Synthesis, Extraction and Optimization of Silica Production from Teff straw (Eragrostis tef)
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Date
2019-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
Silica is one of the important chemicals widely used in manufacturing sectors for different
applications. Some of the applications of silica are in detergents and cleaners as extenders, in
rubber and tire as fillers, in shoe sols, Ink-receptive Coatings, adsorptive, adhesive and others.
As the commercial silica is produced from non-renewable, and there are some ongoing issues
with health hazard due to the crystalline structure of the raw material which is quartz and high
emission of carbon dioxide and waste water, the purpose of this research was to develop biobased
silica
using
teff
straw
as
a
renewable
feed
stock.
This
study
reports
preparation
of
silica
from
teff
straw
ash
by
sol-gel
method.
The
process
of
bio-silica
production
includes
leaching
of
teff
straw with 2.5N of HCl acid. The treated teff straw was decomposed thermally at ashing
temperature 700°C for 2 hours. Before proceeding to the extraction of silica using alkali solution
the silica percentage in the ash was analyzed using AAS spectrometer. The ash was treated with
NaOH solution at different concentration (0.5M, 1.5M and 2.5M), different extraction time
(60min, 90min and 120 min) and various extraction temperatures (75
C) prior to
acidification in order to extract silica in the form of sodium silicate solution (SSS). Design
Expert® version11.1.0.1 with Box-Behenken was applied to investigate the effect of experimental
variables. Significance of the process variables were analyzed by ANOVA. The optimum
parameters for the extraction of amorphous silica were 1.79M of NaOH, 109.99 minutes and
84.17
0
0
0
C, 85
C and95
0
C with maximum yield of 83.23%. Physicochemical properties of extracted silica were
determined by performing XRD and FTIR analysis. The teff straw ash contains about 92% silica.
Description
Keywords
Silica Production, Teff straw, Eragrostis tef, Synthesis, Optimization