Please use this identifier to cite or link to this item: https://dspace.ctu.edu.vn/jspui/handle/123456789/21871
Title: High-purity amorphous silica from rice husk: Preparation and characterization
Authors: Nguyen, Nguyen Ngoc
Le, Xuan Thanh
La, The Vinh
Bui, Thi Van Anh
Keywords: Amorphous silica
Rice husk
Adsorbents
Agricultural waste
Waste recycling
Issue Date: 2018
Series/Report no.: Vietnam Journal of Chemistry;No 56(06) .- Page.730-736
Abstract: Amorphous silica has a wide range of applications in chemical, biological and environmental sectors. In this work, we studied the preparation of amorphous silica from rice husk, an abundant silica-rich agricultural waste in Vietnam. We investigated and compared two methods of preparation: (1) via selective removal of alkaline and alkaline-earth oxides from rice husk ash to yield amorphous silica; and (2) via selective precipitation of silica from aqueous solutions which had been prepared by dissolving rice husk ask in NaOH Solutions. The obtained silica was chạracterized by using XRD, EDX, SEM and BET techniques. The results show that the best obtained silica is a white amorphous and porous powder with high purity of SiO₂, in the form of aggregates of 50nm-sized primary particles, and a specific surface area of 186 m² /g. The SiO₂ recovery is around 8.3 (g) per 100 (g) rice husk. Moreover, in the context of the present work, method (1) can be a more straightforward route for the preparation of amorphous silica in terms of silica’s purity, porousity and amorphousness. In contrast, method (2) is shown for a lower grade of silica purity which could be due to strong adsorption of ions from the solution onto the amorphous SiO₂ precipitate during precipitation process. The obtained silica has promising applications as adsorbents, fillers and fertilizers.
URI: http://dspace.ctu.edu.vn/jspui/handle/123456789/21871
ISSN: 2525-2321
Appears in Collections:Vietnam Journal of Chemistry

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