ADSORPSI REDUKTIF [AuCl4]- OLEH ASAM ASKORBAT TERIMOBILISASI PADA Mg-Al HT DAN RECOVERY EMAS HASIL REDUKSINYA MENGGUNAKAN NATRIUM SITRAT; REDUCTIVE ADSORPTION OF [AuCl4]- BY ASCORBIC ACID IMMOBILIZED ON Mg/Al HYDROTALCITE AND RECOVERY OF THE REDUCED GOLD USING SODIUM CITRATE
AGUSTINA SUS ANDREANI, Sri Juari Santosa
2015 | Skripsi | FMIPA UGMReductive adsorption of [AuCl4]- by using ascorbic acid immobilized on Mg/Al hydrotalcite (Mg/Al HT) and recovery of the reduced gold using sodium nitrate have been conducted. The aim of this research was to recover pure gold from dissolved [AuCl4]-. Mg/Al HT was synthesized by co-precipitation method at pH 10 with Mg (II) and Al (III) molar ratio of 2:1. Ascorbic acid was then immobilized on the synthesized Mg/Al HT to form hybrid of Mg/Al HT and ascorbic acid (Mg/Al HT-AA) and followed by its application to reductive adsorption of [AuCl4]-. Au(0) as the reduction product was recovered by using sodium citrate as capping agent in order to form gold nanoparticles. Gold nanoparticles were separated from the solution using centrifugation to obtain Au(0) solid. The formation of gold nanoparticles as the product of [AuCl4]- reduction on 60 mg Mg/Al HT-AA using sodium citrate as capping agent was optimum at pH 5, concentration of sodium citrate 70 mM and sonication for 2 hours. The results showed that the average size of gold nanoparticles was 32 nm at SPR 531 nm. By centrifugation at 13,000 rpm for 8 minutes, gold precipitation can be obtained from the gold nanoparticles which were previously capped by sodium citrate. Characterization using FTIR and XRD showed that the obtained gold precipitation still contained impurities derived from citric and Mg/Al HT.
Kata Kunci : gold nanoparticles; sodium citrate; Mg/Al HT
