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

Fipronil is a broad spectrum insecticide used against a wide range of insect pests to control crops and livestock. World Health Organization (WHO) classifies fipronil as class-II moderately hazardous chemical and the United States (US) Environmental Protection Agency (EPA) as Group C – possible human carcinogen. The usage of fipronil and its metabolites should be regulated and appropriate methods should be investigated for its removal from the environment. In this study, adsorption behavior of fipronil onto amine coated iron oxide nanoparticles in both aqueous solution and eggshell is investigated and amine functional groups show high adsorption efficiency for fipronil.

Abstract

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−Fe₃O₄) 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−Fe₃O₄ 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−Fe₃O₄ 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−Fe₃O₄ nanoparticles were shown to be effective adsorbents for removal of fipronil from aqueous solution and eggshells.

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