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[Display omitted] • The preparation process of the CDI electrode is simplified. • Laser-induced graphene (LIG) can be directly used as a CDI electrode. • LIG electrode is modified by one-step electrodeposition of Co 4 S 3. • The LIG6/Co 4 S 3 -15 presents a high adsorption capacity of 2702.79 mg g−1. • UO 2 2+ adsorption is attributed to the synergistic action of EDLs and pseudocapacitance. It has been proved that capacitive deionization (CDI) technology possesses a significant potential for uranium capture. However, the CDI performance has been limited by the complex preparation process of the electrodes and the poor adhesion between electrode materials and collectors. Here we combine the laser-induced graphene (LIG) and the electrodeposition to develop the LIG/cobalt sulfide (LIG/Co 4 S 3) electrodes with good adsorption performance. The obtained LIG6/Co 4 S 3 -15 electrode has both electrical double layers (EDLs) and pseudocapacitance properties, with a specific capacitance of 24.27 F g−1, which is 1.82 times higher than that of LIG6 (13.36 F g−1). The LIG6/Co 4 S 3 -15 electrode exhibited a high adsorption capacity of 2702.79 mg g−1. The advantages of this electrode preparation method are mainly attributed to the synergistic effect of the following aspects: (i) simplified graphene preparation by avoiding wet chemistry and post-treatment steps; (ii) simplified tedious electrode preparation such as electrode slurry distribution and sheet coating; (iii) the three-dimensional structure of LIG provides not only the conductive network but also the site for Co 4 S 3 nanosheet growth, thus avoiding nanosheet aggregation. The abundant pore structure of the conductive graphene substrate and the layered structure of the Co 4 S 3 nanosheets enable the LIG6/Co 4 S 3 -15 electrode with fast charge/ion transport, high hydrophilicity and superior pseudocapacitance, allowing uranyl (UO 2 2+) to be firstly electrosorbed, then physicochemically adsorbed, and finally electrocatalytically reduced/deposited onto the electrode. This study will offer a simple and environmentally friendly method for the synthesis of electrodes and provide a reference for the design of efficient electroadsorption materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • A rich-mesoporous biocarbon (CSKN-15) was synthesized and analyzed. • The ultra-high U-selective electrosorption coefficient from the mixed solution. • The diffusion process of U(VI) into the pores is the key in the electrosorption. • Faradaic reactions were first carefully analyzed in the electrosorption of U(VI). • The formation mechanism of uranium peroxide species was revealed. Constructing the excellent rich-mesoporous carbon and exploring its electrosorption process are keys to promote the electrosorption industrialization of uranium. In this work, we develop a rich-mesoporous biocarbon by using alkali-thermal-pyrolysis and ammonia low-temperature plasma, and then systematically investigate its electrosorption kinetics and mechanism of U(VI) considering a series of Faradaic side reactions. After the above treatment, the electrosorption efficiency of U(VI) onto biocarbon improves from 49.75% to 94.45%, and the ultra-high U-selectivity coefficient (S U/M) is higher than 120 from the mixed solution. The kinetic diffusion process of U(VI) into the pores is crucial, even in different water systems. Importantly, Faradaic side reactions are proved to be non-negligible factors in the electrosorption of uranium. Especially, the oxygen reduction at the cathode can convert dissolved oxygen into H 2 O 2 , which oxides the amorphous electro-reduced U(V, IV) to U(VI), and finally forms crystalline uranium peroxide species. To sum up, this work not only offers an excellent uranium-selectivity electroadsorbent, but firstly confirms the influence of Faradaic side reactions that has been ignored in the current electrosorption of uranium. [ABSTRACT FROM AUTHOR]

[Display omitted] • Modified carbon black (CB) by O 2 plasma technology for improving CDI capacity. • The effect and mechanism of plasma modified CB (PCB) to improve CDI were explored. • PCB improved the salt removal performance 6.9 times that of the original CB (OCB) • PCB can be applied to improve CDI of various active materials. • PCB has universal applicability in purifying brine, heavy metals and radionuclides. Previous research on capacitive deionization (CDI) mainly focuses on electrode active materials, while the research on conductive additive and their modification for improving CDI performance are rarely reported. In this work, we mainly investigate the effect and mechanism of oxygen (O 2) plasma-modified carbon black (PCB) to enhance CDI performance. The CB treated with O 2 plasma at 100 W for 10 min (CB-100 W-10 min) was assembled with activated carbon (AC) to form a CB-100 W-10 min/AC electrode with excellent desalination performance (32.54 mg g−1), 6.9 times that of the original CB/AC electrode (OCB/AC, 4.91 mg g−1). The roles of the specific surface area, hydrophilicity, electrical conductivity, and specific capacitance of CB in enhancing the performance of CDI were explored, and the interaction mechanism between H 2 O molecules and CB was investigated using molecular dynamics (MD) simulations. The advantages of PCB are mainly attributed to the synergy of the following aspects: (i) The excellent three-dimensional network structure acts as a "bridge" between activated carbon and increases the contact sites for allowing more PCB and AC to participate in the electrosorption process; (ii) Shorter electron transmission paths and more electron transmission channels between PCB and AC promote the electrosorption rate; (iii) High surface roughness and oxygen-containing functional groups of PCB boost hydrophilicity and dispersibility. Interestingly, we found that PCB possesses universal applicability in the enhancement of deionization performance of various active materials for purification of brine, heavy metals and radionuclides. This work unprecedentedly applies plasma technology to the modification of conductive additive, providing new ideas for material modification and improvement of CDI technology. [ABSTRACT FROM AUTHOR]