Adsorbent characterization
The size and morphology of the synthesizedMNHAPwascharacterized
by scanning electron microscopy analysis using a JSM-5600
LV microscope (JEO, Ltd., Japan). The sample composition and
element contents were analyzed by energy dispersive analysis system
of X-ray (EDAX) using a EDX-GENESIS (EDAX, Ltd., USA). The
structure of the synthesized magnetic adsorbents was analyzed
by X-ray powder diffraction (XRD) pattern recorded on a D/max
2550 X-ray Diffractometer (RigaKu, Japan) using Cu K radiation
( = 0.1541 nm) in steps of 0.05◦ (2) min−1 from 10◦ to 80◦ (2).
The Brunauer–Emmett–Teller (BET) specific surface areawasdetermined
by nitrogen adsorption–desorption at 77.30K (Metallurgy
ASAP 2010, USA). The zeta potential of MNHAP suspensions was
measured using a Zeta Meter 3.0 (Zeta Meter Inc.) equipped with a
microprocessor unit. The magnetic properties were characterized
by magnetization curves using a HH-50 vibrating sample magnetometer
in the condition of sensitivity 20 mV.