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Validation of analytical methods for measurements of microplastics (MP) is severely hampered because of a general lack of reference materials, RM. There is a great need to develop such reference materials. This study presents a concept of three-component kit with immobilised MP in solid NaCl, a surfactant and clean water that can be applied for the production of many types of MP RMs. As proof of concept, an RM for polyethylene terephthalate (PET) particles in water was prepared and evaluated for its homogeneity. The particles ranged from 30 μm (Feretmin) to about 200 μm adapted by wet sieving. A specific number of PET particles were immobilized in about 0.29 g of solid NaCl by freeze-drying 1 mL of a NaCl suspension. By using manual and automated counting, twenty reconstituted 1-L water samples were evaluated for homogeneity with respect to number of PET particles from 30 μm to > 200 μm/L of water. The number of particles was 730 ± 120 (mean ± one standard deviation (SD); n = 10) and 865 ± 155 particles (n = 10) obtained by optical microscopy in two independent laboratories. This corresponded to relative SDs of 16.4 and 17.9% and a mean of 797 ± 151 particles (18.9% RSD, for n = 20). Homogeneity studies of the NaCl carrier without reconstitution resulted in 794 ± 60 particles (7.5% RSD). The homogeneity of PET in the salt carrier was also evaluated directly with respect to mass of PET per vial using an ultra-micro balance. An average mass of 293 ± 41 μg of PET was obtained (14, % RSD for n = 14). Micrographs were recorded to demonstrate the absence of major sources of contamination of the RM components. Information about the particle size distribution and particle shapes was obtained by laser diffraction (LD) and dynamic image analysis (DIA). In addition, the identity of the PET polymer was confirmed by Raman and FT-IR spectroscopy. The RM was developed for a large-scale inter-laboratory comparison of PET particles in water (ILC). Based on the homogeneity results, the material was found to be sufficiently homogeneous to be of meaningful use in the ILC. In a 3-day process, more than 500 samples of PET particles in the NaCl carrier were prepared with good potential for further upscaling with respect to the number of vials or with other kinds of polymers. The stability of PET was not evaluated but it was deemed to be stable for the duration of the ILC.

As swipe samples from enrichment activities typically contain uranium particles with a detectable amount of fluorine, the question was raised whether the analysis of fluorine in particles could complement the information on the uranium isotope ratios. For this, uranium oxyfluoride particles were prepared from the controlled hydrolysis of uranium hexafluoride (UF 6 ). The relative amount of fluorine was characterized by scanning electron microscopy combined with energy-dispersive X-ray spectrometry (SEM-EDX), as well as ion-microprobe secondary ion mass spectrometry (IM-SIMS). Of particular interest was the assessment of the reduction of the amount of fluorine over time, and after exposure to UV-light and high temperatures. Micro-Raman spectrometry (MRS) was applied to look for differences in molecular structure between these various sample types. Both SEM-EDX and IM-SIMS showed a general reduction of the fluorine-to-uranium ratio after 1–2 years of storage. The exposure to UV-light and high temperatures was found to have accelerated the loss of fluorine. A distinct peak at 865 cm − 1 Raman shift was detected for the majority of particles analyzed by MRS. For the particles that were heat-treated, the Raman spectra were similar to the spectrum of U 3 O 8 . Although often large variations were observed between particles from the same sample, the three particle measurement techniques (IM-SIMS, SEM-EDX and MRS) showed some consistent trends. They therefore appear promising in terms of the ability to place bounds on particle age, as well as shedding light on the complex processes involved in UO 2 F 2 particle ageing.

Sn4+-containing LDH was prepared using the co-precipitation method at constant pH, and characterized using X-ray diffraction, UV–vis diffuse reflectance spectroscopy and TG/DTG methods. The obtained product was further exposed to different thermal treatments in order to obtain nano-sized coupled ZnO/SnO2 systems with enhanced photocatalytic performances than the ones obtained by mixing the two semiconductor oxides. The formation of a well-defined ZnO/SnO2 system and the crystallite size, fully investigated using XRD, micro-Raman scattering and UV–vis DR techniques, were found to be influenced by the nature of the precursors and the calcination temperature. The photocatalytic activity of the ZnO/SnO2 systems, evaluated for the photodegradation of methyl orange (MO) dye, was studied as a function of the initial pH, catalyst loading and the calcination temperature. The metal dispersion supplied by layered structures proved to be an advantage when preparing coupled ZnO/SnO2 systems, the photocatalytic activity being ∼2.3 times higher comparing with the physical mixtures performances. The maximum photocatalytic activity of the coupled ZnO/SnO2 system having a layered precursor was observed when using neutral pH, at a catalyst loading of 1 g/L calcined at 600 °C for 4 h.

In this paper the porosity and adsorption properties of dolomitic sorbents, prepared via thermal decomposition of dolomite, are presented. Thermal decomposition of carbonates, as a result of heating, is governed by a number of factors, e.g. temperature, heating time, atmosphere over a heated sample and sample weight and each of these has its role in the creation of new solid phase. It has been experimentally stated that the heating of dolomite at 800 °C leads to the partial decomposition (magnesium carbonate dissociation) and the creation of a new solid—a mixture of calcite and magnesium oxide. The increase of heating time and a sample weight result in the decrease of new sorbents porosity. Of the sorbents prepared in various atmospheres, the most developed porous structure is achieved by the sample heated in the inert one. Adsorption properties of new sorbents have been estimated by means of gas chromatography (GC) method. Some information about the energetic heterogeneity of the examined sorbents may be obtained from the adsorption energy distribution function χ(e).

