Use of eco-friendly magnetic materials for the removal of polycyclic aromatic hydrocarbons and metals from environmental water samples

Abstract

Highly toxic pollutants including polycyclic aromatic hydrocarbons (PAHs) and metals such as copper and lead are released into the environment from a variety of sources. One way to remove them from aqueous media is to use magnetic hybrid adsorbents that can be easily separated from the medium after the adsorption process. This work reports the synthesis of a magnetic hybrid matrix consisting of cobalt ferrite as the inorganic phase and natural organic matter (NOM) as the organic phase, where NOM was used instead of the traditional solvents. Tests showed that a hybrid produced using ferric sulfate (FAST) presented higher adsorption efficiency, compared to a hybrid produced using ferric chloride (FACT). PAH adsorption assays were performed using a deionized water solution containing benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF), benzo(a)pyrene (BaP), and dibenzo(a,h)anthracene (DahA), which resulted in removal percentages in the range 83.9-97.6% (q = 41.3-53.7 mg g-1) at equilibrium after 30 min. Tests using real seawater and produced water samples confirmed the efficiency of the hybrid, with removal percentages in the range 86.5-96.3% (q = 43.2-48.1 mg g-1). The highest adsorption of PAHs was achieved using FAST, which was therefore selected for evaluation of metal removal, showing excellent adsorptive capacity, removing 84.5 and 92.0%, respectively, of the copper and lead present in seawater samples. Here, FAST provided efficient removal of both organic and inorganic species, demonstrating its potential for use in technological and environmental applications, including in the manufacturing sector.