Photo-swing extraction system for the separation of lanthanide using a pyrene group-containing thermosensitive polymer combined with carbon nanotubes

A novel photo-swing extraction system for lanthanide separation was developed using a copolymer of acid phosphoxy ethyl methacrylate (Phosmer-M), N-isopropylacrylamide (NIPAM), and (1-pyrene)methyl methacrylate (Phosmer-M/NIPAM/PyMMA). Single-walled carbon nanotubes (CNTs) were successfully dispersed in the Phosmer-M/NIPAM/PyMMA as a result of the π-π interactions of the pyrene groups. The phase transition of the copolymer was successfully induced via photo-irradiation as a result of heat generation by the CNTs. The extraction of Eu(III) was increased by the photo-irradiation because of changes in volume and hydrophobicity of the copolymer. Separation of the lanthanides was improved by the photo-irradiation, especially for the combination of Eu(III)/Sc(III).