Deposition of magnetite on AgI-silica core-shell particles by homogeneous precipitation method

• Main Authors: Kobayashi, Yoshio, Fujisaku, Toshimi, Ayame, Tetsuya, Nakagawa, Fomohiko, Gonda, Kohsuke, Fakeda, Motohiro, Ohuchi, Noriaki, Mine, Eiichi, Fakezawa, Tsutomu
• Format: Conference Proceeding
• Language: English
• Subjects: AgI; Atmospheric measurements; Core-shell; homogeneous precipitation method; Iron; Magnetic resonance imaging; particle; Particle measurements; Saturation magnetization; silica; Silicon compounds; X-ray scattering
• DOI: 10.1109/ICONSET.2011.6167925

A method for magnetite-deposition on Agl-SiO 2 core- shell (Agl/SiO 2 ) particles is proposed. A colloid solution of 1.0×10 -3 M Agl nanoparticles was prepared mixing silver perchlorate at 1.0×10 -3 M and potassium iodide at 2.0×10 -3 M at 5°C, and then adding 3-mercaptopropyltrimethoxysilane at 4.5×10 -5 M at 20°C. Agl/SiO 2 particles with an average size of 42.7±10.3 nm and a Agl core size of 23.5±5.8 nm were prepared using a Stober method at 20°C in water/ethanol solution with 8.0×10 -3 M tetraethylorthosilicate and 1.1×10 -3 M NaOH in the presence of 1.0×10 -3 M Agl nanoparticles. Preparation of magnetite nanoparticle colloid solution was performed with a homogeneous precipitation method using 5.0 M urea aqueous solution and 1.0×10 -2 M iron chloride aqueous solution with Fe 2+ /Fe 3+ molecular ratios of 1/0, 2/1, 1/2 and 0/1 in (50/50) (v/v) water/1-propanol solution at 80°C. Magnetite that revealed ferromagnetic property were produced using the ratios of 1/0, 2/1 and 1/2. Magnetite-deposition on the Agl/SiO 2 particles was performed preparing the magnetite by the homogeneous precipitation method using 1.0×10 -2 M iron chloride and 5.0 M urea in the presence of the Agl/SiO 2 particles ([Agl] = 2.0×10 -4 M). Tiny magnetite nanoparticles were deposited on the Agl/SiO 2 particle surface. The magnetite-deposited Agl/SiO 2 particles were ferromagnetic, and were drawn close to magnet. These results confirmed that the homogeneous precipitation method was suitable to magnetite-deposition.