Coal remains an important component of the electricity system of Bosnia and Herzegovina, while the country is simultaneously undergoing a gradual energy transition toward lower-carbon technologies. This study evaluates the quality of coal from major mining areas in Tuzla Canton using laboratory results for composite samples from Kreka, Đurđevik and Banovići. The principal indicators were total moisture, ash, combustible matter and lower heating value (LHV). Eight mining areas were compared using five analytical samples per area, giving 40 observations for the primary statistical analysis. An additional 15 observations from five Banovići separation products were evaluated separately. Marked differences were identified among mining areas. Mean LHV ranged from 7,836 kJ/kg at PK Dubrave to 19,794 kJ/kg at Jama Omazići. Lignite from the Kreka area had substantially higher mean total moisture than the analysed brown coals, while several brown-coal areas were constrained by high ash content. Across the 40 primary observations, LHV showed a moderate negative correlation with total moisture (r = -0.43) and with ash (r = -0.37). A multiple linear model using moisture and ash explained approximately 98.4% of the observed LHV variation, although the small number of samples and the compositional nature of the variables require cautious interpretation. The findings demonstrate that coal reserves alone are insufficient for evaluating the future role of coal: fuel quality, preparation efficiency, plant efficiency, emissions intensity, economic performance and regulatory conditions must be considered together. The results support a transition strategy that combines improved coal characterisation and combustion efficiency in the medium term with accelerated deployment of renewable generation, storage, grid modernisation and just-transition measures.

Natural zeolites may exhibit certain limitations in the adsorption of metal ions from aqueous solutions due to their heterogeneous mineral composition, variable content of exchangeable extra-framework cations, and the presence of impurities. In this study, natural clinoptilolite zeolite was modified using an ethanolic extract derived from lemon peel waste to evaluate the effect of this sustainable modification approach on Cu(II) adsorption from synthetic aqueous solutions. Batch adsorption experiments were conducted using 50 mL of Cu(II) solution at 300 rpm for 60 min. A one-factor-at-a-time (OFAT) approach was applied to investigate the effects of initial solution pH (2–6), initial Cu(II) concentration (10–100 mg/L), and adsorbent dosage (500-2500 mg) for both unmodified natural zeolite (UN-zeolite) and fruit-waste-extract-modified zeolite (FWEM-zeolite). All experiments were performed in triplicate. At pH 6, complete Cu(II) removal (100%) was achieved using UN-zeolite, whereas FWEM-zeolite reached a removal efficiency of 84.37%. At initial Cu(II) concentrations of 10 and 50 mg/L, complete removal was achieved using UN-zeolite, whereas FWEM-zeolite achieved removal efficiencies of 87.97% and 80.91%, respectively. Increasing the UN-zeolite dosage resulted in complete Cu(II) removal at 2000-2500 mg, while FWEM-zeolite reached its maximum removal efficiency of 91.9% at a dosage of 1000. Overall, modification with lemon peel waste extract did not improve Cu(II) removal compared with the unmodified natural zeolite under the investigated conditions. Nevertheless, FWEM-zeolite maintained high Cu(II) removal efficiency, particularly at elevated initial concentrations, demonstrating the potential of fruit-waste-derived extracts as sustainable modifying agents for natural mineral adsorbents

Water pollution by heavy metal ions poses a significant environmental problem due to their toxicity, persistence, and potential for accumulation in living organisms. Nickel requires particular attention, as it can occur at elevated concentrations in galvanic industry wastewater. Therefore, the aim of this study was to investigate the efficiency of peanut shells as a natural and readily available biosorbent for the removal of Ni(II) ions from galvanic wastewater within the context of circular economy principles. As an agricultural residue, peanut shells represent a potentially economically and environmentally acceptable alternative to conventional adsorbents. The experimental study examined the influence of key process parameters on adsorption efficiency, primarily wastewater pH, initial Ni(II) concentration, and biosorbent mass. Based on the obtained results, optimal process conditions were determined and adsorption efficiency was evaluated. The adsorption equilibrium was analysed using the Freundlich and Langmuir isotherm models. The results demonstrated that peanut shells can serve as low-cost biosorbents for the efficient removal of Ni(II) ions from galvanic wastewater. For both samples, the highest removal efficiency was achieved at pH 6 and an initial Ni(II) concentration of 1000 mg L-1. The Freundlich adsorption isotherm model showed good agreement with the experimental data, with R2>0.9 for Sample 1 and R2>0.8 for Sample 2. The comparable adsorption performance of the two samples indicates that peanut-shell residue previously used can be further valorised as a biosorbent for Ni(II) removal. The multiple use of the same biomass residue contributes to waste reduction and improved resource utilisation, supporting the potential application of peanut shells within a circular economy approach.

