Removal of actinide metals from solution

Claim 1

A process for the removal of an actinide metal, with an atomic number equal to or greater than 89 in the Periodic Table of the elements, from solution which process comprises contacting the solution containing the actinide metal, in the form of a soluble compound thereof with a substrate comprising the product obtained by reacting an inorganic solid containing surface hydroxyl groups with a compound of formula: (I) wherein Y is an -OR3 group in which R3 represents a hydrogen atom or an alkyl, aryl or acyl group containing up to 20 carbon atoms or Y is a halogen atom, X represents an -NR4R5 group in which R4 and R5, which may be the same or different, are hydrogen atoms or alkyl or aryl groups containing up to 20 carbon atoms or groups of formula: - (CR26)nNR7R8 in which R6, R7 and R8 represent a H atom, an alkyl or aryl group containing up to 20 carbon atoms, n is an integer between 1 and 10 and wherein R4, R5, R6, R7 and R8 may be the same or different or X is a saturated or unsaturated cyclic group in which one or more ring positions are occupied by nitrogen atoms, R is a divalent organic group containing up to 20 carbon atoms and R1 and R2 are organic radicals containing up to 20 carbon atoms, under conditions which effect reaction between the group Y- and an -OH group on the surface of the inorganic solid thereby bonding the compound (I) to the inorganic solid.