Magnetic flower-like α-Fe2O3@N–C particles as an efficient adsorbent for removal of 2,4-dichlorophenol: Thermodynamics, kinetics and adsorption mechanism

Magnetic flower-like α-Fe2O3@N–C particles were synthesized by hydrothermal self-assembly method and oxygen-limited carbonisation in a glycerol and ethanol solution system using glucose as the carbon source, iron nitrate as the magnetic source and particle skeleton and urea as the nitrogen source. Four hydrothermal temperatures of 120 ​°C, 140 ​°C, 160 ​°C and 180 ​°C were used to modulate the adsorbent structure. Hydrothermal temperature of 140 ​°C, solution pH ​= ​7, and a dosage of 0.06 ​g are the optimum conditions. The adsorption capacity of 2,4-dichlorophenol (2,4-DCP) onto MC-2 was determined as 108.556 ​mg ​g−1 at 25 ​°C. Experiments show that the adsorbents all fitted well to the Langmuir isothermal adsorption model and the quasi-secondary kinetic model, and the adsorption behaviour was dominated by monolayer chemisorption. The adsorption process was heat absorbing and spontaneous. Raman and XRD analysis showed that the adsorbent had a stable α-Fe2O3 skeleton and carbon layers. FTIR and XPS analysis showed that the adsorbent had hydrogen bonding, electrostatic interaction and π-π bonding to 2,4-dichlorophenol.