Abstract:
The silica nanopowder has been in demand every dawn due to its application in various
emerging technological advancements [1]. This is due to its desired features such as
chemically stable, friendly to the environment, easily biocompatible among others
[2,3]. The material has been extracted from various sources mainly from agricultural
wastes. The purpose of the study was to utilize locally available beach sand from Marine
National Park from Malindi, Kilifi County, Kenya in facile extraction of silica
nanopowder via a simple alkali fusion method. The sand was first purified using 6 N
HCl solution to eliminate metal oxide impurities. Then, the purified sand was reacted
with NaOH to form of sodium silicate (Na
2
SiO
) solution which was then precipitated
using HCl acid to form tetraortosilicate acid, Si(OH)
3
(silica gel). The gel was then
heated to form amorphous silica (SiO
2
4
). The percentage yield of the extracted silica was
35.0139 ± 0.11 %. The extracted silica was characterized using XRF, XRD and FT-IR.
The XRF analysis 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 spectrum of extracted
silica showed a broad diffraction peak at 2θ = 21.76
revealing its amorphous nature.
The average particle size of the extracted silica was 45.15 nm. The FT-IR analysis showed
o
hydroxyl (-OH) in silanol (Si-OH) and siloxane (Si-O-Si) as important functional groups
of the extracted silica. The results showed a low-cost technique for the production of
highly pure nanosized silica that can be employed in vast industrial applications.
