Novel Fe3O4 Nanoparticles with Bioactive Glass-Naproxen Coating: Synthesis, Characterization, and In Vitro Evaluation of Bioactivity

Immune response to biomaterials, which is intimately related to their surface properties, can produce chronic inflammation and fibrosis, leading to implant failure. This study investigated the development of magnetic nanoparticles coated with silica and incorporating the anti-inflammatory drug naproxen, aimed at multifunctional biomedical applications. The synthesized nanoparticles were characterized using various techniques that confirmed the presence of magnetite and the formation of a silica-rich bioactive glass (BG) layer. In vitro studies demonstrated that the nanoparticles exhibited bioactive properties, forming an apatite surface layer when immersed in simulated body fluid, and biocompatibility with bone cells, with good viability and alkaline phosphatase activity. Naproxen, either free or encapsulated, reduced nitric oxide production, an inflammatory marker, while the BG coating alone did not show anti-inflammatory effects in this study. Overall, the magnetic nanoparticles coated with BG and naproxen showed promise for biomedical applications, especially anti-inflammatory activity in macrophages and in the bone field, due to their biocompatibility, bioactivity, and osteogenic potential.

Repurposing Kraft black Liquor as Reductant for Enhanced Lithium-Ion Battery Leaching

The economic advantages of H2 SO4 make it the acid of choice for the hydrometallurgical treatment of waste lithium-ion batteries (LIBs). However, to facilitate the full dissolution of the higher valency metal oxides present in the cathode black mass, a suitable reducing agent is required. Herein, the application of industrial black liquor (BL) obtained from the Kraft pulping for papermaking is investigated as a renewable reducing agent for the enhanced leaching of transition metals from LIB powder with H2 SO4 . The addition of acidified BL to H2 SO4 significantly improved the leaching efficiency for a range of LIB cathode chemistries, with the strongest effect observed for manganese-rich active material. Focusing on NMC111 (LiMnx Coy Niz O2 ) material, a linear correlation between the BL concentration and the leaching yield of Mn was obtained, with the best overall leaching efficiencies being achieved for 2.0 mol L-1 H2 SO4 and 50 vol % of BL at 353 K. A quasi-total degradation of oxygenated and aromatic groups from the BL during NMC111 dissolution was observed after leaching, suggesting that these chemical groups are essential for LIB reduction. Finally, the leached transition metals could be easily recovered by pH adjustment and oxalic acid addition, closing the resource loop and fostering resource efficiency.

Spotlight on Luminescence Thermometry: Basics, Challenges, and Cutting-Edge Applications

Luminescence (nano)thermometry is a remote sensing technique that relies on the temperature dependency of the luminescence features (e.g., bandshape, peak energy or intensity, and excited state lifetimes and risetimes) of a phosphor to measure temperature. This technique provides precise thermal readouts with superior spatial resolution in short acquisition times. Although luminescence thermometry is just starting to become a more mature subject, it exhibits enormous potential in several areas, e.g., optoelectronics, photonics, micro- and nanofluidics, and nanomedicine. This work reviews the latest trends in the field, including the establishment of a comprehensive theoretical background and standardized practices. The reliability, repeatability, and reproducibility of the technique are also discussed, along with the use of multiparametric analysis and artificial-intelligence algorithms to enhance thermal readouts. In addition, examples are provided to underscore the challenges that luminescence thermometry faces, alongside the need for a continuous search and design of new materials, experimental techniques, and analysis procedures to improve the competitiveness, accessibility, and popularity of the technology.

