Global Challenges最新文献

This study investigates the influence of hydrogen (H₂) enrichment on the performance, combustion, and emission characteristics of a dual-fuel diesel engine operated with Mahua biodiesel/diesel blend (BDf20), in which H₂ is injected into the intake manifold at flow rates of 4, 6, 8, 10, and 12 L min⁻¹ under varying engine loads. As a result, the optimum engine performance is achieved at 10 L min⁻¹ H₂. At a peak load of 5.02 kW, BDf20 + H₂ (10 L min⁻¹) improves brake thermal efficiency (BTE) by 16.75%, and reduces brake specific fuel consumption (BSFC) by 10.83% compared to conventional diesel. For emission characteristics, unburnt hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO₂) decrease by 42.65, 44.74, and 20.91%, respectively, although NOx emissions increased by 17.1% due to higher combustion temperatures. Moreover, combustion characteristics show a 9.91% rise in peak in-cylinder pressure, a 20.82% increase in heat release rate, and an 8.26% longer ignition delay period. The results confirm the effectiveness of H₂ enrichment in improving combustion performance while significantly reducing pollutant emissions, showing that combining H₂ with biodiesel enhances the global Sustainable Development Goals (SDG) by advancing clean and renewable energy solutions.

High-nickel lithium-ion battery cathode materials are increasingly favored for their superior energy density but face challenges related to toxicity, cost, and critical material supply. This study assesses the current state of play in commercial cathodes, and presents a screening of the literature micro-dopants for LiNiO₂ (LNO), aiming to identify excellent electrochemical performance without compromising affordability or safety. Literature examples of tungsten, niobium, and zirconium doped cathode material all showed good performance, but are considered risky for further consideration due to the high costs and increased supply risk with these materials. A lithium excess sulfate doped material exhibited the best balance of sustainability and performance, delivering improved capacity retention and low raw material cost, with the only compromise of a very slightly elevated supply risk. The study highlights the trade-offs between performance metrics and sustainability considerations, offering a framework for more commercially viable cathode design.

Coal-fired power industry is a major carbon emitter which is responsible for global warming. The carbon market is an important tool to decarbonize the coal-fired power industry. This study extends the cited Chinese literature on how carbon net expenditures impact investments at the technology level. A metric, the long-term carbon net expenditure, is introduced to estimate the carbon net expenditure of decarbonization projects throughout their service life. The analysis suggests that retrofitting existing coal-fired power units for biomass co-firing will become economically feasible from 2043, and implementing carbon capture retrofitting will be viable from 2047. Enhancing the carbon market's long-term development path is essential to promoting these decarbonization efforts.

The finite supply of water on this planet led researchers to investigate nanocomposites, which are unique compounds with great performance and many applications. Many researchers are now interested in photocatalytic degradation methods due to their ability to facilitate both spontaneous and non-spontaneous reactions using light energy. The review's objective is to explain what nanocomposites mean, their types, various preparation procedures, and various characterisation approaches, and to employ nanocomposites in catalytic applications for wastewater treatment. It also seeks to compile some of the research on this topic. Through bibliometric analysis, the lineage and the extent to which countries are interested in publishing research on this issue in various methods of narration are illustrated. Nanocomposites can be used as catalysts to remove more than 90% of Cr (VI) after 120 min, phosphate (99.77%), ammonia (65.65%), Nitrite (99.98%) and remove several dyes such as Direct Blue 14 (94.57%), Congo Red (90.23%), Sunset Yellow (83.56%), brilliant cresol blue (BCB) (98.80%), neutral red (NR) (98.33%), methylene blue (MB) (99.6%) and more. Finally, challenges faced by nanocomposites in wastewater treatment are analyzed and summarized.

Air pollution poses a significant threat to global public health, with African megacities facing its severe consequences due to rapid urbanization, industrialization, and transportation challenges. In Africa, air pollution is responsible for 1.1 million deaths annually, with household air pollution accounting for two-third and ambient air pollution one-third of this burden. However, these percentages are likely to change in the near future due to the projected rapid urbanization and industrialization in the region. In the next 25 to 50 years African megacities are projected to grow rapidly and therefore experience a significant increase in air pollution-related health risks. Poor policy prioritization, limited monitoring infrastructure and conflicting interests and priorities further complicate the problem. In this paper, the key drivers of air pollution are discussed in African megacities, including urbanization, industrialization, transportation, and energy use. Further it is highlighted that there are significant challenges and barriers, as well as a pressing need for air quality monitoring, coordinated policies and effective air quality management to ensure sustainable development, mitigate the adverse health impacts of pollution and improve the quality of life across the continent.

