Adsorption and Desorption of Rare Earth Ions with Polyacrylic Acid Synthesized by Plasma-initiated Polymerization

Polyacrylic acid (PA) was synthesized by plasmainitiated polymerization of acrylic acid and ethylenediacrylate. Adsorption and desorption of rare earth ions, such as Eu(III), Ce(III), Y(III), Ho(III), and Er(III) with PA were studied. Batchwise adsorption experiments demonstrated that PA had the characteristics to adsorb the above rare earth elements and to cause adsorption of the rare earth elements onto PA that depended on pH. The elements on PA were quantitatively desorbed with 0.1 M EDTA (pH 8.5). The rates of adsorption of the elements onto PA and desorption of the elements from PA were fast enough to apply PA to the column method. Adsorption and desorption of the elements were quantitatively done by the column packed with PA. The influence of co-existing ions, such as Cl^-, Br^-, SO₃^2-, SO₄^2-, S₂O₃^2-, SCN-, C10₄-, HPO₄^2- and CH₃COO^-, on adsorption of Eu(III) and Ce(III) onto PA was investigated. As a result, the adsorption of Eu(III) and Ce(III) was not influenced by the co-existing of the above anion in the amount 100 fold molar of Eu(III) or Ce(III).