One-step and biogenic synthesis of magnetic Fe3O4–Fir sawdust composite: Application for selective preconcentration and determination of gold ions

Abstract Sawdust–Fe 3 O 4 composite was prepared by one step and biogenic approach using a single iron precursor and sawdust as both reducing agents and template. The selectivity of composite toward Au(III) and its physicochemical properties, increased by modification with 3-aminopropyltriethoxysilane and synthetic ligand (3,5-dinitrobenzoylisothiocyanate); as the surface area and the adsorption capacity of sawdust, magnetic sawdust and modified composite were 4.24, 47.9 and 17.1 m 2  g −1 and 3.2, 16.45 and 188.68 mg g −1 , respectively. Application of this selective sorbent for preconcentration of gold ions from environmental solutions was investigated. The isotherm models and thermodynamic parameters have also been studied.