STUDI KINETIKA ADSORPSI Au(III) OLEH KULIT BUAH MANGGIS (Garcinia mangostana L.); KINETICS STUDY OF Au(III) ADSORPTION BY MANGOSTEEN RIND (Garcinia mangostana L.)

Shaleh, Faisal, Sri Sudiono

2015 | Skripsi | FMIPA

Kinetics study of Au(III) adsorption by mangosteen rind has been conducted. The purposes of research are to determine of kinetics model, rate constant (k) and activation energy of adsorption-reduction of Au(III) by mangosteen rind. The first step was carried out by isolating mangosteen rind. This study includes refining dried mangosteen and maserisation. The result of maserisation was used to determine kinetic model and activation energy by interacting mangosteen rind into [AuCl4]? solution with time and temperature variations. The concentration of Au(III) measured by atomic absorption spectometry, while the mangosteen rind was characterized by Infra Red Spectroscopy (IR), X-Ray Diffraction (XRD) and photomicroscop instruments. The result shows that Ho pseudo-second order kinetic was the most suitable model with the adsoprtion rate constant (k) at 40, 50 and 60 °C are 2.05×10-3 ; 3.63 × 10-3 ; 3.60 × 10-3 g.mg-1.min-1, respectively. The adsorption rate increased by increasing temperature. Activation energy determined by Arrhenius equation was 24.65 kJ/mol. XRD characterization after adsorption process shows 4 characteristics of gold metals at 2?: 38º, 44º, 64º, and 77º. The result proves that mangosteen can be used as adsorben for adsorption-reduction of Au(III) to Au(0).

Kata Kunci : adsorption kinetic; activation energy; adsorption-reduction, mangosteen rind; Au(III)