Edible Natural Deep Eutectic Solvents (NADES) offer a route to ready-to-use extracts without solvent removal. This study examined how rational formulation design influences physicochemical properties, extraction performance, energy efficiency, thermal behavior, and cytocompatibility during bioactive recovery from Nigella sativa seeds. Twelve formulations spanning malic acid–polyol, citric acid–polyol, binary polyol, and ternary acid–polyol families were evaluated under standardized ultrasound-assisted conditions and compared with ethanolic ultrasound-assisted extraction, Soxhlet extraction, and cold-pressed oils. Selected NADES formulations outperformed the conventional systems. E1 (malic acid:glycerol:water) achieved the highest total phenolic content and lowest specific energy consumption (40.00 kJ mg−1 GAE), below the Soxhlet benchmark (55.17 kJ mg−1 GAE), whereas E9 (glycerol:xylitol:water) exhibited the greatest ABTS activity. Neat-NADES apparent pH and viscosity were inversely associated with total phenolic content, while viscosity and density were inversely associated with ABTS activity. ATR-FTIR showed stable, solvent-dominated fingerprints over 15 days, whereas DSC better differentiated neat NADES from their extracts. Most systems remained cytocompatible at 10,000× dilution, while acid–polyol formulations reduced viability at 500×; partial neutralization of N5/E5 restored viability. NADES performance was formulation- and application-dependent, requiring joint optimization of composition, acidity, viscosity, energy efficiency, and biologically compatible concentration.

The rapid growth of the global population has increased the consumption of chicken eggs, leading to the generation of significant quantities of eggshell waste. The sustainable valorization of this biowaste represents an important environmental and resource management challenge. In this study, CaO was synthesized from waste chicken eggshells via calcination at 800 °C and evaluated as a green precipitating agent for the removal of toxic Pb(II) from aqueous solutions. The effects of key precipitation parameters, including initial pH, stirring speed, contact time, and CaO dosage, were systematically investigated. The results showed that the removal efficiency increased with increasing pH, mixing intensity, contact time, and CaO dosage, reaching a maximum Pb(II) removal of 90% under investigated conditions of initial pH 9, stirring speed of 500 rpm, contact time of 15 min, and CaO dosage of 500 mg. In the presence of the competing ion Fe(III), the removal efficiency further increased to 99.99%, indicating a potential synergistic effect in the precipitation process. FT-IR analysis confirmed the successful formation of CaO and revealed significant spectral changes after Pb(II) precipitation, including shifts and disappearance of characteristic absorption bands, indicating the formation of insoluble hydroxide and carbonate phases. These findings demonstrate that eggshell-derived CaO is an effective and environmentally sustainable material for Pb(II) removal from aqueous media and represents a promising approach for the valorization of eggshell waste.

The expansion of industrialization and household use of synthetic compounds has generated significant wastewater containing toxic heavy metals. In developing countries, this wastewater is often discharged untreated due to the high cost of advanced treatment technologies. This study used sodium hydroxide as a low-cost, readily available precipitation agent to remove selected metal ions from mono- and binary-component solutions. Unlike most studies focusing on pH and initial ion concentration, this work investigated operational parameters such as stirring speed (0–800 rpm) and time (0–30 min) while keeping pH and concentration constant. Results showed that higher stirring speeds and longer stirring times enhanced metal ion removal, with Pb(II) efficiency increasing from 86.64% at 100 rpm to 94.33% at 800 rpm. In binary mixtures, similar improvements were observed. These findings highlight that simple, low-cost operational adjustments can significantly improve metal removal efficiency, which is particularly relevant for water treatment in resource-limited settings. The two-way ANOVA without replication showed that the type of metal or mixture had a significant effect on removal efficiency, while stirring speed and time within the investigated ranges did not have a statistically significant effect. These results indicate that differences in removal efficiency are primarily due to the metals’ chemical properties rather than the operational parameters.

