Search Results (10)

This study investigates the synthesis, characterization, and potential applications of silver–copper (AgCu) alloy powders produced from co-precipitated carbonates. The Cu/Ag carbonate samples were analyzed using EDXRF, TGA-DSC, XRD, SEM, and electrical conductivity tests to examine their composition, thermal behavior, structure, and morphology. The results showed slight deviations from the theoretical Cu/Ag ratios in the carbonates, attributed to equilibrium effects during precipitation. Thermal analysis indicated that the reduction process of carbonates with hydrogen was completed at 300 °C, while alloy formation was confirmed by endothermic peaks around 780 °C. XRD and SEM analyses revealed that AgCu alloys formed a solid solution, with smaller crystallite sizes observed at higher Cu contents. Electrical conductivity tests demonstrated that while pure Ag and Cu powders exhibited conductivity increases with compaction, the AgCu alloy showed stable conductivity without a significant decrease. In Pd(II) cementation experiments, AgCu alloys demonstrated higher efficiency in Pd(II) recovery than pure Ag and Cu. These findings suggest that AgCu alloys, particularly with a balanced composition, may offer improved performance for metal recovery applications, providing a promising approach for industrial cementation processes. Full article

This study focuses on the development of new amino-functionalized magnetic Fe₂O₃/SiO₂ nanocomposites with varying silicate shell ratios (1:0.5, 1:1, and 1:2) for the efficient elimination of Hg²⁺ ions found in solutions. The Fe₂O₃/SiO₂–NH₂ adsorbents were characterized for their structural, surface, and magnetic properties using various techniques, including Fourier transform infrared spectrum (FT-IR), powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Braunauer–Emmett–Teller (BET), thermogravimetric analysis (TGA), zeta-potential, and particle size measurement. We investigated the adsorption circumstances, such as pH, dosage of the adsorbent, and duration of adsorption. The pH value that yielded the best results was determined to be 5.0. The Fe₂O₃/SiO₂–NH₂ adsorbent with a silicate ratio of (1:2) exhibited the largest amount of adsorption capacity of 152.03 mg g⁻¹. This can be attributed to its significantly large specific surface area of 100.1 m² g⁻¹, which surpasses that of other adsorbents. The adsorbent with amino functionalization demonstrated a strong affinity for Hg²⁺ ions due to the chemical interactions between the metal ions and the amino groups on the surface. The analysis of adsorption kinetics demonstrated that the adsorption outcomes adhere to the pseudo-second-order kinetic model. The study of adsorption isotherms revealed that the adsorption followed the Langmuir model, indicating that the adsorption of Hg²⁺ ions with the adsorbent occurred as a monomolecular layer adsorption process. Furthermore, the thermodynamic analyses revealed that the adsorption of Hg²⁺ ions using the adsorbent was characterized by a spontaneous and endothermic process. Additionally, the adsorbent has the ability to selectively extract mercury ions from a complex mixture of ions. The Fe₂O₃/SiO₂–NH₂ nanocomposite, which is loaded with metal, can be easily recovered from a water solution due to its magnetic properties. Moreover, it can be regenerated effortlessly through acid treatment. This study highlights the potential use of amino-functionalized Fe₂O₃/SiO₂ magnetic nanoparticles as a highly efficient, reusable adsorbent for the removal of mercury ions from contaminated wastewater. Full article

The presented research is the seed of a vision for the development of a waste-for-product strategy. Following this concept, various synthetic solutions containing low concentrations of platinum group metals were used to model their recovery and to produce catalysts. This is also the first report that shows the method for synthesis of a pyramid-like structure deposited on activated carbon composed of Pd and Pt. This unique structure was obtained from a mixture of highly diluted aqueous solutions containing both metals and chloride ions. The presence of functional groups on the carbon surface and experimental conditions allowed for: the adsorption of metal complexes, their reduction to metal atoms and enabled further hierarchical growth of the metal layer on the carbon surface. During experiments, spherical palladium and platinum nanoparticles were obtained. The addition of chloride ions to the solution promoted the hierarchical growth and formation of palladium nanopyramids, which were enriched with platinum nanoparticles. The obtained materials were characterized using UV–Vis, Raman, IR spectroscopy, TGA, SEM/EDS, and XRD techniques. Moreover, Pd@ROY, Pt@ROY, and Pd-Pt@ROY were tested as possible electrocatalysts for hydrogen evolution reactions. Full article

Spent lead–acid batteries have become the primary raw material for global lead production. In the current lead refining process, the tin oxidizes to slag, making its recovery problematic and expensive. This paper aims to present an innovative method for the fire refining of lead, which enables the retention of tin contained in lead from recycled lead–acid batteries. The proposed method uses aluminium scrap to remove impurities from the lead, virtually leaving all of the tin in it. The results of the conducted experiments indicate the high efficiency of the proposed method, which obtained a pure Pb-Sn alloy. This alloy is an ideal base material for the production of battery grids. This research was carried out on an industrial scale, which confirms the possibility of facile implementation of the method in almost every lead–acid battery recycling plant in the world. Full article

