Efficient NiFe₂O₄@g-C₃N₄ Nanosorbent for Oxytetracycline Adsorption: Removal Modeling and Selectivity

Nanosorbent NiFe₂O₄@g-C₃N₄ was produced via green and ultrasonication methods to remove oxytetracycline (OTC) from aqueous solutions. The prepared material was analyzed using powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive x-ray spectroscopy (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The adsorption capacity of the NiFe₂O₄@g-C₃N₄ nanosorbent for OTC decontamination was studied using a batch experiment under various parameters. The adsorption capacity was notably increased to 1634 mg g⁻¹ under fixed experimental conditions. The kinetic and isothermal analyses were conducted using several optimal pH and temperature models. The adsorption kinetics graphs aligned with the pseudo-second-order model, suggesting chemical adsorption via electrostatic interactions. The adsorption isotherm curves aligned more closely with the Langmuir model than the Temkin and Freundlich models, suggesting a monolayer adsorption mechanism. The adsorption mechanism was clearly elucidated using FTIR investigations. The results of the study indicate that NiFe₂O₄@g-C₃N₄ nanosorbent is a promising candidate for specific elimination of OTC on many different levels for the treatment of wastewater.