The incorporation of intermittent renewable energy sources into a consistently controlled power transmission system hinges on advancements in energy storage technologies. Sodium ion batteries (SIBs) are emerging as a primary and viable alternative material due to their electrochemical activity, presenting a potential replacement for the next generation of lithium-ion battery (LIB) energy storage materials. However, this transition may necessitate significant alterations in the anode material, given the incompatibility of the current anode with sodium ions and the electrolyte. This review provides a comprehensive summary of various anode materials employed in SIBs, categorized according to their storage mechanisms. Additionally, it explores the growing focus on utilizing hard carbon as an anode material, driven by factors such as its relatively high specific capacity compared to graphite, cost-effective production, and eco-friendly properties as it can be derived from biomass. The review further addresses recent progress in hard carbon, detailing production methods, modifications, challenges, limitations in integrating hard carbon into the anode of SIBs, and suggests potential directions for future research.
The field of propellants has recently witnessed dynamic shift, including advancements in propulsion technology and a growing emphasis on the development of environmentally friendly propellants. Nitrate ester (NE) are extensively used in solid propellants, exhibiting chemical instability as they undergo decomposition reactions. Stabilization is a crucial aspect in propellant, ensuring the safety and reliable performance of energetic materials. Stabilizer plays a vital role in inhibiting or slowing down the autocatalytic decomposition reaction of propellants. In response to grow health and environmental concerns, there is a continuous effort to explore and evaluate green stabilizers designed to replace traditional stabilizers, which have been associated with adverse environmental impacts. Therefore, this study aimed to provide an overview of the current research carried out in the field of NE-based propellants, emphasizing the most significant work undertaken on green stabilizer materials for NE-based propellants. A comprehensive review of various environmentally friendly and low-toxicity stabilizers employed in propellants are presented, and their effects on the stability and shelf-life performance of NE-based propellants are discussed. Furthermore, this paper delves into the stabilization mechanisms of green stabilizers to mitigate decomposition reactions, thereby preventing unwanted side effects and ensuring long-term storage stability. Through a comprehensive review of recent developments, the manuscript highlights the successes and challenges associated with the incorporation of green stabilizers in NE-based propellants formulations. Finally, the review concludes by outlining future research directions and opportunities for innovation in sustainable and green stabilizers as well as key issues that need to be addressed and resolved. The comprehensive review and insights provided in this study contribute to the ongoing efforts in developing safer and more sustainable propellant technologies.
Nitrocellulose (NC) has garnered significant interest among researchers due to its versatile applications, contingent upon the degree of nitration that modifies the cellulose structure. For instance, NC with a high nitrogen content, exceeding 12.5%, finds utility as a key ingredient in propellant formulations, while variants with lower nitrogen content prove suitable for a range of other applications, including the formulation of printing inks, varnishes, and coatings. This communication aims to present the outcomes of our efforts to optimize the nitration reaction of bacterial cellulose to produce high-nitrogen-content NC, employing the response surface methodology (RSM). Our investigation delves into the influence of the mole ratio of sulfuric and nitric acids, reaction temperature, and nitration duration on the nitrogen content of the resultant products. Utilizing a central composite design (CCD), we identified the optimal conditions for NC synthesis. Analysis of variance (ANOVA) underscored the substantial impact of these reaction conditions on the percentage of nitrogen content (%N) yield. By implementing the predicted optimal conditions-namely, a H2SO4:HNO3 mole ratio of 3:1, a reaction temperature of 35 °C, and a reaction period of 22 min-we successfully produced NC with a nitrogen content of 12.64%. Characterization of these products encompassed elemental analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM).