Nigella sativa is a herb that has been used for centuries to treat various ailments, including infectious diseases. The aim of this work was to show in laboratory conditions the influence of different temperature regimes and methods of storage of Nigella Sativa oils on their physicochemical properties and microbiological stability. Analyzes have established that the temperature and method of storage have a significant influence on the change in the quality of the oil, especially when it comes to the total acidity of the oil and the peroxide value, where the values increased with the time of storage. The lowest obtained value for the peroxide number was at the first measurement, Pb = 9.99, which meets the prescribed standards for safe use, then the highest obtained value was 34.47 for the sample that was constantly exposed to the sun in a bright bottle. Also, the values of the iodine number increased with time, where the lowest value obtained was 14.56, and the highest was 102.48. Therefore, it is extremely important that the oil is stored in suitable packaging in dark glass bottles, and that it is protected from direct sunlight and high temperatures.

Physical chemical milk is an emulsion of milk fat in an aqueous solution of proteins, milk sugar and mineral salts. The high molar conductivity of goat milk samples compared to cow's milk indicates a high content of mineral substances. That goat milk is rich in total proteins is also indicated by the protein content in the samples, which are higher than the cow's milk samples. However, higher fat content was recorded in cow's milk samples, which also results in higher surface tension of cow's milk. The freezing point and refractive index of goat milk are higher compared to literature data and cow milk samples. The acidity of goat's milk comes from the acidic properties of casein, citrate, phosphate, etc. it is lower than cow's milk and is in accordance with literature data. The viscosity of pasteurized goat's milk at all temperatures is also higher than that of cow's milk.

In accordance with consumer requirements, the water must be adequately purified, and the corresponding parameters within the defined values. Various methods are used for this purpose, of which the ion exchange method can be highlighted as the simplest, most efficient and economically profitable. Ion exchange is a reversible process of ion exchange between a solid phase and an electrolyte solution. The ion exchanger is a macromolecular insoluble material that has chemically bound electrified groups and mobile, oppositely charged ions that compensate for this electrification. Ion exchangers are usually used in the form of compact or granular beds that fill the column through which the solution with the ions to be exchanged flows.They usually contain phenolic, carboxylic, sulfonic amino and other groups, which is why the treatment also results in decarbonization, softening, demineralization and denitrification of water. As the assessment of water quality is based on the most significant physico-chemical parameters, the aim of the work is the analysis of drinking water before and after treatment with an ion exchanger.For this purpose, organoleptic parameters such as smell, taste and color were first analyzed. After that, physico-chemical parameters were analyzed: pH values, electrical conductivity, m-alkalinity, p-alkalinity, water hardness, organic matter content, chloride content, iron and manganese content. An ion exchanger based on resin was used, which after use was regenerated by washing with NaClsolution.The analysis of the water sample, before and after the ion exchange treatment, showed that the treatment process was effective and that the decarbonization and softening of the water was carried out, whereby the water was categorized as soft water (water <9⁰dH).The analyzed water is tasteless, odorless and colorless before and after treatment. The results of the analysis showed that all the values of the analyzedphysico-chemical parametersare in accordance with the Rulebook on the Healthiness of Drinking Water(Official Gazetteof Federation of Bosnia and Herzegovina No.40/10) arebelow the maximum allowed values. KEYWORDS:water, ion exchange, physical-chemical parameters; water treatment

Waste water in the galvanic process contains high concentrations of heavy metals that pose a direct danger to humans and the environment. Conventional methods for their removal are quite expensive and generate a large amount of waste. The development of new and improvement of existing methods for the removal of heavy metals from galvanic wastewater are the subject of many studies. Compared to other purification methods, the adsorption is becoming an increasingly popular method of wastewater purification, especially if the adsorbent is cheap, easily available and does not require any other treatment before use. Therefore, the aim of the work was to investigate the possibility of using natural bentonite for the removal of heavy metal ions from multi-component water systems of the galvanic industry. For this purpose, the physico-chemical characterization of natural bentonite was performed, and then the influence of pH value, time and temperature on the adsorption efficiency was examined. The results of adsorption showed that natural bentonite can be used as an adsorbent for the removal of heavy metal ions from waste galvanic waters, and that at pH 5 it achieves the maximum removal efficiency for Cu(II):Cr(III):Ni(II) ions in the percentage ratio 100 : 99.990 : 99.998. The results showed that the highest removal efficiency for Cu (II) ions was achieved in the first 10 minutes, and 20 minutes for Cr (III) and Ni (II) ions. The maximum efficiency of Cu (II) removal was achieved at all temperatures, while for Cr (III) 99.99% and Ni (II) 100% maximum efficiency was achieved at 35°C, which indicates that the adsorption process is endothermic. The experimental results of the adsorption of Cu (II) metal ions are in good agreement with the Langmuir and Freundlich theoretical models, while for Cr (III) and Ni (II) ions they are in better agreement with the Langmuir adsorption model.