tIn this paper, original thermosensitive copolymers bearing phosphonic acid groups, namely the poly(N-n-propylacrylamide-stat-2-(methacryloyloxy)methylphosphonic acid) (P(NnPAAm-stat-hMAPC1)) weresynthesized, and their sorption properties for three divalent cations (Ni2+, Ca2+, Cd2+) and one triva-lent cation (Al3+) have been investigated. The sorption experiments were performed with increasingrelative amount of cationic pollution compared to the amount of sorption sites (Cn+/P ratio) in monoand multi-component solutions to investigate the sorption mechanisms. Cn+/P proved to strongly affectthe sorption capacity and high capacities were obtained for all cations at highest Cn+/P ratios, reachingone mole of Cn+sorbedper phosphonated moiety. For divalent cations, sorption mechanisms were likelyto be described by electrostatic interactions only, whereas for aluminum trivalent cation the sorptionnot only resulted from electrostatic interactions but also from the formation of coordination binding.The selectivity of the phosphonic acid moieties for aluminum cations was demonstrated, highlight-ing the interest of P(NnPAAm-stat-hMAPC1) for their use for the treatment of metallic pollution fromwastewater.