Conclusions
In this study, the use of activated carbons (CCUC, SSUC
and SCUC) prepared from marine green algae
U.
fasciata
and commercially activated carbon (CAC) were
tested as adsorbents for removal of Pb(II) ions from
aqueous solution. The batch study parameters, pH of
solution, contact time, initial Pb(II) concentration and
adsorbent dose were found to be effective on the adsorption efficiency of Pb(II). The Langmuir, Temkin isotherm models were used for the mathemat-
ical description of the adsorption of lead(II) ions onto
activated carbons, and the isotherm constants were eval-
uated from these isotherms. Results indicated that the
adsorption equilibrium data fitted well to the Langmuir
and Temkin isotherm models. The results show that the
pseudo-second-order mechanism is predominant and
that chemisorption might be the rate-limiting step that
controls the adsorption process. Intra-particle diffusion
should also be taken into account, but it was observed
that intra-particle diffusion is not a rate-determining
step. While comparing the percentage removal and ad-
sorption capacity of activated carbons made from
U.
fasciata
(CCUC, SCUC and SSUC) with commercially
activated carbon (CAC), the activated carbons of
U.
fasciata
are superior adsorbents than commercially acti-
vated carbon. This is due to more negatively charged
binding sites in
U. fasciata
activated carbons than that
of commercially activated carbon. The study revealed
that activated carbon (SSUC) from
U. fasciata
has much
potential as an adsorbent for the removal of Pb(II) ions
from aqueous solution