Abstract:
White jabon fruit (Anthocephalus cadamba Miq.) soaked in peat water which is rich in
humic acid has the potential to be used as a biosorbent to adsorb lead(II) metal based on
the cellulose content of jabon fruit and the active compounds contained in both. This
research aims to determine the adsorption capacity and efficiency of white jabon fruit
biosorbent in a batch system against lead(II) ions under optimum conditions as well as
the appropriate adsorption kinetics and adsorption isotherm models. The optimum
biosorbent conditions were determined by optimizing pH (4, 6, 8 and 10), contact time
(20, 30, 40 and 50 minutes) and adsorbate concentration (80, 100, 120 and 140 mg/L).
The surface morphology of the biosorbent before and after activation with NaOH (1:1,
1:2, 1:3, 1:4 and 1:5 w/w) was analyzed using SEM-EDS, while the functional groups of
the biosorbent before and after the biosorption process were analyzed using FTIR.
Determination of adsorption capacity and efficiency was analyzed using AAS. The results
of the characterization of biosorbents in adsorbing iodine and methylene blue based on
SNI 06-3730-1995 show that the best ratio of biosorbent: NaOH activator to activate
biosorbents is a ratio of 1:3 (w/w). SEM-EDS results show that the biosorbent before
activation contains the elements C, O, Na, Mg, Si, Pb, Cl, K, Ca and Cr while activation
only includes the elements C, O, Na and Cl. Optimum conditions occurred at pH 6,
contact time 40 minutes and adsorbate concentration 140 mg/L with adsorption capacity
and efficiency respectively 6.6385 mg/g and 99.977%. The kinetic model of the
biosorbent adsorption process follows pseudo second order kinetics with a rate constant
of 0.00235 g/mg min (R2=0.9867) which indicates that the adsorption process involves a
chemisorption mechanism. The adsorption isotherm model follows the Freundlich
isotherm equation (R2=0.9862) which indicates that adsorption occurs on a heterogeneous
surface.
