Highly efficient separation of Sc^(3+) and Y^(3+) in acid solution by a graphene oxide membrane with interlayer sieving

Sc and Y are key rare earth elements and are widely used in lamp phosphors,lasers and high-performance alloys.However,highly efficient extraction and separation of Sc^(3+) and Y^(3+) is laborious,harmful,slow,and costly,strongly necessitating more efficient extraction and separation techniques.Here,we produced hydrated Sc^(3+)-and hydrated Y^(3+)-controlled graphene oxide(GO) membranes and find that both hydrated cations were completely self-rejected by the membrane.By combining this selfrejection effect of the larger hydrated Y^(3+)-controlled GO membrane and the rapid passage of the membrane through the smaller hydrated Sc^(3+),we proposed a strategy to separate Sc^(3+) and Y^(3+) by using a hydrated Y^(3+)-controlled GO membrane.The experimental results show that the permeation rate of Sc^(3+) exceeds that of Y^(3+) when the separation factor reaches 4.02,which can be attributed to the interlayer sieving effects of the GO membrane.Our finding illustrates the use of a forward osmosis process with a GO membrane for the efficient separation of Sc^(3+) and Y^(3+) by interlayer sieving,which provides a new effective and eco-friendly method for the separation of rare earth elements.