Photocatalytic reduction of uranium (VI) by 2D-perylene diimide with surface cross-linked polyethyleneimine

The current energy shortage is a cause for concern and nuclear energy is an important sustainable energy source that is vital to the energy transition. As an important resource for the nuclear industry, uranium is present in large quantities in seawater. However, the efficient extraction of uranium from seawater remains challenging due to low uranium concentrations and biofouling. In this work, 2D-perylene diimide-polyethyleneimine (PDI-PEI) photocatalyst have been successfully synthesised by cross-linking polyethyleneimine on the surface of perylene diimide, which enhanced the extraction of uranium from seawater. An electric field is formed on the surface of the material by photocatalysis, where the positively charged part attracts the negatively charged uranyl group, facilitating the adsorption of uranium to the material. The electrons generated on the surface reduce the adsorbed U(VI) to the insoluble U(IV) and can achieve over 99% removal of uranium in solution. In addition, the PDI-PEI exhibited high antibacterial activity to the bacteria by producing reactive oxygen species. In summary, PDI-PEI have good photocatalytic activity, antimicrobial properties and hydrophilicity, which enhance the ability of the material to extract uranium from seawater and provide a versatile method to enhance uranium adsorption.