The intent in this paper is to define how the batch equilibrium results of copper removal from a synthetic solution on natural zeolite can be used for prediction of the breakthrough curves in the fixed-bed system for both a synthetic solution and wastewater. Natural zeolite from the Vranjska Banja deposit, Serbia, has been fully characterized (XRD, chemical composition, DTA/TG, SEM/EDS) as a clinoptilolite with cation exchange capacity of 146 meq/100 g. The maximum adsorption capacity (q_m) in the batch of the mono-component system (synthetic copper solution) obtained using the Langmuir isotherm model was 7.30 and 6.10 mg/g for particle size below 0.043 and 0.6–0.8 mm, respectively. Using the flow-through system with the 0.6–0.8 mm zeolite fixed-bed, almost double the adsorption capacity (11.2–12.2 mg/g) has been achieved in a saturation point for the copper removal from the synthetic solution, compared to the batch. Better results are attributed to the constant high concentration gradient in flow-through systems compared to the batch. The complex composition of wastewater and large amounts of earth alkaline metals disturb free adsorption sights on the zeolite surface. This results in a less effective adsorption in flow-through systems with adsorption capacity in breakthrough point of 5.84 mg/g (~0.95 × qm) and in a saturation point of 7.10 mg/g (~1.15 × qm).

Numerous factors influence the complexity of environmental and waste management problems, and the most significant goal is the reuse of materials that have completed their “life cycle” and the reduction in the use of new resources. In order to reduce impact of waste slag on the environment, in the present study, waste slag, generated in heating plants after lignite combustion, was characterized in detail and tested for application as a replacement for cement in mortar or concrete production. For physical–chemical characterization of slag, different experimental and instrumental techniques were used such as chemical composition and determination of the content of heavy metals, investigation of morphological and textural properties, thermal analysis, X-ray, and infrared spectroscopy. Physical–mechanical characterization of slag was also performed and included determination of activity index, water requirement, setting time and soundness. A leaching test was also performed. Presented results show that waste slag may be used in mortar and concrete production as a partial cement replacement, but after additional combustion at 650 °C and partial replacement of slag with silica fume in the minimal amount of 12%. The maximal obtained cement replacement was 20% (17.8% slag and 2.2% of silica fume).

Solving problems with hazardous waste materials is of crucial importance today. In the presented study, the application of waste vitreous enamel as a cement replacement up to 30% in mortar and concrete production was investigated. The chemical and physical-chemical characterization of the starting material was performed, as well as a leaching test and physical-mechanical characterization of mortar and concrete mixes. Obtained results showed that, due to its chemical composition, the vitreous enamel used must be classified as hazardous waste. At the same time, it possesses pozzolanic properties and satisfies minimal criteria for use as a cement replacement. Testing mortars and concrete mixes indicate that waste vitreous enamel can be applied as a construction material for cement replacement in the maximal amount of 20%. The leaching test was performed in accordance with international standard EN 12457-2 on hardened mortar with a maximal cement replacement of 20%. The results showed that there was no significant release of toxic elements, i.e., that the practical application of hazardous waste vitreous enamel in the construction industry may be fully in line with environmental standards.

In this paper the ability of three natural zeolites from different localities (Vranjska banja-VB, Igroš-I and Baia Mare-BM deposits) to remove copper has been investigated. These three zeolites were subjected to the elementary analysis as well as XRDP and DTA/TG analysis due to complete characterization. Cation exchange capacity of VB, I and BM zeolites were 150.1, 169.2, and 176.5 meq/100g. The maximum adsorption capacity for the copper adsorption on VB, I and BM-zeolites were 7.75, 8.51, and 11.18 mg/g. Based on the obtained results the mathematical expression that describes correlation between the CEC and copper adsorption capacity has been developed. This linear dependance has been tested with the vast variety of experimental results. According to this expression it is possible to predict the copper adsorption capacity for different zeolites based only on their CEC value.

This paper presents the results of experiments performed to determine how the quantity of the binder (bentonite) and the parameters of the laboratory roll press affect the quality of the briquettes obtained from limestone powder. These experiments aim to examine the conditions in which limestone briquettes are formed and to determine their use for agricultural purposes. During the experiments various mass fractions of bentonite was added to limestone (from 1 to 10 %), while the force of roll press drums ranged from 2 to 25 kN. The briquettes have been tested by applying scanning electron microscopy (SEM), differential thermal and thermo-gravimetric (DTA/TG) analyses, X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Bentonite distribution was found to be uniform within the compact briquette structure. Formation of new compounds was not evidenced. The experiments also demonstrated that during briquetting, limestone properties remain unchanged, the changes are only physical, water solubility is not reduced, mechanical properties (impact resistance, compressive strength and abrasion resistance) are satisfactory by the transport and storage terms if the binder mass fraction is over 5% and the briquetting force exceeds 10kN and finally there is no loss due to wind dispersal during application. The only downside of the ?green? briquettes obtained is the time required for their complete disintegration if totally immersed in water.

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins contaminating animal feed, and bentonite clays are widely used as adsorbents to reduce its bioavailability. This study introduces and characterizes a new, previously unexplored bentonite deposit from Bijelo Polje (Bar, Montenegro), with ~55% montmorillonite in the raw material. Size fractions (<0.200 mm, <0.037 mm, <0.005 mm) were obtained by sieving and centrifugation and characterized by laser diffraction, chemical composition, BET, CEC, and quantitative XRD (Rietveld). In vitro AFB1 adsorption (2–50 ppm, pH 3.0, 0.02% w/v adsorbent) simulated monogastric gastrointestinal conditions. Progressive size reduction increased smectite content (from ~55% to 91%), CEC (44–70 meq/100 g), purity, and BET specific surface area (26.5–50.8 m²/g), while reducing impurities and heavy metals to undetectable levels. The finest fraction (<0.005 mm) achieved the highest maximum adsorption capacity (q_max ≈ 240 mg/g), attributed to enhanced surface homogeneity and site accessibility, significantly outperforming coarser fractions and most unmodified natural bentonites. Only the 90% binding, low quartz/calcite). These results demonstrate that simple mechanical fractionation can yield exceptional performance in a novel natural raw material, offering a cost-effective, sustainable alternative to chemical modification for mycotoxin mitigation.