This review thoroughly examines the potential of 2D transition metal borides (MBenes) for sophisticated energy storage applications. The investigation explores their structural stability, electrochemical characteristics, and a range of synthesis methods, including chemical and hydrothermal exfoliation procedures. Because of their strong mechanical characteristics, low diffusion energy barriers, and high theoretical capacities, MBenes perform better as anode materials for lithium-ion batteries (LIBs) than other 2D materials like MXenes. Functionalized MBenes also show adaptability in various applications, such as lithium–sulfur batteries and nitrogen reduction catalysis. Their actual application is hampered by issues including oxidation and surface imperfections, despite their encouraging qualities. This analysis demonstrates MBenes as a promising anode material for next-generation energy storage devices and highlights the necessity for more research into scalable, eco-friendly synthesis techniques for achieving sustainability.

The cover image is based on the article Tannin: An Insight into its Cosmeceutical Properties and Uses by Mario Pagliaro etal., https://doi.org/10.1002/gch2.202500115

Dye-sensitized solar cells (DSSC) have received significant interest in the photovoltaic technology because of their eco-friendly nature, affordability and flexibility. Here, this work presents a DSSC of the configuration; FTO/WO₃/N719 Dye/GO/C with performance metrics – open-circuit voltage (V_oc) of 1.1055 V, short-circuit current density (J_sc) of 22.23 mA cm⁻², a fill factor (FF) of 84.65%, and a remarkable power conversion efficiency (PCE) of 20.80%. The study utilizes a wide frequency range of 10⁻³ to 10¹⁰ Hz to examine charge transport dynamics and evaluate the electrochemical performance of the model cell. Impedance spectroscopy investigates both complex electrical impedance (Z*) and electric modulus (M*) to provide critical insights into ionic transport, charge recombination, ion migration and diffusion mechanisms within the cell. A model equivalent circuit is developed and theoretically validated by fitting experimental alternating current (AC) data to theoretical predictions, allowing the extraction of characteristic time constants for various processes. The results highlight that efficient ion conduction and rapid electron diffusion are essential for optimizing charge collection and minimizing recombination losses. Further, the study emphasizes the critical role of both series and shunt resistances across low- and high-frequency domains, establishing a strong correlation between time constant behavior and overall device efficiency.

Silver particles (AgPs) are increasingly used across a range of industries, including personal care, household, and food packaging, but conventional synthesis methods involve high production costs and negative environmental impacts. Green synthesis using plant extracts offers a sustainable alternative, though limited comparative data on economic and environmental performance exist. This study evaluates three green methods—BX3 (a patented extract), lemon juice (LJ), and green tea (GT)—against a conventional method using sodium borohydride (NaBH₄). Equal-volume reactions are analyzed via ICP-MS, UV–vis spectroscopy, and dynamic light scattering. Techno-economic analysis and life cycle assessment (LCA) assessed costs and environmental impact. BX3 emerged as the most cost-effective and environmentally friendly option, producing AgPs at $13,000/kg with a 75% yield and a global warming potential of 1,900 kg CO₂-Eq/kg. In contrast, NaBH₄ yielded 7.35% at $195,000/kg, 15x more expensive than the BX3 method, and a global warming potential of 74,000 kg CO₂-Eq/kg. GT, while a green method, has the highest cost $690,000/kg, the lowest yield (1.13%), and the worst environmental impact, including a human toxicity value of 92,000 kg 1,4-DCB-Eq/kg-even surpassing the toxic NaBH₄ process. These findings highlight BX3's promise for scalable, low-impact AgP production and broader industrial use.

Biological methanation is increasingly considered for biogas upgrading. Here, the supplementation of conductive magnetite (Fe₃O₄) nanoparticles is investigated as a strategy to enhance H₂-driven biomethanation in a mixed hydrogenotrophic methanogenic community. An enrichment culture, maintained for over 180 days in a fill-and-draw anaerobic bioreactor under H₂/CO₂ feeding, is used to inoculate batch microcosms containing 0, 1.25, and 2.5 gFe L⁻¹ of magnetite. Magnetite addition resulted in a dose-dependent increase in maximum methane production rates—up to 13-fold compared to controls—and sustained high hydrogen-to-methane conversion yields (78–107%). 16S rRNA gene sequencing reveals that archaeal community composition remained dominated by hydrogenotrophic Methanobrevibacter and Methanobacterium spp., whereas bacterial populations shifted from acetogenic Sporomusa and Acetobacterium spp. toward H₂-oxidizing Paracoccus and Thauera spp. at higher magnetite concentrations. Electron microscopy and energy-dispersive X‑ray spectroscopy show that magnetite nanoparticles formed conductive networks bridging microbial cells, and fluorescence in situ hybridization confirmed co-localization of methanogens and Paracoccus within these aggregates. The findings support a direct interspecies electron transfer (DIET) mechanism facilitated by magnetite, whereby Paracoccus spp. oxidize H₂ and shuttle electrons to methanogens, accelerating biomethanation. These results highlight the potential of magnetite-mediated DIET to improve power-to-methane processes and advance biogas upgrading technologies.