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Wastewater containing highly toxic and non-biodegradable heavy metals and organic dyes poses a serious threat to ecological environment and human health. Adsorption has been regarded as a promising technology to purify this kind of wastewater. Therefore, it is of great importance to develop efficient adsorbents. Herein, a magnetically recyclable adsorbent Fe 3 O 4 -CS/PDAC was facilely fabricated by coating poly(acryloyloxyethyltrimethyl ammonium chloride)-modified chitosan on the surface of Fe 3 O 4 nanoparticles. The morphology, physical-chemical and magnetic properties of as-prepared Fe 3 O 4 -CS/PDAC was fully characterized by various techniques. Its adsorption behaviors towards heavy metal Cr(VI) and organic dye sunset yellow (SY) were systematically investigated. Evidently, Fe 3 O 4 -CS/PDAC exhibited adsorption capacities of 163.93 and 769.23 mg/g for Cr(VI) and SY respectively, much higher than other reported adsorbents. Besides, batch experiment results showed that adsorption capacities decreased slightly with pH increasing from 2.0 to 10.0. Furthermore, Fe 3 O 4 -CS/PDAC could be easily separated and effectively regenerated after adsorption. The superior adsorption performance of Fe 3 O 4 -CS/PDAC could be attributed to the electrostatic interaction and ion exchange between target pollutants and the grafted cationic polymer. Owing to its high adsorption capacity over a wide pH range, rapid separation, easy regeneration and good reusability, Fe 3 O 4 -CS/PDAC has great potential for practical application in water treatment. Unlabelled Image • Novel cationic polymer modified magnetic chitosan beads (Fe 3 O 4 -CS/PDAC) were synthesized. • Fe 3 O 4 -CS/PDAC exhibits a high adsorption capacity towards Cr(VI) and sunset yellow over a wide pH range (2.0-10.0). • Superior adsorption performance is attributed to high density of quaternary ammonium groups on the grafted polymer chains. • Electrostatic interaction and ion exchange are involved in the adsorption process. [ABSTRACT FROM AUTHOR]

[Display omitted] • Self-floating cyclodextrin-modified polymer was prepared. • The adsorption performance of TFCD and FTFCD was compared. • FTFCD simplified the recycling process by wrapping a hollow glass microsphere. • Porous structure and hydrophobic cavity favor the dye adsorption. • Polymers exhibited excellent selectivity toward cationic dyes. The separation and recycling processes of current cyclodextrin (CD)-based adsorbents are complicated. Thus, a novel composite based on a large surface area, porous, and self-floating tetrafluoroterephthalonitrile (TFN)-crosslinked CD polymer (FTFCD), was fabricated, characterized and applied to treat cationic dye pollutants. The characterization showed a porosity, good thermal stability, a stable crystal structure, and abundant functional groups on the prepared FTFCD, which had demonstrated great improvement on its adsorption capacity towards attention grabbing pollutants. The removal efficiency of the adsorbents for malachite green (MG) remained above 95% at pH 1 ∼ 10. In addition, the adsorbents were found to rapidly reach equilibrium governed by the pseudo-second-order kinetic model, and the maximum adsorption capacity of FTFCD was 1390.263 mg/g, as corroborated by the Langmuir isotherm model. While the phenolate groups of FTFCD found to electrostatically interacts with the MG strong cationic quaternary amine group, hydrogen-bonding was responsible for the hydroxyl group of FTFCD and the quaternary amine group binding. Meanwhile, the triangular cone configuration of MG makes it easy to be entrapped and absorbed in the hydrophobic cavity. Besides, after regeneration of exhausted FTFCD for five successive cycles, the MG removal efficiency still reached more than 80%. Thus, FTFCD could be applied as a potential alternative adsorbent for cationic dye removal owing to its excellent adsorption performance, convenient recycling, wide pH application, and environmental friendliness. [ABSTRACT FROM AUTHOR]