COMPLEXING AND CHELATING-AGENTS IMMOBILIZED ON SILICA-GEL AND RELATED MATERIALS AND THEIR APPLICATION FOR SORPTION OF INORGANIC SPECIES

Solid materials bearing bonded organic functional groups are reviewed. The properties of the oxide supporting materials, silica gel in particular, their chemical and physical properties and the nature of the surface residues are part of this review. Processes leading to modification of the silica gel surface with mono- and polylayers of other oxides resulting in materials with modified properties as well as their susceptibility to chemical modification are also presented. Data on silanization procedures to bond supporting materials with commercial or synthesized organosilicon compounds have been carefully collected and discussed. Special emphasis has been paid to reactions which change the chemical nature of the bonded organic residues leading to valuable materials for partition, ion, ion-exchange, and affinity chromatography as well as for specific separation methods. Data on the collection, separation and preconcentration of inorganic species using these materials are an important part of this review. The bonded organic residues usually include typical ligating groups which are able to form complexes with inorganic species. Although most of these ligating materials have been seldom used, they have been included in this review. Current and prospective trends in usage of chemically modified supports, primarily for large scale procedures, are discussed. Important progress in the technology of inorganic supporting materials in the form of fibers or aggregates of high specific surface, which can be chemically modified, and which should stimulate future research in solid packings, has been outlined.