Highly Efficient Enrichment of Radionuclides on Graphene\nOxide-Supported Polyaniline

Abstract

Graphene\noxide-supported polyaniline (PANI@GO) composites were\nsynthesized by chemical oxidation and were characterized by SEM, Raman\nand FT-IR spectroscopy, TGA, potentiometric titrations, and XPS. The\ncharacterization indicated that PANI can be grafted onto the surface\nof GO nanosheets successfully. The sorption of U­(VI), Eu­(III), Sr­(II),\nand Cs­(I) from aqueous solutions as a function of pH and initial concentration\non the PANI@GO composites was investigated. The maximum sorption capacities\nof U­(VI), Eu­(III), Sr­(II), and Cs­(I) on the PANI@GO composites at\npH 3.0 and <i>T</i> = 298 K calculated from the Langmuir\nmodel were 1.03, 1.65, 1.68, and 1.39 mmol·g^–1, respectively. According to the XPS analysis of the PANI@GO composites\nbefore and after Eu­(III) desorption, nitrogen- and oxygen-containing\nfunctional groups on the surface of PANI@GO composites were responsible\nfor radionuclide sorption, and that radionuclides can hardly be extracted\nfrom the nitrogen-containing functional groups. Therefore, the chemical\naffinity of radionuclides for nitrogen-containing functional groups\nis stronger than that for oxygen-containing functional groups. This\npaper focused on the application of PANI@GO composites as suitable\nmaterials for the preconcentration and removal of lanthanides and\nactinides from aqueous solutions in environmental pollution management\nin a wide range of acidic to alkaline conditions.