synthesis of nanosilica from silica fume using an acid-base precipitation technique and pva as a nonionic surfactant

the purpose of the present study was to synthesize and characterize nanosilica from alkali-extraction of silica fume under controlled conditions using poly (vinyl alcohol) (pva) as a dispersing agent. the dissolution efficiency of silica fume was affected by various factors such as concentration of the reagent, reaction time and temperature. a maximum dissolution efficiency of 91% was achieved at the sodium hydroxide solution concentration of 2.5 m, after areaction time of 30 minutes and at areaction temperature of 80°c. the microstructure and morphology of the obtained nanosilica powder at the optimum conditions were characterized using scanning electron microscopy (sem). sem images confirmed the formation of smaller and less agglomerated nanosilica particles due to the existence of the surfactant. further, the synthesized nanosilica was characterized by fourier transform infrared (ftir) spectroscopy, x-ray diffractometry (xrf) and x-ray diffraction (xrd). the results show that the synthesized nanosilica consisted of pure silica particles.