Efficient capture of strontium from aqueous solutions using graphene oxide-hydroxyapatite nanocomposites.

Three-dimensional hierarchical flower-like graphene oxide-hydroxyapatite (GO-HAp) nanocomposites were synthesized by a simple biomimetic method in a modified simulated body fluid (mSBF). The obtained GO-HAp nanocomposites were characterized by field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and N-2 adsorption-desorption analysis. The formation mechanism was proposed and the prepared GO-HAp was applied as an adsorbent to remove strontium from large volumes of aqueous solutions. A maximum adsorption capacity of 702.18 mg g(-1) was achieved on GO-HAp, almost two fold higher than that of bare HAp and nine fold higher than that of GO. The effects of pH, adsorbent content, contact time and Sr2+ initial concentrations on Sr2+ removal from solution by GO-HAp were systematically investigated, and the results indicated that the removal of Sr2+ by GO-HAp was weakly dependent on solution pH. The results herein reveal that the GO-HAp nanocomposites had exceptional potential as a suitable material for preconcentration and solidification of radiostrontium from large volumes of aqueous solutions in nuclear waste management and radiostrontium pollution cleanup.