Enhanced Adsorptive Removal of Cr (VI) from Plating Industry Wastewater Using CoFe₂O₄/CTAB Magnetic Nanocomposites

The plating industry is one of the causes of hexavalent chromium Cr (VI) pollution in surface water, raising problems for human health and other living things. In this study, we synthesized CoFe₂O₄ magnetic nanoparticles and coated them with cetyltrimethylammonium bromide (CTAB), a commonly used cationic surfactant, to form CTAB/CoFe₂O₄ magnetic nanocomposite for Cr (VI) adsorptive removal application from aqueous solution. Characteristic properties of CTAB/CoFe₂O₄ were examined using scanning electron spectrometry, surface area apparatus, X-ray diffractometer, Fourier transform infrared spectrometry, zeta potential analyzer, and vibrating sample magnetometer. The CTAB/CoFe₂O₄ had superparamagnetic properties, being easily isolated from an aqueous solution and well regenerated by an external magnet. Besides, the CTAB molecules anchored onto the Co₂FeO₄ nanoparticle surfaces could increase the positive charge and thus facilitate the electrostatic interaction with the Cr (VI) anions. Accordingly, the CTAB/CoFe₂O₄ reached the Cr (VI) adsorption efficiency of 89%, two times higher than the pure CoFe₂O₄, at an optimal pH of 2, an adsorbent dose of 1 g/L, and an initial Cr (VI) concentration of 10 mg/L. The CTAB/CoFe₂O₄ magnetic nanocomposite would promise a high potential for Cr (VI) treatment from plating wastewater with simple separation, good adsorption capacity, and an inexpensive, nontoxic production process.