Preparation of L-Arginine-Modified Silica-Coated Magnetite Nanoparticles for Au(III) Adsorption

L-arginine-modified silica-coated magnetite nanoparticles (Fe3O4/SiO2-GPTMS-Arg) have been synthesized by sol-gel process for adsorption of Au(III) ion in aqueous solution. Modification of L-arginine on silica coated magnetite through a coupling agent of 3-glycidoxypropyl-trimethoxysilane (GPTMS) was performed in a various mole ratio of GPTMS: Arg 1:0; 1:1; 1:2 and 1:3. The products of Fe3O4/SiO2-GPTMS-Arg were characterized with XRD, FTIR, EDX, TGA, and Kjeldahl methods. The results showed that based on characterization data Fe3O4/SiO2-GPTMS-Arg has been successfully synthesized with the optimum mole ratio of 1:2. The optimum adsorption of Au(III) occurs at pH 3 and contact time of 60 min. The adsorption capacity followed Langmuir isotherm model was found 0.638 mmol. g(-1) for the Fe3O4/SiO2-GPTMS-Arg 1:2. Fe3O4/SiO2-GPTMS-Arg nanoparticles show a potential adsorbent for an effective Au(III) ion removal.