Novel cationic polymer modified magnetic chitosan beads for efficient adsorption of heavy metals and dyes over a wide pH range.

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 FeO-CS/PDAC was facilely fabricated by coating poly(acryloyloxyethyltrimethyl ammonium chloride)-modified chitosan on the surface of FeO nanoparticles. The morphology, physical-chemical and magnetic properties of as-prepared FeO-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, FeO-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, FeO-CS/PDAC could be easily separated and effectively regenerated after adsorption. The superior adsorption performance of FeO-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, FeO-CS/PDAC has great potential for practical application in water treatment.