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[Display omitted] • A novel active unit Sb with electrically driven redox reaction with F- is reported. • The antimony active sites initiate the Faradaic-induced pseudocapacitive behavior. • The N-rich carbon laminar framework endows rapid ion diffusion and electron transfer. • The SNTPC2 electrode exhibit a superior F- removal capacity of 178.58 mg g−1. • This system performs excellent selectivity towards F- and outstanding recyclability. Fluoride (F-) contamination has become a pressing environmental concern owing to its extensive origins and severe toxicity. Capacitive deionization (CDI) emerges as a promising technique for efficient defluorination, with the development of electrode materials being pivotal to its efficiency. Herein, we present a novel design of Sb-decorated N-rich carbon composites (SNTPCs) for the formation of a hybrid capacitive engine that integrates Faradaic-induced pseudocapacitance and electrical double layer capacitance, enabling efficient F- electrosorption. This approach features a distinctive N-rich carbonaceous laminar framework that not only guarantees rapid ion diffusion and electron transfer but also provides a dense electrical double layer for F- storage. The Sb sites are electrically stimulated to release the intrinsic affinity with F-, forming the Faradaic Sb-F bonds. The SNTPC2 electrode exhibits the exceptional saturation removal capability and dynamic electrosorption capacity for defluorination, reaching 178.58 and 34.77 mg F/g at 1.2 V respectively, which exceeds most reported F- capture electrodes. It also demonstrates excellent selectivity towards F- in complex conditions and exhibits effectiveness across a wide range of pH values. Additionally, the utilized electrode performs outstanding regeneration performance after 20 consecutive cycles. This study provides innovative perspectives for the effective elimination of fluoride pollution in aquatic environments. [ABSTRACT FROM AUTHOR]

Capacitive deionization (CDI) is a promising candidate for the removal of nitrate (NO 3 − ) from water, but the concentrated waste water inevitably produced in the electrode regeneration process would cause secondary pollution. In the present study, a Pd/NiAl-LMO film electrode was successfully prepared and used as an innovative NO 3 − electro-sorption/reduction electrode. Metallic Pd nanoparticles were uniformly doped into NiAl-LMO nanosheets, which created a loose porous nanostructure for NO 3 − electro-sorption and enabled catalytic activity for NO 3 − electro-reduction. Doping Pd nanoparticles into NiAl-LMO improved electron transport in the film electrode. The Pd/NiAl-LMO film electrode possessed larger specific capacitance and lower ion diffusion resistance than the pristine NiAl-LMO electrode. NO 3 − was electro-adsorbed by the Pd/NiAl-LMO electrode with concomitant reconstruction of the original hydrotalcite structure by the intercalation of NO 3 − , then the adsorbed NO 3 − was electro-reduced to N 2 by atomic H∗ during the electrode regeneration process. Our study provides not only a novel CDI electrode but also a new concept for a CDI process to achieve a more environmentally friendly outcome. [ABSTRACT FROM AUTHOR]

[Display omitted] • The terephthalic acid intercalated carbon nanotube composite was developed for phosphate removal by CDI. • ZnZr-COOH/CNT electrode showed greatest phosphate adsorption capacity. • Phosphate adsorption occurred via the electrostatic attraction, inner sphere complexation and coordination exchange. • The energy consumption of CDI dephosphorization was sixteenth of that of chemical phosphate removal process. The discharge of phosphate from sewage water can lead to water eutrophication and endanger the aquatic ecosystem. Capacitive deionization (CDI) has displayed great potential for salt removal and nutrient recovery due to its excellent performance such as environmental friendliness and energy efficient. In this study, the terephthalic acid intercalated carbon nanotube composite material (ZnZr-COOH/CNT) was developed as an anode and its selective removal of phosphate in CDI was investigated. At a applied voltage of 1.2 V, ZnZr-COOH/CNT electrode exhibited great adsorption capacity of phosphate with low concentration (∼10 mg/L) at a wide range of pH (3 – 10), with the equilibrium concentration as low as 0.3 mg/L which was less than the national first-class emission standard (0.5 mg/L). Moreover, the adsorption of phosphate by ZnZr-COOH/CNT composite electrode was mildly disturbed by the coexisting ions (Cl−, NO 3 –, SO 4 2− and HCO 3 –). X-ray Photoelectron Spectroscopy (XPS) analysis indicated that the zirconium and zinc were coordinated with phosphate to form inner sphere complex, and the hydrogen bond was formed between the hydroxyl group of phosphate and the carboxyl group of electrode material, which enhanced the selective adsorption of phosphate. Furthermore, the energy consumption of CDI dephosphorization was calculated as low as 0.0075 kWh/g P and 0.043 kWh/m3 water at 1.2 V. This study was expected to provide the potential electrode materials and theoretical basis for the application of CDI dephosphorization. [ABSTRACT FROM AUTHOR]

