Organically functionalized bentonite for the removal of perfluorooctane sulfonate, phenanthrene and copper mixtures from wastewater

Abstract The co-occurrence of a wide range of hydrophobic and hydrophilic contaminants with contrasting physicochemical properties in wastewaters makes practical remediation a challenge. Applications of ion exchangers such as clays are an environmentally friendly option in a cleanup strategy. However, clays often require chemical functionalization to adsorb non-polar contaminants. In this study, the most readily available low-cost Iranian bentonite was modified with Arquad® 2HT-75 (IBA) and further tailored with palmitic acid (IBAP) in order to prepare effective adsorbents. They were used for the removal of perfluorooctane sulfonate (PFOS), phenanthrene (PHE) and copper ions (Cu2+) both in single (S) and binary (B) contaminant conditions in simulated and real wastewater. The IB showed a large affinity for Cu2+ in both single (qmax: 43.43 mg/L) and binary (qmax: 43.95 mg/L) systems. Adsorption of PFOS and PHE was dramatically enhanced by the functionalized clays IBA (KF (PFOS): 11.1 and KF (PHE): 9.65 mg (1-n) Ln g−1) and IBAP (KF (PFOS): 10.2 and KF (PHE): 16.68 mg (1-n) Ln g−1). The co-occurrence of PFOS or PHE with Cu2+ enhanced their adsorption onto clays indicating that Cu2+ can form bridges between clays and PFOS or PHE in different mechanism to increase adsorption of PFOS or PHE in binary solutions. The surface-tailored organoclay IBAP showed great potential for the complete removal of PFOS, PHE and 86.6% of Cu2+ from real wastewater, which is usually considered challenging.