This study explores the impact of nitrate ions on the efficiency of cementing noble metals from diluted waste solutions at a temperature of 30 °C. The research involved measuring the effectiveness of different cementing metals (such as Zn, Al, Mg, and Fe) in the presence of nitrate ions by assessing the change in metal ion concentrations before and after the cementation process using spectrometric analysis. Initial concentrations of noble metals ware Pt = 5 ppm, Au = 7.5 ppm, Pd = 5 ppm, and Rh = 1 ppm. Kinetic studies revealed that 24 h is adequate to achieve apparent equilibrium in solutions with pH 2 and 1 M nitrate ion content. The study identified significant recovery losses for gold and platinum in nitrate solutions, underlining the necessity of nitrate-free solutions in recycling. Zinc and magnesium were effective in cementing Pd and Rh, while aluminum was efficient for Pt reduction in each condition. Complete removal of Au was not achieved with any tested metal, indicating a need for alternative methods.

This study describes the development and characterization of materials based on activated carbon (AC). Pellets composed of dried biomass of willow, knotweed, and maple were formed and pyrolyzed to obtain different types of AC. Nickel (Ni) nanoparticles were synthesized on these materials using a bottom-up strategy by impregnating the carbons with a nickel nitrate solution. To characterize the surface and structure of these materials, SEM, MP-AES, and DSC-TGA techniques were employed. The ash content was analyzed to determine the input of mineral components in the carbons. The DSC-TGA results showed good thermal stability for each of the carbons, even at a temperature of 800 °C. BET analysis was also conducted, and the isotherms revealed well-developed surfaces for most of the specimens. The high efficiency of the impregnation process was confirmed by the MP-AES results: 165 mg of Ni was deposited on 1 g of carbon derived from maple leaves. The adsorbed Ni was well distributed across the carbon surfaces, as demonstrated in micrographs taken with the SEM-EDS apparatus. A comparison with similar materials reported in other studies was also performed.

The catalytic hydrogenation of carbon dioxide (CO₂) to methane (CH₄), commonly known as the Sabatier reaction, is a promising pathway for carbon capture and utilization (CCU). Nickel-based catalysts are cost-effective alternatives to noble metal systems, especially when supported on activated carbons derived from plant biomass. This review critically examines the basics of CO₂ methanation, the role of catalyst composition and support materials, and the growing interest in biomass-derived activated carbons. Special emphasis is placed on synthesis routes, physicochemical properties, catalytic performance, and sustainability aspects. A comparative assessment of catalysts derived from different biomass sources is included, pointing out the most important factors influencing activity, durability, and economic feasibility.

The Cahn-Hilliard method descries the driving force of the process of phase separation. Considering a binary (two-phase) alloy of conserved composition variable, the C-H model makes it possible to trace the process at which the domain creates pure subdomains of each component. Gururajan et al. have offered a simplified reference implementation of the aforementioned model, using the C language and FFTW libraries. It allows to perform a reverse Fourier transform to acquire a domain composition profile at a given time. Being a proof-of-concept, this approach does not stress on performance and the dedicated tools, like OpenPhase might not provide the flexibility necessary for new implementations. The following work aims on analyzing the C-H algorithm with regards of optimization, taking the Gururajan, among others, as a reference problem. Utilizing the models accompanied by replicable results facilitates the analysis of FFTW and GSL libraries, answering whether to search the replacement implementations and where (if necessary) work on code performance and parallelization. Finally, the improved model is intended to be used on external (non-random) initial composition, taken from ongoing simulations, in hope of preparation of the pearlitic steel model in the future.