Efficient and recoverable magnetic AC-Fe₃O₄ nanocomposite for rapid removal of promazine from wastewater

Because of its high adsorption efficiency, facile magnetic separation process, and rapid adsorption kinetics, a magnetic activated carbon-Fe₃O₄ (AC-Fe₃O₄) nanocomposite was fabricated and applied as a nanoadsorbent for the effective exclusion of a pharmaceutical substance from wastewater. This nanocomposite was characterized using several analytical techniques, including X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, N₂ sorptometry, transmission electron microscopy (TEM), magnetic property analysis, and isoelectric point (pH_IEP) analysis. The efficacy of the magnetic nanocomposite adsorption was studied using a type of phenothiazine antipsychotic drug (promazine) as the adsorbate. Adsorption parameters such as the nanoadsorbent dosage, initial drug concentration, pH of the solution, and adsorption kinetics were investigated. The results demonstrated that the adsorption equilibrium was rapidly attained after 6 min with almost complete elimination (99.97%) of the promazine. A batch system was used to determine the adsorption kinetics and isotherm of promazine onto the AC-Fe₃O₄ nanocomposite, and the obtained results corresponded to pseudo-second-order-kinetic and Langmuir isotherm model, respectively. The nanocomposite exhibited an adsorption capacity of 101.01 mg g⁻¹, with a negligible loss in efficiency after five adsorption cycles. Therefore, this nanocomposite could be used as an efficient platform to remove contaminants from wastewater.