Preparation and characteristics of biosilica derived from marine diatom biomass of Nitzschia closterium and Thalassiosira

Abstract

In this study, biosilica of high purity was successfully prepared from marine diatom ( Nitzschia closterium and Thalassiosira ) biomass using an optimized novel method with acid washing treatment followed by thermal treatment of the biomass. The optimal condition of the method was 2% diluted HCl washing and baking at 600°C. The SiO 2 contents of N . closterium biosilica and Thalassiosira biosilica were 92.23% and 91.52%, respectively, which were both higher than that of diatomite biosilica. The SiO 2 morphologies of both biosilica are typical amorphous silica. Besides, N . closterium biosilica possessed micropores and fi bers with a surface area of 59.81 m 2 /g. And Thalassiosira biosilica possessed a mesoporous hierarchical skeleton with a surface area of 9.91 m 2 /g. The results suggest that the biosilica samples obtained in this study present highly porous structures. The prepared porous biosilica material possesses great potential to be used as drug delivery carrier, biosensor, biocatalyst as well as adsorbent in the future.

Mini-Review: Potential of Diatom-Derived Silica for Biomedical Applications

“…Organic impurities can be removed from the silica frustule by either a chemical pre-treatment with acids or other oxidative agents, or by exposing the frustules to high temperatures. Some studies, aimed at assessing the efficacy of preliminary hydrochloric acid treatments for organic mass removal, showed that acid concentration greatly influenced both the removal rate of impurities and the state of preservation of the frustule shape, with strong acidic pre-treatments causing frustule erosion [56]. Potassium permanganate can be also used to pre-treat frustules for organic compound removal [57,58].…”