties of polyurethane composites: a review
PublikacjaPolyurethane composites are materials of great interest nowadays due to their wide range of available forms and applications in industry. Controlling and achieving unique properties via matrix modifications and addition of various specific nanofillers seems be one of the key elements to success. The purpose of this work is to briefly present some examples of graphene nanoderivatives, their syntheses, properties and influence on...
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The effect of chemical modifications on rheologicalproperties of collagen from of Baltic cod (Gadus morhua)skin stabilized by interaction with κ-carrageenan.
PublikacjaZbadano wpływ stężenia aldehydu glutarowego i EDC N-[3-(dimetyloamino)propylo]-N'-etylokarbodiimid na reologiczne właściwości kompleksu k-karagenu z kolagenem wydzielonym ze skór dorsza bałtyckiego (Gadus morhua) 0,5 M roztworem kwasu octowego i wytworzonych z nich błon. Stwierdzono, że dodanie do dyspersji aldehydu glutarowego, którego stężenie zmieniano od 0,05 do 0,2% powodowało natychmiastowy wzrost jej lepkości. Dodatek aldehydu...
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The Substantial Improvement of Amphotericin B Selective Toxicity Upon Modification of Mycosamine with Bulky Substituents
PublikacjaAbstract: Background: It is assumed that the unfavorable selective toxicity of an antifungal drug Amphotericin B (AmB) can be improved upon chemical modification of the antibiotic molecule. Objective: The aim of this study was verification of the hypothesis that introduction of bulky substituents at the amino sugar moiety of the antibiotic may result in diminishment of mammalian vitro toxicity of thus prepared AmB derivatives. Methods:...
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Chemical surface etching methods for ground tire rubber as sustainable approach for environmentally-friendly composites development– a review
PublikacjaGround tire rubber (GTR) has been used as a sustainable low-cost modifier in various composites. However, due to the hydrophobic nature of GTR, it is in compatible with most matrices and results in deterioration in both mechanical and physical properties of composites. This necessitates pre-modification of the powdered rubber to improve the interfacial bonding at the rubber-matric interface. The most common GTR modification research...
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Functional properties of packaging materials from chemical modified stach.
PublikacjaThis work is focused on study of the mechanical and barrier properties of films obtained from potato starch modified with sodium tetrahydroxozincate generated in situ. The results show that the chemical modification of starch improved the water vapor permeability by about 25%, unfortunately decreased the elongation at break by 60%, when compared with unmodified starch films. However, placitization of films with glycerol at a concentration...
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Au nanoparticles identifiction with the use of AFM Volta potential mapping
Dane BadawczeThe specific physical, chemical and electrochemical electrical properties of gold nanoparticles have led to their extensive use as high-performance chemical and biochemical sensors. The described properties relate to surface plasmon resonance, fluorescence quenching or enhancement, high electrical conductivity and light scattering. The described nanoparticles...
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Compatibility of Sustainable Mater-Bi/poly(ε-caprolactone)/cellulose Biocomposites as a Function of Filler Modification
PublikacjaDespite their popularity and multiplicity of applications, wood–polymer composites (WPCs) still have to overcome particular issues related to their processing and properties. The main aspect is the compatibility with plant-based materials which affects the overall performance of the material. It can be enhanced by strengthening the interfacial adhesion resulting from physical and/or chemical interactions between the matrix and...
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Green chemical and hybrid enzymatic pretreatments for lignocellulosic biorefineries: Mechanism and challenges
PublikacjaThe greener chemical and enzymatic pretreatments for lignocellulosic biomasses are portraying a crucial role owing to their recalcitrant nature. Traditional pretreatments lead to partial degradation of lignin and hemicellulose moieties from the pretreated biomass. But it still restricts the enzyme accessibility for the digestibility towards the celluloses and the interaction of lignin-enzymes, nonproductively. Moreover, incursion...
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Surface modifications of ti and its alloys
PublikacjaThis article reviews the various surface modification techniques pertaining to titanium and titanium alloys including physical treatment, mechanical treatment, and chemical and electrochemical treatment. The proper surface modification expands the use of titanium and its alloys in the biomedical field for long-term implants retaining the excellent properties of substrate material and improving the specific surface properties required...
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Solid-State Modification of Poly(butylene terephthalate) with a Bio-Based Fatty Acid Dimer Diol Furnishing Copolyesters with Unique Morphologies
PublikacjaCopolyesters based on poly(butylene terephthalate) (PBT) and a bio-based fatty acid dimer diol (FADD) were prepared by solid-state modification (SSM). The chemical incorporation of the FADD into the backbone of the PBT was proven using various techniques. It was clear that the incorporation rate was diffusion-limited rather than reaction-limited. From quantitative 13C NMR a nonrandom chemical microstructure was obtained at all...
