Synthesis and chelating properties of resins with methylthiourea, guanylthiourea and dithiocarbamate groups

Three types of reactive groups: methylthiourea, dithiocarbamate and guanylthiourea are introduced into the structure of ion-exchange/coordinating resins having vinylbenzyl chloride/divinylbenzene matrix. All of them contain sulphur atom(s), and the presence of this element changes the affinity of the resins towards the investigated cations (Cu(II), Cd(II), Zn(II), Ni(II), Pb(II), Ag(I)). It has been found that the introduction of purely coordinating groups leads to the decrease in the distribution coefficients for all the investigated metal cations compared to the starting resin with amino groups. Introduction of dithiocarbamate groups results in a very high uptake of the metal ions at both the pH studied. The highest affinity displayed by this resin is towards silver for which log Kd was 4.42 at pH 5.6. The polymeric resins were characterized using elemental analysis for nitrogen and sulphur, swelling and FTIR.