Ultralayered Co3O4 as a new adsorbent for preconcentration of Pb(II) from water, food, sediment and tobacco samples

Abstract

In this study, ultralayered Co3O4 adsorbent was synthesized and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The surface area of the solid material was found to be 75.5m(2)g(-1) by BET method. The ultralayered Co3O4 was used for the first time as an effective adsorbent for the preconcentration of the Pb(II) ions in various samples prior to flame atomic absorption detection. Analytical parameters affecting the solid phase extraction of Pb(II) such as pH, adsorption and elution contact time, eluent volume and concentration, sample volume and common matrix ions were investigated. The recovery values for Pb(II) were found to be ≥ 92% even in the presence of 75,000 mg L(-1) Na(I), 75,000 mg L(-1) K(I), and 75,000 mg L(-1) Ca(II) ions. 10s vortexing time was enough for both adsorption and elution contact times. The elution was easily made with 2 mL of 2.0 mol L(-1) HNO3. The reusability (170 cycles) and adsorption capacity (35.5 mg g(-1)) of ultralayered Co3O4 were excellent. The preconcentration factor of the method and detection limit were found to be 175 and 0.72 µg L(-1), respectively. The described method was validated with certified reference material (RM 8704 Buffalo River Sediment, BCR-482 Licken and SPS-WW1 Batch 111-Wastewater) and spiked real samples. It was also applied for the preconcentration of Pb(II) ions in various water (well water, mineral water, waste water and sea water), food (cauliflower and barley), street sediment and tobacco samples.

Keywords: Adsorbent; Contact time; Flame atomic absorption spectrometry; Lead; Solid phase extraction; Ultralayered cobalt oxide.