Improving Re(VII) Adsorption on Diisobutylamine-Functionalized Graphene Oxide

In this study, we synthesized a series of diisobutylamine-functionalized graphene oxides as adsorbents (GO-DEA-DIBA) by adjusting synthetic conditions for the efficient adsorption of rhenium(VII) (Re(VII)). Results indicated that the best mass ratio was 10 mg of sodium carbonate to 5 g of distilled water, and a cooling time of 44 min could prevent the exfoliation of functional groups and achieve higher uptake capacity of Re(VII). The maximum uptake of Re(VII) was found to be 140.82 mg g–1 at 303 K with an initial Re(VII) concentration of 800 mg L–1. More importantly, it can be clearly seen that mixed ions (Cu2+, Zn2+, and Mn2+) could almost separate with Re(VII) on the adsorption of ReO4– onto the GO-DEA-DIBA with a weak acidity solution. Re(VII) was adsorbed on the GO-DEA-DIBA via charge interactions between tertiary amine groups and ReO4– by infrared spectroscopy and X-ray photoelectron spectroscopy analysis. In addition, adsorption behavior, adsorption isotherms, desorption, and regeneration are also discussed. This study not only discusses the thermodynamic stability of functional graphene oxide but also provides a new method for the separation of Re(VII) from solution using GO-DEA-DIBA owing to its environmental friendliness and relatively low cost.