To obtain a uniform size, the particles were
ground and passed through a 20 mesh screen. The obtained
adsorbents were subsequently degreased using Soxhlet extrac-
tion to improve the adsorption efficiency. The extracting solvents
for CM were n-hexane and ethanol in a 1:1 ratio (V/V);
chloroform and methanol were used in a 1:1 ratio (V/V) for
treating SB, and no extraction was used for PF. Following the
process, the adsorbents were rinsed with distilled water and
dried in a 50 8C oven for 24 h. The biosorbents were stored in a
brown glass bottle until use.
2.2. Characterization of the biosorbents
The surface properties of the three biosorbents were analyzed
using scanning electron microscopy (SEM) (Hitachi S-3000N) and
Fourier transform infrared spectroscopy (FTIR) (Perkin Elmer
Model 1600). A zeta potential (ZP) analyzer (ZEN3600, MALVERN
Nano-ZS) was used to determine surface charges, and elemental
analysis (HORIBA 7021H) was used to determine elemental
composition. The BET surface area was measured using a surface
area and porosity analyzer (Micromeritics TriStar 3000). The cation
exchange capacities (CEC) of the biosorbents were measured to
determine the ion exchange potential of the adsorbent surface. The
pH of the test biosorbent was determined using distilled water and
a biosorbent in a 1:1 weight ratio.