2.3. Characterization of activated carbon/Fe3O4 nanoparticle
composite
The XRD measurement was carried out on an XRD diffractometer
(D8 Advance, Brucker, Germany). The patterns with the Cu Ka
radiation (k = 1.54051 Å) at 40 kV and 40 mA were recorded in
the region of 2h from 10 to 70.
The morphology of the composite materials were examined by
SEM, using a Hitachi S-4800 Scanning Electron Microscope (Hitachi
Co., Japan), and TEM, using Philips CM 300 Transmission Electron
Microscopy.
Nitrogen adsorption–desorption isotherms were performed at
196 C in a Brunauer–Emmett–Teller (BET) sorptometer (model:
BET 201-A). The BET surface area was deduced by analyzing the isotherm
in the relative pressure range of 0.05–0.3. Micropore volume
(Vmicro) was calculated after applying the Dubinin–Radushkevich
(DR) equation to the N2 adsorption isotherm. The total pore volume
(Vt) was obtained from the amount adsorbed at a relative pressure
of 0.99 and the mesopore volume (Vmeso) was determined as the difference
between these two values. The pore size distributions were
calculated using the BJH method.
The magnetic properties of the materials were studied with a
vibrating sample magnetometer (PPMS6000, US) at room temperature,
and the hysteretic loop was obtained in a magnetic field that
varied from 7 to +7 T.