Akira Kishimoto

Preparation of colored iron particles by multistratification with alternate thin layers of SiO2 and TiO2

Coloring ferromagnetic fine particles was achieved only by coating the particles with SiO2 and TiO2 alternate layers of appropriate thickness that act as light interference filters. We propose a new model called the “hemisphere model” for the calculation of the optimum thickness of layers on spherical particles to obtain any specific colored particles. The stratification of alternative thin layers of SiO2 and TiO2 layers was achieved by deposition of amorphous SiO2 and quasigranular TiO2 layers by the sol-gel method.

Recovery of Poly Sulfide Anions in Basic Solution Produced by the Decomposition of H2S by Fullerene

To remove poly sulfide anions from basic solution, a fullerene/toluene solution was mixed with an aqueous solution containing S2 2- ions and agitated until the color of the aqueous phase changed from yellow to transparent. The treatment was repeated several times. During each treatment, white precipitates were produced in the aqueous phase and black crystals were formed after 4th treatment. XRD results indicated that former was elemental sulfur and the latter, fullerene-sulfur compounds. Thus, we succeed in extracting and separating poly sulfide ion from aqueous solution. By the fifth treatment, c.a. 675 S2 2- ions per one fullerene were successfully collected from the aqueous solution. This reaction can be applied to recovery of other anion species in basic solution.