A new sorbent based on MWCNTs modification for separation/preconcentration of trace amounts of Cd(II), Cr(III), Cu(II), Ni(II), and Pb(II) and their determination by flame atomic absorption spectrometry

Mohammad Ali Karimi,Abdolhamid Hatefi-Mehrjardi,Sayed Zia Mohammadi,Javad Yarahmadi,Alireza Mohadesi

doi:10.1186/s40543-015-0065-2

Mohammad Ali Karimi, Abdolhamid Hatefi-Mehrjardi + Show 3 more

Open Access

https://doi.org/10.1186/s40543-015-0065-2

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Abstract

A new solid phase extraction (SPE) method has been developed for the separation/preconcentration and determination of lead, cadmium, chromium, nickel, and copper ions using a new sorbent. The method is based on the application of multiwalled carbon nanotubes modified with ethylenediamine-N,N-diacetic acid (MWCNTs-EDDA) as a selective sorbent in SPE for the separation and preconcentration of Pb(II), Ni(II), Cd(II), Cu(II), and Cr(III). The determination of these heavy metals was followed by flame atomic absorption spectrometry (FAAS). All quantitative determinations were performed by FAAS, and surface modification of synthesized adsorbents has been confirmed on the basis of characterization with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The parameters such as pH, amount of adsorbent, shaking time, eluent type and its concentration, and matrix effect have been investigated and optimized. The maximum adsorption capacity of the adsorbent at optimum conditions was found to be 51.7, 67.6, 49.9, 57.8, and 62.3 mg g-1 for Cd(II), Cr(III), Cu(II), Ni(II), and Pb(II), respectively. In the presented study, MWCNTs were functionalized by EDDA and it was applied as an adsorbent for the separation and preconcentration of trace level of Pb, Ni, Cd, Cu, and Cr ions. This method is effective, selective, rapid, and simple for the determination of trace amounts of Pb, Ni, Cd, Cu, and Cr ions and can be successfully applied to analyze the trace amounts of mentioned ions in wastewater and herbal samples without evident interference from the complex matrix. Furthermore, the sorption has high capacity, and the precision and accuracy of the method are also satisfactory.

Highlights

A new solid phase extraction (SPE) method has been developed for the separation/preconcentration and determination of lead, cadmium, chromium, nickel, and copper ions using a new sorbent
We report a new method using multiwalled carbon nanotubes modified with ethylenediamine-N,N-diacetic acid (MWCNTs-EDDA The requirement ligand (EDDA)) as a selective sorbent in SPE for separation and preconcentration of Pb(II), Ni(II), Cd(II), Cu(II), and Cr(III) prior to their determination by flame atomic absorption spectrometry (FAAS)
The observed dispersing property of Multiwalled carbon nanotubes (MWCNTs)-COOH was better than that of MWCNTs, and the diameter of MWCNTs-EDDA appeared wider than that of MWCNTs and MWCNTs-COOH. These results confirm MWCNTs modified by the EDDA

Summary

Introduction

A new solid phase extraction (SPE) method has been developed for the separation/preconcentration and determination of lead, cadmium, chromium, nickel, and copper ions using a new sorbent. Heavy metal pollution on the planet is increasing day by day and has become an environmental problem throughout the world. Heavy metals, such as Cd, Cr, Cu, Ni, As, Pb, and Zn, have high solubility in the aquatic environments and can be absorbed by living organisms, enter the food chain, and accumulate in the human body. Direct determination of heavy metals is often not sensitive enough to determine heavy metal ions in environmental samples because of their low concentrations, which are near or below the detection limit of the instrument, and matrix interferences. A preconcentration and/or separation of analytes is frequently necessary to improve the analytical detection limit, increasing the sensitivity, facilitating the calibration, enhancing the accuracy of the results, and simplifying the matrix of the sample (Baghban et al 2012; Das et al 2006; Hu et al 2002a; 2002b; Palanivelu et al 1992; Prasad et al 2006; Rajesh and Manikandan 2008; Soylak et al 2003)

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