Application of Mn₃O₄/Fe₃O₄ synthetic nanoadsorbent for Cd(II) ion preconcentration

In this work the synthesis, characterization and application of magnetic nanoadsorbents based on nanoparticles of magnetite (Fe₃O₄) agglomerated with hausmanite (Mn₃O₄) for preconcentration of the ions cadmium (Cd²⁺) in aqueous media were applied, applying the atomic absorption technique (FAAS) to determine concentrations of the order of magnitude μg L^-1 . The nanoadsorbent was synthesized by the co-precipitation method in alkaline medium, resulting in Mn₃O₄/Fe₃O₄ nanoparticles of 8 to 20 nm in diameter and 38,19 m2 g^-1 of specific surface area measured by the BET method. After the adsorption process, the nanosorbent loaded with the Cd²⁺ ions was stripped with magnet and desorbed using 0,10 mol L^-1 HCl. The concentration in the solution desorbed was determined by FAAS. The main effects of the variables and the effects of their interactions on the preconcentration factor (FPC) were investigated using factorial planning 24 . The sample preparation procedure developed in this study presented FPC of 17 times, considering the maximum limits allowed by the legislation and the LQ of the determination technique, the preconcentration using nanoadsorbent and subsequent determination by FAAS is an excellent alternative for water analysis, guaranteeing economy, lower environmental impact and veracity of the results. (author)