Solid-phase extraction of lead and copper by chelating cellulose functionalized with thioglycollic acid

Abstract

A chelating cellulose (SRY-Cell) containing thioglycollic acid as the chelating group was synthesized and studied for its sorption efficiencies with respect to Pb and Cu from an aqueous solution in both batch and column experiments. The influence of the pH on the adsorption, 250 μg each of Pb and Cu on SRY-Cell (0.1 g) from a 100 ml solution was studied in the pH range of 1.2∼10.8 by a batch process. Pb and Cu were quantitatively retained on the proposed adsorbent at pH>5. The effects of the flow rate of the sample solution through a column (polypropylene syringe, 78×16 mm i.d., 1.0 g of SRY-Cell was packed) were studied over the range of 10∼30 ml min⁻¹. The retention of these metals on the SRY-Cell was not affected by the flow rate of the sample solution up to 30 ml min⁻¹. Based on these results, the solution passed through the column at a flow rate of about 15 ml min⁻¹. The extracted metals were stripped from the column using 20 ml of 1 M HCl at a flow rate of 5.0 ml min⁻¹. The maximum sorption capacities were found to be 0.89 mmol g⁻¹ and 0.64 mmol g⁻¹ for Pb and Cu, respectively. The adsorbent was chemically stable and the adsorption-desorption cycles could be repeated at least 20 times. The method was applied to the concentration and determination of Pb and Cu in solar salt and water samples.