Phosphatidyl-assisted fabrication of graphene oxide nanosheets with multiple active sites for uranium(vi) capture

Abstract

A novel kind of graphene oxide-based (GO-based) adsorbent was successfully prepared by chemical modification with cetyltrimethylammonium bromide (C₁₆TAB) and phytic acid (PA) for adsorbing uranium (U(VI)). A close relationship between PA and GO interlayer spacing was investigated; the optimal spacing was 3.88 Å with 4.5 mL PA. A series of adsorption experiments were carried out with the as-prepared product (denoted as GO–C₁₆TAB–PA) to capture U(VI) ions. The adsorption capacity of the GO–C₁₆TAB–PA adsorbent can reach 923 mg g⁻¹ (298.15 K) with an excellent removal rate (∼90%), which demonstrates a 527% increment compared with that of pristine GO in the same environment (pH = 8, C_o = 500 mg L⁻¹). Meanwhile, the adsorption equilibrium time of GO–C₁₆TAB–PA was shortened by 50% compared with that of pristine GO. In addition, the GO–C₁₆TAB–PA adsorbent exhibited superior recyclability with a six-adsorption–desorption-cycle test. Finally, the fabricated GO–C₁₆TAB–PA adsorbent exhibited excellent adsorption performance in simulated seawater, providing a theoretical guide and methodology for further seawater extraction of uranium(VI).