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Mercury emission has become a global concern due to the potential risks Hg poses to human health and the environment. Currently, copper-based compounds, such as CuCl2, CuO, CuS, and CuSe, have attracted great attention in mercury emission control, because of their low cost and decent removal efficiency. This review provides an overview of the recent progress on adsorptive and catalytic oxidation removal of elemental mercury over copper-based composites. Supported CuCl2can majorly serve as an inexpensive and efficient catalyst toward Hg0oxidation. Nevertheless, the high volatility and water solubility of mercury chloride may cause halogen release and a potential leaching risk of mercury, respectively. Due to its superior redox property, CuO is fairly active in Hg0oxidation. Metal incorporation can distinctly strengthen the mercury removal performance. However, CuO-based composites can be easily poisoned or suppressed by flue gas constituents owing to the generation of inactive copper sulfates/nitrates or competitive adsorption. CuS-based composites appear to be the most promising sorbents for mercury capture, because of strong Hg0affinities and remarkable tolerances to steam and sulfur dioxide. CuSe-based composites show mercury capture performances similar to those of CuS-based composites. However, tedious synthetic processes and expensive Se precursors hinder their industrial implementation.

The demand for large format lithium-ion batteries (LIBs) is rising as they are easier to integrate and control at a system level. While, with increasing size, there is an augmented risk of overheating due to increased heat generation. For 18650 and 21,700 batteries, they can be efficiently cooled either from the base or from the side. Given the widespread adoption of large format 4680-cylindrical cells, it is imperative to possess a comprehensive understanding of their thermal management strategies. The present study proposes a liquid immersion system to investigate the cooling performance of a group 4680 LIBs and assess the impact of thermal management performance on battery pack. A comparison is made among different cooling strategies, including natural convection, forced convection, and SF33 coolant liquid cooling, under various discharge rates. The results indicate that the utilization of two-phase immersion cooling system proved highly efficient in maintaining the cell temperature within the range of 34–35 °C across all tested conditions, exhibiting excellent temperature uniformity. Finally, the influential factors affecting the pool cooling heat transfer were discussed, including the battery surface structure, intracavitary pressure, coolant properties and so on. This study provides fundamental research for direct liquid-cooling technology, which exhibits significant potential in augmenting the durability and safety aspects of LIBs.

Mercury emissions from combustion of coal, biomass, and solid waste threaten human life and the environment. As the principal mercury species in flue gas, elemental mercury (Hg0) can easily escape from available air pollution control instruments because of its chemical inertness, high volatility, and aqueous insolubility. Recently, graphitic carbon nitride (g-C3N4) seems to be an intriguing candidate for Hg0emission control. This review highlights the latest advances in adsorptive and photocatalytic removal of Hg0by g-C3N4-based composites. Metal oxide (MeOx)- and halide-modified g-C3N4can effectively capture Hg0from simulated flue gas. Nonetheless, acidic flue gas components can degrade the performances of MeOx/g-C3N4adsorbents, while halide-modified g-C3N4suffers from release of halogen and potential leaching risk of mercury. Metal sulfide (MeSx)-modified g-C3N4appears to be the best candidate for Hg0capture owing to its superior tolerance to sulfur dioxide, fast adsorption rate, and high mercury capacity. Combining bismuth oxyhalides (BiOX) with g-C3N4can promote photocatalytic oxidation of elemental mercury under visible light irradiation; nonetheless, the Hg0removal efficiency is still unsatisfactory, and the underlying photocatalysis mechanism is not yet clear.

The application of phase change materials (PCMs) for thermal storage in construction can effectively reduce building energy consumption. However, high costs and vulnerability to leaks have hindered their application. The present study proposes two approaches for the synthesis of porous supporting matrices derived from rice husk, resulting in the formation of rice husk silica (RHS) and rice husk carbon (RHC). Then, n-octadecane and the porous materials were combined by vacuum impregnation, while the leakage resistance performance of the composite PCMs was enhanced by applying epoxy resin coating to create a shell-core structure. The results show that the n-octadecane/RHS and n-octadecane/RHC composite PCMs exhibit high latent heat potential of 106.5 J/g and 116.3 J/g, respectively. Both porous supporting structures provided the PCMs with robust structural stability and exceptional thermal conductivity. The thermal conductivity of the n-octadecane/RHS composite PCMs and n-octadecane/RHC composite PCMs reached 0.52 W/(m K) and 0.41 W/(m K), respectively. The thermal properties of the biogenic porous core/shell-based shape-stabilized PCMs were characterized by an analog T-history method, and the results demonstrated that the composite PCMs exhibited excellent and rapid heat storage and exothermic capabilities. After undergoing 300 complete heating and cooling cycles, the composite PCMs demonstrate exceptional thermal reliability and possess a high enthalpy capacity. Finally, the impact of the pore structure of RHS and RHC on the crystallization behavior of n-octadecane was discussed. Both composite PCMs can be regarded as environmentally friendly construction materials with promising thermal and acoustic properties.

