Adsorption Of Hydrogen Sulfide Research Articles

Stimulating Mesoporous Characteristics of Activated Carbon through Pyrolysis of Compacted Hydroxyethyl Cellulose—A Showcase for H2S Removal

Stimulating Mesoporous Characteristics of Activated Carbon through Pyrolysis of Compacted Hydroxyethyl Cellulose—A Showcase for H2S Removal

Understanding and Predicting the Spatially Resolved Adsorption Properties of Nanoporous Materials.

Using knowledge from statistical thermodynamics and crystallography, we develop an image-image translation model, called SorbIIT, that uses three-dimensional grids of adsorbate-adsorbent interaction energies as input to predict the spatially resolved loading surface of nanoporous materials over a broad range of temperatures and pressures. SorbIIT consists of a closed-form differential model for loading-surface prediction and a U-Net to generate spatial differential distributions from the energy grids. SorbIIT is trained using the energy grids and adsorbate distributions (obtained from high-throughput simulations) of 50 synthesized and 70 hypothetical zeolites and applied for predicting the adsorption of carbon dioxide, hydrogen sulfide, n-butane, 2-methylpropane, krypton, and xenon in other zeolites from 256 to 400 K. Employing a quadratic isotherm model for the local differentiation, SorbIIT yields mean R2 values of 0.998 for total adsorption and 0.6904 for local adsorption with a resolution of 0.2 Å, and a value of 0.721 for the structural similarity of the local loading distribution.

Performance assessment of activated carbon thermally modified with iron in the desulfurization of biogas in a static batch system supported by headspace gas chromatography

A static batch arrangement composed of anti-leak vials coupled to gas chromatography is proposed as a complementary system for performance assessment of biogas desulfurization by adsorption. For testing, a modified commercial activated carbon produced by controlled thermal treatment in the presence of iron(III) species improved biogas desulfurization. The adsorbents showed a superior hydrogen sulfide removal compared to ordinary one. Pseudo-first-order, pseudo-second-order, and Bangham’s kinetic models were used to fit experimental data. All studied samples followed pseudo-first-order model, indicating the predominance of physisorption, and Bangham’s model, confirming that the micropores structure played an important role for gases diffusion and adsorbent capacity. Additionally, the materials were characterized by N2 adsorption–desorption, X-ray diffraction, infrared spectroscopy, scanning electron microscopy and energy-dispersive spectroscopy. The thermal treatment associated with iron impregnation caused significant modifications in the surface of the materials, and the iron species showed two main benefits: an expressive increase in the specific area and the formation of specific adsorption sites for hydrogen sulfide removal. The results reinforce the advantages of iron-modified adsorbents in relation to their non-modified counterparts. The analytical methodology based on the confinement of multiple gases contributes to improving the understanding of the hydrogen sulfide adsorption process using pressure swing adsorption technology.Graphical

Adsorption and partial catalytic oxidation of hydrogen sulfide to elemental sulfur using facilely prepared materials derived from sludge of groundwater treatment

AbstractRealizing the use of biogas as fuel or a gas engine, it is needed to upgrade to natural gas standards when it comes to pure biomethane, meaning impurities must be removed to a certain low concentration. Among these tasks, hydrogen sulfide (H2S) removal steadfastly gets the most attention. In the present work, partial catalytic oxidation was used to convert H2S to less harmful forms. Adsorbents/catalysts applied to this process were prepared from the sludge of a groundwater treatment plant using a simple combination of drying and calcination methods. As a relevant result, the as‐prepared sample (dried at 105°C for 24 h) exhibited high activity, with 90 ± 2% H2S conversion after 120 min of reaction time, while the sample calcined at about 500°C for 5 h (TP‐500) showed the highest H2S conversion (96 ± 2%); the lowest 28 ± 1% belonged to the case of TP‐700. The main compositions of the TP‐500 sample were crystalline calcite and amorphous iron oxides. The average size of calcite crystallites was ~45 nm, with a specific surface area of ~76 m2/g. Moreover, the presence of oxygen in the catalytic process and the “self‐outflow process” of sulfur desorption were the vital keys that allowed the partial H2S oxidation to take place continuously. After a reaction time of 2 h, the adsorption capacity of the best sample was 460.8 mg/g. Thus, it is obvious that inexpensive catalysts derived from sludge precursors can be effectively used for H2S removal from mixtures with air, supporting the treatment of raw biogas in the coming time.

