From the aspect of their chemical and mineralogical composition, bauxites are very complex multicomponent raw materials. The paper presents the characterization of bauxite from several different deposits: Brazil, Milići, Čitluk and Kosovo. Chemical characteristics were determined by a combination of different analytical methods: gravimetry, potentiometric titration, atomic absorption spectroscopy (AAS) and UV-VIS spectrophotometry. Mineralogical composition was determined using X-ray diffraction and thermal analysis methods. Chemical and structural characterization is complemented by the results of scanning electron microscopy with EDX analysis. The information obtained was used for the assessment of the quality of investigated bauxites from the aspect of their application in the production of alumina.

This study examined the characteristics of granulated activated carbon (GAC) as an adsorbent for the removal of organic matter from the surface water of the Jala River. The adsorbent was characterized by XRD, FTIR, Raman spectroscopy, BET and SEM/EDS methods, while a detailed physicochemical characterization was performed for the water sample. The adsorption process was carried out under the following laboratory conditions: T(water) = 25 °C, individual doses of GAC off 1, 2 and 4 g/L, stirring speed of 200 rpm and time of 60 min. The research showed that GAC has good structural and textural morphological characteristics and that it can be successfully applied to remove organic matter from water (70.53%) using the lowest dose.

The binary adsorption isotherms of volatile organic compounds (VOCs), and water vapor from the air have been the fo-cus of much research in recent years. The content of adsorbed VOCs in the presence of water vapor can be determined by the volumetric or gravimetric method, in a static or dynamic mode. This study focuses on the adsorption technique in a static mode for isotherm measurement of the co-adsorption of VOCs and water vapor from the air using the gravimetric method. The content of VOCs is determined using a total organic carbon analyzer, while the amount of the adsorbed water was calculated from the difference between total adsorption (VOCs and water) and the adsorbed VOCs. This paper presents several adsorption isotherms with different VOCs (toluene, benzene, methanol, ethanol and isopropyl alcohol) and adsorbents (ZSM-5 zeolite, silica gel and Na-Form mordernite) in the presence of water vapor. The well-known adsorption isotherm models (Langmuir, extended Langmuir, Freundlich, extended Freundlich and Hill) were used to treat experimental results. The adjusted R-Squared (adj. R2) values obtained for those non-linear models for isotherms (total adsorpton (qe,tot) as a function of equilibrium concentration of VOC (Ce) and the adsorbed VOC (qe) as a func-tion of equilibrium concentration of VOC (Ce) are used to determine the best-fit isotherm model. The modeling results showed that the 3-parameter models could fit the data better than the 2-parameter model, with relatively higher adj. R2. Experimental results demonstrate that the presented adsorption technique can be used for isotherm measurement of the co-adsorption of VOCs and water vapor from the air.

Acetaldehyde is one of the most common carcinogenic organic compounds (pollutants) that can be found in the air in urban and industrial areas, as well as in indoor spaces. Generally, the most efficient method for removing pollutants from the air is adsorption with suitable adsorbents. To choose a suitable adsorbent, it is necessary to know its characteristics, the most significant of which is the adsorption capacity, i.e., the maximum amount of adsorbed substance per gram of adsorbent under given conditions. Nowadays, there is still a search for an adequate method that would provide an answer to how much and which organic substances are adsorbed on adsorbents. This paper presents the possibility of applying the FTIR analysis method for the identification and detection of adsorbed acetaldehyde on different types of zeolites. Adsorption of acetaldehyde from the gaseous phase was performed on ZSM zeolite (ZEOflair 100, ZEOflair 110), NaA zeolite (ZEOflair 1000), and the Na-form of mordenite (ZEOflair 800). Initial concentrations of acetaldehyde in the air ranged from 0.071 mol/m³ to 1.239 mol/m³, and the adsorption was carried out at atmospheric pressure, T=25 °C, and relative humidity (rH) 65%. On the FTIR spectra of the examined samples after adsorption, peaks were observed at a wavelength of 1700 cm⁻¹, which are characteristic of the carbonyl group of acetaldehyde. It was observed that the peak areas were proportional to the amounts of adsorbed acetaldehyde, which were very small and ranged from 0.107 mmol/g to 2.98 mmol/g of zeolite. Results indicate that FTIR is a rapid, non-destructive method suitable for qualitative and semi-quantitative analysis of low-level acetaldehyde adsorption, especially in the absence of co-adsorbed water.

Electrochemical deposition of silver coatings on different substrates—namely copper and two types of steel—was performed on an industrial scale, followed by their characterization.The coatings were evaluated in terms of hardness, surface roughness, and adhesion, while current efficiency and coating thickness were calculated from the mass changes of the samples during electrodeposition. In addition to assessing the influence of substrate type on coating quality, the effect of current density on coating adhesion and morphology was also investigated. Steel 1 (WNR 1.7231), copper, and Steel 2 (WNR 1.0032) were used as cathode materials for silver electrodeposition. Their chemical composition was determined by XRF analysis. The results showed that both current density and substrate type significantly affect the properties of the obtained coatings. All coatings were matte white and provided complete surface coverage on all substrates. The highest surface roughness and hardness values were obtained for coatings deposited at a current density of 0.75 A/dm2. The highest current efficiency was achieved at 0.5 A/dm², while the greatest coating thickness was obtained at 1.0 A/dm2.

This study presents a chemical and mineralogical analysis of stone samples from Jošanica quarry collected from three different locations—Field A, Field B, and Field C. Mineralogical analyses were conducted using XRD analysis. The analyses showed that calcite was the dominant mineral in most of the samples, while dolomite was significantly present in some of the samples. Chemical analysis revealed that calcium was dominant in samples 2 (Field B), 3a, and 3b (Field C), with only negligible amounts of magnesium. In contrast, samples 1a, 1b, and 1c (Field A) contained a significant amount of magnesium. Based on the MgCO₃ content, the amount of dolomite in the stone samples was calculated. The content of CaCO₃ in its bound form in dolomite was lower than that in the stone samples, indicating that CaCO₃ was present in another form. According to the dolomite content, samples 1a, 1b, and 1c (Field A) are classified as limestone–dolomite, while samples 2 (Field B), 3a, and 3b (Field C) are classified as limestone due to their high calcium carbonate content. The results of a mineralogical analysis confirmed the results of the chemical analysis.