Biogenic Nano Silica Synthesis from Rice Husk and its potential in Rhodamine 6G adsorption

Abstract

Rhodamine dye is frequently employed as dying agent in paper, leather, plastic and textile industries. 15-20% of utilized dye is excreted out as effluent affecting aquatic life. Waste treatment hence becomes a necessary step in reducing its amount to minimum. Utilization of Silica nanoparticles have been exponentially increased since past decade in efficient removal of dye via electrostatic adsorption. In current study, we synthesized amorphous silica nanoparticles via biological route utilizing rice husk owing to its enriched silica content (90% of husk’s ash). Biosynthesized Silica Nanoparticles (SiNPs) were characterized with scanning electron microscope with an average size of 95 nm. X-Ray Diffraction was used to assess the crystalline structure and diffused peak at 22θ . Infrared Spectroscopy was performed to assess the composition of nanoparticles which was confirmed by a sharp dip at 1101 cm-1 showing Si-O-Si stretching. Stability of aqueous SiNPs was apparent owing to presence of sharp peak at -26.6 mV via Zeta potential. Surface area and surface porosity was confirmed by Brunauer-Emmet-Teller (BET) analysis with a surface area of 99.6886 m²/g and with total pore volume of 0.426528 cm³/g. Dye adsorption was increased by optimization of physiochemical parameters including pH (7), temperature (25° C), time (30 min), sorbent concentration (1000 mg/L) and agitation (250 rpm) by taking optical density at 525 nm. The study showed significant dye removal up to 84.5% by using optimized SiNPs thereby proving their excellent potential to be employed in industrial removal of Rhodami