Fabrication and Characterization of Silica Nanoparticles from Beach Sand

Silica nanoparticles (SNPs) have many important applications including anti-reflection coating, self-cleaning surface and drug carriers. They are usually synthesized from the commercial precursor such as tetraethyl orthosilicate (TEOS). On the other hand, the natural silica can be found abundantly in organic materials such as rice husk and palm shell or in inorganic material such as beach sand and clay. Therefore, obtaining SNPs from the natural resources is very strategic for economic and technology considerations. This motivates the current study performing the synthesis and characterization of SNPs derived from the beach sand as one of natural resources available. Fort this purpose, the silica sands were mixed with sodium hydroxide (NaOH) for 2 hours at 90⁰ C, prior to filtering process for gaining the sodium silicate solution (SSS) which was further refluxed with hydrochloric acid (HCl) of 3 and 5 M until its pH reached the value of 7, and finally dried. The characterizations carried out on the resulting SNPs included UV-Vis and FTIR spectroscopies, XRD and SEM. The XRD study confirmed that the resulting samples are amorphous silica phase with the average crystallite size of 4.8 and 2.9 nm for the SNPs synthesized with 3 and 5 M chloric acid, respectively. The image analysis of SEM results revealed that the obtained SNPs have the average diameter of 11.6-12.00 nm. The formation of SNPs was further confirmed with the UV-Vis and FTIR spectroscopies. On the basis of investigation results, it was shown that the desired silica nanoparticles can be successfully derived from the beach sand.