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Effect of hybrid modification by ceramic layer formation in MAO process and laser remelting on the structure of titanium bio-alloy Ti13Nb13Zr
PublikacjaTo improve the biological properties of titanium alloy Ti13Nb13Zr, hybrid modifications involving micro-arc oxidation (MAO) and Nd: YAG laser remelting were carried out in two combinations. The first consisted of laser modification before the production of the ceramic layer by the micro-arc oxidation process, and the second combination involved Nd: YAG laser modification after the MAO process. The creation of developed surface...
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Insights into the Thermo-Mechanical Treatment of Brewers’ Spent Grain as a Potential Filler for Polymer Composites
PublikacjaThis paper investigated the impact of twin-screw extrusion parameters on the properties of brewers’ spent grain. The chemical structure, antioxidant activity, particle size, and color properties, as well as the emission of volatile organic compounds during extrusion, were investigated. The main compounds detected in the air during modifications were terpenes and terpenoids, such as α-pinene, camphene, 3-carene, limonene, or terpinene....
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A novel luminescent chemical sensor for the determination of Pb 2+ and Cu 2+ ions
PublikacjaSilica xerogel surface grafted with aminopropyl (PrNH2) groups was additionally treated by cetyltrimethylammonium bromide (CTAB) surfactant and ascorbic acid (asc) in alkaline solution. This material symbolized as SiO2-PrNH2-CTAB/asc, proved to be a stable luminescent material, exhibited an emission band peaked at 393 nm under excitation wavelength 335 nm. Time evolution of the band intensity suggests changes of defect concentration...
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The phenomenon of increasing capacitance induced by 1T/2H-MoS2 surface modification with Pt particles – Influence on composition and energy storage mechanism
PublikacjaIn this paper, several approaches to the synthesis of molybdenum-based electrode materials for supercapacitors are presented, including anodization, hydrothermal process and annealing. For the material prepared via anodization of a molybdenum plate, followed by a hydrothermal process in thiourea aqueous solution, a thorough study of the Pt-surface modification through repetitive cycling in 1 M sulfuric acid with Pt acting as a...
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Surface modification of PMMA polymer and its composites with PC61BM fullerene derivative using an atmospheric pressure microwave argon plasma sheet
PublikacjaThis paper presents the results of experimental investigations of the plasma surface modification of a poly(methyl methacrylate) (PMMA) polymer and PMMA composites with a [6,6]-phenyl-C61-butyric acid methyl ester fullerene derivative (PC61BM). An atmospheric pressure microwave (2.45 GHz) argon plasma sheet was used. The experimental parameters were: an argon (Ar) flow rate (up to 20 NL/min), microwave power (up to 530 W), number...
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Application of cyanated asphaltenes in gas-phase adsorption processes for removal of volatile organic compounds
PublikacjaThe paper presents an innovative, chemically modified (methylcyanated) asphaltene-based adsorbent that can be an inter-esting low-cost alternative for traditional adsorbents. Adsorption properties of adsorbents were examined by inverse gas chromatography technique, adsorption isotherms, and breakthrough curves. A significant increase in retention volume for pyridine, 2-pentanone, nitropropane, toluene, and 1-butanol was observed....
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Controlling the europium oxidation state in diopside through flux concentration
PublikacjaThis paper explores the connection between the H3BO3 flux concentration and the co-existence of Eu2+ and Eu3+ dopants within CaMgSi2O6 crystals (diopside). The samples were synthesised using a solid-state synthesis method under varying atmospheric conditions, including oxidative (air), neutral (N2), and reductive (H2/N2 mixture) environments. Additionally, some materials underwent chemical modification by partially substituting...
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Susceptibility to Degradation in Soil of Branched Polyesterurethane Blends with Polylactide and Starch
PublikacjaA very important method of reducing the amount of polymer waste in the environment is the introduction to the market of polymers susceptible to degradation under the influence of environmental factors. This paper presents the results of testing the susceptibility to degradation in soil of branched polyesterurethane (PUR) based on poly([R,S]-3-hydroxybutyrate) (R,S-PHB), modified with poly([D,L]-lactide) (PLA) and starch (St). Weight...
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Review of the Application of Graphene-Based Coatings as Anticorrosion Layers
PublikacjaDue to the excellent properties of graphene, including flexibility that allows it to adjust to the curvature of the substrate surface, chemical inertness, and impermeability, graphene is used as an anticorrosion layer. In this review, we present the current state-of-the-art in the application of graphene in the field of protective coatings. This review provides detailed discussions about the protective properties of graphene coatings...
