Adsorption of Au(III) on diethylenetriamine-functionalized silica coated on iron sand magnetic material

Abstract

Diethylenetriamine-functionalized silica coated on magnetic material of iron sand (MM@SiO2−DETA) has been synthesized through sol-gel technique for adsorption of Au(III) in aqueous solution. Synthesis was carried out by coating magnetic material of iron sand as the core with diethylenetriamine-modified silica using sodium silicate solution and N1-(3-trimethoxysylilpropyl)diethylenetriamine (TMPSDETA) as silica and diethylenetriamine group sources, respectively. Adsorption of Au(III) in aqueous solution was performed in a batch system and three variables namely solution pH, temperature, contact time, and concentration of Au(III) were examined. The Au(III) not adsorbed was analyzed with a flame atomic absorbance spectrophotometer (FAAS). The maximum adsorption of Au(III) on MM@SiO2−DETA occurred at pH≈2 and pseudo-second order equation model fitted best to describe the adsorption kinetics with the rate constant of 7.41x10−2 g/mg.min. The adsorption equilibrium data followed Langmuir isotherm model with the adsorption capacity of 285.71 mg/g.