Catalytic Oxidation of Phenol in Aqueous Solution using Fe - Sulfonated Carbon Catalyst
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Date
2018-07
Authors
Journal Title
Journal ISSN
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Publisher
Addis Ababa University
Abstract
The main objective of this research was to mineralize phenol in aqueous solution using Fe –
Sulfonated carbon catalyst. Two fairly different catalysts (Fe/AC and Fe/AC − SO
iii
3
H) in terms of
impregnation (FeSO
4
. 7H
2
O for 8hr) and sulfonation (with high concentrated sulfuric acid 98 %
for 15hr under N
2
) were successfully synthesized and compared. The synthesized catalysts were
characterized using: pH of zero point of charge, bulk density, total acid density, FT-IR
spectroscopy, iron stability, TGA, reusability and performance comparison test with D-optimal
experimental design through varying pH of the solution. The result shows that Fe/AC − SO
3
H
with maximum acid density, higher iron stability with high reusable capacity. In addition to this,
the performance comparison test ensured a maximum phenol removal efficiency and TOC
reduction of 8 % and 21.6 % respectively, for Fe/AC − SO
3
H catalyst higher than former catalyst.
Thus, from synthesized catalysts Fe/AC − SO
3
H was selected based on the above characterization
and further performance analysis was taken place to search for optimal condition.
The selected Fe/AC − SO
3
H catalyst was studied for its activity to catalyze mineralization of
phenolic aqueous solution using heterogeneous fenton process. Design-Expert 7.0.0 three-levelthree-factor
with full
factorial
was
applied
for
experimental
design
and
statistical
analysis
using
a
respective
process variables; reaction temperature 30, 60 and 90℃, hydrogen peroxide
concentration of 1000, 3500 and 6000 mg/L and 60, 150 and 240 min of reaction time. From the
analysis of experimental results the interaction effects were studied and the optimal mineralization
reaction process conditions, which will maximize the percentage of TOC reduction, were found to
be 57.12 ℃ reaction temperature, 2869.72 mg/L hydrogen peroxide concentration and 119.38 min
reaction time which gave 97.94% of TOC reduction. The experimental results were fitted well with
the derived response model with the R
2
statistic measure, it is evident that the fit successfully
accounted for greater proportion of variance as all the models explained ≈ 98.08 %, 99.8 % and
89.85 % for temperature 30 ℃, 60 ℃and 90 ℃ respectively, of the total variation in the data. In
average only 4.09 % of the total variations were not explained by FKM and GLKM. However, as
GLKM contains more coefficients than the FKM, R-square statistic, a generally accepted best
indicator of the fit quality in the comparison of models with those that are nested, is used.
Description
Keywords
Sulfonation promoted catalyst, phenol mineralization, iron stability, catalyst reusability