Enhanced adsorption of PFOA with nano MgAl2O4 @CNTs: influence of pH and dosage, and environmental conditions

Perfluorooctanoic acid (PFOA) has received extensive attention due to its widespread distribution in the envi-ronment and concerns of its exposure to human health. Nano-MgAl2O4 modified carbon nanotubes (CNTs) were synthesized, characterized, and used as nanoadsorbents to remove ppb (������g/L)-levels of PFOA from drinking wa-ter and brackish groundwater. Nano-MgAl2O4 @CNTs composite materials were characterized by UV-Vis, FT-IR, DLS, p-XRD, BET, and SEM with EDX. The adsorption isotherms and kinetic studies were fitted to a Freundlich and to a pseudo-second-order models, respectively. Composite nano-MgAl2O4 @CNTs remove over 99% of PFOA (100 ppb) from water in 3 hours, and completely (100%) in 3.5 hours. The optimal pH range is under mild alkaline conditions (pH = 7.5-9.0). Electrostatic and hydrophobic interactions drive the PFOA adsorption onto MgAl2O4 @CNTs. The adsorption data of ground and drinking water samples indicated that nano-MgAl2O4 @CNTs is an efficient nanoadsorbent for PFOA removal.