| Summary: | Amino hybrid silica coated magnetite (M-HAS) was synthesized. M-HAS
was synthesized by one pot sol gel process by mixture of sodium silicate
(Na2SiO3) solution from rice husk ash as precursor, (3-aminopropyl)-
trimethoxysilane (APTMS) as source of amine functional group and activated
magnetite . The functional groups of M-HAS been characterized by Infrared
Spectroscopy (FTIR), while X-ray Diffraction (XRD) used to indicate crystallinity
and transmission electron microscopy (TEM) used to confirm the particle size .
The adsorbed metal ion was quantitatively calculated using Atomic Adsorption
Spectroscopy (AAS). Desorption was done using thiourea solution in HCl and
thiosulfate solution with variation of concentration and time contact. Variation of
the concentration Cu(II) and Ni(II) was used to study multimetal sorption.
The result of characterizations showed that M-HAS has been successfully
retrieved. The result showed that adsorption of Au(III) followed Langmuir
isotherm model with capacity of adsorption 39.39mg/g and adsorption energy
amount 24.076 KJ/mol. The result of desorption studies showed that the optimum
condition for Au(III) desorption was in 2.5% thiourea solution in HCl 0.2 M for
20 minutes to contact and thiosulfate 0.2 M for 10 minutes to contact. Adsorption
kinetics could well be approximated more favorably by pseudo second order
kinetic model with k = 1,1897 g mg-1 min-1 and 1,1093 g mg-1 min-1. Au(III)
desorbed until 88.07% using thiourea solution, and 94.40% using thiosulfate
solution. Study of multimetal adsorption indicated M-HAS has a high selectivity
to Au (III) with the order of adsorption capacity of Au (III)> Cu (II)> Ni (II).
Used of thiourea and thiosulfat solution more selective to Au(III) than Cu(II) and
Ni(II).
|
|---|