Preparation of a Weakly Acidic Cation Exchanger Based on Kenaf and Its Adsorption Characteristics of Copper(II) and Platinum-group Metal Ions

A weakly acidic cation-exchanger based on kenaf were prepared, and the adsorption of copper ion and platinum-group metal ions on the cation-exchanger were studied. The kenaf was pretreated with concentrated hydrochloric acid at about 100°C for 2 hour. Next, the reducing terminal group (aldehyde group) formed by the hydrolysis of cellos in kenaf was oxidized with solid potassium permanganate to give a weakly acidic cation-exchanger with a carboxyl group. The adsorption capacity was 2.80 Cu(II) meq g−1– R. The optimum pH range for the adsorption of Cu(II) was more than about 2.5. The adsorption was rapid and the adsorption equilibrium was attained within about 30 min. Thus, the synthesized exchanger could be used in a column with a high flow rate. Cu(II), and only Ru(III), Rh(III) and Pd(II) among the platinum-group metal ions were adsorbed on a synthesized exchanger. The Cu(II) and above platinum-group metal ions loaded on a synthesized exchanger were separated from each other by elution with a 0.05 – 1.0 mol L−1 hydrochloric acid solution, such as Cu(II) – Pd(II) – Ru(III) and Cu(II) – Rh(III) – Ru(III). Furthermore, the recoveries of Cu(II) and platinum-group metal ions contained in a laptop board were also investigated.