Synergetic Improvement of the Reactive Performance of Hydrogen Sulfide Adsorption on a Three-Dimensional Ordered Macroporous La-Doped ZnO Sorbent

Synergetic Improvement of the Reactive Performance of Hydrogen Sulfide Adsorption on a Three-Dimensional Ordered Macroporous La-Doped ZnO Sorbent

Hydrogen Sulfide Adsorption Mechanism and Breakthrough Curves of Highly Stable Na-, Na-H-, Ca- and K-Mordenites.

Hydrogen sulfide (H2S) is a hazardous gas found in natural gas and biogas, lethal over 100 ppm. When released into the atmosphere, it can turn into sulfur dioxide. One option to remove H2S is using porous materials such as zeolites. Among them, mordenite stands out due to its channel structure, wide availability, and low cost. In this work, we evaluated the H2S adsorption capacity of mordenite using a volumetric static method. The results show the adsorption capacity of H2S in mordenite varies with the exchanged cation. The highest was measured in Na-mordenite (~4.08 mmol H2S/g mordenite). The experimental breakthrough curves for this zeolite confirmed Langmuir-type adsorption and strong affinity between Na+ cations and H2S. Despite this interaction, the XRD diffractograms of Na-mordenite show that the material retained its crystalline structure. More information about the differences in the amount of H2S adsorbed in the zeolites caused by the change in exchanged cation was obtained by H2S adsorption followed by FTIR spectroscopy. The spectra show differences in the position of the peaks related to the different adsorption modes of H2S caused by a change in the polarizing power of the cations due to their charge and position inside the zeolite pores.

Equilibrium and kinetic studies in adsorption of H2S using coconut shell activated carbon xerogel: Effect of mass adsorbent and temperature

The presence of acid gases like hydrogen sulfide (H2S) in natural gas, refinery gas, and coal gas necessitates their removal from the gas stream to prevent corrosion of pipelines and production equipment and to ensure safety due to the toxic nature of H2S. A study was conducted to synthesize an adsorbent that is made from coconut shell which is modified to form coconut shell-activated carbon xerogel (CSACX). The main objective is to determine the kinetic models’ equation and adsorption isotherms that are most suitable for the adsorption of hydrogen sulfide by using CSACX. Two parameters were studied which were the adsorbent mass and the gas temperature. The adsorption process could be mathematically represented using the Thomas Model, Yoon-Nelson Model, and Adam-Bohart. It is expected that the adsorption process is mathematically represented using the Thomas and Yoon-Nelson Model for both the effect of mass of adsorbent and effect of gas temperature. The kinetic models used were Pseudo-First Order and Pseudo-Second Order. Suitability of equation was determined by correlation coefficient (R2). The higher the R2, the more suitable the equation is to process. It is expected that the adsorption processes using the CSACX fit both pseudo-first and pseudo-second order equation. This means that both physisorption and chemisorption occur during the adsorption process.

Development of a method for cleaning gas emissions of industrial enterprises from hydrogen sulfide

Purification of gas emissions from various enterprises from hydrogen sulfide is one of the important environmental problems. Various methods are used to clean it. This article discusses the adsorption method of purification using granular carbonate sludge as an adsorbent. Its samples were obtained, and laboratory studies of the process of hydrogen sulfide adsorption from gas emissions were carried out.

Lithium-Ion Doping for Enhanced Hydrogen Sulfide Adsorption on Metal–Organic Frameworks: Grand Canonical Monte Carlo and Density Functional Theory Simulations

Lithium-Ion Doping for Enhanced Hydrogen Sulfide Adsorption on Metal–Organic Frameworks: Grand Canonical Monte Carlo and Density Functional Theory Simulations

Optimization of hydrogen sulfide adsorption performance by tar based porous carbon prepared by template method

