Milan Z. Momčilović

This study examines the potential degradation of the anthraquinone textile dye Reactive Blue 19 (RB 19) and the azo dye Reactive Orange 16 (RO 16) through the application of thermally activated peroxydisulfate. The influence of basic operating parameters, such as the initial pH value of the solution, initial peroxydisulfate concentration, and temperature, was investigated. The degradation reaction followed pseudo-first-order kinetics for both dyes under investigated conditions. The degradation rate constants for these dyes increased with a rise in the concentration of peroxydisulfate up to a certain threshold, as well as with an increase in temperature, and in an acidic environment. The findings offer significant insights into the implementation of advanced oxidation processes utilizing thermally activated persulfate for the remediation of textile dye contaminated wastewater.

Textile dye contamination in aquatic environments represents a major ecological issue due to its persistence, harmful effects on aquatic organisms, and possible risks to human health. In this work, wood waste modified with bismuth was evaluated as a low-cost sorbent for the removal of textile dyes Reactive orange 16 from water. Sorption behaviour was examined through kinetic and equilibrium analyses in order to better understand the interaction between the dye molecules and the sorbent surface. The obtained results were best described by the pseudo-second-order kinetic model and the Langmuir isotherm model (r² ≥ 0.99), indicating predominantly monolayer sorption on homogeneous active sites. The prepared material exhibited a maximum sorption capacity of 415.22 mg/g, highlighting its potential application as an effective and sustainable sorbent for wastewater treatment.

?-wollastonite (?-CaSiO3) microfibres were successfully synthesized using a one-step, template-free hydrothermal reaction involving calcium nitrate and sodium metasilicate in an alkaline medium. The synthesis of microfibres was completed at 220 ?C within only 240 min under an autogenous pressure of 19 bar (1.9 MPa). This method avoids the formation of xonotlite as an intermediate phase, eliminating the need for subsequent calcination to achieve wollastonite. X-ray diffraction (XRD) confirmed the ?-wollastonite phase, while post-calcination analyses indicated enhanced crystallinity and structural characteristics. Scanning electron microscopy (SEM) revealed a needle-like morphology and N2 adsorption-desorption analysis demonstrated a developed surface area of 26 m2 g-1 with notable mesoporosity. These advantageous features facilitated the integration of ?-wollastonite into the synthesis of a glass?ceramic composite, which was characterized for its morphological, structural, textural, and in vitro bioactivity properties. The composite was prepared by mixing ?-wollastonite and bioactive glass powders in a 1:4 mass ratio, followed by compaction through uniaxial pressing and sintering at 1000?C for various time intervals. For comparison, compacted pure bioactive glass samples were also sintered under identical conditions. Structural, morphological, textural and in vitro bioactivity characterizations demonstrated that the incorporation of ?-wollastonite led to a more uniform and narrower pore size distribution and promoted neck formation between particles, indicating its potential for bone regeneration applications.

Chocolate is one of the most popular and widely consumed confectionery products. However, elevated cadmium (Cd) content in this commodity threatens food safety and human health. It is crucial to monitor the presence of Cd in chocolate and to evaluate its associated health risks. This study assessed the Cd levels in milk and dark chocolates from the Serbian market (n = 155). Cadmium concentrations varied between 0.010 and 0.29 mg/kg. The obtained values were used to evaluate the hazard quotient (HQ) and cancer risk (CR). The estimated weekly intakes (EWIs) were below the tolerable limits for all samples. However, in some samples, the EWI reached 60.9% and 63.5% of the tolerable limit for toddlers and other children, respectively. No health risk was found based on the HQ. On the other hand, based on CR values, all chocolate products can be classified as posing a moderate risk. The Monte Carlo simulation indicated that toddlers and other children were more exposed to non-carcinogenic risk, whereas vegetarians, adults, pregnant women, and other children were more exposed to cancer risk. Sensitivity analysis indicates that body weight, exposure frequency, and ingestion rate are the most influential factors for non-cancer and cancer health risks.

Carbon microspheres have been synthesized by the hydrothermal method with fructose and a phosphoric acid solution at two different concentrations, which were used as precursors. The obtained materials were characterized by elemental analysis, X-ray powder diffraction (XRPD) analysis, scanning electron microscopy (SEM), nitrogen adsorption/desorption measurements, and Fourier transform infrared (FTIR) spectroscopy. Batch sorption experiments were performed to remove methylene blue (MB) from aqueous solutions by varying the initial concentration of MB (C₀) from 50 to 500 mg/dm³, contact period, solution pH value, and temperature. Prepared sorbents consisted of microsphere particles with diameters in the range of 0.6–2.7 µm. The synthetic route was found to govern the microporous–mesoporous structure and surface acidic functional groups of the final product. A phosphoric acid concentration of 40 wt.% gave carbon material with a specific surface area of 932 m²/g and a total pore volume of 0.43 cm³/g. It was found that the extent of MB sorption by the obtained carbon microspheres increased with initial dye concentration, contact time, and especially solution pH but slightly decreased with increasing temperature. Kinetic studies showed that the dye sorption process followed pseudo-second-order kinetics.

A high consumption of solid fats is linked to increased inflammation and a risk of cardiovascular diseases. Hence, in recent years, there has been increasing interest in the development of oleogels as a fat substitute in food products. Oleogels are edible gels that contain a large amount of liquid oils entrapped in a 3D network and that can potentially be applied to spreads, bakery goods, meat, and dairy products in order to lower their saturated fat content while maintaining a desirable food texture and mouthfeel. In this work, alginate cryogels were studied as templates for three different edible oils in the process of oleogel formation. Two different freezing regimes to obtain cryogels were employed in order to evaluate better the textural and morphological capabilities of cryogels to adsorb and retain edible oils. It was shown that rapid freezing in liquid nitrogen produces alginate cryogels with a lower density, higher porosity, and a greater ability to adsorb the tested oils. The highest uptake and holding oil capacity was achieved for olive oil, which reached a value of 792% and 82%, respectively. The best chewiness was found for an oleogel containing olive oil, whereas oleogels with the other two tested oils showed better springiness. Hence, the results presented in this work demonstrated that alginate-based cryogels can be effectively used as templates for oleogels and potentially find applications in the food industry.

The human health risks of cadmium (Cd), lead (Pb), and nickel (Ni) in fifty regular and slim cigarette brands available in the Serbian market were evaluated. Distributions on per-cigarette basis concentrations of these metals, as determined by graphite furnace atomic absorption spectrometry, were used as inputs in the probabilistic risk assessment. The contents of these metals in cigarettes varied significantly. Larger quantities of the studied metals were observed in regular cigarettes than in slim cigarettes, but the concentration levels per cigarette tobacco mass were higher in slim cigarettes. The metal concentrations in counterfeit cigarettes were marginally higher than those in authentic brands. Based on the mean concentrations, Pb was the most abundant toxic metal, followed by Ni and Cd. The calculated values of the cumulative hazard index (HI) and incremental lifetime cancer risk (ILCR) indicated a low non-carcinogenic risk and low but not negligible carcinogenic risk from Cd, Pb, and Ni. The mean HI and ILCR values obtained using probabilistic and deterministic approaches were similar. A Monte Carlo simulation was employed to minimize the uncertainty of health risk estimation. The sensitivity analysis revealed that the most influential factor was cigarette mass followed by Cd content.