References:  
Early warning sensors for monitoring mercury in water, Journal of Haz. Mat.
Bis[2-(methacryloyloxy)ethyl] phosphate radiografted into track-etched PVDF for uranium (VI) determination by means of cathodic stripping voltammetry, Reac. & Func. Polym.

The Laboratoire des Solides Irradiés (LSI) in Palaiseau has developed a nanoporous membrane capable of selectively trapping metal ions in solution. These ions are passively adsorbed and form complexes with specific chemical compounds that are pre-grafted in the pores. The metal ions are then detected using an electrochemical voltammetry technique. This technique has already been applied successfully to a long list of metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn, Sb and Se).

The nanopores are produced by irradiating a polymer membrane with heavy ions (at the GANIL center in Caen), after which chemical compounds are grafted onto these pores under electron beams. The researchers have now tested a chemical functionalization that targets uranyl (UO₂²⁺) ions. In particular, they found that the uranyl ions form real complexes with the grafted compound, and by measuring the photoluminescence they were able to determine a very low detection limit of 6 µg.l^-1.

This limit can be further reduced by optimizing the complexation process. Another issue to be investigated is the impact of radiation on uranyl sequestration, in the context of analyzing a water sample that contains radioelements.

This work, which is of interest to companies such as Vinci and Total, was conducted in collaboration with the University of Maryland (USA).