Assessment of cadmium and iron adsorption in sediment, employing a flow injection analysis system with on line filtration and detection by flame atomic absorption spectrometry and thermospray flame furnace atomic absorption spectrometry

Abstract

This work presents an evaluation of iron and cadmium adsorption in sediment of the Furnas Hydroelectric Plant Reservatory located in Alfenas, Minas Gerais (Brazil). The metal determination was done employing a flow injection analysis (FIA) with an on-line filtering system. As detection techniques, flame atomic absorption spectrometry (FAAS) for iron and thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) for cadmium determinations were used. The developed methodology presented good limits of detection, being 190μgL−1 for iron and 1.36μgL−1 for cadmium, and high sampling frequency for both metals 144 and 60 readings h−1 for iron and cadmium, respectively. Both metals obey the Langmuir model, with maximum adsorptive capacity of 0⋅169mgg−1 for iron and 7⋅991mgg−1 for cadmium. For iron, a pseudo-first-order kinetic model was obtained with a theoretical Qe=9⋅8355mgg−1 (experimental Qe=9⋅5432mg g−1), while for cadmium, a pseudo-second-order kinetic model was obtained, with a theoretical Qe=0.3123mgg−1 (experimental Qe=0⋅3052mgg−1).