This study provides a method of preparation of tar based porous carbon (TPC) for H2S adsorption by high-temperature carbonization with tar as precursor and zinc chloride (ZnCl2) as template. Response surface methodology (RSM) was used to systematically investigate the effects of carbonization temperature, mass percentage of template and carbonization time on the cumulative adsorption (CAC) of H2S. The adsorption kinetics and isotherms, thermodynamics, and TPC’s properties were explored to obtain its adsorption mechanism on H2S. The results demonstrate that TPC was a microporous material with a rich surface functional group structure. The specific surface area and pore volume of the optimal sample (TPC-750-66-90) could reach 890.08 m2/g and 0.440 cm3/g, respectively, accompanied by a CAC of 34.01 mg/g. FTIR and XPS analysis results indicate that there were abundant oxygen- and nitrogen-containing groups on the surface of TPC, which helped to promote the chemisorption on H2S. The adsorption kinetics and isotherms fitting and thermodynamic calculation of H2S adsorption demonstrate that both physisorption and chemisorption played important roles, and the adsorption was a spontaneous, exothermic, random, and monolayer process. According to the regeneration tests, TPC could maintain at least 70% of its initial capacity after three rounds of regeneration. All the above results demonstrated that porous carbon preparation through high-temperature carbonization is a promising method for tar utilization, and the prepared porous carbon as adsorbent for gas pollutants like H2S has wide application potential in areas including kitchen trash, sewage treatment facilities, and biogas purification.

Adsorption of Hydrogen Sulfide on Activated Carbon Materials Derived from the Solid Fibrous Digestate.

The goal of this work is to develop a sustainable value chain of carbonaceous adsorbents that can be produced from the solid fibrous digestate (SFD) of biogas plants and further applied in integrated desulfurization-upgrading (CO2/CH4 separation) processes of biogas to yield high-purity biomethane. For this purpose, physical and chemical activation of the SFD-derived BC was optimized to afford micro-mesoporous activated carbons (ACs) of high BET surface area (590-2300 m2g-1) and enhanced pore volume (0.57-1.0 cm3g-1). Gas breakthrough experiments from fixed bed columns of the obtained ACs, using real biogas mixture as feedstock, unveiled that the physical and chemical activation led to different types of ACs, which were sufficient for biogas upgrade and biogas desulfurization, respectively. Performing breakthrough experiments at three temperatures close to ambient, it was possible to define the optimum conditions for enhanced H2S/CO2 separation. It was also concluded that the H2S adsorption capacity was significantly affected by the restriction to gas diffusion. Hence, the best performance was obtained at 50 °C, and the maximum observed in the H2S adsorption capacity vs. the temperature was attributed to the counterbalance between adsorption and diffusion processes.

A simulation study of reducing carbon dioxide and hydrogen sulfide adsorption in dehydration beds

In natural gas dehydration units, a problem that may arise is the increased concentration of carbon dioxide and hydrogen sulfide in their feed. During the adsorption stage, these gases are adsorbed along with water by the dehydration bed. During the regeneration stage, these adsorbed gases are desorbed from the bed. Their presence along with water and high temperatures causes the equipment and pipes in the regeneration path to corrode. Therefore, minimizing the adsorption of these gases in dehydration beds is imperative. Based on simulations of Aspen Adsorption, three solutions have been described and investigated in this article. The first solution is using 3 A adsorbent which has a lower adsorption capacity for carbon dioxide and hydrogen sulfide than other adsorbents like 4 A. But this adsorbent also has a lower adsorption capacity for water, so the first solution needs more cycles for the gas dehydration process. This reduces the adsorbent lifetime. Increasing the duration of the adsorption stage is the second solution. This solution has little effect and cannot solve the problem. The third solution is layering the dehydration bed with different adsorbents. This solution can reduce carbon dioxide and hydrogen sulfide adsorption by 48.7% and 49.9%, respectively, when 3 m of 3 A adsorbents are used at the bottom and 3.5 m of 4 A adsorbents are used at the top of the bed.

Performance of Various Fuels: Gasoline, Liquefied Petroleum Gas and Biogas from Agricultural Biomass Waste in a Two-Stroke Internal Combustion Engine

