Magnetic Solid-Phase Extraction of Fipronil from Aqueous Solution and Eggshells Using Amine-Coated Iron Oxide...

Fipronil, as a broad use insecticide, is regulated under directives and standards in many countries since it is classed as Class II moderately hazardous pesticide and Group C possible human carcinogen. In this study, amine coated iron oxide (NH₂ -Fe₃ O₄ ) is used as a new adsorbent with high adsorption capacity in the removal of fipronil from aqueous solution and eggshells.The adsorption performance was studied through batch adsorption under different concentrations of fipronil (10-200 μg/mL), different nanoparticles amount (0.1-1 mg) at different pH (4.5-6.0) and temperature (25-75 °C). Results showed that NH₂ -Fe₃ O₄ nanoparticles (0.1 mg) have excellent adsorption efficiency (97.06 %) at 25 °C, and pH 5.5. It also showed higher adsorption capacity towards fipronil sulfide, fipronil sulfone and fipronil desulfinyl with removal efficiencies of 92.82 %, 86.35 % and 76.24 % from aqueous solution and 97.62 %, 76.97 % and 62.65 % from eggshells, respectively. Fipronil adsorption process on NH₂ -Fe₃ O₄ nanoparticles showed best fitting to Langmuir adsorption isotherm indicating monolayer chemical adsorption by physicochemical interactions spontaneously on homogenous surfaces. Having higher adsorption capacity and reusability NH₂ -Fe₃ O₄ nanoparticles were shown to be effective adsorbents for removal of fipronil from aqueous solution and eggshells.