Cu(II), Zn(II), Ni(II), and Cd(II) Complexes with HEDP Removal from Industrial Effluents on Different Ion Exchangers

Abstract

The aim of this research is to investigate sorption characteristic of polyacrylate anion exchangers and chelating ion exchangers for the removal of Cu(II), Zn(II), Ni(II), and Cd(II) complexes with HEDP (1-hydroxyethylene-1,1-diphosphonic acid) from aqueous solutions. Optimum sorption conditions were determined as a function of phase contact time (1−180 min), pH (5−13), ion exchanger dosage (0.1−1.0 g), temperature (293−333 K), and chloride ions concentration (0.01−0.5 mol/L of NaCl). The Langmuir, Freundlich, Temkin, and Dubinin−Radushkevich (D−R) models were applied to describe the adsorption isotherm of Cu(II), Zn(II), Ni(II), and Cd(II) complexes with HEDP on Amberlite IRA 458 and Amberlite IRA 958 as well as Purolite S-920 and Purolite S-930. In the case of M(II)−HEDP complexes the adsorption capacities of Amberlite 458 were found to be 1.96 meq/g for Cu(II), 3.94 meq/g for Zn(II), 2.98 meq/g for Ni(II), and 4.25 meq/g for Cd(II). The metal ions were desorbed using 1 M HCl. The ion exchange capacity ...