Adsorption of uranium(VI) from aqueous solution using a novel magnetic hydrothermal cross-linking chitosan

Abstract

The magnetic hydrothermal cross-linking chitosan (HCC–Fe3O4) was prepared by hydrothermal carbonization and was characterized by FT-IR, X-ray diffraction and scanning electron microscopy. The as-prepared HCC–Fe3O4 was used as adsorbent to remove uranium(VI) as functions of contact time, pH, temperature and initial uranium(VI) concentration batch wise. The results indicated that the magnetic HCC–Fe3O4 was favorate for solid–liquid separation and the maximum uranium(VI) adsorption capacity was 263.1 mg/g at pH 7.0 and 25 °C. The adsorption isotherm of uranium(VI) was well fitted by the Langmuir model. The adsorption is a chemical reaction in nature proved by the well described with pseudo-second-order model. The obtained thermodynamics parameters of positive ΔH, positive ΔS, and negative ΔG denoted the adsorption was an endothermic, disorder increasement, and spontaneous process. These results demonstrated that HCC–Fe3O4 was a promising adsorbent for the enrichment of uranium(VI) from aqueous solutions.