Preparation of Hollow Calcium Silicate Microparticles by Simple Emulsion

Eiichi Toorisaka,Syotaro Nagamatsu,Yasunobu Saruwatari,Makoto Hirata,Tadashi Hano

doi:10.4236/jeas.2014.44012

Eiichi Toorisaka, Syotaro Nagamatsu + Show 3 more

Open Access

https://doi.org/10.4236/jeas.2014.44012

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Abstract

Hollow calcium silicate microparticles were prepared by mixing a water-in-oil (W/O) emulsion containing silicate ions in aqueous phase with an oil phase containing a calcium/di-2-ethylhexyl phosphoric acid (D2EHPA) complex. The inorganic precipitation reaction at the oil-water interface was accelerated by using a simple W/O emulsion. Hollow microparticles were obtained when the mole ratio of D2EHPA and calcium in the oil phase was nearly 2:1. The shell formation of the par-ticles depended on the acceleration of the precipitation reaction, which could be accomplished by controlling the concentrations of the calcium and silicate ions.

Highlights

Hollow microparticles have a huge potential as functional materials, such as the protection of their contents from an outside severe environment, the controlled release of chemicals, and the immobilization of gaseous and liquid materials
The complex of calcium ion and ioncarrier Di-2-ethylhexyl phosphoric acid (D2EHPA) in the oil phase was formed by the solvent-extraction process, described above
The formation of the calcium-D2EHPA complex proceeds by the ion exchange of calcium ion with the hydrogen ion of D2EHP; The calcium ion is extracted into the oil phase

Summary

Introduction

Hollow microparticles have a huge potential as functional materials, such as the protection of their contents from an outside severe environment, the controlled release of chemicals, and the immobilization of gaseous and liquid materials They have recently been applied in a variety of applications including catalysts, cosmetics, pharmaceuticals and bioreactors [1]-[3]. [11], to prepare inorganic hollow microparticles This method needs neither special techniques nor special equipment and allows for the preparation of particles by a simple operation. Thereby, an insoluble calcium silicate shell is formed in the vicinity of the interface by ion exchange between the calcium and sodium ions During this process, the acceleration of the complex transport to the internal aqueous phase is an important factor for shell formation. The preparation conditions and morphology of the prepared hollow particles were examined

Materials

Preparation of Calcium-Loading Solution

Analysis

Preparation of Hollow Particles Using Metal-Loading Solution

Conclusion