Hydrogen (H2) represents a promising avenue for reducing carbon emissions in energy systems. However, achieving its widespread adoption requires more effective and scalable synthesis methods. Herein, we investigated the isothermal carburization process of the MoO3 catalyst. This reaction was carried out at a constant temperature of 700 °C in a 60% CO/He stream, with hold reaction times varying (60-min, 90-min, and 120-min). This investigation was conducted using a micro-reactor Autochem with the aim of enhancing the yield of H2. The study focused on evaluating the chemical reduction and carburization behavior of the MoO3 catalyst through X-ray diffraction (XRD), transmission electron microscopy (TEM), and CHNS elemental analysis. The XRD analysis revealed the formation of carbides, Mo2C, and MoO2, serving as active sites for subsequent H2 production in the thermochemical water splitting (TWS) process. The carburization at a 60-min hold time exhibited enhanced H2 production, generating approximately ~ 6.60 µmol of H2 with a yield of up to ~ 32.90% and a conversion rate of ~ 54.83%. This finding emphasizes the essential role played by the formation of carbides, particularly Mo2C, in the carburization process, contributing significantly to the facilitation of H2 production. These carbides serve as exceptionally active catalytic sites that actively promote the generation of hydrogen. This study underscores that the optimized duration of catalyst exposure is a key factor influencing the successful carburization of MoO3 catalysts. This emphasizes how important carbide species are to increasing H2 efficiency. Additionally, it is noted that carbon formation on the MoO3 active sites can act as a potential poison to the catalysts, leading to rapid deactivation after prolonged exposure to the CO precursor.
The wide availability and diversity of dangerous microbes poses a considerable problem for health professionals and in the development of new healthcare products. Numerous studies have been conducted to develop membrane filters that have antibacterial properties to solve this problem. Without proper protective filter equipment, healthcare providers, essential workers, and the general public are exposed to the risk of infection. A combination of nanotechnology and biosorption is expected to offer a new and greener approach to improve the usefulness of polysaccharides as an advanced membrane filtration material. Nanocellulose is among the emerging materials of this century and several studies have proven its use in filtering microbes. Its high specific surface area enables the adsorption of various microbial species, and its innate porosity can separate various molecules and retain microbial objects. Besides this, the presence of an abundant OH groups in nanocellulose grants its unique surface modification, which can increase its filtration efficiency through the formation of affinity interactions toward microbes. In this review, an update of the most relevant uses of nanocellulose as a new class of membrane filters against microbes is outlined. Key advancements in surface modifications of nanocellulose to enhance its rejection mechanism are also critically discussed. To the best of our knowledge, this is the first review focusing on the development of nanocellulose as a membrane filter against microbes.
Chemical contaminants such as heavy metals, dyes, and organic oils seriously affect the environment and threaten human health. About 2 million tons of waste is released every day into the water system. Heavy metals are the largest contributor which cover about 31% of the total composition of water contaminants. Every day, approximately 14 000 people die due to environmental exposure to selected chemicals. Removal of these contaminants down to safe levels is expensive, high energy and unsustainable by current approaches such as oxidation, biodegradation, photocatalysis, precipitation, reverse osmosis and adsorption. A combination of biosorption and nanotechnology offers a new way to remediate these chemical contaminants. Nanostructured materials are proven to have higher adsorption capacities than the same material in its larger-scale form. Nanocellulose is very promising as a high-performance bioadsorbent due to its interesting characteristics of high adsorption capacity, high mechanical strength, hydrophilic surface chemistry, renewability and biodegradability. It has been proven to have higher adsorption capacity and better binding affinity than other similar materials at the macroscale. The high specific surface area and abundance of hydroxyl groups within lead to the possible functionalization of this material for decontamination purposes. Several research papers have shown the effectiveness of nanocellulose in the remediation of chemical contaminants. This review aims to provide an overview of the most recent developments regarding nanocellulose as an adsorbent for chemical contamination remediation. Recent advancements regarding the modification of nanocellulose to enhance its adsorption efficiency towards heavy metals, dyes and organic oils were highlighted. Moreover, the desorption capability and environmental issue related to every developed nanocellulose-based adsorbent were also tackled.