RETRACTED: Preparation of Amidoxime-Functionalized β-Cyclodextrin-Graft-(Maleic Anhydride-co-Acrylonitrule) Copolymer and Evaluation of the Adsorption and Regeneration Properties of Uranium

Abstract

The β-cyclodextrin-graft-(maleic anhydride-co-acrylonitrule) copolymer (β-CD-g-(MAH-co-AN)) synthesized through radical polymerization reactions of β-cyclodextrin (β-CD) with maleic anhydride (MAH) and acrylonitrule (AN) in the special monomer proportion, chemically modify with amidoxime groups to obtained the new adsorbent, which was terms as amidoxime-functionalized β-cyclodextrin-graft-(maleic anhydride-co-acrylonitrule) copolymer (β-CD-g-(MAH-co-AO)). Based on the characteristic results of Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), X-ray Diffraction (XRD), and thermalgravity analysis (TGA) techniques, the grafted nitrile groups were successfully converted to amidoxime groups by reaction with hydroxylamine. In this report, the influence of different factors such as pH value and ionic strength, solid-liquid ratio, contact time, initial U(VI) concentration, and temperature on adsorption was investigated by a batch adsorption experiment. The adsorption process fitting results show that the adsorption followed the Langmuir isotherm model and the maximum adsorption capacity was 0.747 g/g at pH 4.0. In addition, the regeneration performance was investigated by varying the concentration of eluent, temperature, and contact time. Under the desorption condition of 0.10 M HNO3, the adsorbents can be reused 12 times in the case that the adsorption capacity was not significantly reduced. The functionalized copolymer exhibits high selectivity under circumstance of other co-existing ions is present in the solution.

Uncommon Sorption Mechanism of Aromatic Compounds onto Poly(Vinyl Alcohol)/Chitosan/Maleic Anhydride-β-Cyclodextrin Hydrogels

“…This is accompanied by the incidence of shoulders in the DTG curves ( Figure 4B at temperatures around 270 °C (Tm,3)), which might be related with the chitosan degradation temperature [61]. Further, the functionalized MA-β-CD have the weight loss at 300 °C, consistent with the weight loss of β-CD [62].…”

An Efficient Uranium Adsorption Magnetic Platform Based on Amidoxime-Functionalized Flower-like Fe3O4@TiO2 Core–Shell Microspheres

“…As shown in Figure E, the pore diameters of Fe 3 O 4 @TiO 2 -AO (13 nm) were between those of Fe 3 O 4 (4 nm) and Fe 3 O 4 @TiO 2 (25 nm), which was additional compelling evidence that indicated the formation of an anatase nanosheet layer and amidoxime grafting on Fe 3 O 4 . TGA in Figure F revealed that Fe 3 O 4 @TiO 2 -AO and Fe 3 O 4 @TiO 2 -AO-U­(VI) suffered from appreciable weight loss from 200 to 500 °C compared with Fe 3 O 4 @TiO 2 , and the apparent degradation of Fe 3 O 4 @TiO 2 -AO (∼19% weight loss) indicated that a large number of amidoxime groups had been grafted onto Fe 3 O 4 @TiO 2 . , The hydrophilic ability of the Fe 3 O 4 @TiO 2 -AO composite was evaluated by the dispersibility in aqueous solution. The Fe 3 O 4 @TiO 2 -AO particles remained well dispersed and stable after 10 h, and it took 38 h for the particles to settle down completely (Figure S4).…”

“…The addition of N,N′-methylenebisacrylamide enabled the linear molecules to join together, forming a network structure. Then, potassium persulfate (K 2 S 2 O 8 , 0.5 wt %) was added to the mixture and heated to 80 °C in an oil bath for 3 h. The product (denoted as Fe 3 O 4 @TiO 2 -CN) was separated by a magnet and then washed and dried in vacuum at 45 °C for 12 h. 30 The amidoxime-functionalized Fe 3 O 4 @TiO 2 magnetic microspheres were synthesized by treating Fe 3 O 4 @TiO 2 -CN with hydroxylamine solution (NH 2 OH•HCl). Fe 3 O 4 @TiO 2 -CN (0.1 g) was slowly added into a mixture of ethanol and water (volume ratio of 1:1) containing NH 2 OH•HCl with mechanical stirring at room temperature.…”

Amplified Single-Atom U–O Interfacial Effect Originated from U 5f-O 2p Hybridization over UOx/GO for Enhanced Nitrogen Reduction Reaction

“…39 Comparing with pristine GO nanosheets, the FTIR spectra of UO x /GO exhibited a span-new peak at 884.81 cm −1 , which could be attributed to the stretching vibration of the O�U�O. 40,41 Meanwhile, the −OH, −COOH, and −C−O peaks all presented significant dampening after the confinement of the oxygen-enriched uranium precursor, further confirming that the uranium precursor was trapped by the oxygen-containing functional groups on the GO nanosheets.…”