Enhanced Dissolution of Metal Oxides in Hydroxylated Solvents - Towards Application in Lithium-Ion Battery Leaching

The recovery of critical metals from spent lithium-ion batteries (LIBs) is rapidly growing. Current methods are energy-intensive and hazardous, while alternative solvent-based strategies require more studies on their 'green' character, metal dissolution mechanism and industrial applicability. Herein, we bridged this gap by studying the effect of dilute HCl solutions in hydroxylated solvents to dissolve Co, Ni and Mn oxides. Ethylene glycol emerged consistently as the most effective solvent, dissolving up to four times more Co and Ni oxides than using aqueous acidic media, attributed to improved chloro-complex formation and solvent effects. These effects had a significant contribution compared to acid type and concentration. The highest Co dissolution (0.27 M) was achieved in 0.5 M HCl in 25 % (v/v) glycerol in water, using less acid and a significant amount of water compared to other solvent systems, as well as mild temperatures (40 °C). This solvent was applied to dissolve battery cathode material, achieving 100 % dissolution of Co and Mn and 94 % dissolution of Ni, following what was concluded to be a mixed mechanism. These results offer a simple alternative to current leaching processes, reducing acid consumption, enhancing atomic efficiency, and paving the way for optimized industrial hydrometallurgical processes leaning to 'greener' strategies.

Reproducibility Study of the Thermoplastic Resin Transfer Molding Process for Glass Fiber Reinforced Polyamide 6 Composites

Polyamide 6 (PA6) thermoplastic composites have higher recyclability potential when compared to conventional thermoset composites. A disruptive liquid molding manufacturing technology named Thermoplastic Resin Transfer Molding (T-RTM) can be used for processing composites due to the low viscosity of the monomers and additives. In this process, polymerization, crystallization and shrinkage occur almost at the same time. If these phenomena are not controlled, they can compromise the reproducibility and homogeneity of the parts. This work studied the influence of packing pressure, as a process variable, throughout the filling and polymerization stages. To assess the process reproducibility and parts' homogeneity, physical, thermal and mechanical properties were analyzed in different areas of neat PA6 and composite parts. This study showed that a two-stage packing pressure can be successfully used to increase parts' homogeneity and process reproducibility. The use of 3.5 bar packing pressure during the polymerization stage resulted in mechanical properties with lower standard deviations, indicating a higher degree of homogeneity of the manufactured parts and higher process reproducibility. These results will be used for establishing the actual state of the technology and will be a base for future process optimization.

Bio-Based Solar Energy Harvesting for Onsite Mobile Optical Temperature Sensing in Smart Cities

The Internet of Things (IoT) fosters the development of smart city systems for sustainable living and increases comfort for people. One of the current challenges for sustainable buildings is the optimization of energy management. Temperature monitoring in buildings is of prime importance, as heating account for a great part of the total energy consumption. Here, a solar optical temperature sensor is presented with a thermal sensitivity of up to 1.23% °C-1 based on sustainable aqueous solutions of enhanced green fluorescent protein and C-phycocyanin from biological feedstocks. These photonic sensors are presented under the configuration of luminescent solar concentrators widely proposed as a solution to integrate energy-generating devices in buildings, as windows or façades. The developed mobile sensor is inserted in IoT context through the development of a self-powered system able to measure, record, and send data to a user-friendly website.

Water-Soluble Polymeric Carbon Nitride Colloidal Nanoparticles for Highly Selective Quasi-Homogeneous Photocatalysis

Heptazine-based polymeric carbon nitrides (PCN) are promising photocatalysts for light-driven redox transformations. However, their activity is hampered by low surface area resulting in low concentration of accessible active sites. Herein, we report a bottom-up preparation of PCN nanoparticles with a narrow size distribution (ca. 10±3 nm), which are fully soluble in water showing no gelation or precipitation over several months. They allow photocatalysis to be carried out under quasi-homogeneous conditions. The superior performance of water-soluble PCN, compared to conventional solid PCN, is shown in photocatalytic H2 O2 production via reduction of oxygen accompanied by highly selective photooxidation of 4-methoxybenzyl alcohol and benzyl alcohol or lignocellulose-derived feedstock (ethanol, glycerol, glucose). The dissolved photocatalyst can be easily recovered and re-dissolved by simple modulation of the ionic strength of the medium, without any loss of activity and selectivity.