Diphonix Resin® in sorption of heavy metal ions in the presence of the biodegradable complexing agents of a new generation

This paper presents the equilibrium and kinetic studies of Cu(II), Zn(II), Co(II), Pb(II) and Cd(II) complexes with Dissolvine GL-38 (GLDA) and Enviomet™ C140 (EDDS) from aqueous solution by the chelating ion exchanger Diphonix Resin®. The selected complexing agents Dissolvine GL-38–tetrasodium salt of N,N-bis(carboxylmethyl)-l-glutamic acid and Enviomet™ C140–trisodium salt of ethylenediaminedisuccinic acid belong to the group of a new generation of complexons which easily undergo biodegradation but their complexes are not biodegradable. The effect of pH, phase contact time and concentration has been studied using the batch technique at room temperature. After achieving the best conditions for complexes sorption, isotherms were obtained and fitted to the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) models. The kinetic data were fitted using the pseudo-first-order, pseudo-second-order and intraparticle diffusion models. The respective characteristic rate constants were presented. The results showed that the sorption processes of Cu(II), Zn(II), Co(II), Pb(II) and Cd(II) complexes with Dissolvine GL-38 and Enviomet™ C140 on Diphonix Resin® followed well the pseudo-second-order kinetics.