Facile Extraction and Characterization of Silica Nanopowder from Marine National Park beach sand via Alkali Fusion Route

Abstract

The current study showed utilization of locally available beach sand from Marine National Park in facile extraction of highly amorphous silica via a simple alkali fusion method. The purification of the silica sand was done using 6 N HCl solution to increase its purity. The method entailed formation of sodium silicate (Na2SiO3) solution from silica sand, precipitation using HCl acid to form tetraortosilicate acid, Si(OH)4 (silica gel) which is then heated to form amorphous silica (SiO2). The percentage yield of the extracted silica was 35.0139±0.11%. The extracted silica was characterized using X-Ray Fluorescence Spectrometer (XRF), X-Ray Diffractometer (XRD) and Fourier Transform Infrared Spectrophotometer (FT-IR). The XRF characterization revealed that the extracted silica content was 94.16±0.47 % which increased from 81.32±0.81% (Silica sand). The XRD results revealed a highly crystalline quartz as the main component of silica sand. The XRD spectra of extracted silica showed a broad diffraction peak at 2θ = 21.76o revealing its amorphous nature. The average particle size of the extracted silica was 45.15nm. The FT-IR characterization of the extracted silica showed hydroxyl (-OH) in silanol (Si-OH) and siloxane (Si-O-Si) as important functional groups. The results showed a low cost technique for the production of highly pure amorphous nanosized silica as a potential mineral that can be employed in vast industrial fields.