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The pollution of heavy metal ions in water poses a serious threat to human being and ecosystems. Here, we report polyamidoxime (PAO) brush grafted graphene oxide (GO) as a highly efficient adsorbent for extraction of toxic metal cations from water. Surface-initiated atom transfer radical polymerization was used to grow polyacrylonitrile (PAN) brushes on GO, followed by conversion of the nitrile groups in PAN into amidoxime groups, which had high binding affinity toward heavy metal cations. The PAO brush grafted GO demonstrated significantly fast adsorption kinetics and large adsorption capacity. At optimal pH 5, the PAO brush grafted GO can achieve maximum adsorption capacities of 116.7 mg g −1 for Pb(II), 258.6 mg g −1 for Ag(I), 192.2 mg g −1 for Cu(II), and 167.9 mg g −1 for Fe(III), which were significantly larger than those of small molecule functionalized GO. Mechanism analysis suggested that the enhanced adsorption performance was due to the myriads of functional groups in PAO brushes that were easily accessible to metal ions because of the swelling of the polymer brushes in water.

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Herein, we report a convenient method for the preparation of a selfassembled supramolecular material containing phosphoric acid (PM) choosing phytic acid and melamine as the two organic building blocks. The PM was chosen as an adsorbent for the first time for the fast adsorption and recovery of U(VI) from acidic aqueous media. The batch adsorption experiments showed that PM-9 possesses a very fast adsorption kinetic with the adsorption process for U(VI) from acidic water reaching equilibrium within 2 min. A considerable adsorption capacity of 1034.9 mg/g and an excellent selectivity 58.6% toward U(VI) in acidic aqueous solution were obtained. The adsorption capacity in dynamic column experiment was determined to be 251.0 mg g −1 , with the recovery efficiency as high as 99.4% when using Na 2 CO 3 as a stripping agent. The adsorption mechanism was probed by FT− IR, XRD, SEM, XRF, and XPS, implying the double bond oxygen atom of phosphoric acid and the nitrogen atom of amino group complexes with uranyl ions in the acidic media.

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