Adsorption properties with respect to certain toxic substances as well as porosity investigations of raw and thermally modified dolomite are presented. After the partial decomposition of dolomite at 800°C a new so-called ‘dolomitic’ adsorbent of the calcium carbonate skeleton and pumice structure was obtained. Its physicochemical properties are significantly different from those of the raw material, e.g. the specific surface area increases 37 times and the adsorption capacity for SO2 increases approximately 15 times, which makes the new adsorbent useful in the protection of the environment.

In this paper the results of the qualitative analysis of the basic elements and impurities of the domestic feldspar are presented. From n-octane and toluene adsorption measurements the components of the free surface energy were calculated and from the porosity investigations the pore size distribution curves were obtained. The adsorption and mercury porosimetry data showed the energetical and structural heterogeneity of the examined material. Having in consideration the industrial application of this mineral, preliminary tests of the chemical purification from iron additives by some acids were carried out. It appeared that the best results were achieved after etching it with aqua regia (nitrochloric acid).

Samples of dolomite were heated up to the temperature at which the decomposition of MgCO 3 took place, and then some surface properties were investigated. Adsorption isotherms of n-octane and toluene were determined as well as the pore size distribution and the specific surface area. The decomposition of MgCO 3 resulted in an increase of the specific surface area and in certain changes of dolomite porosity. From the adsorption measurements the film pressure for both adsorbates was determined, and then the dispersion and the polar components of the surface free energy of dolomite were calculated and discussed. Based on the derivative of the film pressure with respect to the amount adsorbed the surface heterogeneity was estimated. It appears that two kinds of active sites for n-octane adsorption, and one kind for toluene adsorption, may be expected on the surface of dolomite.

Samples of the secondary uranium minerals collected in the abandoned uranium mine at Pecs (Hungary) were investigated by two micro-techniques: scanning electron microscopy (SEM/EDX) and micro-Raman spectroscopy (MRS). They were applied to locate U-rich particles and identify the chemical form and oxidation state of the uranium compounds. The most abundant mineral was a K and/or Na uranyl sulphate (zippeite group). U(VI) was also present in the form showing intensive Raman scattering at 860 cm−1 which can be attributed to uranium trioxide. This research has shown the successful application of micro-Raman spectroscopy for the identification of uranyl mineral species on the level of individual particles.

The St. Michael Archangel's Church in Szalowa, Poland, was selected for closer investigation with respect to the indoor/outdoor air exchange and its influence on the air quality and work arts preservation. Chemical composition, size and abundance of particulate matter and concentration of gases NO2, SO2, O-3 inside and outside the church were determined. To study seasonal variation of the weather condition (temperature, inversion level, wind direction) and the influence of seasonal sources of the air pollution (like heating of the nearby houses), samples were collected in winter and summer time. It was stated that suspended particulate matter inside the wooden church has in general an outdoor source. Several groups of particles were distinguished such as the organic ones, soil dust, nitrates and sulphates. In case of organic and soil dust particles, the concentration inside was higher than outside. From the results, in comparison to literature data, one can conclude that accumulation of particulate suspended matter in the church is more intense than in other types of buildings. Gaseous pollutants were detected but their concentration was negligible.

The physicochemical properties of ' dolomitic' sorbents formed through the partial decomposition of dolomite have been discussed in two papers published previously dealing with the influence of temperature and the time of heating. When carried out at 800o C, the newly formed solid consisted of sponge- like calcite and finely powdered magnesium oxide which was resistant mechanically and exhibited considerably greater porosity than the raw material. Long-term heating led to a decrease in the porosity and to the partial elimination of pores. The corresponding ' dolomitic' sorbents prepared in an inert atmosphere showed even greater porosity and a different internal structure when compared to those formed in the presence of carbon dioxide. However, no changes were observed as far as the chemical composition was concerned.

The adsorption properties of Polish feldspar towards hydrocarbons from the gaseous phase have been studied and the adsorption energy distribution functions for n-octane, benzene and toluene are presented. It appears that there are three types of adsorption sites present on the feldspar surface examined. Treatment of feldspar with aqua regia led to the elimination of low-energy interaction centres. The adsorption properties of the raw and leached feldspar with respect to Cr VI ions have also been studied. The kinetic curves for the sorption of Cr VI ions exhibited two stages which suggest two different mechanisms of sorption. The adsorption capacity depended on the pH with a maximum for pH = 4.8. The excess adsorption isotherm of Cr VI on the raw feldspar surface showed a maximum value at 20 mmol/dm3 equilibrium concentration of Cr VI ions.

The partial decomposition of dolomite performed within the temperature range 800-1000°C provides new sorbents, the so-called 'dolomitic' sorbents, composed of calcite and magnesium oxide. Their surface properties, such as their porosity and adsorption capabilities towards hydrocarbons, are discussed. The 'dolomitic' sorbents show a much higher specific surface area and pore volume when compared to the raw dolomite; moreover, their porous structure depends on the temperature of heating. The adsorption of selected hydrocarbons on the examined sorbents was also investigated and the adsorption energy distribution functions calculated from the adsorption data.