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

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.