Removal performance of phosphorylated graphene oxide-chitosan composite towards Eu(III)

In this work, a novel phosphorylated graphene oxide (GO)-chitosan (CS) composite (denoted as GO-CS-P) was rationally prepared and applied for Eu(III) enrichment. According to the macroscopic experimental results, the sequestration of Eu(III) by GO-CS-P was ultrafast and the sorption equilibrium reached within 5 min. Based on Langmuir model fit, the maximum sorption capacity of Eu(III) at pH 5.5 and 293 K was calculated to be 106.14 mg/g, being higher than a variety of the previously reported materials. More importantly, GO-CS-P could effectively and selectively capture Eu(III) from the aqueous solution of high salinity and multiple components. The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) analyses suggested that Eu(III) mainly formed inner-sphere complexes with the surface phosphonate and carboxyl groups. Overall, the newly synthesized GO-CS-P composite possessed great application potential in the remediation of trivalent lanthanide/actinide-polluted groundwater.