Green Synthesis of Fe3O4 Nanoparticles and its Applications in Wastewater Treatment.

Abstract

In this paper, extract of Citrus aurantium (CA) was used as a green approach for the preparation of Fe3O4 nanoparticles. The green Fe3O4 (Fe3O4/CA) was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy analysis (EDX), Fourier-transform infrared (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) surface area measurement, vibrating sample magnetometry (VSM), and zeta potential (ZP) measurements. The synthesized Fe3O4/CA was used to remove methylene blue (MB) dye from an aqueous solution. A four-factor central composite design (CCD) combined with response surface modeling (RSM) was used to maximize the MB dye removal. The four independent variables, which were initial dye concentration (10-50 mg/L), solution pH (3-9), adsorbent dose (ranging from 200-1000 mg/L), and contact time (30-90 min), served as inputs to the model of the % dye removal. The findings yielded by an analysis of variance (ANOVA) confirmed the high significance of the regression model. The predicted values of the MB dye removal were in good agreement with the corresponding experimental values. Optimized conditions for the maximum MB dye removal (93.14%) by Fe3O4/CA were the initial dye concentration (10.02 mg/L), pH (8.98), adsorbent mass (997.99 mg/L), and contact time (43.71 min). The validity of the quadratic model was examined, and good agreement was found between the experimental and predicted values. Our findings demonstrated that green Fe3O4 NPs can be used as an adsorbent for MB dye removal.