2.5. Isotherm studies
Series of 100 mL adsorbate solution with concentration range of
5–400 mg/L was agitated with 1.0 g of oil palm shell (6.5–8 mm) at
150 rpm for 480 min. At the end of the contact time, the concentration
of adsorbate ions was analyzed. The amount of adsorbate ions
adsorbed at equilibrium, Qe (mg/g), was calculated using equation:
Qe ¼ ðCo CeÞ
V
W ð1Þ
where Co and Ce (mg/L) are concentrations of adsorbate ions at initial
and equilibrium stages, respectively. While V (L) is the volume
of adsorbate solution and W (g) is the mass of adsorbent