Enhanced removal of phenol by novel magnetic bentonite composites modified with amphoteric-cationic surfactants

Magnetic bentonite (MBent) was modified by both amphoteric surfactant (BS) and cationic surfactant (CT). The structural characteristics of BS-CT-MBent were explored along with the factors primarily influencing their effectiveness in phenol sorption. The results indicated that BS-CT-MBent showed high separation potential and good stability. The carbon contents of BS-CT-MBent increased while specific surface areas decreased with increasing the BS and Cr loading level. The sorption capacities of BS-CT-MBent for phenol (198.74-205.81 mmol kg(-1)) were improved compared to MBent (16.34 mmol kg(-1)). The phenol sorption capacities on BS-CT-MBent increased with an increase of BS or CT loading level, while the phenol sorption efficiency decreased at high BS and CT loading level. The phenol sorption capacities decreased with an increase of pH, temperature and with a decrease of background electrolyte concentration. Hydrophobic phases formed by surfactants were the main phenol sorption domains and the hydrophobic partition was the key mechanism. (C) 2019 Elsevier B.V. All rights reserved.