Comparison of some magnetic nanoparticles based on iron oxide for separation and determination of cadmium metal ion by atomic spectrometry in seawater, wastewater and urine samples

Abstract

ABSTRACT Magnetic nanoparticles based on iron oxide can be synthesised easily and separated with a magnetic bar. To determine heavy and dangerous metal of cadmium, for the first time, five types of magnetic nanoparticles based on iron oxide were used for separation and measurement of heavy and dangerous metal ion of cadmium. To obtain the high specific surface area for nanocomposite, the silicate nanoparticles were used and TAR ligand was used for adsorption of the cadmium metal to the nanocomposite. The used complex ligand was 4-(2ʹ–thiazolylazo) – resorcinol which has a thiol group with a high tendency to silver and gold ion metals. To increase the specific surface, absorption and extraction of cadmium ion, the magnetic silica nanoparticles were used. To obtain more accuracy and precision for ion determination, the optimisation of the effective parameter is important. In this research, MINITAB software was used for the performance of response surface modelling (RSM) optimisation method. To determine the heavy metal ion of cadmium, the flame atomic absorption spectrometry was used. Under the optimum conditions (pH = 4.1, the concentration of ligand = 1.5 mM, temperature = 27ºC) and using the magnetic nanoparticle with high specific surface, a preconcentration factor of 180, the linear range 0.4–110 (µg L−1), recovery (98%), limit of quantification of 0.34 µg L−1 and a limit of detection of 0.11 µg L−1 for cadmium ion were obtained. To obtain the precision of the method, each measurement was repeated 5 times, and the relative standard deviation value for cadmium ion concentration of 8.0 µg L−1 was obtained to be 3.1%. Finally, to evaluate the suggested method, the detection and measurement of cadmium ion in seawater, wastewater and urine sample were performed.