Preparation, characterization and application of N-2-Pyridylsuccinamic acid-functionalized halloysite nanotubes for solid-phase extraction of Pb(II).

Halloysite nanotubes (HNTs) were chemically modified with N-2-Pyridylsuccinamic acid (PSA) to produce a new nano-adsorbent (HNTs-PSA) for selective solid-phase extraction of Pb(II). The new adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), thermogravimetric analysis (TGA), and elemental analysis to evaluate the surface modification. Under the optimized conditions (pH 5, flow rate 1.5 mL min(-1)), Pb(II) was retained on the column packed with HNTs-PSA, and then was quantitatively eluted by 1.5 mL 0.5 mol L(-1) HCl and determined by inductively coupled plasma-optical emission spectrometry. An enrichment factor of 67 was obtained using 30 mg of HNTs-PSA. The maximum adsorption capacity for Pb(II) was found to be 23.58 mg g(-1). The detection limits of this method for Pb(II) was 0.32 μg L(-1). The relative standard deviation under optimum conditions was 3.4% (n = 11). The developed method was validated by analyzing a certified reference material, and then successfully applied to the determination of Pb(II) in actual samples.