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New silica based supports for use in HPLC separations have been prepared by the coating of a series of copolymers containing various molar fractions of vinylpyrrolidone (VP) and methacryloyloxypropyl beta cyclodextrin (βW7 MAHP) units on LiChrospher Si100. These chromatographic supports were fully characterised using the following techniques: thermogravimetric analysis, specific area and porous volume measurements, scanning electron micrography, NMR, EDAX and RAMAN spectroscopy. It was demonstrated that the interactions of the copolymer with the silica surface imply the VP units through H-bonding between the amide groups and the silanol functions explaining the increase of the polymer adsorption with the VP residue content. The analysis of the surface area, porous volume and pore size distribution showed that the coating process involved first the largest pores of silica and in a second step the smallest ones. From the 29Si NMR spectroscopy and scanning electron microscopy analysis, it appears that only the supports with high amounts of polymer adsorbed ensured a complete passivation of the silanol groups.

A series of acyclic pyrazole derivatives was prepared by condensation reactions. These compounds were covalently immobilized on silica gel through a flexible 3-glycidoxypropyltrimethoxysilane spacer arm. These materials were used as sorbents for the recovery of heavy and alkali metal ions from aqueous solutions. They exhibit good selectivity between heavy metal ions and alkali ions with an affinity especially high towards mercury. The comparison with liquid-liquid extraction shows that the capacity is not affected by the grafting of the pyrazole rings on the surface of silica. In addition, the solid-liquid process is more convenient in terms of facility of use.

A series of acyclic pyrazole derivatives was prepared by condensation reactions. These compounds were covalently immobilized on silica gel through a flexible 3-glycidoxypropyltrimethoxysilane spacer arm. These materials were used as sorbents for the recovery of heavy and alkali metal ions from aqueous solutions. They exhibit good selectivity between heavy metal ions and alkali ions with an affinity especially high towards mercury. The comparison with liquid-liquid extraction shows that the capacity is not affected by the grafting of the pyrazole rings on the surface of silica. In addition, the solid-liquid process is more convenient in terms of facility of use.