Preparation, characterization and application of thiosemicarbazide grafted multiwalled carbon nanotubes for solid-phase extraction of Cd(Ⅱ), Cu(Ⅱ) and Pb(Ⅱ) in environmental samples

Thiosemicarbazide-grafted multi-walled carbon nanotubes were prepared and employed to investigate the pre-concentration of Cd（Ⅱ）, Cu（Ⅱ） and Pb（Ⅱ） from aqueous solution prior to their determination by ICP-OES. The resulting material was characterized by FT-IR, TGA and SEM. Various factors influencing the separation and pre-concentration were investigated. The enrichment factor typically is 60. Under optimized experimental conditions, the maximum adsorption capacities of Cd（Ⅱ）, Cu（Ⅱ） and Pb（Ⅱ） were found to be 1.98, 10.94, 3.69 mg/g, and the relative standard deviations are 〈 3.5% （n = 6）. The new adsorbent shows superior reusability and stability. The procedure was successfully applied to the determination of trace quantities of Cd（Ⅱ）, Cu（Ⅱ） and Pb（Ⅱ） in water samples.