Efficacious Removal of Organic Contaminants from Water Using a Novel CoO-NiO@MgAlO Nanocomposite.

Herein, novel MgAlO-based quadruple nanocomposites containing different contents of Co/Ni bimetallic doping were synthesized employing gelatin as a green capping agent. Typically, MgAlO (MgAlO-1), 5% NiO-5% CoO@MgAlO (MgAlO-2), 2.5% CoO-5% NiO@MgAlO (MgAlO-3), and 5% CoO-2.5% NiO@MgAlO (MgAlO-4) were synthesized via a one-pot method. The prepared quadruple nanocomposites were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), surface analysis, and Fourier transform infrared spectroscopy (FTIR) spectroscopy. MgAlO-1, MgAlO-2, MgAlO-3, and MgAlO-4 exhibited surface areas of 75.4, 118.4, 141.1, and 123.0 m g, respectively, and possessed q values of 46.8, 60.9, 72.4, and 60.2 mg g, respectively, toward the indigo carmine (INCR) dye. The INCR sorption onto MgAlO-1, MgAlO-2, MgAlO-3, and MgAlO-4 followed the pseudo-second-order model, and the liquid film diffusion model controlled the INCR sorption onto MgAlO-1, MgAlO-2, MgAlO-3, and MgAlO-4 nanocomposites. MgAlO-3 was selected as the best sorbent for eliminating INCR, and it exhibited enhanced performance at pH 6.0. The MgAlO q value increased proportionally with the INCR concentration (20 to 100 mg L), and increasing the temperature affected the sorption positively, indicating endothermic sorption. The Langmuir model best fitted among the tested isotherm models, and it predicted a maximum adsorption capacity of 181.0 mg g. MgAlO-3 was tested for removing INCR from tap water, groundwater, and seawater at 313 K, and it showed an average efficiency of 97.1%, with a standard deviation of 2.4%.