A polymer inclusion membrane functionalized by di(2-ethylhexyl) phosphinic acid with hierarchically ordered porous structure for Lutetium(III) transport

This study investigated a newly developed polymer inclusion membrane (PIM) composed of di(2-ethylhexyl) phosphinic acid (P227) as the carrier and poly(vinylidene fluoride) (PVDF) as the base polymer for the high-performance transport of Lutetium (Lu(III)). Scanning electron microscopy (SEM) indicated that the PIM functionalized by 40 wt% P227 (P227@PIM (40 wt%)) showed a hierarchically ordered porous structure on its glass side surface. The diameter of the pores on glass side surface changed from ~8 μm of the outer layer to ~1 μm of the inner layer. This surface morphology led to a rougher surface and larger contact area, allowing a better accessibility of the membrane to the solution. Additionally, P227@PIM (40 wt%) showed a large difference in Lu(III) transport efficiency at opposite transport direction. The permeability (P) from the air side to the glass side was as high as 5.97×10-2 m h-1 and was only 7.04×10-3 m h-1 in the opposite direction. Furthermore, the transport efficiency of Lu(III) reached almost 85% after 5 h, and the time required was further decreased to 3 h by using a dual-membrane transport apparatus. The results reported here indicate that both the morphology and transport direction of the PIM have strong effects on the transport efficiency, and the dual-membrane apparatus will further enhance the transport efficiency. •A simple polymer inclusion membrane (PIM) functionalized by di(2-ethylhexyl) phosphinic acid (P227) was made.•The SEM images showed the PIM had a hierarchically ordered porous structure on its glass side surface.•The PIM showed a large difference in Lu(III) transport efficiency at opposite transport direction.•The transport efficiency of Lu(III) reached 85% after 5 hours and finally reached 96% after 12 hours.•A dual-membrane transport apparatus was designed and attempted to further enhance transport efficiency.