Ultrasound assisted adsorptive removal of Cr, Cu, Al, Ba, Zn, Ni, Mn, Co and Ti from seawater using Fe₂O₃-SiO₂-PAN nanocomposite: Equilibrium kinetics

This work reports the preparation and application of Fe₂O₃-SiO₂-PAN nanocomposite for the removal of Cr³⁺, Cu²⁺, Al³⁺, Ba²⁺, Zn²⁺, Ni²⁺, Mn²⁺, Co²⁺, and Ti³⁺ from seawater. X-ray diffraction (XRD), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscope (TEM), and Brunauer-Emmett-Teller (BET) characterized the synthesized composite. The following experimental parameters (Extraction time, adsorbent mass and pH) affecting the removal of major and trace metals were optimized using response surface methodology (RSM). The applicability of the RSM model was verified by performing the confirmation experiment using the optimal condition and the removal efficiency ranged from 90% to 97%, implying that the model was valid. The adsorption kinetic data was described by the pseudo-second order model. The applicability of the materials was tested on real seawater samples (initial concentration ranging from 0.270-203 μg L^-1) and the results showed satisfactory percentage efficiency removal that range from 98% to 99.9%. The maximum adsorption capacities were found to be 4.36, 7.20, 2.23, 6.60, 5.06, 2.60, 6.79, 6.65 and 3.00 mg g^-1, for Cr³⁺, Cu²⁺, Al³⁺, Ba²⁺, Zn²⁺, Ni²⁺, Mn²⁺, Co²⁺, and Ti⁴⁺, respectively.