Sintesis Hibrida Amonium Kuaterner Silika dari Sekam Padi untuk Adsorpsi Ion Au(III) dalam Campuran Au/Cr; Synthesis of Quaternary Ammonium Silica Hybrid From Rice Hull for Adsorption of Au(III) In An Au/Cr Mixture

Christny Desire Tiwow, Nuryono

2013 | Disertasi | PROGRAM STUDI S2 ILMU KIMIA

Quaternary ammonium silica hybrid (QASH) had been synthesized for the adsorption of Au(III) in an Au/Cr mixture. QASH was synthesized by refluxing a mixture of amino silica hybrid (ASH), metil iodide (CH3I) and sodium hydrogen carbonate (NaHCO3) solution for 24 hours in dark condition. ASH and QASH were characterized by infrared (IR) spectroscopy, X-ray diffraction (XRD) and N2 adsorption-desorption (BET-BJH method). Adsorption of Au(III) in Au/Cr mixture was carried out in a batch system with variation of pH, time and concentration of Au(III). The adsorbed metal were quantitatively determined by using Atomic Absorption Spectrofotometry (AAS). Adsorption kinetics were analyzed using several kinetics models and Langmuir and Freundlich models were used to determine adsorption capacity and energy of adsorption. The FTIR characterization indicated that QASH was successfully synthesized as shown with the presence of spesific absorbance of functional groups such as silanol (Si-OH), siloxane (Si-O-Si), methylene (-CH2-) and methyl (-CH3-). The XRD data showed that the structure of ASH and QASH was amorphous. Kinetic study demonstrated that the adsorption of Au(III) on ASH and QASH followed pseudo-second order with a value of k2=0,0068 g ?mol-1 min-1 for ASH and k2=0,0034 g ?mol-1 min-1 for QASH. The uptakes of Au(III) by ASH and AQSH were optimum at pH 3 with the adsorption capacity for ASH and QASH 46.89 and 26.98 mg/g respectively. The selectivity coefficient of ASH and QASH for Au(III) in the presence of Cr(VI) is 45,6 dan 29,4 respectively.

Kata Kunci : adsorpsi; emas; kuaterner; silika; sekam padi