Magnetic solid phase preconcentration of cadmium in water samples using sulfonic acid functionalized Kit-6 magnetite mesoporous nanocomposites followed by flame atomic absorption spectrometry

Abstract

In this study, a simple and sensitive extraction method has been developed for preconcentration of trace amounts of cadmium ions using Kit-6 magnetite mesoporous nanocomposites (MMNCs) functionalized with sulfonic acid groups as adsorbent in solid phase extraction followed by flame atomic absorption spectrometry. For this purpose, the Kit-6 mesoporous silica was chemically synthesized on the surface of silica-coated magnetite core and functionalized by sulfonic acid groups to obtain Fe3O4@SiO2@Kit-6-SO3H. The synthesized nanocomposites were characterized by XRD, SEM, VSM and EDX methods. Various parameters affecting adsorption/desorption efficiencies were investigated using Taguchi orthogonal array design. The maximum extraction efficiency of cadmium ions was obtained at pH = 8, sorbent weight = 0.1 g, ionic strength = 0, stirring time = 15 min, sample volume = 100 mL, time of desorption = 5 min, concentration and volume of HCl solution as desorption solvent 0.1 M and 3 mL, respectively. The linear dynamic range, limit of detection, enhancement factor and relative standard deviation (RSD %) of the proposed method were obtained as 0.5–100 µg L−1 (R2 = 0.9982), 0.4 µg L−1, 26.9 and 3.5%, respectively. Finally, the study of proposed MMNC adsorbent for real sample and investigating the interference potential of foreign ions successfully confirmed the ability of MMNCs for preconcentration and determination of trace levels of cadmium ions.