Abstract:
The aim of this study was to determine the efficiency and adsorption capacity of
activated carbon of white jabon fruit in adsorbing chromium(VI) ions, determine the
kinetic model and adsorption isotherm and the percent regeneration of activated carbon
of white jabon fruit. The making of white jabon fruit carbon is carried out by
carbonization process at 300℃ for 30 minutes. Jabon fruit carbon was activated with
NaOH solution with a ratio of carbon and activator 1:3 (w/w). Characterization of
activated carbon refers to SNI 06-3730-1995. Functional groups of activated carbon
were analyzed using FTIR, activated carbon morphology and elemental composition of
activated carbon were analyzed using SEM-EDS. Surface area, pore volume and pore
radius were analyzed using BET method and metal ion concentrations were analyzed
using ICP. The yield of carbon obtained was 66.55%. The results of characterization of
activated carbon obtained a moisture content of 1.86%, ash content of 1.29%,
adsorption capacity of iodine 1149.92 mg/g and adsorption capacity of methylene blue
24.9824 mg/g. The FTIR results showed that the functional groups of activated carbon
in white jabon fruit were N-H, aliphatic C-H, aromatic C-H, C=O, C-O-C and O-Cr.
The best adsorption conditions were obtained at pH 2, contact time 30 minutes and
adsorbate concentration of 40 mg/L with an efficiency of 87.19% and an adsorption
capacity of 1.6651 mg/g. The percentage of regeneration reached 98.53%. The pHpzc
obtained was 6.8. pH<pHpzc so that the surface of activated carbon is positively
charged. Based on the results of the BET, activated carbon from white jabon fruit has a
surface area before adsorption of 2.3899 m2/g, after adsorption of 0 m2/g and after
regeneration of 1.4250 m2/g. Based on the results of the SEM-EDS, it is known that
activated carbon has the elements C, O, Na, N, Cl, K and Cr with open pores and a
smoother surface. The adsorption kinetics model follows a second-order pseudo
equation with the equations y = 0.367x-1.677, R2 = 0.9919 and k = 0.0569 g/mg min.
The adsorption isotherm model follows the Langmuir isotherm with the equation
y = 2.0535x + 0.1867 and R2 = 0.9925. Activated carbon from white jabon fruit has the
potential to be reused in adsorption of chromium(VI) ions.