• MoS 2 /NOMC electrode exhibited an electrosorption capacity of 28.82 mg/g. • Porous architecture of electrodes facilitated the desalination performance. • Increased conductivity and hydrophilicity were beneficial to the CDI process. • Capacitive and diffusion-controlled processes contributed to electrosorption. • A good regeneration property of MoS 2 /NOMC was demonstrated. Capacitive deionization (CDI) is a promising technology for seawater and brackish water desalination but still suffers from several drawbacks, such as low electrosorption capacity and less efficient desalination performance. In this study, MoS 2 /NOMC (nitrogen-doped highly ordered mesoporous carbon) composite with enhanced hydrophilicity, conductivity and capacitance was successfully synthesized by a hydrothermal process. The MoS 2 /NOMC electrodes showed efficient desalination performances with an electrosorption capacity of 28.82 mg/g at 1.6 V in 250 mg/L NaCl solution and a maximum electrosorption capacity of 30.49 mg/g based on Langmuir fitting. The mechanism of the enhanced desalination performance of MoS 2 /NOMC electrodes was explored through the characterization of the contributions of the capacitor-controlled (electrical double layer capacitor without charge transfer) and diffusion-controlled processes (charge transfer with N-doping of NOMC as well as the various oxidation states (from + 2 to + 6) of molybdenum atoms (Mo) in MoS 2). Capacitor-controlled process played a major role (with the contribution of 73.17%) for the improved desalination performances of MoS 2 /NOMC electrodes compared to the diffusion-controlled process (with the contribution of 26.83%). In addition, MoS 2 /NOMC electrodes showed an excellent regeneration performance, indicating the potential of MoS 2 /NOMC composite as a promising CDI electrode material. [ABSTRACT FROM AUTHOR]

• Floriform WO 3 /C electrode were developed for electrosorption of U(VI) from water. • The charge/discharge process of WO 3 /C primarily belongs to capacitive controlled behavior. • WO 3 /C electrodes achieve a maximum U(VI) electrosorption capacity of 449.9 mg g−1 at 1.2 V. • Electrosorption of U(VI) is credited to synergistic effect of EDLs and pseudocapacitance from WO 3 /C. Decontamination and recovery of uranium(VI) [U(VI)] from radioactive wastewater is vital to sustainable nuclear power production and reclamation of radioactive waste. As a promising technology of water treatment, capacitive deionization for adsorption of U(VI) started to attract attention. Herein, for the first time, a floriform WO 3 /C composite was developed as a pseudocapacitive electrode material for electrosorption of U(VI) from water. The as-prepared WO 3 /C composite was constructed from dozens of 2D nanosheets with a thin amorphous carbon layer, resulting in uniform flower-like particles with hierarchical nanostructure and superior open pore network. The charge/discharge process of WO 3 /C was demonstrated as prominent capacitive controlled behavior by quantization of capacitance contributions. As a result, the WO 3 /C electrodes achieved a maximum U(VI) electrosorption capacity of 449.9 mg g−1 at 1.2 V and good cycling stability after consecutive adsorption-desorption, which is superior to the conventional physical adsorption processes. The superior CDI performance of the WO 3 /C electrode is credited to the synergistic effect of EDLs and pseudocapacitance based on the combination of WO 3 and carbon layer with hierarchical nanostructure. Overall, the facile preparation strategy, the superior electrosorption performances, and the high cycling stability, endow the floriform WO 3 /C electrodes to be a promising electrode material for electrosorption of U(VI) from wastewater. [ABSTRACT FROM AUTHOR]