Abstract:

Spherical silica nanoparticles with average particle size of 10 nm were synthesized using sodium silicate extracted from oil shale ash as silica source. The results showed that the addition of poly(ethylene glycol)（PEG） could effectively prevent the aggregation of silica nanoparticles and tune the particle size, the optimal PEG concentration was found to be 3.0%. Ultrasonication is a key factor to the formation of small, uniform nanoparticles and an optimized hydrolysis-condensation period for ultrasonication is 0.5 h. The azeotropic distillation evidently suppresses agglomeration and a possible mechanism of azeotropic distillation was also proposed.

Key words: oil shale ash, nanoparticles silica, ultrasonic, azeotropic distillation