MWCNT/nano-ZrO_2 as a new solid phase extractor: its synthesis, characterization, and application to atomic absorption spectrometric determination of lead


Abstract: Nanoscale ZrO_2 was synthesized on a multiwall carbon nanotube (MWCNT) and designed as a new solid phase extractor for metal ion preconcentration. The characterization of the synthesized material was achieved by transmission electron microscope (TEM) and X-ray diffraction (XRD). Then the new nanoscale material was applied to preconcentration of lead(II) from various matrices. Different experimental factors including pH of the sample solution, sample volume, flow rate of the sample solution, and volume and concentration of the eluent for the preconcentration step were examined. The effect of interfering ions on the recovery of the lead(II) was also investigated. The recovery of lead(II) under the optimum conditions was found to be 104 \pm 2% at 95% confidence level. The preconcentration factor was 30 when 150 mL of sample solution and 5 mL of eluent were used. The analytical detection limit for Pb(II) was 0.80 \mu g L^{-1} after preconcentration. The adsorption capacity of the new nanosorbent was 115 mg g^{-1}. The accuracy of the method was confirmed by analyzing standard reference materials (Silty Clay 7003). The results demonstrated good agreement with the certified values. The method was applied for the determination of lead in tap water and clay samples.

Keywords: Preconcentration, lead, nanosorbent, atomic absorption spectrometry, multiwalled carbon nanotube, zirconium dioxide

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