Flexible aqueous zinc-air batteries with high energy density and safety have garnered significant attention. Gel polymer electrolytes have emerged as the preferred option over conventional liquid electrolytes due to their ability to prevent electrolyte leakage. In this study, a composite PANa-PVP-TiO2(NH2) hydrogel with high alkaline resistance and ionic conductivity is designed, where the inorganic TiO2(NH2) nanoparticles are evenly distributed and integrated into the organic dual network of polyacrylate sodium and polyvinyl pyrrolidone. The organic-inorganic hybrid structure enhances the absorption and retention capabilities for electrolyte solution, leading to impressive ionic conductivity of the gel polymer electrolyte throughout the operation of flexible aqueous zinc-air batteries. Additionally, the incorporation of TiO2(NH2) nanoparticles and the dual network construction effectively strengthen the mechanical strength and flexibility of the gel polymer electrolyte, suppressing by-products and zinc dendrite formation. The enhancements lead to the extended cycling longevity of zinc symmetric batteries and excellent power density, as well as the prolonged cycle life of flexible aqueous zinc-air batteries.
Traditional open circulating cooling water systems use a lot of water and electricity to remove waste heat. In coastal areas, closed seawater circulating cooling water systems have been used as an alternative to improve cooling efficiency. However, a comprehensive comparison of the design and advantages of the two types of cooling systems is lacking. Also, the best way to match and optimize the seawater system with the circulating water system in the closed seawater circulating cooling water system has not been fully explored. In this paper, a closed seawater cooling system under multiperiod is constructed, taking into account monthly changes in environmental factors. The mixed integer nonlinear programming model is solved by using GAMS software to evaluate and compare the economics and operability of the two cooling schemes. Meanwhile, the matching relationship of the internal subsystems of the closed seawater circulating cooling water system after coupling the air coolers is studied in depth, and the cooling load is allocated reasonably. The cases show that seawater cooling saves 9.22% of circulating water and reduces the total cost by 8.93% compared with cooling tower. The cost of the closed seawater cooling system can be reduced by 24.37% after coupling air coolers, and there is a direct corresponding matching relationship between circulating water and seawater.
Polylactic acid, a biodegradable polymer derived from renewable resources, is increasingly used in food packaging due to its transparency, renewability, and food safety. However, its mechanical properties, heat resistance, and barrier performance present significant challenges that limit its application. Currently, there is a lack of comprehensive literature addressing methods to optimize polylactic acid’s performance for various food packaging application. Hence, this review provides an overview of polylactic acid production processes, including the synthesis of lactic acid and lactide, as well as methods such as polycondensation and ring-opening polymerization. We critically examine the advantages and limitations of polylactic acid in various food packaging contexts, focusing on strategies to enhance its mechanical properties, barrier performance against oxygen and water vapor, surface hydrophobicity, thermal stability, and resistance to ultraviolet light. Furthermore, we summarize recent advancements in polylactic acid applications for food packaging, highlighting innovations in antioxidant, antimicrobial, and freshness indicator packaging. These developments underscore the significant potential of polylactic acid in the food packaging sector and offer valuable insights for future research directions.
Single-atom catalysts are highly effective in catalyzing a wide range of reactions owing to their capacity to have precise coordination patterns and fully leverage the potential of metal atoms. Although several techniques have been reported for the preparation of single-atom catalysts, adopting a convenient method to construct them still has a challenge. In this work, we report a convenient method for the preparation of Zr-based single-atom catalyst that takes advantage of the nanoconfined environments between the template and silica wall in template-occupied silica SBA-15. After introducing Zr-containing precursor into the nanoconfined environments of the template-occupied silica SBA-15 using solid-phase milling, Zr-based single-atom catalysts were produced via the following calcination step. Density functional theory calculations and experimental findings show that Zr atoms form Zr–O–Si structure in the silica walls. The Zr single-atom catalyst synthesized using the nanoconfined environments exhibited notably superior catalytic performance in the synthesis of benzyl acetate from the esterification reaction between acetic acid and benzyl alcohol (63.3% yield), outperforming the counterpart that synthesized without such nanoconfined environments (19.8% yield).
