Interaction mechanisms of U(VI) and graphene oxide from the perspective of particle size distribution

Graphene oxide (GO) is an ideal adsorbent due to excellent physicochemical properties. Humic acid (HA) is ubiquitous in aquatic and soil environment, which can affect the migration of metal ions. In this study, we investigated the sorption mechanisms of U(VI) onto GO surfaces in the presence of HA. pH dependent and ionic strength independent sorption process were observed and the concentration of HA is positively proportional to U(VI) sorption capacities. Results also suggest that a pre-mixing HA + U(VI) gave better results than a pre-mixing of GO + HA, which can be explained by the size distribution of different GO systems.