A low-temperature process involving the formation of dry ice to separate carbon dioxide (CO2) from a CO2-containing mixture is proved to be energy efficient. An accurate prediction of the phase equilibria of the components is necessary for the development of such a process. The current work extended a model for simultaneous calculation of phase stability and flash computations for a multicomponent and multiphase system to a system involving the formation of dry ice. This study derived composition-independent correlations of solid–vapor and solid–liquid and introduced these correlations into a Gibbs energy minimization algorithm with the stability variable of phase in predicting the phase diagram of pure CO2and the solid–fluid-phase equilibria of a methane (CH4)–CO2binary mixture. A CO2solid-phase equation of state (EoS) based on Gibbs free energy and a fluid-phase EoS based on Helmholtz free energy were used in this study. Experimental data were compiled for a CH4–CO2mixture involving the solid–vapor, solid–liquid, and solid–liquid–vapor equilibria. In general, modeling results agreed with the experimental data, and discrepancies between the modeling and experimental data have been well identified and discussed. The solid–vapor-phase equilibrium region that can be used for low-temperature CO2separation was suggested.

The thermal management of lithium-ion batteries (LIBs) has become a critical topic in the energy storage and automotive industries. Among the various cooling methods, two-phase submerged liquid cooling is known to be the most efficient solution, as it delivers a high heat dissipation rate by utilizing the latent heat from the liquid-to-vapor phase change. In this study, a novel two-phase liquid immersion system was proposed, and the cooling performance of an 18650 LIB was investigated to evaluate the effects of thermal management on the performance of the battery pack. Four cooling strategies, namely natural, forced convection, mineral oil (single-phase), and SF33 fluid (two-phase) cooling, were compared under different discharge rates and dynamic load conditions. The results suggest that two-phase immersion cooling with SF33 fluid was highly effective to keep the cell temperature under 34 °C under all tested conditions, and the temperature change of the battery did not exceed 5 °C. A large amount of heat from the battery during high C discharge was absorbed by the boiling of SF33, allowing it to effectively maintain the cell temperature in an optimal temperature range (33–34 °C). Finally, the mechanism of pool heat transfer was determined through visual analysis. Initially, small bubbles appeared near the wires and battery terminals, which acted as gasification cores. Subsequently, small bubbles arose around the surface of the battery body, most of which grew to reach the interface. Eventually, the vapor condensed near the top condenser coils. This study provides a foundation for the further development of direct two-phase liquid-cooling technology, which can be an effective method for enhancing the life and safety of LIBs.

A simplified approach for the fabrication of CuO/TiO 2 @C is demonstrated. In this study, low cost CuO/TiO 2 @C photocatalysts (CSs loading 0.25–2 wt.%) were prepared, characterized and evaluated for gas-phase Hg 0 oxidation. The obtained CuO/TiO 2 @C photocatalysts were used to remove gaseous elemental mercury under UV light and LED respectively, and the optimum doping of content of CSs was determined. The results showed that the CuO/TiO 2 @C photocatalysts were highly efficient in oxidizing Hg 0 , reaching above 64% when the CSs doping reached 0.5 wt.%. We have proposed that the probable mechanism by which CuO/TiO 2 @C photocatalysts remove gaseous elemental mercury: with CSs doping, CSs can act as sensitizer and transfer electrons to the semiconductors, triggering the formation of very reactive radicals to improve photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

•Three test modes for the guarded hot plate method were presented and compared.•Numerical simulation was used to deduce the optimal test parameters for the PCM wallboard test.•The uncertainty of numerical stimulation was calculated based on the orthogonal design.•A method was proposed to obtain the accurate phase change temperature of the PCM wallboard.•Optimum test parameters were recommended for the PCM wallboard test.