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[Display omitted] • A magnetic phosphate-functionalized calcium alginate (MPCA) was synthesized. • The mechanical strength improved after in situ magnetization and phosphorylation. • The adsorption process involves multiple adsorption mechanisms. • The excellent magnetic separation of U(VI) from eluent and soil. • An effectiveness in the engineering linked remediation of uranium contaminated soil. The increasingly hazardous and radioactive environmental issues arising from the uranium-contaminated water and soil make it urgent to develop high-yield and efficient adsorbents and the green engineering remediation technology, as well as the engineering remediation evaluation. In this work, we successfully synthesis a phosphate-functionalized magnetic calcium alginate hydrogel (MPCA) in batches by using a simple in-situ coprecipitation method. MPCA keeps maximum adsorption proportion of uranium (≥60.01 %) in the mixed multi-nuclide solution, and high adsorption capacity in different natural simulated uranium-contaminated water systems. In the engineering remediation of natural uranium-contaminated soil, MPCA removes 83.9 % of uranium and 99.8 % of radium in muddy water, even removes 92.9 % of uranium in the soil leaching wastewater. This work also validates a promising green engineering linked soil remediation technology, which combines soil leaching and adsorption separation. The remediated soil meets international emission standards, 92.9 % of uranium in the leachate is removed, 93.2 % of adsorbed uranium is desorbed and enriched. In addition, the reuse of adsorbed leachate and desorbed MPCA also minimize the consumption of engineering water and the derived radioactive water pollution. [ABSTRACT FROM AUTHOR]

[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]