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[Display omitted] • A novel phosphorylated porous polymer was obtained through the simple "knitting" strategy. • The resulted polymer TPP-DFP has a high BET surface area of 1397.62 m2/g with a rich porosity. • The polymer TPP-DFP was the first time used for uranium adsorption from water. • The maximum uranium adsorption capacity of TPP-DFP was 414.26 mg/g. As the nuclear resource industry rapidly progresses, efficient adsorbents play a vital role in separating and eliminating uranium from aqueous solutions. Herein, 9,9-dimethyl-fluorenylphosphonic acid was designed as a phosphate functional monomer and the triptycene as a rigid backbone monomer. Through the "knitting" strategy, a novel triptycene-based phosphorylated hyper-crosslinked porous polymer (TPP-DFP) was obtained by the above monomers. The resulted polymer TPP-DFP has a high BET surface area of 1397.62 m2/g with a rich porosity. The porous polymer TPP-DFP was the first time used for uranium adsorption from water and showed outstanding adsorption performance. The maximum uranium adsorption capacity of TPP-DFP was 414.26 mg/g, which was higher than that of most of other porous adsorbents. In the presence of impurity ions such as Ca2+, Mg2+, Al3+, Co2+, Ni2+, V5+, NO3−, CO 3 2− etc., TPP-DFP exhibited high selectivity (Su up to 99%) for uranium. In addition, TPP-DFP has excellent reusability, and the removal percentage of uranium can reach more than 95% after 5 adsorption–desorption cycles. According to the XPS experiment, the mechanism of interaction between TPP-DFP and U(VI) was mainly due to the complex formed by the phosphate functional groups and U(VI). The theory DFT calculation indicated a 1:2 ratio of U(VI) and phosphate functional group on the two-distinct graft chain, which was consistent with the experimental results. Accordingly, the "knitting" polymerization technique showed potential for preparation effective adsorbents for uranium extraction from water. [ABSTRACT FROM AUTHOR]

[Display omitted] Hydroxylated titanium carbide Ti 3 C 2 (OH) 2 , a representative of MXenes, is employed to investigate adsorption behaviors for uranium and thorium using density functional theory based simulation methods. The structural analysis of the complexes compares very well to existing computational and experimental literatures. A closer look at the adsorption configurations and energies indicates that the main adsorption sites are deprotonated O s atoms of the OH groups terminated on the Ti 3 C 2 (OH) 2 MXene surface. The most stable models for U(VI) and Th(IV) adsorbed on the Ti 3 C 2 (OH) 2 MXene in the gas phase are bidentate and tridentate configurations, respectively. The adsorption ability of Th(IV) on the Ti 3 C 2 (OH) 2 MXene is stronger than that of U(VI). More importantly, the aqueous solution has a remarkable effect on the coordinated environment of uranyl and Th4+ ions in the binding configurations. Uranyl and Th4+ ions adsorbed on the Ti 3 C 2 (OH) 2 MXene in the aqueous environment form pentavalent coordinated structures. Extra OH– ligands from water molecules are found to interact with U and Th atoms compared with the adsorption configurations in the gas phase. Moreover, U-O ax double bonds in the uranyl break to form U-OH bonds in the adsorption model. For all the stable adsorption configurations, the coordinating interaction is the dominant factor, and Th-O s bonds present more covalent nature than U-O s bonds due to the larger charge transfers between Th and O s atoms. This work gives supplement to the experimental observations and will provide deeper insights into the physical chemistry behind the removal of uranium and thorium by using MXenes. [ABSTRACT FROM AUTHOR]