Constructing Two-Dimensional (2D) Heterostructure Channels with Engineered Biomembrane and Graphene for Precise Scandium Sieving

The special properties of rare earth elements (REE) have effectively broadened their application fields. How to accurately recognize and efficiently separate target rare earth ions with similar radii and chemical properties remains a formidable challenge. Here, precise two-dimensional (2D) heterogeneous channels are constructed using engineered E. coli membranes between graphene oxide (GO) layers. The difference in binding ability and corresponding conformational change between Lanmodulin (LanM) and rare earth ions in the heterogeneous channel allows for precisely recognizing and sieving of scandium ions (Sc3+). The engineered E. coli membranes not only can protect the integrity of structure and functionality of LanM, the rich lipids and sugars, but also help the Escherichia coli (E. coli) membranes closely tile on the GO nanosheets through interaction, preventing swelling and controlling interlayer spacing accurately down to the sub-nanometer. Apparently, the 2D heterogeneous channels showcase excellent selectivity for trivalent ions (SFFe/Sc approximate to 3), especially for Sc3+ ions in REE with high selectivity (SFCe/Sc approximate to 167, SFLa/Sc approximate to 103). The long-term stability and tensile strain tests verify the membrane's outstanding stability. Thus, this simple, efficient, and cost-effective work provides a suggestion for constructing 2D interlayer heterogeneous channels for precise sieving, and this valuable strategy is proposed for the efficient extraction of Sc. The unique non-channel protein, LanM, is successfully modified to the biological membrane by genetic engineering for the first time, integrating it within the interlayer of GO membrane using interaction to construct a LP-GO heterostructure membrane. Utilizing the difference in binding ability between LanM with rare earth elements (REE), efficiently isolating Sc3+ ions amidst REE (SFCe/Sc approximate to 167), is focused on. image