This paper describes a single-stage synthesis process for activated carbon using cherry seeds. The influences of the carbonization temperature and the time were investigated. Using the BET method, the surface area of the obtained activated carbons was determined, as well as the pore distribution, while SEM images provided further insight into the structure of the surface. Next, the adsorption isotherm was derived. For the test, Pd(II) chloride complex ions were used. It was found that the obtained activated carbon were suitable for palladium(II) recovery from diluted aqueous solutions. Out of the tested parameters of carbon synthesis, the most optimal one was found to be 500 °C for 3 h. Additionally, it was confirmed that the increase in the adsorption temperature affects the increase in palladium load from 1.6 mg/g at 20 °C to 15.6 mg/g at 50 °C (for the best-performing sample). This fact may suggest that the process of adsorption is associated with chemical reactions. Full article

The paper presents tests of lead oxidation in a Barton reactor with a capacity of 1200 kg PbO/h, divided into two series. The first series was carried out in conditions of high humidity of the air supplied to the reactor (59–61%), and the second series in conditions of low humidity (19–21%). The study used lead of various purity levels, the main impurities of which were bismuth and silver. The obtained results show that the use of air with a humidity of about 60% in the process allows us to obtain high-quality PbO and has a positive effect on processing parameters such as the amount of lead processed and the efficiency of the process. The mentioned processing parameters significantly influence the production cost of lead oxide. The effect of lead impurities on the process of lead oxidation and the quality of the obtained product was noticed. This dependence is especially visible in the case of the process efficiency, the amount of lead processed per time unit and the amount of formed scrap. The increase in the content of impurities adversely affects each of the parameters mentioned. Optimal parameters of lead oxide regarding the expected acid absorption at the level above 16 g H₂SO₄/100 g PbO and the degree of oxidation at the level of 75% were obtained for the air humidity of about 60% with the content of pollutants below 100 ppm. The paper presents data on the process parameters and the relationships between them, unpublished in the literature. Full article

A highly effective method of the processing of steelmaking dust in an arc-resistant furnace has been presented. The aim of the research was to investigate the possibility of processing steelmaking dust in terms of waste minimization and selective recovery of valuable components. For this purpose, an electric arc resistance furnace was used. Granulated steelmaking dust with reducer (coal dust) was the input material. The products of the process are zinc oxide, iron alloy and slag, with properties meeting high ecological requirements. The technology does not generate solid waste. Zinc recovery is over 99% and iron recovery over 98%. The content of heavy metals (Zn + Pb + Cu) in glassy slag is below 0.2%, which ensures very low leachability. Full article

The problem of urban logistics operations in the context of their impact on the environment has become the key challenge. Due to that, there has been a growing interest in increasing the use of alternative fuels, including electro-mobility. However, an important barrier to the utilisation of electric freight vehicles (EFVs) is their travel range and battery capacity. The paper is focused on the idea of EFV utilisation improvement by implementation of charging stations in unloading bays. First, the Authors analysed the efficiency of chosen vehicles during daily work. Next, the potential improvement of their travel range was analysed, considering the short-time charging processes carried out during delivery operations, using the charging systems provided in unloading bays. Moreover, the concept of wireless chargers utilisation was proposed as a challenge for future work. According to the analysis, utilisation of unloading bays equipped with short-time battery chargers could improve significantly the travel range of EFVs. As a result, it could improve the efficiency of electric vehicles in last mile deliveries in city areas. Full article

CuO-ZnO-Al₂O₃ catalysts are designed for low-temperature conversion in the process of hydrogen and ammonia synthesis gas production. This paper presents the results of research into the recovery of copper and zinc from spent catalysts using pyrometallurgical and hydrometallurgical methods. Under reducing conditions, at high temperature, having appropriately selected the composition of the slag, more than 66% of the copper can be extracted in metallic form, and about 70% of zinc in the form of ZnO from this material. Hydrometallurgical processing of the catalysts was carried out using two leaching solutions: alkaline and acidic. Almost 62% of the zinc contained in the catalysts was leached to the alkaline solution, and about 98% of the copper was leached to the acidic solution. After the hydrometallurgical treatment of the catalysts, an insoluble residue was also obtained in the form of pure ZnAl₂O₄. This compound can be reused to produce catalysts, or it can be processed under reducing conditions at high temperature to recover zinc. The recovery of zinc and copper from such a material is consistent with the policy of sustainable development, and helps to reduce the environmental load of stored wastes. Full article

Atmospheric emissions of anthropogenic origin are one of the most important problems in cities. A particularly discrete ecological footprint in urban environment is made by urban freight transport. This problem has become the key challenge for all stakeholder groups involved in freight transport in urban areas. Over the recent years, there has been a growing interest in using alternative fuel vehicles in urban logistics, including those equipped with electric drive systems. This paper presents a multi-criteria analysis (MCA) of selected electric vehicles (EVs) in the context of their application for the purposes of deliveries in cities. In methodological terms, we present a unique MCA-based approach for evaluation of Electric Freight Vehicles (EFVs). A successful attempt is made to build a multistep MCA procedure based on two carefully selected MCDA methods (PROMETHEE II and fuzzy TOPSIS) to handle both certain and uncertain data sets in a single decision process. In practical terms, we successfully demonstrate the usefulness of the proposed approach by creating a set of decision maker’s preference models (based on certain and uncertain data) of carefully selected EFVs and provide sensitivity and robustness analyses of the obtained solutions. Full article