Synthesis and Characterization of Colloidal Nanosilica via an Ultrasound Assisted Route Based on Alkali Leaching of Silica Fume

Document Type : Research Paper


Cement Research Center, School of Chemical Engineering, Iran University of Science and Technology, Tehran, I. R. Iran


Colloidal nanosilica is currently being produced by various methods which are mainly high energy intensive
and/or not environmentally friendly. It is therefore essential to develop new energy-efficient and environmentally
friendly technologies. This paper introduces a new ultrasound assisted route based on alkali leaching of
silica fume for synthesis of colloidal silica nanoparticles. The effects of sonication time on the particle size
distribution of the colloidalnanosilica are studied via dynamic light scattering (DLS). The results show that the
shape and size of nanoparticles are strongly depended on the ultrasonic time. DLS results show that average
diameter of the produced colloidal nanosilicadecreases sharply from 337.10 nm to 93.27 nm during the first
5 minutes of sonication. Continued sonication up to 30 minutes, however, shows relatively slight decrease in
average diameter of the colloidal nanosilica. Further, the produced colloidal nanosilica is characterized by
scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD)
and Fourier transform infrared (FTIR) spectroscopy.