The Method of Obtaining Amorphous Nanosized Silicon Dioxide from Rice Production Waste

Abstract

The method of using rice husk, which is a rice production waste, as a raw material for the production of silicon dioxide as an alternative to synthetic silicon dioxide – aerosil is considered. A low-energy process for extracting silicon dioxide and cellulose from the husk by alkaline digestion in an NaOH solution was proposed, followed by treating the black liquor with an acid solution and calcining the precipitate at 575 °C during 5 hours. The yield of inorganic products from rice husk is determined based on the ash content of the pulp. It was shown that the product obtained mainly consists of silicon dioxide (SiO2) of amorphous structure, has an average particle size of less than 100 nm, which makes it possible to characterize it as nanosilica. At the same time, silicon dioxide consists of 51.7 % silicon and 48.3% oxygen against theoretical amounts of 30.4 % silicon and 69.6 % oxygen, respectively. The output of silicon dioxide is 8.8 % by weight of rice husk. At the same time, the process allows to obtain another valuable nanocellulose product.

Synthesis of Copolymer from 1,3,5-Trioxane and -Caprolactone Catalysed by Treated Bentonite as Eco-Catalyst

“…12,13 The mechanism of RH thermochemical conversion during heat treatment and development of production technology for the silicon(IV) oxide is described by many researchers. [14][15][16][17] Over the last 15 years, an increase in the number of publications on the use of ingredients derived from rice husk for the production of tires and rubber products has been observed. These are short reports on the use of carbonized RH as a nanostructured filler, 18 products of heattreated (873-1073 K) rice husk in elastomeric compositions based on butadiene-styrene rubber, 19 silica (as a product of rice husk combustion) for fuel-saving tires (Italian company Pirelli 20 ).…”