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Grafting and reactive extrusion technologies for compatibilization of ground tyre rubber composites: Compounding, properties, and applications
PublikacjaChemical modification of ground tyre rubber (GTR) to compatibilize it with the matrix is a well-known approach. Based on our recent review of the surface etching methods used in GTR modification, the purpose of the current work is to take a deeper look into more advanced methods such as grafting and reactive extrusion. While grafting is more efficient in achieving compatibility, however, it usually involves multi-step synthesis...
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Molecular and structural basis of inner core lipopolysaccharide alterations in Escherichia coli: incorporation of glucuronic acid and phosphoethanolamine in the heptose region.
PublikacjaIt is well established that lipopolysaccharide (LPS) often carries nonstoichiometric substitutions in lipid A and in the inner core. In this work, the molecular basis of inner core alterations and their physiological significance are addressed. A new inner core modification of LPS is described, which arises due to the addition of glucuronic acid on the third heptose with a concomitant loss of phosphate on the second heptose. This...
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Poly-L-Lysine-modified boron-doped diamond electrodes for the amperometric detection of nucleic acid bases
PublikacjaBoron-doped diamond (BDD) is a very promising supporting material used in the construction of biosensors for molecular recognition. The direct immobilization of structurally-organized huge molecules, such as poly-L-Lysine (PLL) provides the possibility of determining organic molecules, e.g. nucleic acid bases (e.g. adenine, guanine) or peptides and proteins. This paper describes the direct method for chemical and electrochemical...
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Haemocompatibility Of Non-Functionalized And Plasmachemical Functionalized Detonation Nanodiamond Particles
PublikacjaThe purpose of this paper is to present the innovative design of microwave plasma system for modification of detonation nanodiamond particles (DNP) using a special rotating drum placed inside the reactor. Nanodiamond particles manufactured by detonation method reveal the biological activity depending on surface functionalization. Plasmachemical modification of detonation nanodiamond particles gives the possibility of controlling...
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In-situ monitoring of electropolymerization processes at boron-doped diamond electrodes by Mach-Zehnder interferometer
PublikacjaIn this work, the Mach-Zehnder interferometer was designed to monitor the electrochemical processes conducted at boron-doped diamond electrode surface. The diamond electrodes were synthesized via Microwave Plasma-Assisted Chemical Vapor Deposition on optical grade quartz glass. The achieved transmittance in working are of diamond electrodes reached 55 %. A cage system-based Mach-Zehnder interferometer was used which allowed the...
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Tuning of the Electrochemical Properties of Transparent Fluorine-doped Tin Oxide Electrodes by Microwave Pulsed-plasma Polymerized Allylamine
PublikacjaWe report here the dry, one-step, and low-temperature modification of FTO surfaces using pulsed plasma polymerization of allylamine (PPAAm). PPAAm/FTO surfaces were characterized by X-ray photoelectron spectroscopy, spectroscopic ellipsometry, and contact angles to understand the morphological, structural, and optical properties. FTO were coated with a very thin layer of adherent cross-linked, pinhole-, and additive-free allylamine...
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Kinetics and mechanism of the chemically modified starches during gelatinization.
PublikacjaNative starch was silicated by means of microwave-assisted reactions with varying doses of reagents. Resulting products were characterized by DSC and HMR-relaxation methods. It was observed that the hydratation of the silicated starches during gelatinization decreases when compared to that of the native potato starch. The amount of unfrozen water for ungelitinizated silicated starches are less than in control samples. At the same...
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Poly(ε-Caprolactone)/Brewers’ Spent Grain Composites—The Impact of Filler Treatment on the Mechanical Performance
PublikacjaWaste lignocellulose materials, such as brewers’ spent grain, can be considered very promising sources of fillers for the manufacturing of natural fiber composites. Nevertheless, due to the chemical structure differences between polymer matrices and brewers’ spent grain, filler treatment should be included. The presented work aimed to investigate the impact of fillers’ reactive extrusion on the chemical structure and the poly(ε-caprolactone)/brewers’...
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Elucidating the impact of enzymatic modifications on the structure, properties, and applications of cellulose, chitosan, starch and their derivatives: a review
PublikacjaPolysaccharides, as one of the most prominent natural biopolymers, display numerous biological activities and industrial applications. Nevertheless, some polysaccharides lack biological properties or display weak biological activities. Besides, practical usages of polysaccharides still remain challenging because of their poor solubility and inappropriate hydrophilic/hydrophobic balance. Hence, enzymatic or chemical modifications...
