Facile methods for the preparation of micro- and mesoporous amorphous silica from rice husk
- PDF / 1,411,715 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 3 Downloads / 229 Views
ORIGINAL ARTICLE
Facile methods for the preparation of micro- and mesoporous amorphous silica from rice husk Mohamed El-Sakhawy 1
&
Abeer M. Adel 1 & Mohamed A. Diab 1 & Mona Al-Shemy 1
Received: 19 May 2020 / Revised: 19 October 2020 / Accepted: 23 October 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Silica was obtained from rice husk (RH) by five different methods. (1) Burning RH as received in muffle at 850 °C for 2 h, (2) RH was firstly burned at 450 °C to reduce its volume. The obtained ash was refluxed with 1N HCl; after washing and drying, ash was burned at 700 °C for 3 h. (3) Un-grinded (or grinded (method 4)) RH was firstly soaked in water, treated with 1N HCl, and burned at 700 °C. (5) To utilize cellulosic fiber, RH was autoclaved with 15% NaOH, and silica was precipitated from the residual liquor. Silica hydrogel was prepared from the obtained ashes by reflux with 2.5 N NaOH followed by neutralization with 1N HCl to form silica gel. The silica gel was filtered, washed, and freeze-dried. XRF analysis confirmed the excellent removal of metal oxide impurities from RHs by acid leaching treatment. Silica precipitated from black liquor shows the most homogeneous particle size. Mesoporous silica with purity over 99% and with a homogeneous particle of average size 41.3–71.3 nm was synthesized using CTAB surfactant as the structure-directing template and RH ash as the silica source. Keywords Mesoporous silica . Amorphous silica . Rice husk . Silica hydrogel
1 Statement of novelty Silica was obtained from rice husk by five different simple methods. Silica hydrogel was prepared from the obtained ashes and used successfully to prepare micro- and mesoporous amorphous silica. Mesoporous silica with purity over 99% was synthesized using CTAB surfactant (as a structuredirecting template) and rice husk ash (as a silica source).
2 Introduction Amorphous silica has an excellent recognized performance, due to its application in different industries and electronics for being a good semiconductor [1]. Also, it has diverse properties such as nontoxicity; large surface area; chemically, physically, and thermally stable; compatible with various materials; largely available; and relatively inexpensive [2]. Mesoporous silica has * Mohamed El-Sakhawy [email protected] 1
Cellulose and Paper Department, National Research Centre, 33 El-Bohouthst., Dokki, P.O. 12622, Giza, Egypt
particles with pore sizes in the range of 2–50 nm. Due to their high surface area, controllable narrow pore size distribution, and ability of surface chemistry functionalization, mesoporous silica has received great attention for numerous applications in adsorption, separation, catalysis, wastewater treatment, and drug delivery [3, 4]. However, the large-scale manufacture of mesoporous silica is difficult due to the high cost and toxicities of both the templates and the silica source. Mesoporous silica is produced via poly-condensation of silica species (like tetraethyl- (TEOS) or tetramethyl- (TMOS) orthosilicate) in t
Data Loading...