The Philippines is an agricultural country with massive agricultural waste. The Biofuels Law (Republic Act 9367) aims to minimize the dependence on fossil fuels and encouraged the use of bio-based fuel sources as an alternative fuel in rural areas where farming is the only source of income, and energy is scarce. Biogas is a renewable energy carrier consisting of methane and carbon dioxide mixture. Because of its improved mixing ability with air, clean-burning nature and high-octane number that resists knocking, biogas is an excellent alternative source of energy for internal combustion engines. The single-cylinder two-stroke spark-ignition (43 cm3) was designed to be fed with a variety of fuel in order to assess engine performance parameters such as brake power, brake speed, brake-specific fuel consumption (BSFC) and thermal efficiency at different throttling positions (low- and high-load throttle). This study evaluated the engine performance of biogas (cow, swine and cow-swine manure), liquefied petroleum gas (LPG) and gasoline with two-stroke engine oil (2T) in a dynamometer without modifying the compression ratio. To optimize its use as a fuel for power generation, biogas was purified using hydrogen sulfide adsorption and carbon dioxide absorption. The results showed that biogas fuel from swine manure generated the highest electrical power load of 761 W with a methane concentration of 51% and a BSFC of 1.4 kg/kW-h. The LPG achieved the highest engine speed at 14,700 rpm with 549 W. In conclusion, the purified biogas fuel can be used in a small-scale internal combustion engine.

Adsorption capacity of biocarbons from residue of supercritical extraction of raw plants

Abstract Bioadsorbents prepared by chemical activation (H3PO4) of the residue of supercritical extraction of green tea leaves and marigold flowers were characterized by elemental analysis, Boehm titration, adsorption/desorption isotherm and scanning electron microscopy (SEM). The adsorption performance aimed at the removal of malachite green, nitrogen oxide and hydrogen sulfide was investigated. The impacts of various influential parameters of malachite green adsorption such as: contact time (8 h), initial dye concentration (20–140 mg/L), temperature (25–65 °C) and adsorbent mass (0.015–0.025 g) were investigated. The adsorption kinetic follows pseudo second-order reaction kinetics (R 2 > 0.99). The adsorption process was best described by the Langmuir isotherm and the maximum capacity of the monolayer was from 126.58 mg/g to 333.33 mg/g for the biocarbons obtained. The negative values of Gibbs free energy indicate the spontaneous character of the process. The presence of steam in the stream of the mixture of gases had a positive effect on adsorption of nitrogen oxide and hydrogen sulfide by the bioadsorbents obtained. The most effective adsorbent of malachite green and toxic gas pollutants proved to be the biocarbon obtained from the residues of supercritical extraction of green tea leaves.

ความสามารถในการดูดซับก๊าซไฮโดรเจนซัลไฟด์ของถ่านชีวภาพที่ผลิตจากชีวมวลเหลือใช้

ความสามารถในการดูดซับก๊าซไฮโดรเจนซัลไฟด์ของถ่านชีวภาพที่ผลิตจากชีวมวลเหลือใช้

A computational study of adsorption of H2S and SO2 on the activated carbon surfaces

An effort has been made to explore the adsorption potential of activated carbon (AC) structures for adsorption of hydrogen sulfide (H2S) and sulfur dioxide (SO2) employing density functional theory (DFT) at GGA level. 2-ring, 3-ring, 6-ring, and 9-ring carbon structures are used as adsorbent surfaces. The above mentioned rings are examined by creation of defect and inclusion of hydrogen as well to get the clear view close to experimental observations of adsorption properties of activated carbon. The adsorption properties depend upon many factors including whether adsorbate adsorbs in planer or non-planer mode, defect creation in the adsorbent substrate, atomic hydrogen insertion in the system and size of the adsorbent system. Our calculations show that side by side (planer) interaction binds the molecules much more strongly in comparison with molecules adsorbed upon the surface in non-planer mode. If vacancy is created at the central position of the surface, the molecules bind with substantial binding energy. However, overall Eads of the molecules varies randomly and no consistency could be achieved. Additionally, smaller sized structures are favorable relative to the bigger surfaces. The highest Eads for both the molecules is −2.97 eV, though not on the same substrate system. Finally, it can be argued that activated carbon is very useful material for adsorbing the noxious gases.

Sour Gas Adsorption on Silica Gels.

