Promising amide acid modified monolayer graphene for simulating the ultraefficient separation of 90Sr2+ from 137Cs+

The effective separation of coexisting 90 Sr 2+ and 137 Cs + in nuclear wastewater has been a persistent critical issue for water purification and recovery of valuable radioactive materials. In this study, a new monolayer amide modified graphene solid-phase adsorbent material, aminographene-aminocarbonylmethylglycine (AGO-AMG), with specific selectivity was developed to separate Sr 2+ from Cs + . At pH = 12, the simulated separation process of radioactive 90 Sr 2+ from 137 Cs + via AGO-AMG resulted in the highest separation factor ( β Sr/Cs ) = 2982; this value was the largest β Sr/Cs reported in the literature. The adsorption behavior was evaluated through the Langmuir and Freundlich isotherm models, demonstrating a maximum adsorption capacity of 421.94 mg/g for Sr ions. Adsorption elution recirculation experiments were used to examine the separation effect of AGO-AMG, and the results from these experiments confirmed its stable recycling ability. In addition, at ultralow concentrations of 30 ppb of Sr 2+ and Cs + , the removal rate of Sr 2+ remained at approximately 90%, indicating that AGO-AMG had good working ability at ultralow concentrations. Furthermore, the rapid separation capacity of the three-dimensional AGO-AMG films showed that the removal rate of the AGO-AMG films for Sr 2+ could be maintained between 97% and 99% when a syringe was used to add the feed solution at a rate of 4 mL/min and a pH = 12. Therefore, AGO-AMG could be considered a new and efficient solid-phase adsorbent material for the effective separation of 90 Sr 2+ from 137 Cs + in seawater after the discharge of nuclear contaminated water and has industrial application potential.