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.

In this research, the results of bentonite characterization by XRF and SEM/EDS before and after adsorption are presented. The influence of adsorbent mass and initial ion concentration on the capacity and efficiency of adsorption of lead (II) ions using bentonite is determined by adsorption experiments for initial lead (II) concentrations of 200, 300 and 400 mg/L, adsorbent dosage of 0,5, 1 and 2 g, at pH 5, temperature 25 °C, stirring rate of 200 rpm, contact time between adsorbent and lead (II) ions of 2,5minutes. The obtained results showed that with an increase in the adsorbent mass, the adsorption capacity decreases for all three tested initial concentrations, while the adsorption capacity increases with an increase in the initial concentration of Pb(II) ions for all three investigated masses of adsorbent. On the other hand, the adsorption efficiency increases with increasing adsorbent mass, while the adsorption efficiency decreases with increasing initial ion concentration.KEYWORDS:adsorption; lead; bentonite; mass; concentration

The paper deals with the assessment of risks related to drinkingwater quality, the analysis of physicochemical and microbiological parameters that are key to assessing human safety and health. Through a detailed analysis of these parameters, the paper investigates whether the appropriate physicochemical and microbiological parameters are within the framework defined by the regulation, and whether they may pose a threat to human health.Physicochemical parameters include aspects such as pH values, electrical conductivity, oxidizability, concentrations of various chemical compounds (such as nitrates, nitrites, ammonia, chlorides, heavy metals, etc.) and represent the degree of pollution bychemicals that may pose a threat to human health, while microbiological parameters relate to the presence of pathogenic bacteria, viruses and parasites that can cause various diseases in humans.The paper uses data from laboratory analyses of water samples monitored at 32 locations in the Tuzla Canton during two seasons. Through this assessment, the paper highlights the importance of regular monitoring of drinking water quality, as well as the implementation of adequate measures to prevent potential health hazards for users.KEYWORDS:public water fountains, physical-chemical analysis, microbiological analysis

Bentonite clay is a valuable material in various process industries, thanks to its specific properties. Easy availability, low cost and their effectiveness are the main factors that have made bentonite adsorbent in the edible oil industry. The textural characteristics of bentonite clay play an important role in its performance. In its natural form, as an aluminosilicate material, bentonite does not show satisfactory sorption and catalytic properties, and it needs to be activated. The main goal of this research is to increase the adsorption capacity of bentonite clay by modifying its properties by treatment with organic acid. Activation of bentonite clay in the experimental part was performed with different concentrations of sulfuric acid. The chemical composition of the natural bentonite sample was determined using XRF alongside the influence of acid activation of bentonite with H2SO4 on the surface characteristics (such as specific surface area, pore volume and average pore diameter, adsorption capacity and isotherm type) of bentonite clay. The XRF analysis of the natural bentonite, which contains 56.35% SiO2 and 19.82% Al2O3 as its primary components, confirms that it is an aluminosilicate material. Except for SiO2, which recorded a consistent increase in quantity from 56.35% to 74.15% with increasing acid concentration, the composition of other components, after activation slightly decreased or remained the same. The acid concentration that yielded the highest increase in specific surface area, as measured by the Brunauer–Emmett–Teller (BET) method, was selected as the optimal concentration for activating bentonite. The specific surface area almost tripled (from 95.519 m2/g to 346.467 m2/g)) by activation with 15% sulfuric acid, with an activation time of 3 hours and a bentonite: acid ratio of 1:5. The research results show the effectiveness of acid modification in terms of improving the characteristics of the porous structure of bentonite samples.

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.

Medicinal plants have become an increasing subject of interest worldwide due to the large amount of biologically active substances that have potential beneficial health properties. One of the more interesting popular medicinal plants is hawthorn (Crataegusspp.), a deciduous branched shrub that is increasingly used for health purposes. Various parts of this plant, including berries, flowers and leaves, are rich in nutrients and beneficial bioactive compounds that are effective in the treatment of numerous diseases. Honey is a natural sweetener produced by bees from plant secretions. Known for its nutritional and medicinal values, it gives strength to the body, which is why it is indispensable in the human diet. The combination of these two ingredients represents a significant source of vitamins and minerals in daily use, but also for use in various pharmaceutical and medical purpose. Taking into account all of the above, the aim of the work is to test samples of the mixture of honey and hawthorn in different proportions and determine the physical and chemical characteristics: pH value, electrical conductivity, refractive index, viscosity, water activity, HMF, DPPH. Based on the analysis, appropriate conclusions will be drawn and more information will be obtained about their quality and possible use as a food supplement. On the basis of the conducted analyses, it can be concluded that the parameter values are within the permitted limits defined by the Rulebook (Official Gazette Bosnia and Herzegovina No. 37/09). The analysis of the mentioned parameters showed that the chemical composition of the sample plays a major role in the value of the measurement results, and that Sample III has the best antioxidant properties. KEYWORDS:physicochemical characteristics; honey; hawthorn (Crataegus spp.);mixture; food suplement

Water hardness and deposition of incrustation is a problem in households and industry. In this regard, several technologies have been developed with the purpose of water softening and preventing the deposition of incrustation. The ion exchange method is the most commonly used method and is considered a conventional method. However, due to the shortcomings of this method, there is a need to develop adequate alternative methods. The potential of the method using biosorbents such as moss Leucobryum glaucum and Spaghnum peat moss for the purpose of removing water hardness has recently become the subject of intensive research with growing interest. In this study, the method using Leucobryum glaucum as a biosorbent was tested and a comparison was made with the conventional method and previously conducted studies that used other biosorbents.

In this article, the corrosion inhibition of steel DIN 2391 St 37-4 in acidic medium 5% H2SO4 with and without the presence of eco inhibitors of leaf (Petroselinum Sativum) was examined. Inhibitory properties of parsley leaves (Petroselinum Sativum) on steel DIN 2391 St 37-4 were examined by potentiodynamic polarization - Tafel extrapolation, and FTIR method in order to categorize the oxide layer. The test was performed in static medium and with stirring at 600 rpm. By Tafel extrapolation based on changes in corrosion potential, the inhibitor behaves as mixed. Increasing the concentration of inhibitors increases the efficiency of inhibition. Corrosion processes are inhibited by adsorption of organic matter on the surface of steel DIN 2391 St 37-4, forming a film. The obtained results indicate that parsley leaf (Petroselinum Sativum) is an effective eco inhibitor for the tested steel in 5% sulfuric acid.

In this research, the results of bentonite characterization (pH value of bentonite suspension, point of zero charge, cation exchange capacity,  SEM, XRF, DTG) are presented. The results of lead (II) removal efficiency at initial lead (II) concentrations of 200, 300 and 400 mg/L, and biosorbent dosage of 1 gram in 50 ml of lead(II) solution,  are also presented, as well as the values of the Freundlich and Langmuir constants from the Freundlich and Langmuir adsorption isotherms. The obtained results showed that removal efficiency is high for all three examined initial lead (II) concentrations, and it is above 99%. The lead (II) removal efficiency slightly decreases with an increase in initial lead concentration. Experimental data obtained from adsorption experiment with contact time of 2.5 minutes, stirring rate 100 rpm, temperature 250C and pH value 5 are better fitted with the linearized Langmuir equation isotherm, giving an R2 value closest to unity (0.9994), than to linearized Freundlich equation (0.9886).