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Octacalcium phosphate (OCP) is a material from the calcium phos-phate group with a crystal structure similar to hydroxyapatite. The removal process of lead and cadmium in aqueous solution using octacalcium phosphate material was investigated. OCP material was synthesized by the solution pre-cipitation method. The structural and phase properties of OCP before and after the removal process were determined by the X-ray diffraction (XRD) method. Microstructural and semi-quantitative analysis of the material was investigated by scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDS). Characteristic bands and functional group determination were revealed using the Fourier-transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). As target pollutants, Cd(II) and Pb(II) were chosen in adsorption experiments. Results show that OCP in the first 10 min has a very fast removal rate for Pb(II); the equilibrium state was reached after 10 min with more than 98 % adsorption efficiency. Results for Cd(II), results showed the same removal rate but somewhat lower adsorption efficiency, amounted to approximately 63 %.

The pottery produced from the Rujište deposit in Serbia has been protected under the guidance of UNESCO and the Sector for Intangible Cultural Heritage of Serbia since 2019. A study was conducted to evaluate the mineralogical characteristics of the raw clay from this deposit. This study used various techniques, such as X-ray diffraction (XRD), infrared (IR) spectroscopy, X-ray fluorescence (XRF), and differential thermal analysis (DTA) to characterize the clay. This study found that the clay contained mostly clay minerals (56.3%–41.9%), with illite, smectite, and chlorite as the predominant phases. Other phases identified were quartz, feldspars, carbonates, and iron-bearing minerals (43.8%–58.1%). The chemical analyses revealed a high abundance of silica (>52 wt.%) and alumina (~16 wt.%), with Fe2O3 (~6 wt.%), K2O (~2.8 wt.%), and a similar content of MgO as the main constituents. The physical features that were investigated included the granulometry (clay: ~31%–44%, silt: ~ 26%–23%, and sand: ~ 42%–32%), specific surface area (97 to 107 m2 g−1), cation exchange capacity (12.5–13.7 mmol 100 g−1), and color (yellowish to moderate brown). The preliminary results suggest that most of the raw clay from the Rujište deposit might be suitable for use in traditional pottery manufacture.

Atenolol (ATL) is a popular medication which is widely used to treat hypertension and angina. It is often found in aqueous environments, posing potential risk to human health and ecological well-being. In this study, carbon aerogel was prepared by supercritical CO2 drying of resorcinol–formaldehyde resin subsequently carbonized at 600 °C in an inert atmosphere. This porous material was characterized by SEM, BET, FTIR, and XRD and used for the first time for the removal of ATL from aqueous solutions under varying experimental conditions. Carbon aerogel in the form of microbeads exhibited a relatively high specific surface area of 376.02 m2/g and median pore radius of 9.83 nm. The isotherm models of Langmuir, Freundlich, Temkin, Redlich-Peterson and Brouers-Sotolongo were used to interpret the equilibrium data. Although most of the applied models fitted the data well, the calculated values for maximum sorption capacity (qmax) showed a huge deviation when compared to experimental value of 76.66 mg/g. The pseudo-first and pseudo-second-order kinetic models, Chrastil’s model, and the intraparticle diffusion model were employed for fitting the kinetic data. The rate of the process was rapid with most of the uptake attained in the first 20 min of the contacting. The sorption optimum was achieved at pH pH 9.0 and for sorbent’s dosage of 750 mg/L. Reusability study of the spent aerogel conducted in seven cycles evidenced slight decrease of approximately 1 % in removal efficiency across the cycles indicating that the sorbent maintained its high effectiveness and stability throughout its usage.

This study is focused on the detailed examination of the combustion properties and kinetic analysis of a cellulose acetate fibrous bundle (CAFB), separated from used cigarette filters. It was shown that the faster rate of CAFB heating allows a large amount of heat to be supplied to a combustion system in the initial stages, where the increase in heating rate has a positive response to ignition behavior. The best combustion stability of CAFB is achieved at the lowest heating rate. Through the use of different kinetic methods, it was shown that combustion takes place through two series of consecutive reaction steps and one independent single-step reaction. By optimizing the kinetic parameters within the proposed reaction models, it was found that the steps related to the generation of levoglucosenone (LGO) (by catalytic dehydration of levoglucosan (LG)) and acrolein (by breakdown of glycerol during CAFB burning—which was carried out through glycerol adsorption on a TiO2 surface in a the developed dehydration mechanism) represent rate-controlling steps, which are strongly controlled by applied heating rate. Isothermal predictions have shown that CAFB manifests very good long-term stability at 60 °C (which corresponds to storage in a sea shipping container), while at 200 °C, it shows a sudden loss in thermal stability, which is related to the physical properties of the sample.