One of the essential factors for water adsorption on silica gels is the concentration of silanol groups on the silica surface. However, no systematic investigation on the adsorption of sour gas components, methane (CH4), carbon dioxide (CO2), and hydrogen sulfide (H2S) on silica gels with different textural properties and surface silanol concentrations, has been conducted. Three silica gels of 22, 30, and 60 Å pore sizes, with silanol concentrations of αtotal = 2.516, 2.340, and 2.152 OH nm-2, respectively, were studied in this work. The adsorption data for CH4, CO2, H2S, and H2O at T = 0, 25, and 50 °C on the 22 and 30 Å pore size silica gels were presented, and a comparison of the data for the 60 Å pore size silica gel on the same adsorbates was conducted. All three silica gels showed an adsorption affinity in the order of H2O > H2S > CO2 > CH4. The isosteric heats of adsorption of H2O and H2S had a greater dependence on the silanol concentration than CO2 and CH4. At p < 10 bar, there was no difference in the adsorption per m2 of CH4 between the silica gels (n ads = 1.7 mmol m-2, for all silicas at p = 10 bar), while higher pressures resulted in greater adsorption capacity in the larger pore volume silica gels (at p = 20 bar: n ads = 3.0, 3.3, and 3.4 mmol m-2 for the 22, 30, and 60 Å pore size silicas, respectively). H2S adsorption at low pressures (p < 4 bar) was larger on the samples with larger silanol concentrations (at p = 3 bar: n ads = 6.1, 4.7, and 4.5 mmol m-2 for the 22, 30, and 60 Å pore size silicas, respectively), but above p = 4 bar, the 60 Å pore size silica had a greater adsorption capacity than the 30 Å pore size (at p = 5 bar: n ads = 8.0, 6.0, and 6.2 mmol m-2 for the 22, 30, and 60 Å pore size silicas, respectively).

Characterization of Plantain Peels Activated Carbon Supported with Iron Nanoparticles after Adsorption of Hydrogen Sulfide from Biogas

Characterization of Plantain Peels Activated Carbon Supported with Iron Nanoparticles after Adsorption of Hydrogen Sulfide from Biogas

Adsorption of hydrogen sulfide by iron-based adsorbent derived from fly ash and iron slag.

In this article, an innovative sorbent (Fe-FA) is prepared from fly ash; ferrous sulfate-containing waste slag (FSS), which are industrial wastes; and NaOH by a hydrothermal method at 100°C. As a result, in comparison to several conventional sorbents, such as ZnO, Fe2O3, 13X zeolite, and activated carbon, Fe-FA had the best adsorption performance for H2S adsorption. Fe-FA had not only a higher adsorption capacity (near 150mg/g) but also a longer breakthrough time (near 400min) when gas hourly space velocity was 8000h-1. Then, characterizations of XRD, BET, NH3-TPD, FTIR, and XPS analyzed basic properties of Fe-FA and revealed reasons for the excellent adsorption performance. In general, the excellent adsorption performance of Fe-FA for H2S is mainly due to the high content of iron species (almost 50%) and suitable mesoporous structure in the Fe-FA.

Kinetics models of hydrogen sulphide adsorption from hydrogel biochar derived from empty fruit bunch (EFB)

This research aims to investigate the detailed state of adsorption kinetics modelling and research on the application of hydrogen sulfide adsorption by hydrogel derived from empty fruit bunch (EFB), the determination of the kinetics parameters, and the comparison between models in a selection of the best-fit model.The kinetics modelling used are pseudo-first-order and pseudo-second-order models. The correlation coefficient was used to evaluate the suitability of the equation R2. After obtaining the results, the comparison was made by comparing the R2 of each model. The pseudo-second-order model has a higher value of correlation coefficient, R2, making it the most suitable kinetics model for adsorption systems.The R2 for pseudo-first-order on the effect of dry bed height was 0.8814, whereas its effect on powder bed height was 0.9537, and that of the wet bed height was 0.9607. Meanwhile, the R2 for pseudo-second-order on the effect of dry bed height was 0.89, on the effect of the powder bed height was 0.99, and on the effect of the bed height of wet was 0.99, the highest among kinetic models. Based on the results, the pseudo-second-order model best describes the adsorption of hydrogen sulfide (H2S) by hydrogel biochar.The kinetics modelling used are pseudo-first-order, and pseudo-second-order models for hydrogen sulfide adsorption by hydrogel originating from empty fruit bunches (EFB).Based on the results, the pseudo-second-order model best describes the adsorption of hydrogen sulfide (H2S) by hydrogel biochar. Kinetic studies are important in understanding the reactions and design of the process.The authenticity results of this article were found to be 17% similar. The novelty of this paper is the kinetics study of the new adsorbent developed based on EFB to adsorb H2S.