Determination of lead(II) in environmental water samples by solid-phase extraction using a novel modified carbon hybridised sepiolite combined with flame atomic absorption spectrometry

Abstract

ABSTRACT In this work, carbon hybridised sepiolite nanofibers (C/Sep) were successfully prepared via hydrothermal and post-calcination processes. The synthesised nanocomposite was then modified with 2-[(5-bromo-2-pyridyl)azo)-5-(diethl-amino) phenol (PADAP) as a chelating agent. Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray (EDX) spectroscopy and X-ray diffraction (XRD) analyses were employed for characterisation of the sorbent (C/Sep/PADAP). Application of the sorbent was studied for separation/preconcentration of Pb(II) prior to the determination by flame atomic absorption spectrometry (FAAS). Experimental factors including solution pH, sorption and desorption time, eluent type and concentration, sorbent dosage and sample volume were evaluated. A preconcentration factor of 125 with a linear range of 7.0–1100 µg L−1 was obtained for Pb(II) detection using this method. Beside, the detection limit (3σ) of the extraction procedure for Pb(II) was 1.1 µg L−1. The applicability of the proposed assay for determination of Pb(II) in actual water samples was also investigated.