Abstract Selective removal and recovery of Cu2+ ions from industrial effluent was accomplished by a new redox-accelerated capacitive deionization (CDI) electrode with a hierarchical graphene oxide/MIL-88A/activated carbon composite (GO/MIL-88A/AC). The optimal electrode (E4, 6 wt %) exhibits a well-balanced charge storage mechanism with 81.7% capacitive and 18.3% diffusion-controlled sorption contributions, which facilitates fast mass transport accompanied by faradaic redox mechanisms of the systematic composite loading variation (0–8 wt %). The high specific capacitance (142 F g–1), low charge transfer resistance (1.3 Ω), and high Coulombic efficiency (99.99% for 500 cycles) via electrochemical measurements confirmed enhanced conductivity and reversibility. At optimum CDI operating conditions (1.2 V, 20 mL min–1, pH 4), the electrode exhibited an impressive electrosorption capacity (58.03 mg g–1, 95% removal). Kinetic studies showed a pseudo-first-order model (k1 = 0.0658 min–1, R2 = 0.9934) with high consistency between experimental (58.03 mg g–1) and theoretical capacities (64.01 mg g–1), and the linear driving force model gave a high mass transfer coefficient (kLDF = 0.0962 min–1), confirming efficient ion diffusion within the hierarchical structure. The improved performance is due to the combined contribution of pseudocapacitive property (GO), active Fe3+/Fe2+ sites of MIL-88A, and electric double-layer capacitance (AC) for the coupled electrosorption–desorption process. This work demonstrates the potential of a hybrid redox-capacitive system for energy-efficient Cu2+ recovery from industrial wastewater treatment.
Abstract Integrated adsorption and catalysis using recovered palladium (Pd) from waste presents an attractive paradigm for maximizing its resource utilization efficiency, while the rational design of multifunctional materials that can simultaneously regulate adsorption performance and catalytic activity remains a challenge. In this work, a series of triphenylphosphine (PPh3)-based vinyl-covalent organic frameworks (COFs) with varying PPh3 doping levels TMDF-(PPh3)x (x = 0, 0.1, 0.2, 0.3) were constructed employing a defect engineering strategy. The PPh3 moieties within the framework serve as unique Pd adsorption sites, leading to high-efficiency performance in selective Pd adsorption with high adsorption capacity (828.1 mg g–1) and fast adsorption kinetics (60 min). Meanwhile, owing to the electronic properties and spatial effect of PPh3, the recovered Pd2+@TMDF-(PPh3)0.2 can be utilized as an excellent candidate in Pd-catalyzed Suzuki-Miyaura coupling reactions. Moreover, the rigid vinyl-based framework ensures five consecutive adsorption and catalysis cycles without apparent loss of performance. This work provides a paradigm for the integrated adsorption and catalysis using recovered Pd from waste through the rational design of multifunctional COFs materials.
Abstract The influence of cross-linking density on the mechanical properties of silicone rubber (SR) is well-established, but its role in ablation and thermal protection under thermomechanical coupling remains unclear. Herein, vinyl methyl silicone rubber (VMQ) composites with different vinyl contents were prepared to regulate the cross-linked network. Results indicated that the low vinyl content reduced cross-linking density, enhanced segmental mobility and stress relaxation, and achieved a tensile strength of 7.12 MPa and an elongation at break of 923%. During stress ablation, the low-cross-link-density network relieved stress concentrations caused by tensile loading, thermal stress, and pyrolysis shrinkage, thereby suppressing microcrack propagation in the ceramicized protective layer and maintaining a continuous thermal-insulation barrier. Consequently, burn-through was delayed: a 3 mm thick specimen under 10% strain and a heat flux of 1 MW/m2 reached 82 s. These findings provide molecular design guidance for flexible SR composites combining mechanical robustness and ablation resistance.
Abstract Porous materials are extensively utilized in the catalytic elimination of environmental pollutants. However, the intrinsic role of pore size in modulating catalytic performance remains poorly understood. Herein, we report that the reactivity of ammonium nitrate (AN), a critical meltable intermediate in the reaction of NH3 selective catalytic reduction (NH3–SCR), can be effectively manipulated by simply adjusting the mesopore size of silica supports, while preserving identical active sites. For the investigated catalysts of Fe2O3 confined in mesoporous silica (Fe2O3@meso-SiO2), we demonstrate that catalytic activity exhibits a strong positive correlation with mesopore size for both SBA-15 and KIT-6 confined catalysts in the medium- to low-temperature range, independent of the mesoporous architecture. AN-temperature-programmed desorption (AN-TPD) revealed that the behavior of AN can be systematically tuned by mesopore size. Larger pores raise the equilibrium vapor pressure of molten AN via the Kelvin effect, enriching the local gaseous AN concentration. Following Le Chatelier’s principle, this elevated concentration shifts the surface adsorption equilibrium of AN on active sites and accelerates the reaction between AN and NO to yield N2. Our work underscores the importance of pore size engineering for tuning the local concentration of meltable reactive intermediates, offering a new avenue for the rational design of high-performance NH3–SCR catalysts.
Abstract In order to decarbonize coal-fired power plants (CFPPs), this study proposed an integrated system combining CFPPs and carbon capture technologies and utilizing the power-to-liquid/gas (PTL/PTG) approach to convert captured CO2 into high-value-added syncrude and synthetic natural gas (SNG). Afterward, a two-level scheduling model was developed to optimize both economic efficiency and low-carbon performance. The first level applied a price-based demand response mechanism to adjust the electricity load and determine the optimal time-of-use price, while the second level employed a time-related scheduling mode for the system configuration. As a result, for a typical 600 MWe CFPP, the highest daily profit can reach $484367, exhibiting improvements of 12.59% and 14.69% over systems operating under fixed operation conditions and electricity prices, respectively. Additionally, we also investigated the impact of varying electricity, syncrude, and SNG prices on system performance and compared the highest profits with systems incorporating carbon capture and storage technologies.
