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[Display omitted] • A hybrid ZIF-8@FeNPs was successfully prepared. • The removal mechanism of Sb (V) was proposed. • Sb(V) in mining wastewater (1.121 mg·L−1) was removed 89.7 %. • ZIF-8@FeNPs was separated and recycled. The removal of antimonate (Sb(V)) species from wastewaters has become a growing concern due to their known genotoxicity and carcinogenicity. In this paper, a hybrid ZIF-8@FeNPs material was synthesized from Zeolite Imidazole Framework-8 (ZIF-8) and zero-valent iron nanoparticles (n ZVI) and subsequently used to remove Sb(V) from aqueous solution. Characterization indicated that ZIF-8@FeNPs were successfully synthesized and that the valence state of Sb(V) did not change during the removal process, where adsorption of Sb(V) was facilitated by the high specific surface area and porosity of the hybrid. Advanced characterization also showed that Zn-OH and iron oxides were adsorbed on the material after complexation with Sb(V). Kinetic, isothermal, and thermodynamic modeling indicated that the adsorption process followed pseudo-second-order kinetics, via multilayer adsorption which was spontaneous and endothermic. A Sb(V) removal mechanism based on adsorption was proposed. In mining wastewater containing 1.121 mg·L−1 Sb(V), 89.7 % could be removed by the material. During repeated reuse of ZIF-8@FeNPs for the removal of 1 mg·L−1 Sb(V) through four successive cycles, the removal efficiency was still relatively high (39.1 %) after the fourth cycle indicating good potential for practical applications. In addition, ZIF-8@FeNPs also exhibited magnetic properties, which demonstrated that Sb(V) could be easily recovered from wastewater post removal by ZIF-8@FeNPs. [ABSTRACT FROM AUTHOR]

[Display omitted] • COFs and CNTs composites were synthesized by in-situ synthesis. • The synergistic effect improved the adsorption capacity and selectivity. • The removal mechanism of samples was clarified through various characteristic modes. • The problem of U (VI) removal from the rare earth tailings wastewater had been solved. The wastewater containing uranium produced in the mining process is harmful to the environment and life safety due to the inherent biotoxicity and radioactivity of uranium. In this paper, 4,4′-diamino-[1,1′-biphenyl]-3,3′-diol and 2,4,6-triformylphloroglucinol were in situ synthesized β -ketoenamine covalent organic frameworks (COFs) on the surface of carbon nanotubes (CNTs) to obtain a composite of CNT/COF-OH for removal uranium in the rare earth tailings wastewater. Grafting COFs with a large number of specific uranium-binding groups and redox-active sites on the surface of CNTs, CNT/COF-OH can effectively enhance the uranium ion selectivity and adsorption capacity. Furthermore, CNTs have good electron transport capacity and π-conjugation properties, electrons can be effectively transferred from CNTs to COFs, which increases the electron density of the adsorption functional groups, resulting in an increase of the adsorption energy and reductive activity for U (VI), thus improving the removal efficiency. In addition, the skeleton of COFs can be supported by CNTs, thus reducing collapse. Through the synergistic effect of composite, CNT/COF-OH had a good uranium adsorption capacity of 518.2 mg g−1. The adsorption capacity of CNT/COF-OH was increased by 390.7 %, 54.6 %, and 84.5 % compared with those of single CNTs, COF-OH, and mixed CNT + COF-OH, respectively. The selective separation coefficient of CNT/COF-OH was 1.6 times higher than that of COF-OH. The experiment of uranium removal was carried out in the rare earth tailings wastewater using CNT/COF-OH, the removal rate reached 96.7 %. The COFs modified CNTs with synergistic effect have important theoretical and practical significance for the safety problems caused by harmful ions in wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • Advantages and limitations of MSPs for wastewater treatment were discussed. • IX can be a resourceful tool to recover metal by products from wastewater. • Equilibrium and kinetic models for batch and continuous systems were summarized. • Integrated systems are pointed out as future perspectives for by-products recovery. A future scenario of water scarcity, combined with minerals resources exhaustion, led to the development of treatments capable to achieve water reuse and by-products recovery. Whereas most membrane separation processes (MSPs) guarantee a wastewater treatment at reuse level, their concentrate represents in most cases a liability due to its greater complexity and environmental impact. However, rather than its treatment, the concentrate from mining wastewater treatment is presented as an opportunity for by-products recovery by ion exchange (IX) resins. It was summarized the efficiency and limitations of MSPs (pressure-, thermal-, osmotic-, and electrical-driven processes) for reuse water reclamation from acid mining wastewater, followed by a critical discussion of IX process for metallic compounds recovery from their concentrate. The advantages of IX over conventional treatment and disposal practices were highlighted, with special attention given to factors that affect the IX equilibrium, kinetics, and thermodynamics, in batch and continuous operation, in addition to the models used to describe them. Models for error estimations were presented as well along a criticism for the use of linearized models for data interpretation. An overview of the lab-scale studies pointed out that IX would be an interesting alternative for concentrated solutions valorization. As an attempt to scale up IX for pilot- and full-scale applications, it was presented a step-by-step mass balance that allows for a batch system design and resins mass estimation for a given concentrate flow rate. Finally, future perspectives are presented pointing out to integrated IX system, impregnated resins, and columns systems, that represents knowledge gaps to be covered in the next few years. [ABSTRACT FROM AUTHOR]