Samarium (III) adsorption on bentonite modified with N-(2-hydroxyethyl) ethylenediamine

A new material has been synthesized using dry process to activate bentonite followed by N-(2-hydroxyethyl) ethylenediamine connecting chlorosilane coupling agent. The synthesized new material was characterized by elemental analysis, FT-IR and thermogravimetry which proved that bentonite was successfully modified. The most interesting trait of the new material was its selective adsorption for rare earth elements. A variety of conditions of the new material were investigated for adsorption. The optimal conditions were determined with respect to pH and shaking time. Samarium (Sm) was quantitatively adsorbed at pH 4 and shaking time of 2 min onto the new material. Under these conditions the maximum static adsorption capacity of Sm(III) was found to be 17.7 mg g−1. The adsorbed Sm(III) ion were quantitatively eluted by 2.0 mL 0.1 mol L−1 HCl and 5% CS (NH2)2 solution. According to IUPAC definition, the detection limit (3σ) of this method was 0.60 ng mL−1. The relative standard deviation (RSD) under optimum conditions was less than 3% (n = 8). The new material also was applied for the preconcentration of trace Sm(III) in environmental samples with satisfactory results.