Carboxylic acid cation exchange non-woven for enrichment and removal of heavy metal ions in seawater

In this work, A weak acid cation exchange textile (CET) was prepared by ⁶⁰Co γ-rays irradiation grafting with acrylic acid (AA) onto polypropylene (PP) non-woven (PP-g-AA). The feasibility of PP-g-AA as ion exchanger for enrichment and removal of four heavy metal ions (Cu(II), Zn(II), Cd(II), Pb(II)) in seawater was investigated. The exchange capacity of CET with the grafting degree of 45% is 3.7 mmol/g. The results indicated that the PP-g-AA CET could efficiently absorb the Cu(II), Zn(II), Cd(II), Pb(II) metal ions although there are large amount of Na(I), K(I), Mg(II), Ca(II) ions existing in seawater. The CET in Na⁺ form (PP-g-AA being deal with NaOH) was better for the enrichment of these four metals than CET in H⁺ form. The dynamic adsorption for metal ions by CET was superior to the static adsorption. Metal ions retained on CET could be desorpted with 1mol/L HNO₃. All the results indicated that carboxylic acid cation exchange polypropylene textile had great potential for the enrichment and removal of heavy metals in seawater.