Bio-nanosilica obtained from rice husk using ultrasound and its potential for dye removal

Bio-nanosilica was obtained from rice husk thought an alternative ultrasound process and, the material was used to adsorb Crystal Violet (CV) dye from aqueous effluents. Ultrasound modified bio-nanosilica (UM-nSiO2) presented better characteristics than standard nano-silica (nSiO2), demonstrating that ultrasound technique has great potential to generate a promising material for adsorption purposes. The adsorption study was carried out by the kinetic curves, equilibrium isotherms and thermodynamics. Pseudo-second order model was the best to represent the kinetic curves. To represent the equilibrium curves, BET and Freundlich were suitable. Bio-nanosilica attained adsorption capacity of 495 mg g−1 and removal percentage of 98%, being an efficient adsorbent for CV dye.