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Preparation and photocatalytic properties of BaZrO 3 and SrZrO 3 modified with Cu 2 O/Bi 2 O 3 quantum dots
PublikacjaIn this study, we report a novel method of BaZrO3 and SrZrO3 surface modification by two different types of quantum dots (QDs, Cu2O and Bi2O3), which improved the photocatalytic performance of the obtained materials under UV-Vis light irradiation. Pristine BaZrO3 and SrZrO3 were prepared by the hydrothermal method. The deposition of Cu2O- and Bi2O3-QDs was carried out by chemical reduction. The morphology of the nanoparticles was...
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Scalable Route toward Superior Photoresponse of UV-Laser-Treated TiO2 Nanotubes
PublikacjaTitanium dioxide nanotubes gain considerable attention as a photoactive material due to chemical stability, photocorrosion resistance, or lowcost manufacturing method. This work presents scalable pulsed laser modification of TiO2 nanotubes resulting in enhanced photoactivity in a system equipped with a motorized table, which allows for modifications of both precisely selected and any-large sample area. Images obtained from scanning...
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Peptide modification with thiomalonoamide moiety
PublikacjaAbstract: Meldrum acid derivatives under the thermal decomposition are well known source of ketenes. Recently we investigated chemical properties of thiocarbamolyl meldrum acids. We found that 5-(α-alkylamino- α'-sulfhydryl)methylene Meldrum's acids hated in the presence of amines produce thiomalonamides. We used this reaction to the one pot synthesis of series of short peptides containing thiomalonoamide motif.
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The extended version of restriction analysis approach for the examination of the ability of low-molecular-weight compounds to modify DNA in a cell-free system
PublikacjaOne of the primary requirements in toxicology is the assessment of ability of chemicals to induce DNA covalent modification. There are several well-established methods used for this purpose such as 32P-Postlabeling or HPLC-MS. However, all of these approaches have difficult to overcome limitations, which prevents their use in genotoxin screening. Here, we describe the simple protocol exploiting specificity of restriction enzymes...
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Sorption of Chlorinated Solvents on Pine and Oak sawdust
PublikacjaThe article presents assessment of pine and oak sawdusts as sorbents for removal of chlorinated solvents from water. Sawdusts as potential sorbents were characterized with elemental analysis and BET analyses. Sorption capacity was determined for both pine and oak sawdust towards 1,1,2-trichloroethane, tetrachloroethene and 1,1,1,2-tetrachloroethane. Pine sawdust was able to adsorb greater amounts of chlorinated solvents compared...
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Preparation and characterization of asphaltene based adsorbents for gas-solid adsorption systems
PublikacjaThe dissertation presents results of the experimental research on asphaltene-based adsorbents (support coated with asphaltene layer) for gas-solid adsorption systems, with special reference to volatile organic compounds (VOCs) removal from gas streams. Analysis of gas adsorption properties revealed that asphaltenes isolated from oxidized bitumen have strong affinity toward VOCs. Interactions with target gas molecules, and selectivity...
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Tailoring a low-energy ball milled MnCo2O4 spinel catalyst to boost oxygen evolution reaction performance
PublikacjaThe development of cost-efficient oxygen evolution reaction (OER) catalysts is one of the most important tasks facing modern techniques for hydrogen production. In this work, for the first time, a low-energy ball milling process of MnCo2O4 (MCO) spinel powders, with a mechanical modification time exceeding 1 day was used. After 6 days of ball-milling, the obtained overpotential of the electrocatalyst reached the value of 375 mV...
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Highly effective asphaltene-derived adsorbents for gas phase removal of volatile organic compounds
PublikacjaA novel nitrated asphaltene-derived adsorbent (Asf-Nitro) was prepared using facile isolation and modification procedures. The successful modification was confirmed by Fourier-transform infrared spectroscopy (FTIR). The nitrated adsorbent was evaluated in terms of dispersive and specific interactions, Lewis acid-base properties and adsorption isotherms by means of inverse gas chromatography (IGC). Nitration was found to be extremely...
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Selected biotrends in development of epoxy resins and their composites
PublikacjaEpoxy resins and their fibre or particulate composites are widely used in various industries, including building, naval, aircraft, automotive and aerospace. Modern polymer science and technology focus on the development of green polymers and composites. There are two major areas of interest in the case of epoxy resins: the development of bio-based resins and the production of composites with natural fibers. One of the most interesting...
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Sewage sludge pretreatment by low thermal disintegration for better efficacy of sludge digestion process
PublikacjaThe wastewater water treatment plant (WWTP) sector and it is developing technologies strive to be implement circular economy. The methane production from the sludge digestion process constitute promising source of the renewable energy for WWTP and approaching circular economy assumptions. For this reason, the objective of the study was to examine the modification of sludge characteristics due to the low temperature pretreatment....