Extraction of Some Divalent Metal Ions (Cadmium, Nickel and Lead) from Different Tea and Rice Samples Using Ghezeljeh Nanoclay (Geleh-Sar-Shoor) as a New Natural Sorbent

This article presents the method of extraction-preconcentration of Lead, Cadmium, and Nickel ions from food samples using the Ghezeljeh montmorillonite nanoclay (Geleh-Sar-Shoor) as a new native adsorbent in batch single component systems. The extraction-preconcentration of heavy metals were carried out by applying the solid phase extraction (SPE) method followed by atomic absorption spectroscopy (AAS), and inductively coupled with plasma atomic emission spectroscopy (ICP-AES). The Ghezeljeh nanoclay was characterized by using Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy-energy dispersive spectrometer operating (SEM-EDS), X-ray diffractometry (XRD), X-ray fluorescence (XRF), Cation Exchange Capacity (CEC) measurements, BET specific surface area and Zeta potential. According to BET theory, the specific surface areas of the Ghezeljeh nanoclay was calculated to be ۱۹.۸ m۲ g-۱ whereas the cation exchange capacity was measured to be ۱۵۰ meq/۱۰۰ g. The results of XRD, XRF, FT-IR, Zeta potential and BET surface area of the nanoclay confirmed that montmorillonite was the dominant mineral phase. Based on SEM images of this clay, it can be seen that the distance between the plates is nm level. For all three ions, the detection and quantification limits, dynamic linear range, preconcentration factor, and adsorption capacity were obtained. The effect of various interfering ions was studied. The experimental method was successfully applied for the extraction of heavy metals in different tea and rice samples.

Keywords:

Adsorption , Clay , Solid phase extraction , Lead , Cadmium , nickel