Effect of adsorbent composition on H2S removal on sewage sludge-based materials enriched with carbonaceous phase

Ansari, Adil; Bagreev, Andrey; Bandosz, Teresa J.

doi:10.1016/j.carbon.2004.11.042

Cited by 52 publications

(38 citation statements)

References 27 publications

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“…Generally, the carbonaceous phase was able to increase the capacity; however, that increase was not as significant as one would expect. It was concluded that the reason for this is the high acidity of the specific carbon phase used (12). It provided a high surface area, but with the presence of a certain critical amount of acidic carbonaceous phase, the performance of the materials decreased and the H2S removal capacities were even smaller than those for sludge-derived adsorbents.…”

Section: Introductionmentioning

confidence: 99%

Inorganic−Organic Phase Arrangement as a Factor Affecting Gas-Phase Desulfurization on Catalytic Carbonaceous Adsorbents

Ansari

Bandosz

2005

Environ. Sci. Technol.

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Dried sewage sludge was physically mixed with waste paper (paper-to-sludge ratios from 25% to 75%). To increase the catalytic activity, from 1% to 6% calcium hydroxide was added to the mixtures. Then the precursors were carbonized at 950 degrees C. The performance of materials as H2S adsorbents was tested using a home-developed dynamic breakthrough test. The samples, before and after the adsorption process, were characterized by adsorption of nitrogen, potentiometric titration, thermal analysis, XRF, and SEM. Differences in the performance were linked to the surface properties. Itwas found that mixing paper with sludge increases the amount of H2S adsorbed/oxidized in comparison with that adsorbed/oxidized by the adsorbents obtained from pure precursors (sludge or waste paper) and the capacity is comparable to those of the best activated carbons existing on the market. Although both sewage sludge and waste paper provide the catalytic centers for hydrogen sulfide oxidation, the dispersion of the catalyst and its location within accessible pores is an important factor. The presence of cellulose in the precursor mixture leads to the formation of a light macroporous char whose particles physically separate the inorganic catalytic phase of the sewage sludge origin, decreasing the density of the adsorbent and thus providing more space for storage of oxidation products. This, along with calcium, contributes to a significant increase in the capacity of the materials as hydrogen sulfide adsorbents. On their surface about 30 wt % H2S can be adsorbed, mainly as elemental sulfur or sulfates. The results demonstrate the importance of the composition and arrangement of inorganic/ organic phases for the removal of hydrogen sulfide. The interesting finding is that although some microporosity is necessary to increase the storage area for oxidation products, the carbonaceous phase does not need to be highly microporous. It is important that it provides space for deposition of sulfur, which is formed on the inorganic-phase catalyst. That space can be in meso- and macropores as shown in the case of char derived from the waste paper.

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Section: Introductionmentioning

confidence: 99%

Inorganic−Organic Phase Arrangement as a Factor Affecting Gas-Phase Desulfurization on Catalytic Carbonaceous Adsorbents

Ansari

Bandosz

2005

Environ. Sci. Technol.

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“…As a result of surface reactions, H 2 S can be oxidized to either sulphur or SO 2 [8]. Activated carbons of different characteristics have also been prepared from sewage sludge pyrolysis or carbonization [10][11][12][13], obtaining pollutant removal results comparable to those corresponding to commercial catalytic activated carbons [13].…”

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confidence: 99%

Use of sewage sludge combustion ash and gasification ash for high-temperature desulphurization of different gas streams

Gil-Lalaguna

Sánchez

Murillo

et al. 2015

Fuel

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Due to its metal content, sewage sludge ash appears as a potential sorbent material for H 2 S removal at high temperature. The desulphurization ability of the solid by-products of combustion and gasification of sewage sludge has been evaluated in this work. Ash characterization results revealed that metal fraction in sewage sludge did not remained completely inert during the combustion and gasification processes. Iron content was lower in the gasification ash and X-ray patterns showed different crystalline phases in the solids: Fe 2 O 3 in the combustion ash and Fe 3 O 4 in the gasification ash. These differences resulted in a lower sulphur capture capacity of the gasification ash.Desulphurization tests were carried out in a lab-scale fixed bed reactor operating at 600-800 ºC. Different gases containing 5000 ppmv H 2 S (H 2 S/N 2 mixture and synthetic gasification gas) were used. The H 2 S breakthrough curves were negatively affected by the reducing atmosphere created by the gasification gas and by the presence of steam in the reaction medium. However, H 2 S breakthrough curves alone do not provide enough information to evaluate the sulphur capture capacity of the sorbent materials. Ultimate analyses of the spent solid samples showed that the total amount of H 2 S removed from the gas was only partially captured in the ash. Thermodynamic data pointed to a significant fraction of sulphur forming part of other gases, such as SO 2 . In the best 2 operating conditions, an outlet gas with less than 100 ppmv of H 2 S was obtained during 300 min, thus resulting in a sulphur loading of 63 mg S·g -1 ash . This experimental sulphur content was 39% lower than the maximum theoretical value predicted by equilibrium simulations.

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“…Lake sediment is the mainly solid waste in the waterbodies. It has high fixed carbon content, which is a suitable raw material for the preparation of biochar . Meanwhile, the utilization of lake sediment can solve the disposal and sustainable development problems.…”

Section: Introductionmentioning

confidence: 99%

Influence of surface characteristics on carbon disulfide catalytic hydrolysis over modified lake sediment biochar and research on deactivated mechanism

Song

Sun

et al. 2019

Surface & Interface Analysis

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A series of lake sediment biochar (LSB) catalysts modified by metal oxides and basic functional groups were utilized for removal of carbon disulfide (CS2) in yellow phosphorus tail gas. The influences of preparation and modification conditions for surface characteristics of Fe‐KOH/LSB on removal of CS2 were investigated. Surface area and pore structure analyses indicated that preparation processes were aimed to increase the micropore structure of LSB. Diffuse reflection using transform of Fourier infrared radiation results showed that Fe had high hydrolysis activity for CS2 and low oxidation activity for H2S. Thermogravimetric/differential thermal analysis results indicated that low calcination temperature was not conducive to the generation of Fe2O3 and high calcination temperature led to the oxidation of LSB. CO2 temperature programmed desorption results stated that high alkalinity site strength could improve the catalytic hydrolysis performance. High KOH content could enhance alkalinity site strength but led to the block of pore. These modification factors mainly controlled the catalytic hydrolysis ability of Fe‐KOH/LSB. X‐ray photoelectron spectroscopy results claimed that the deactivation of Fe‐KOH/LSB was attributed to the generation of S and sulfate, and the consumption of active component. In the deactivation process, S and sulfate generated and covered the activity sites, and Fe2O3 was converted into FeSO4 or Fe2(SO4)3, which led to the deactivation.

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Effect of adsorbent composition on H2S removal on sewage sludge-based materials enriched with carbonaceous phase

Cited by 52 publications

References 27 publications

Inorganic−Organic Phase Arrangement as a Factor Affecting Gas-Phase Desulfurization on Catalytic Carbonaceous Adsorbents

Inorganic−Organic Phase Arrangement as a Factor Affecting Gas-Phase Desulfurization on Catalytic Carbonaceous Adsorbents

Use of sewage sludge combustion ash and gasification ash for high-temperature desulphurization of different gas streams

Influence of surface characteristics on carbon disulfide catalytic hydrolysis over modified lake sediment biochar and research on deactivated mechanism

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