The initial quicker rate
of HA adsorption may be due to the large number of adsorption sites
available for adsorption and the following decrease in adsorption rate
is probably due to the saturation of the active sites and attainment of
equilibrium. The rapid adsorption phenomenon is advantageous in the
process application since the shorter contact time effectively attains
for a smaller size of the contact equipment, which in turn directly affects
both the capacity and operation cost of the process [26].