Removal mechanism of 17β-estradiol by carbonized green synthesis of Fe/Ni nanoparticles

Even a small concentration of estrogen released into the environment can cause great damage to the surrounding ecosystem, with potential teratogenic and carcinogenic hazards to many organisms. In this study, carbonized green synthesized Fe/Ni NPs, with a maximum adsorption capacity of 44.32 mg g-1 coupled with over 98.3% removal efficiency, were used to remove 17β-estradiol (E2) from water. Adsorption best conformed to pseudo-second-order kinetics (R2 = 0.998-0.999) and the Freundlich model (R2 = 0.990-0.997). SEM images reveal that the carbonized material had increased specific surface area and pores. Zeta Potential, FTIR and XPS spectra confirmed that carbonized material was negatively charged and contained functional groups with a high affinity for E2. Liquid chromatography during removal of E2 suggested no new substances were generated. Therefore, the synergistic effect of carbonized-Fe/Ni NPs surface functional groups is a key issue, including dehydration bonds, hydrogen bonds, and the accumulation of Π and Π. In practice the application of carbonized-Fe/Ni NPs demonstrated their ability to remove 51.8% and 48.7% of E2 from domestic sewage and livestock wastewater, respectively. This work provides a strong basis for the practical removal of E2 using carbonized-Fe/Ni NPs material.