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Advance Catalysis Chemistry
Synthesis of Fe/MgO nano-crystal
catalysts by solgel method for hydrogen
sulfide removal
Vu Anh Tuan ID: 2011323066
Department: Chemical and Biomolecular Engineering
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Introduction
1. Raw biogas contains: 5580% methane (CH4) and 2045% carbon
dioxide (CO2) with small amounts of water vapor, trace amount of
hydrogen sulfide (01% H2S), and other impurities.
2. alkaline/amine scrubbing, chemical oxidation, adsorption, bio filtration,
and catalytic wet oxidation.
3. The mechanism of H2S oxidation on Fe/MgO
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Introduction
4. Method synthesis MgO: solgel, hydrothermal, flame
spray pyrolysis, laser vaporization, chemical gas phase
deposition and surfactant methods.
5. Fe/MgO nano-crystal catalysts were then prepared by
wet impregnation.
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Result and discussion
MgO catalyst support media
1. Effects of calcination temperatures on MgO synthesis
Fig. 3d. This diffraction pattern agreeswell with the peaks of standard MgO.This confirms that MgO was formed tohigh purity from the synthesis. Thisresult also shows that the crystalsmatch with the lattice parameters: a =4.2198 , b = 4.2198 , c = 4.2198 , =90.0000 , = 90.0000 , = 90.0000 and
Z = 4.00.
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Results and discussion
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Result and discussion
2. Effects of precursor molar ratios on the MgO crystal size
The crystal size of MgO (d, nm) was calculated from the (2 0 0)
diffraction peak using the well-known Scherrer equation.
K is a dimensionless constant that may range from 0.89 to
1.39 depending on the specific geometry of the scattering objects
and B variables are the angles between the incident and
diffracted beams () and the full width at half maximum,
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Results and discussion
(c) BET surface areaand the pore volumewere 178.46m2/g and0.00311 ml/g
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Result and discussion
Characterization of the Fe/MgO catalysts
From the XRD data,the
Fe/MgO nano-crystal size
was calculated to be 17.5 nm.
From the BET analysis,
the BET surface area and
the pore volume were
171.59m2/g and 0.00298 ml/g
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Result and discussion
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Results and discussion
Catalytic activity in H2S oxidation.
1. H2S oxidation in a semi-batch reactor.
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Result and discussion
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Result and discussion
Characterization of the fresh and spent catalysts for H2Sdegradation
The fresh catalyst and the catalyst with regeneration samples had
the same brown color, while the spent catalyst without regenerationhad some black spots on the surface. The EDX characteristic results
showed 3 elements consisting of Fe, O, and Mg on the fresh and spent
catalysts with regeneration. In contrast, 4 elements consisting of S, Fe,
O, and Mg were found in the spent catalysts without regeneration.
The appearance of the S element can be determined from the
FTIR results provided in Fig. 9.
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Results and discussion
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Results and discusion
H2S absorption in packed column1. Effects of catalyst concentration on
the removal of H2S from biogas
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Results and discussion
2. Effect of L/G ratios on the H2S removal from biogas
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Results and discussion
3. The regeneration of the catalysts.
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Conclusion
1. The Fe/MgOnano-crystal catalysts were synthesized by a solgel
method. MgO nano-crystals with the sizes ranging from 12.9 to
36.3nm Fe3+ from ferric nitrate solution was supported on the MgO
nano-crystals by a wet impregnation technique to give 17.5nm
Fe/MgO crystals
2. The H2S removal from a biogas in a packed column scrubber using
the Fe/MgO nano-crystal catalysts with a sufficient air flow rate and
L/G ratio for the catalyst regeneration shows an outstanding
possibility. In addition, the reaction of the catalysts with methane was
not observed.
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