Vortex assisted magnetic solid phase extraction of lead(II) and cobalt(II) on silica coated magnetic multiwalled carbon nanotubes impregnated with 1-(2-pyridylazo)-2-naphthol

In the present study, silica coated magnetic multiwalled carbon nanotubes impregnated with 1-(2-pyridylazo)-2-naphthol was synthesized and characterized by using instrumental techniques such as, Fourier transform infrared spectroscopy (FT-IR), BET surface area analysis, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The novel adsorbent has been used for magnetic solid phase extraction of Pb(II) and Co(II) at trace levels. The parameters including pH of solution, adsorbent dose, sample volume, temperature and matrix effect were optimized. Quantitative recoveries for analytes were obtained at pH 6.5 with 100 mg of adsorbent. Limit of detection values for lead and cobalt were 1.76 mu g L-1 and 0.55 mu g L-1. Preconcentration factor and standard deviation of both metals were 15 and lower than 33%. Kinetic data shows that the adsorption process follows pseudo second order kinetic. Positive values of Delta H degrees and Delta S degrees show that adsorption of Pb(II) and Co(II) is feasible and endothermic in nature. The validation of the method was carried out to waste water certified water reference materials. The presented separation-preconcentration method was applied to determination of lead and cobalt contents of water samples from Kayseri-Turkey. (C) 2016 Elsevier B.V. All rights reserved