Starch-coated green synthesized magnetite nanoparticles for removal of textile dye Optilan Blue from aqueous media

Starch-coated Fe3O4 magnetic nanoparticles were synthesized and tested as adsorbents for Optilan Blue dye removal from aqueous solutions. The four tested magnetite samples were prepared through an environmentally friendly synthetic route which uses water as solvent and biocompatible sodium bicarbonate as precipitating agent. In addition to the control sample, three of the Fe3O4 nanoparticle samples were synthesized using fruit waste extracts from avocado (Persea americana) and watermelon (Citrullus lanatus) as surfactants. The Box-Behnken design approach was applied in order to determine the optimum experimental conditions for dye removal from aqueous solutions, selecting as independent variables initial concentration of dye, pH, temperature and adsorbent dose. A significant removal of the dye was obtained with an initial concentration of 50 mg L-1 with 0.6 g L-1, pH 2, at 35 degrees C. Three adsorption isotherms viz: the Langmuir, Freundlich and Temkin models were used to analyze the adsorption data, and kinetic and thermodynamic studies were also conducted. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.