▎ 摘　　要

Little is known on the interaction of graphene oxide (GO) with layered clay mineral and its effects on the U(VI) retention properties of layered clay mineral. In this study, the interaction of GO with Na-montmorillonite (denoted as MMT in this study) typical of layered clay mineral is characterized in detail. Besides, the differences between single (i.e., GO or MMT) and binary adsorbent system for U(VI) sorption as a function of contact time, pH and sorption isotherms are studied. The results show that after GO is added to MMT, there is a change in morphology, interlayer spacing, surface area, surface charge, surface functional groups and consequently U(VI) retention properties of MMT. GO with much smaller particle size can enter the interlayer as well as distribute on the surface of MMT, which provides more active binding sites for increasing the maximum sorption capacity of MMT for U(VI) by >50% at pH 5.0. This study provides a systematical study of U(VI) migration in single and binary geological media by combining macroscopic and microscopic investigations, which can facilitate the assessment of co-migration of GO and radionuclide in environments. (C) 2018 Published by Elsevier B.V.