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The aim of this paper is to present methods applied to obtain and to investigate the properties of magnetic fluids on strongly polar carrier liquids, such as short-chain-length alcohols and water. The high degree of colloidal stability of these colloids is achieved by double-layer sterical stabilization of Fe2O3 and CoFe2O4nanoparticles dispersed in the carrier liquid, the adequate choice and efficient...
Anionic dodecyl sulfate (DS−>) surfactant proved to be an efficient hole scavenger in the TiO2-mediated photocatalytic reduction of Hg(II) in aqueous solution. While oxygen did not affect the efficiency of mercury deposition in this system, chloride ions strongly hindered it, owing to the formation of anionic chloromercurate(II) complexes. Also pH significantly influenced the reduction of Hg(II)an...
Kinetically labile bromo complexes are formed with main-group metal ions of s2> and s0> electron configurations both in homogeneous aqueous solutions and in water droplets inside reverse micelles. The local concentration of the Br-> ligand in the inner water pool can reach extremely high values if it is the counterion of the surfactant as in the case of cetyltrimethylammonium bromide (CTAB)...
Luminescent properties of particles are strongly sensitive to the local field that is dependent on the particle size. The particle size distribution, thus, determines the photoluminescence spectrum profile of a powder suspended in an aqueous medium. The distribution of the radii of CdS particles was determined during their sedimentation in water. Photoluminescence spectra were measured at room temperature...
Various metal oxide semiconductor nanoparticles (TiO2, ZnO, SnO2) were stabilized in the interlamellar space of clay minerals with a layered structure. In the first step, metal oxide/hydroxide nanosol particles were prepared by acidic hydrolysis, and the incorporation of the nanoparticles was next carried out between the layer silicates by a heterocoagulation method. Metal oxide semiconductor/layer...
Photoelectrochemical solar cells comprising a colloidal TiO2 photoelectrode and sensitized with anthocyanin pigments, delphinidin purple and cyanidin 3,5-diglucose extracted from Hibiscus sabdariffa and Ribesnigra plants, respectively, have been fabricated. A sunlight-to-electricity conversion efficiency of 3.16% under simulated solar light was obtained with the cell sensitized with the delphinidin...
Actomyosin is a natural nanomachine which generates a force up to 5pN per skeletal myosin motor domain and moves at a speed of 10 μm s-1>. The working stroke per skeletal myosin motor domain per ATP hydrolysis was evaluated as at least 60 nm by Yanagida et al. (1985 Nature 316366–369) which lead to the loose coupling model of Oosawa and Hayashi (1986 Advances in Biophysics 22:151–183). A dynamic...
Photooxidation of oxalic acid over a TiO2 surface in the presence of Ag+> and Cu2+> ions was studied. Reduction of metal ions and oxidation of oxalic acid were followed under irradiation of aqueous suspensions of pH 2.5–3.5. It has been demonstrated that, after the completion of silver deposition, the small metal particles on the TiO2surface enhance the efficiency of the semiconductor by a factor...
Functional coatings from inorganic–organic hybrid materials were deposited on polyethylene films and technical polyester fabrics The differently modified inorganic–organic hybrids were based on 3-glycidyloxpropyltrimethoxysilane (GPTMS) and bisphenol A (BPA). The GPTMS–BPA hybrids were modified by UV-active components. The modification was performed by filling of the inorganic organic network with...
The structure and surface pressure of compressed monolayers consisting of silica nanoparticles at the water–air interface have been studied by means of molecular dynamics computer simulations. The simple “hexagonal array of monodisperse particles” model overestimates the range of the repulsive interparticle potentials between the nanoparticles in a monolayer. On the basis of the results of the simulation...
Scanning-angle reflectometry using p-polarized laser light is a sensitive in situ method to characterize the structure of very thin surface layers when the reflectance is scanned around the Brewster angle of the substrate. Monolayers of silica particles (of size 40 nm and of different hydrophobicity) on the water surface were investigated with this method. We used both a uniform-layer model to evaluate...
The scope of this work consisted of precipitating directly zinc oxide particles from zinc nitrate and zinc sulphate solutions using sodium hydroxide at pH 10,5, 2 h and 25 or 60 °C. For the zinc nitrate system, the effect of additives at 25 °C, such as sodium sulphate and sodium dodecyl sulphate, was also investigated. Precipitated powders were characterized in terms of their crystalline structure...
Clay-modified electrodes can provide an efficient method for studying the porosity of negatively charged, layered stuctures, i.e., swollen clay films. Diffusion transport processes of electroactive solute probes within hydrophilic and hydrophobized montmorillonite clay films have been studied. Cyclic voltammetry was performed in a three-electrode cell. Results regarding film permeability, the structure...
Activated carbon prepared from poly(ethylene terephthalate) was treated with nitric acid at ambient temperature and at the boiling point of the suspension. The morphology of the products was investigated by scanning electron microscopy, nitrogen adsorption observations and by small-angle X-ray scattering. The effect of acidic treatment on acid–base surface properties was studied by quasi-equilibrium...
Silver, palladium, and rhodium nanoparticles were prepared by heterogeneous nucleation in the interlamellar space of a layered kaolinite support. Disaggregation of the lamellae of nonswelling kaolinite was achieved by intercalation of dimethyl sulfoxide. The kaolinite was suspended in various metal precursor solutions and the adsorbed metal cations were reduced with NaBH4.The diameter of the silver...
Polyamide 6 hydrophobic clay composites were prepared from two organophilized montmorillonites and from a nontreated layered silicate. An ω-amino acid and an aliphatic amine were used for treatment to assure coupling and weak interaction of the components, respectively. Homogenization was carried out by melt-mixing, followed by injection molding to prepare specimens for composite testing. Matrix and...
The main aim of the present work was to study the effect of various Al- and Si-containing precursors on the gel structures prepared by sol–gel methods. The purpose of the investigations of the effect of aluminum nitrate, chloride, and isopropoxide was to form a homogeneous aluminosilicate gel structure with high Al incorporation and to get optically clear, bulk gel samples. The selection of aluminum...
Since drug release from dosage forms has importance for absorption from the gastrointestinal system, physicochemical characterisation of pharmaceutical systems is essential during the development of an optimal formulation with high efficacy and quality. Interfacial parameters of several pharmaceutical excipients were studied regarding their possible modifying effect on drug release from the dosage...
The soil as an adsorbent has various active sites leading to rather complicated adsorption mechanisms with environmental pollutants, like pesticides. According to earlier results the chloroacetanilide type herbicides as solutes resulted in two-step isotherms on soils and quartz. This phenomenon has not been observed yet concerning trace compounds in the environment. In this case the so-called distributed...
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