Carbon thin films deposited by the magnetron sputtering technique were evaluated by Raman spectroscopy to study the influence on their crystallinity caused by different parameters like the carbon deposition time, the different buffer-layers and substrates employed and also two distinct heat treatments. The present results showed that the choice of these parameters plays an important role in the production of these films. The results also indicate the possibility of using the technique for the production of carbon thin films to be employed in future in applications with controlled content of structural defects, predominance of ordered sp² bondings and tendency of graphitization.

The present investigation explores the potential of two synthesized zeolites, derived from coal fly ash (CFA; thermoelectric waste) and sugarcane bagasse ash (SCBA; agro-industrial waste), for the selective adsorption of cesium in wastewater. The synthesized zeolites (ZCFA and ZSCBA) were characterized and compared with a commercial zeolite to evaluate their physicochemical properties and effectiveness in removing cesium ions (Cs⁺) from simulated radioactive wastewater. The results obtained from X-ray diffraction, scanning electron microscopy, and elemental analysis confirmed the successful synthesis of high-purity zeolite from both solid wastes. The impurities present in the ashes impacted the Si/Al ratio and consequently influenced the exchange capacity. After adsorption experiments, neutron activation analysis (NAA) revealed that ZSCBA adsorbed 33.4% of Cs₂O by weight, outperforming both ZCFA (26.0%) and commercial zeolite (27.9%). The superior performance of ZSCBA is attributed to its distinct Si/Al ratio and lower levels of impurities, highlighting the impact of these factors on adsorption selectivity. The findings in this study demonstrate the feasibility of valorizing agro-industrial waste for synthesizing zeolites, offering a sustainable approach for managing these residues while producing valuable materials for environmental remediation.

Carbon thin films were produced by the magnetron sputtering technique. The deposition of the carbon films was performed on Co buffer-layers previously deposited on c-plane (0001) sapphire substrates. The samples were thermally treated under vacuum conditions and characterized by Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The XRD peak related to the carbon film was observed and the Raman spectroscopy indicated a good degree of crystallinity of the carbon film.

This study investigated the effect of biochar addition (14% w/w) on the concentration of nutrient ions present in the leachate from a commercial green roof substrate after contact with rainwater. Biochar sample was produced from wood sawdust at 450 ˚C via slow pyrolysis. The sawdust biochar was characterized by physico-chemical and hydraluic prosperties and techniques including X-ray fluorescence, Fourier transform infrared spectroscopy, X-ray diffraction, Raman and differential thermal analysis. The physical and chemical properties of green roof substrate were also determined. The biochar effectively reduced the total amount of nitrate, sulfate, and phosphate in the leachates relative to the substrate alone but did not show a significant effect on ammonium leaching. The results indicated that wood sawdust-biochar has appropriate characteristics to be applied as a component of substrates, as it has a porous structure and adsorption capacity, as well as adequate physical-hydric properties. In addition, the management of biochar obtained from agricultural waste can contribute to the achievement of the Sustainable Development Goals when used in sustainable alternatives such as green roofing.

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.