Preparation of amidoxime modified imidazole copolymers and the efficient extraction of U(VI) from the alkaline aqueous solution

Hydroxyl-functionalized cationic porous organic polymers for efficient enrichment and detection of phenolic endocrine disrupting chemicals in water and snapper

Endocrine-disrupting chemicals (EDCs) can disrupt the normal functioning of the endocrine system in organisms, leading to various health issues. Therefore, monitoring EDCs in the environment and food is of significant importance. In this study, a hydroxyl-functionalized ionic porous organic polymer (OH-IPOP) has been synthesized for the first time using 2-benzimidazolemethanol as a monomer. The OH-IPOP exhibited excellent adsorption performance towards phenolic EDCs. An efficient method for determination of phenolic EDCs (p-tert-butylphenol, bisphenol B, bisphenol A and bisphenol F) in environmental water and snapper samples was successfully established by with OH-IPOP as solid-phase extraction sorbent and determination with high-performance liquid chromatography-ultraviolet detection. The method showed good linearity (r2 > 0.998), low detection limits (0.008-0.020 ng mL-1 for lake water, 1.00-3.00 ng/g for snapper), high recovery rates (82.3-106 %), and good precision (relative standard deviation < 6.6 %), making it a highly efficient adsorbent for the enrichment of EDCs in complex sample matrices.

Synthesis and fabrication of segregative and durable MnO2@chitosan composite aerogel beads for uranium(VI) removal from wastewater

To address the imperative need for efficient removal of uranium-containing wastewater and mitigate radioactive contamination risks associated with nuclear energy, the development of materials with high removal efficiency and facile separation is crucial. This study designed and synthesised MnO2@chitosan (CTS) composite aerogel beads by in-situ growing δ-MnO2 on porous CTS aerogel beads. This approach not only mitigates the agglomeration of MnO2 nanospheres but also significantly enhances the porous structure and surface area of MnO2@CTS. These cost-effective and eco-friendly millimeter-scale spherical aerogels exhibited convenient separation properties after adsorption. These characteristics help mitigate the risk of equipment seam blockage and secondary pollution that are often associated with powdered adsorbents. Additionally, MnO2@CTS exhibited remarkable mechanical strength (stress approximately 0.55 MPa at 60 % strain), enabling rapid separation and easy regeneration while maintaining high adsorption performance even after five cycles. Significantly, MnO2@CTS exhibited a maximum adsorption capacity of 410.7 mg/g at pH 6 and 298 K, surpassing reported values for most CTS/MnO2-based adsorbents. The chemisorption process of U(VI) on MnO2@CTS followed the pseudo-second-order kinetic and Dubinin-Radushkevish models. X-ray photoelectron spectroscopy analysis further confirmed the reduction of U(VI) to U(V/IV). These findings highlight the substantial potential of MnO2@CTS aerogel beads for U(VI) removal from aqueous solutions, positioning them as a promising solution for addressing U(VI) contamination in wastewater.

A nanofiber with a p-π conjugated structure designed based on the Jahn-Teller effect for the removal of cupric tartrate from wastewater

Copper organic complexes with strong chemical stability and high solubility in water are difficult to eliminate with traditional adsorbents. In this work, a novel amidoxime nanofiber (AO-Nanofiber) with the p-π conjugated structure was fabricated through homogeneous chemical grafting coupled with electrospinning and applied to capture cupric tartrate (Cu-TA) from aqueous solutions. The adsorption capacity of Cu-TA by AO-Nanofiber was 198.4 mg/g at an equilibrium time of 40 min, and the adsorption performance remains basically unchanged after 10 times adsorption-desorption cycles. The capture mechanism of Cu-TA by AO-Nanofiber was jointly validated by experiments and characterization such as Fourier Transform Infrared Spectrometer (FT-IR), X-ray Photoelectron Spectroscopy (XPS), and Density functional theory (DFT) calculations. These results demonstrated that the lone pair of electrons of the N atom from the amino groups and the O atom from hydroxyl groups in the AO-Nanofiber is partially transferred to the 3d orbital of the Cu(II) ions in Cu-TA, leading to the Jahn-Teller distortion of the Cu-TA and the more stable structure of AO-Nanofiber@Cu-TA was generated.

Layered double hydroxide intercalated with dimethylglyoxime for highly selective and ultrafast uptake of uranium from seawater

In this study, we demonstrate the first example of a MgAl layered double hydroxide intercalated by a ketoxime compound (dimethylglyoxime, DMG), that is, MgAl-DMG-LDH (abbr. DMG-LDH), which exhibits excellent capture of uranium (U(VI)) both at high (ppm) and low (ppb) concentrations. The as-formed DMG-LDH shows an enormous maximum U(VI) sorption capacity (qUm) of 380 mg g^-1 and an exceptionally rapid sorption rate (k₂ = 2.97 g mg^-1 min^-1), reaching a high uptake of 99.14% within 5 min. For natural and contaminated seawater with high concentrations of Na⁺, Ca²⁺, Mg²⁺ and K⁺ concomitant cations, the DMG-LDH still can trap ∼85% U, displaying highly effective sorption toward U. The interaction mechanism between UO₂²⁺ and DMG^2- provides an important reference for the development of highly effective capture of U(VI) by ketoxime materials. The DMG-LDH is currently the best ketoxime material for uranium extraction from nuclear waste and seawater.