KAJIAN ADSORPSI – DESORPSI [AuCl4]- PADA Mg/Al HIDROTALSIT; ADSORPTION - DESORPTION STUDY OF [AuCl4]- ON Mg/Al HYDROTALCITE

Nur Aini Iksan, Sri Juari Santosa

2011 | Disertasi | PROGRAM STUDI PASCA SARJANA ILMU KIMIA

Mg/Al hydrotalcite has been synthesized and its application to adsorp [AuCl4]- has been studied. The synthesis was done by coprecipitation method of Mg(NO3)2 and Al(NO3)3 at pH 8.9 with Mg(II) and Al(III) molar ratio of 2: 1. The product was characterized by infrared spectroscopy (FTIR), X-ray diffractometer (XRD) and atomic absorption spectroscopy (AAS). The applications of Mg/Al hydrotalcite as adsorbent was studied by studying kinetics, and determining capacity and energy of adsorption. The elution of [AuCl4]- from Mg/Al hydrotalcite was performed to analyze the possibility to obtaine back [AuCl4]- . The Mg/Al hydrotalcite had a chemical formula Mg0,755Al0,245(OH)2(NO3) 0.245.0,298 H2O. The results of characterization by XRD showed d003 = 8.62 Å, d006 = 4.38 Å, and d009 = 2.56 Å, whereas the analysis by FTIR showed the absence of CO3 2-. Adsorpsi of [AuCl4]- by Mg/Al hydrotalcite first order with rate constants of adsorption (k1A) 1.41 x 10-2 min-1. Adsorption capacity and energy for [AuCl4]- on Mg / Al hydrotalcite determined according to Langmuir isotherm model were 279.62 mg/g and 24.29 kJ/mol, respectively. FTIR spectra and XRD diffractogram of Mg/Al hydrotalcite after elution of AuCl4 - using NaOH 0.5 M were the same as those of Mg/Al hydrotalcite before use as adsorbent. Thus, Mg/Al hydrotalcite is potential enough to used as [AuCl4]- adsorbent

Kata Kunci : Mg/Al Hidrotalsit, Adsorpsi, Desorpsi dan [AuCl4]-