Magnetite/ß-cyclodextrin/fly ash composite as an effective and recyclable adsorbent for uranium(VI) capture from wastewater.

ABSTRACT

As a novel adsorbent for the separation of uranium(VI) from wastewater, Magnetite/ß-cyclodextrin/fly ash composite (Fe3O4/ß-CD/FA) was first prepared via a chemical coprecipitation technology. The characterization results indicated that Fe3O4 and ß-CD had been successfully loaded on FA, which had brought abundant oxygen-containing functional groups, providing numerous adsorptive sites for the removal of uranium(VI). At pH = 5.0 and T = 25 °C, the maximum uranium(VI) removal efficiency and capacity of Fe3O4/ß-CD/FA were higher to 97.8% and 444.4 mg g-1, respectively. Pseudo-second-order and Langmuir models fitted better with the experimental data, illustrating that chemical adsorption dominated the uranium(VI) removal process. In addition, Fe3O4/ß-CD/FA showed good anti-interference ability and recoverability. After five cycles, the removal rate of uranium(VI) on Fe3O4/ß-CD/FA was still higher to 90.4%. The immobilization of uranium(VI) on Fe3O4/ß-CD/FA was mainly ascribed to the synergism of redox reaction, complex reaction, chemical reaction and electrostatic interaction. Given the above, Fe3O4/ß-CD/FA would be regarded as an efficacious, green and promising adsorbent for uranium(VI) separation from wastewater.