Selective Separation of Trace Amounts of Cadmium (II) and Copper (II) Ions from Solution on Activated Carbon Impregnated with 2, 4, 6-Tri-2-pyridy1-1, 3, 5-triazine

Abstract

The selective adsorption of metal ions with activated carbon impregnated 2, 4, 6-tri-2pyridy1-1, 3, 5-triazine (TPTZ-AC) was studied for the preconcentration of traces of cadmium(II) and copper(II) ions. TPTZ-AC was prepared as follows 5.0 g of activated carbon and 2.0 g of TPTZ are added into 50 cm³ of 3 mol⋅dm^-3 hydrochloric acid. The mixture is stirred 30 min and TPTZ-AC is filtrated after standing for one day, and then it is dried in an oven at 110°C for 2 h. 0.5 μg of cadmium(II), 20 μg of copper(II)and lead(II) were collected completely from 100 cm³ solution in the presence of 5 cm³ of 2% potassium iodide over the pH ranges 5.0-11.0, 4.0-9.0 and 5.0-8.0 respectivery, by stirring with 50 mg TPTZ-AC for 10 min, but nickel(II) and cobalt(II) were not collected quantitatively. Cadmium(II) and copper(II) in the presence of iron010 and aluminum(III) (each 50 mg) were collected completely over the pH range 5.0-8.0. Leadan was not collected selectively. Adsorption time was 10 min in a ultrasonication bath using 50 mg of TPTZ-AC and desorption of adsorbed metals took 5 min in the bath using 1-5moldm^-3 nitric acid. The composition of complex formed with cadmium(II) or copper(II), TPTZ and iodide ion were 1: 1: 2, respectively. The proposed method was successfully applied to the determination of cadmium and copper in several sediments by atomic absorption spectrometry. This method is very simple and rapid, and is suitable for the determination of trace amounts of cadmium(II) and copper(II) in the sample containing large amounts of iron(III) and aluminum(III).