A Simple Process to Prepare Silica Aerogel Microparticles from Rice Husk Ash

Abstract

Abstract-Biocompatible silica aerogel microparticles are promising drug delivery vehicles because of their large surface area and open pore structures. A simple process has been developed in this work to prepare silica aerogel microparticles from rice husk ash, using water-in-mineral oil emulsion for sol-gel, followed by aging in ethanol to strengthen gel network and drying with scCO 2 . This process obviates drawback of current methods for silica aerogels. The effects of speed of agitation of water-oil mixture, sol-to-oil ratio and surfactant concentration have been investigated on particle size and size distribution, BET surface area, cumulative pore volume and pore diameter. A surface area of 654 m 2 /g, higher than the values reported for similar materials, could be obtained.Index Terms-Rice husk ash, silica aerogel microparticles, supercritical carbon dioxide, water-in-oil emulsion.

Silica Aerogel Microparticles from Rice Husk Ash for Drug Delivery

“…The fourth column in the L9 array of the Taguchi design was intentionally left blank to estimate the variance and the significance of the results. Table summarizes the different levels for each parameter; these levels were chosen based on our previous work and preliminary set of experiments . The response data were analyzed with the Minitab 15 statistical software.…”

“…Table 1 summarizes the different levels for each parameter; these levels were chosen based on our previous work and preliminary set of experiments. 13 The response data were analyzed with the Minitab 15 statistical software.…”

“…Biobased materials are more preferred in the pharmaceutical industry to make new drug delivery devices . In this regard, rice husk (RH) is a better replacement for expensive and toxic precursor solutions such as TMOS and tetraethylorthosilicate (TEOS) to produce aerogels . RH is an abundantly available natural-agricultural waste material.…”

“…6 In this regard, rice husk (RH) is a better replacement for expensive and toxic precursor solutions such as TMOS and tetraethylorthosilicate (TEOS) to produce aerogels. 13 RH is an abundantly available natural-agricultural waste material. It is burnt to produce rice husk ash (RHA) which contains 70−98 wt % silica, which is amorphous and biocompatible 14,15 and small quantities of several other elements.…”

Influence of chemical and thermal treatment on the purity of silica extracted from rice husk

“…They are used as a fuel in some regions, in other countries they are treated as waste, they are usually disposed of by burning in the field, which results in damage to the either and the environment [1,2]. It was found that RH contains good amounts of amorphous porous silica, containing about 15-20 % silica [3][4][5]. High levels of silica content have encouraged many researchers to research how amorphous silica is extracted with high purity [5].…”