Material suitable for the extraction of metal cations in aqueous medium, comprising a solid support on which are covalently attached polyazacycloalkane compounds having a ring comprising 4 nitrogen atoms and in which each of the nitrogen atoms of the ring is substituted by a coordinating group, each of the coordinating groups borne by the nitrogen atoms of the ring of a attached to the support being, independently of one another: - a coordinating group Rc corresponding to the following general formula: -(CH 2) n -C(=O)-NR 1 R 2 in which: n = 1, 2 or 3; R 1 and R 2 are identical or different and each represent a hydrogen atom or an alkyl radical comprising from 1 to 4 carbon atoms, or an alkenyl radical comprising from 1 to 4 carbon atoms, or an aryl radical; or else - a coordinating and connecting group RcL corresponding to the general formula below: -(CH 2) p -C(=O)-NR 3 - -, in which: p = 1, 2 or 3; R 3 represents a hydrogen atom or an alkyl radical comprising from 1 to 4 carbon atoms, or an alkenyl radical comprising from 1 to 4 carbon atoms, or an aryl radical; - - represents a linear or branched, saturated or unsaturated hydrocarbon-based chain, optionally entirely or partially cyclized and optionally interrupted by one or more heteroatoms, connected by at least one covalent bond to the solid support, said material corresponding to one of the formulae below in which k, which represents the number of bonds between the cyclic entity and the solid support, is an integer equal to 1, 2 or 3; or said material corresponding to the following formula: in which: a, b, c and d are three identical or different integers, each of a, b, c and d being equal to 2 or 3; each of the 3 groups Rc, which are identical or different, represent a group corresponding to the general formula: -(CH 2) n -C(=O)-NR 1 R 2 as defined above; and p, R 3 and - - are as defined above. - a coordinating group Rc corresponding to the following general formula: -(CH 2) n -C(=O)-NR 1 R 2 in which: n = 1, 2 or 3; R 1 and R 2 are identical or different and each represent a hydrogen atom or an alkyl radical comprising from 1 to 4 carbon atoms, or an alkenyl radical comprising from 1 to 4 carbon atoms, or an aryl radical; or else n = 1, 2 or 3; R 1 and R 2 are identical or different and each represent a hydrogen atom or an alkyl radical comprising from 1 to 4 carbon atoms, or an alkenyl radical comprising from 1 to 4 carbon atoms, or an aryl radical; - a coordinating and connecting group RcL corresponding to the general formula below: -(CH 2) p -C(=O)-NR 3 - -, in which: p = 1, 2 or 3; R 3 represents a hydrogen atom or an alkyl radical comprising from 1 to 4 carbon atoms, or an alkenyl radical comprising from 1 to 4 carbon atoms, or an aryl radical; - - represents a linear or branched, saturated or unsaturated hydrocarbon-based chain, optionally entirely or partially cyclized and optionally interrupted by one or more heteroatoms, connected by at least one covalent bond to the solid support, p = 1, 2 or 3; R 3 represents a hydrogen atom or an alkyl radical comprising from 1 to 4 carbon atoms, or an alkenyl radical comprising from 1 to 4 carbon atoms, or an aryl radical; - - represents a linear or branched, saturated or unsaturated hydrocarbon-based chain, optionally entirely or partially cyclized and optionally interrupted by one or more heteroatoms, connected by at least one covalent bond to the solid support, a, b, c and d are three identical or different integers, each of a, b, c and d being equal to 2 or 3; each of the 3 groups Rc, which are identical or different, represent a group corresponding to the general formula: -(CH 2) n -C(=O)-NR 1 R 2 as defined above; and p, R 3 and - - are as defined above.