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• Synthesis of a novel U (VI) adsorbent HCP-Phenylalaninol (HCP-PAO), a porous hypercrosslinked aminol. • The hypercrosslinked product is simple to synthesize and shows porosity, large surface area and good thermodynamic stability properties. • HCP-PAO shows efficient U (VI) adsorption performance (Q e = 369.5 mg/g, pH = 7) and long service life. • HCP-PAO shows good selective toward uranium at simulated seawater. Uranium mining from seawater has sparked a lot of research curiosity. Here, we synthesized a porous hypercrosslinked phenylalaninol (HCP-PAO) for U (VI) adsorption from water, in which phenylalaninol bearing amino and hydroxyl groups was used as the monomer, and biphenyl dichlorobenzyl (BCMP) was used as the external crosslinker. The resulting porous adsorbent has a surface area of 562.6 m2/g and a pore volume of 0.41 cm3·g−1. The pore size distribution is focused around 3–4 nm, indicating that it is a typical mesoporous polymer. The adsorbent had the most promising adsorption performance at pH = 7, reaching adsorption saturation in a 100-ppm uranium-doped solution for 2 h (adsorption capacity of 369.5 mg/g). HCP-PAO was particularly sensitive to uranium in complicated settings (56.3 % removal rate), and the adsorption mechanism closely resembled the Langmuir model and the pseudo-second-order model well. The practically consistent adsorption capacity of the HCP-PAO after five adsorption/resolution studies indicated its high recyclability. The mechanism of uranium extraction by HCP-PAO is the synergistic coordination of –NH 2 and –OH with U (VI). HCP-PAO had an adsorption capacity higher than 100 mg/g at pH = 8 which is close to the pH of natural seawater, and showed good selectivity for U (VI) in simulated seawater experiments (removal rate over 55 %). Our research suggests that the novel hypercrosslinked product HCP-PAO can be applied as an adsorbent to efficiently capture U (VI) from water, and also it has great potential in seawater uranium extraction as well as expanding the research concept of porous uranium adsorbent. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carboxyl and amidoxime bifunctional polymer was grafted on MIL-101 via surface initiated ATRP; • Highly efficient uranium adsorbent, adsorption capacity reached 1086 mg·g−1; • Synergistic effect of carboxyl and amidoxime groups promote uranium adsorption; • High uranium selectivity and reusability of adsorbent in simulated seawater. Nuclear energy can effectively alleviate the carbon emission problem caused by fossil fuels. Herein, a highly effective uranium adsorbent MIL-101-SMA-AO modified with carboxyl and amidoxime groups was prepared by a surface-initiated atom transfer radical copolymerization (ATRP) of styrene and maleic anhydride on MIL-101 (Cr) and the subsequent amidoximation. MIL-101-SMA-AO shows ultra-high BET specific surface area (greater than1300 m2∙g−1) and high efficiency adsorption performance, the maximum uranium adsorption capacity reached 1086 mg·g−1. It also shows high selectivity for U (VI) in a simulated seawater and excellent recyclability, the uranium adsorption capacity slightly dropped after five adsorption/desorption cycles. The affecting factors of uranium adsorption process were investigated by batch adsorption experiments under different adsorption conditions. Besides, the results of adsorption kinetics and thermodynamics show that the adsorption process of MIL-101-SMA-AO on U (VI) is controlled by chemical rate and is monolayer adsorption. The synergistic effect of carboxyl and amidoxime groups on the strong chelation with uranium were thought to afford the adsorbent high adsorption property and selectivity for uranium. MIL-101-SMA-AO provides a valid and promising program for the study of uranium extraction from seawater. [ABSTRACT FROM AUTHOR]

[Display omitted] • A porous Ag+ decorated PCN-222@graphene oxide-chitosan foam adsorbent was developed. • The adsorbent exhibited the excellent macrostructure and antibacterial property. • The adsorbent showed high U(VI) adsorption capacity, Q e reached 348.8 mg/g. • Mechanisms were coordination, electrostatic interaction and intraparticle diffusion. • The adsorbent possessed great potential to efficiently recover U(VI) from seawater. In this study, a 3D porous Ag+ decorated PCN-222 @ graphene oxide-chitosan foam adsorbent (APGC foam), which is grounded upon the growth of Ag+ decorated zirconium-metalloporphyrin metal–organic framework (PCN-222) on an EDTA-silane modified graphene oxide-chitosan foam substrate (EGC foam) for recovering U(VI) ions out of the seawater, was designed and synthesized with the in-situ growth and solvothermal method. The successfully synthesized APGC foam with excellent antibacterial property not only overcame the difficulty of powder adsorbents in practical application, but also reduced the negative impact of bacteria on the adsorption performance of porous material. The APGC foam showed excellent adsorption capacity (348.8 mg/g), selectivity and reusability of U(VI) adsorption at nearly seawater pH, and this also exhibited excellent adsorption performances in the seawater. The influence factors in the adsorption process were investigated by static and dynamic adsorption in different conditions. Moreover, the U(VI) adsorption mechanism of APGC foam was determined as the comprehensive effect of coordination, electrostatic interaction and intraparticle diffusion. All results indicated that APGC foam was an encouraging adsorbent to recover U(VI) out of the seawater. [ABSTRACT FROM AUTHOR]