IMMOBILISASI ASAM ASKORBAT PADA Mg/Al HIDROTALSIT DAN APLIKASINYA UNTUK ADSORPSI-REDUKSI AuCl4?; IMMOBILIZATION OF ASCORBIC ACID ON Mg/Al HYDROTALCITE AND ITS APPLICATION TO ADSORPTION-REDUCTION OF AuCl4

RAHMA HIDAIYANTI, Sri Juari Santosa

2013 | Disertasi | PROGRAM STUDI S2 ILMU KIMIA

Immobilization of ascorbic acid on Mg/Al hydrotalcite has been conducted and applied to adsorption-reduction of AuCl4£¼. Mg/Al hydrotalcite has been synthesized by coprecipitation method of Mg(NO3)2 and Al(NO3)3 at pH 10 with Mg(II) and Al(III) molar ratio of 2 : 1. The synthesized Mg/Al hydrotalcite as well as its immobilization product with ascorbic acid (Mg/Al HT-AA) before and after being used to adsorption-reduction of AuCl4£¼ were characterized by X-ray Diffraction and FT-IR Spectroscopy. The effect of pH on adsorption-reduction of AuCl4£¼, kinetic and isotherm adsorption were also studied. The gold metal formed was confirmed by XRD difractogram. Immobilization of ascorbic acid was optimum at pH 5 with adsorption capacity which followed Langmuir isoterm model was 90.91 mg/g. Adsorption of AuCl4£¼ by Mg/Al HT-AA was optimum at pH 3 and followed pseudo-second order kinetic model and Langmuir isotherm model with rate constant (k) and adsorption capacity of 7.79 x 10-4 g/mg minute and 38.46 mg/g respectively. Characterization with XRD showed that Au(III) could be reduced to Au(0) with peak of gold particles in difractogram of XRD d111, d200, and d220 at 2,36; 2,03 and 1,44 A.

Kata Kunci : Mg/Al hidrotalsit; asam askorbat; adsorpsi-reduksi; AuCl4?