The immobilization processes for nuclear waste have gained significant attention from the scientific community due to the growing global activity in the nuclear industry. Although these processes have been studied and applied since the mid-20th century, many questions remain that require further in-depth research, including the immobilization itself and the deposition of wasteforms in repositories designed to safeguard against future exposure. In this study, highly phase-pure zeolite A was synthesized via hydrothermal processing of coal fly ash from a Brazilian thermal power plant and loaded with Cs to evaluate thermal stability, structure, and immobilization in Nb-aluminoborosilicate and geopolymer matrices. Cs adsorption, confirmed by XRD peak intensity and Raman band changes, showed a 26 wt.% incorporation (INAA) after 24-hour sorption using simulated CsCl solution, a notable result given the fly ash impurities. The zeolite structure remained stable during the heating up to 960 °C, forming water-insoluble phases (pollucite and cesium aluminum oxide) right after structural collapse between 700 °C and 900 °C. Up to 40 wt.% of Cs-loaded waste was incorporated into a monolithic ceramic via thermal treatment of Nb-aluminoborosilicate glass and zeolite A at 900 °C for 2 hours, yielding a dense body (2.4 g/cm³) with low porosity (3.6%) and water absorption (1.63%). In contrast, raw Cs-loaded zeolite A showed high porosity (48%), water absorption (33%), and low density (1.44 g/cm³). Crystalline Cs phases formed at lower temperatures (900 °C) due to the devitrification nature of the glass. Geopolymer matrices immobilizing Cs-loaded zeolite exhibited water leachability comparable to similar materials, meeting nuclear waste disposal requirements.

Glucose is a monosaccharide-type carbohydrate that serves as a fundamental building block of biomass. In this research, glucose was hydrolyzed using a Deep Eutectic Solvent (DES) as the solvent and AlCl₃  as the catalyst. The effects of temperature and catalyst concentration were investigated as key variables in the reaction. The glucose conversion results were tested using the UV-Vis spectrophotometer. The yields of glucose conversion were analyzed using the Response Surface Methodology (RSM) with Design Expert Version 13 software. The results of RSM analysis show that glucose conversion increases linearly with rising reaction temperature. The effect of catalyst concentration indicates that glucose conversion decreases at higher catalyst levels. The reaction temperature and AlCl₃ catalyst concentration that can be recommended for optimum conditions from the Design Expert data processing results are 112.869 C and 1.913% with a predicted conversion value of 93.844%.

Silver nanoparticles (AgNPs) exhibit outstanding antimicrobial properties, making them highly valuable in biomedical applications. This study presents the synthesis of a graphene oxide-silver nanoparticle (GO-Ag) nanocomposite via a redox chemical reaction, where the hydroxyl groups reduced silver ions present in graphene oxide (GO). Graphene oxide was obtained through electrochemical exfoliation of graphite, followed by ultrasonic exfoliation in the presence of silver ions to form GO-Ag. The materials were characterized using ultraviolet-visible (UV-Vis) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). UV-Vis, FTIR, and Raman spectra confirmed GO synthesis. In contrast, XRD and UV-Vis spectra verified the presence of silver nanoparticles in GO-Ag by detecting the surface plasmon resonance (SPR) band and silver’s characteristic diffraction peaks. SEM analysis showed the successful formation of silver nanoparticles on GO sheets. The disc diffusion method assessed Antimicrobial activity against Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). GO-Ag nanocomposite displayed significant antibacterial activity, as evidenced by the formation of inhibition zones, whereas GO alone showed no antimicrobial effect. The enhanced antibacterial properties of GO-Ag are attributed to the synergistic interaction between GO and AgNPs. The increased surface area of silver nanoparticles further enhances their antibacterial effectiveness by facilitating better interaction with bacterial membranes. These findings highlight GO-Ag’s potential for use in antimicrobial coatings, wound dressings, and biomedical devices. This study demonstrates an effective, environmentally friendly approach to synthesizing antimicrobial nanocomposites, paving the way for their application in various medical and industrial fields.

Two MnO_x, namely ?-MnO₂@Mn₂O₃ and ?-MnO₂ catalyst, were successfully synthesized using two different organic acids, tartaric and maleic acid, as a reduction in the redox process of KMnO₄. The obtained catalysts are used in the AOP degradation reaction for paper mill effluent. The organic content in the effluent is analogous to the COD number in the effluent. The degradation process is depicted as a decrease in the COD number. The catalyst properties were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and N₂ sorption. The obtained materials were then studied for PMS activation using Oxone® as a sulfate radical source for COD removal reactions. The ?-MnO₂@Mn₂O_3, which is compromised by Mn (IV) and Mn (II, III), by using 0.3 gL^-1 ?-MnO₂@Mn₂O₃ has the best efficiency with almost 75% COD removal, higher than the ?-MnO₂ catalyst. The activation energy of the ?-MnO₂@Mn₂O₃ is measured up to 11.4 kJ mol^-1.