Resource utilization of chlorosilane residual liquid to prepare nano-silica in reverse microemulsion system

Abstract

Nano-silica particles were prepared using chlorosilane residual liquid as raw materials in an inverse microemulsion system formed by three different surfactants (TX-100, CTAB, SDS) with n-hexanol, cyclohexane, and ammonia. The phase behavior of inverse microemulsions and the preparation of nano-silica were investigated. The results showed that the system composed of non-ionic surfactant TX-100 had a larger inverse microemulsion region than other two system and was more suitable for the preparation of nano-silica. The prepared nano-silica had uniform sphericity and good dispersibility, the average particle diameter of 31 nm, and the variance of 1 nm. XRD, FT-IR, N2 adsorption/desorption experiments and TG-DSC analysis were used to characterize the prepared nano-silica. The results showed that the prepared nano-silica was amorphous mesoporous silica with a BET specific surface area of 472.5 m2/g. They have a good thermal stability, and the phase structure and main chemical functional groups of nano-silica would not change after calcination at 600 °C, but the nano-silica would undergo a phase change at 1135 °C, which changed from amorphous to crystalline. The new technology not only broadened the source of preparation of nano-silica materials, but also provided new ideas for the treatment of chlorosilane residual liquid and the sustainable development of polysilicon industry.