Manipulating diffusion energy barrier in graphene oxide subnanochannels for precise radionuclide separation

Abstract

Nuclear energy plays a crucial role as a clean energy source in modern society. The use of nuclear energy will result in the generation of a large amount of radioactive nuclear wastewater. Separation of nuclides from radioactive wastewater is crucial for the safe disposal of nuclear wastes and the sustainable development of resources. However, it remains a great challenge to achieve precise separation between different radionuclide ions due to their similar properties. Herein, we constructed a radiation-resistant graphene-based membrane via ethylenediaminetetraacetic acid (EDTA) functionalization with highly stable and aligned two-dimensional subnanochannels, which exhibits adjustable ion diffusion energy barrier and ultrahigh radionuclide ion selectivity. The functional groups within the GO-EDTA channel exhibit strong affinitive binding interactions with Sr 2+ and La 3+ . The mono/multivalent metal-ion selectivity up to 485 and 1300 for Cs + /Sr 2+ and Cs + /La 3+ , respectively, outperforms other reported membranes. Besides, the channel can still maintain stable separation performance under irradiation conditions. Furthermore, using quartz crystal microbalance, we break down the contributions of partitioning at the pore mouth and intrapore diffusion to the overall energy barrier for salt transport, indicating that the precise separation of ions is achieved by regulating the diffusion energy barrier. This work provides a mechanism for the design of membranes with high ionion selectivity and demonstrates the application potential of nuclear resource recycling.

Bibliographic Information