Synthesis of magnetic biochar composites for enhanced uranium(VI) adsorption.

Abstract Magnetic biochar composites were successfully fabricated by pyrolysis of siderite and rice husk under N 2 condition. The results of a variety of characterization implied magnetic biochar displayed porous structures with larger specific surface area. The batch adsorption experiments showed high adsorption properties of magnetic biochar composites toward U(VI) (52.63 mg/g at pH 4.0), whereas U(VI) adsorption was significantly influenced by Na 2 CO 3 and HA. U(VI) adsorbed onto magnetic biochar was reduced to U(IV) by Fe 3 O 4 according to XPS and XANES analyses. In addition, no significant effect of ionic strength of NaCl and EXAFS results, illustrated the inner-sphere surface complexation of U(VI) on magnetic biochar. Owing to the simple synthesis procedure, low cost, high adsorption efficiency, easy separation and environmental friendly, magnetic biochar can be considered as a potential adsorbent for the purification of U(VI)-bearing wastewater in environmental remediation. Graphical abstract Unlabelled Image Highlights • Magnetic biochar was obtained by pyrolysis the rice husk and siderite. • The magnetic biochar has the advantages of low cost and high efficiency. • The interaction mechanism of U(VI) on magnetic biochar was adsorption and reduction. [ABSTRACT FROM AUTHOR]