Adsorption Of Sulfide Research Articles

Effect of modification of ZIF-8 nanoparticles by triethylenetetramine on hydrogen sulfide uptake

In the present work, the incorporation of triethylenetetramine into the zeolitic imidazolate framework (ZIF-8) was explored to assess its effect on hydrogen sulfide uptake. A comprehensive characterization of the synthesized adsorbents was conducted through N2 adsorption-desorption, Thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR), Field emission scanning electron microscope (FESEM), and X-ray diffraction (XRD) methods. The hydrogen sulfide uptake capacity of the modified adsorbents was investigated under diverse pressures and temperatures. The results revealed that at pressures below 1.5 bars, the hydrogen sulfide uptake of ZIF-8 incorporating triethylenetetramine was marginally higher than that of pristine ZIF-8. However, as the pressure increased, the bare ZIF-8 adsorbent exhibited superior hydrogen sulfide uptake compared to the triethylenetetramine-incorporated adsorbents.Furthermore, the hydrogen sulfide adsorption isotherms of the adsorbents were analyzed using the Monte Carlo method, and the computational results aligned well with the experimental data. Additionally, molecular dynamics simulations were employed to investigate the hydrogen sulfide diffusion coefficient in the synthesized adsorbents. The outcomes indicated that the introduction of triethylenetetramine into the ZIF-8 framework led to a reduction in the diffusion coefficient of hydrogen sulfide. This multifaceted approach combining experimental and computational methods provides a comprehensive understanding of the modified ZIF-8 adsorbents and their behavior in hydrogen sulfide uptake.

Exploring the Chemical Permeation Resistance and Surface Adsorption Properties of Polyurethane Coatings.

This work explores the adsorption and permeation of chemical warfare agents on polymer coatings to assess their protective potential. Two highly cross-linked aliphatic polyurethanes (PUs) were synthesized from two diisocyanate trimers, and their adsorption and permeation of dimethyl methylphosphonate (DMMP) and 2-chloroethyl ethyl sulfide (CEES) were analyzed using quartz crystal microbalance with dissipation and gas chromatography. The study revealed distinct adsorption properties for each agent and the PU. CEES, with higher polarity, exhibited greater readsorption compared to DMMP. IPtri-PU (alicyclic structure) showed negligible desorption and resorption, resulting in minimal permeation, unlike Htri-PU (aliphatic structure). Thus, alicyclic PUs are more promising for reducing adsorption and permeation.

Promoting elemental mercury immobilization performance from smelting flue gas over a wide temperature range via cobalt-doped copper sulfide adsorbents

Copper sulfide (CuS) sorbent exhibits great potential for gaseous elemental mercury (Hg0) decontamination, but it still suffers from a narrow operating temperature. Therefore, designing advanced CuS sorbents that have a high activity level for capturing Hg0 and thermal stability at a high temperature range is challenging. Herein, we propose a metal doping strategy to fabricate a bimetallic sulfide adsorbent. Benefiting the unique structure and composition, a mesoporous structure and an abundance of unsaturated sulfur sites ensure that CuxCo(1–x)Sy provides a desirable level of adsorption for Hg0. The experimental results indicate the optimum Co doping mass concentration of 5 %. The Cu0.95Co0.05Sy not only performs satisfactory Hg0 adsorption at elevated temperatures (Hg0 average adsorption efficiency of over 97.3 %, Hg0 average adsorption rate of over 2.7 μg/g/min), but also presents an exciting regeneration and recycle performance (a Hg0 adsorption efficiency of over 94 % after 10 cycles). The adsorption capacity of Cu0.95Co0.05Sy at the breakthrough threshold of 25 % reaches 5.22 mg/g, surpassing most of metal sulfide sorbents for Hg0 immobilization at 150 °C. As far as Hg0 adsorption is concerned, the composition of typical smelting flue gases has almost no effect. According to further studies, unsaturated coordination short-chain sulfur (S22−) sites are essential for adsorption of Hg0 and are capable of directly forming α-HgS from Hg0. In both the contrast experiment and density functional theory calculations, the cobalt doping strategy enhances the thermal stability of the active S22− ligand and the Hg0 adsorption properties. This study not only provide a prospective adsorbent for Hg0 sequestration at wide temperature range, but also explores a method of utilizing gaseous contaminants for resource utilization.

The role of carbon textile surface functionalities in reactive adsorption of vapor and liquid 2-chloroethyl ethyl sulfide: Evaluating interactions at the interface

A carbon textile (CT) was chemically modified to increase its surface activity and promote the adsorption and degradation of 2-chloroethyl ethyl sulfide (CEES) - a surrogate for mustard gas. CT was initially subjected to oxidation (CTO), and then heated under ammonia (CTON) or hydrogen sulfide (CTOS) atmosphere to incorporate nitrogen or sulfur functionalities, respectively. Detoxification experiments were performed in closed vials using either vapor or liquid forms of CEES. The maximum vapor weight uptakes on CT, CTO, CTOS, and CTON were 399, 372, 434, and 489 mg/g, respectively. All textiles were able to prevent the vaporization of CEES liquid droplets. Although similar reaction products were detected in both vapor and liquid systems, the marked differences in the extent of CEES chemical transformation on the surfaces of the textiles indicate distinct detoxification pathways influenced by surface chemistry. Even though the heterogeneous surface of CTO, enriched with oxygen surface groups, facilitated various reactions, hydrolysis was the predominant pathway. The thermal treatment, regardless of the atmosphere, reduced the oxygen content, decreasing the extent of hydrolysis. However, incorporating basic surface groups such as pyridines, amines, or weak acids such as thiols promoted dehydrohalogenation as the main detoxification pathway on these samples.

Utilizing molecular simulation, ideal adsorbed solution theory and ensemble learning algorithms to investigate adsorption and separation of sulfides on amorphous nanoporous materials

Using grand canonical Monte Carlo method, we investigated the adsorption of pure H2S and SO2 gases on amorphous materials, and the separation of CH4-H2S and CO2-SO2 mixtures. At 303 K, the optimal adsorbent for both gases was found to be HCP-Colina-id016, with 16 mmol/g. For CH4-H2S mixture, despite aCarbon-Marks-id002 exhibiting the highest selectivity (approximately 80), the H2S adsorption was low (around 1 mmol/g), while Kerogen-Coasne-id013 demonstrated a high H2S adsorption of 12 mmol/g with a selectivity of 20. In the case of CO2-SO2, HCP-Colina-id018 exhibited a SO2 selectivity exceeding 30, with a high SO2 adsorption of 12 mmol/g. The Ideal Adsorbed Solution Theory underestimated the adsorption and selectivity of both mixtures, particularly evident in CO2-SO2. Molecular simulations revealed that, for the CO2-SO2 system, CO2 underwent condensation, resulting in a sudden drop in the SO2 adsorption isotherm. However, IAST accurately predicted this abrupt change. Based on the adsorption data obtained from molecular simulations, we compared the predictive performance of four ensemble learning algorithms, namely Random Forest (RF), Gradient Boosted Decision Trees (GBDT), Extreme Gradient Boosting (XGBoost), and CatBoost, for H2S and SO2 pure gases in amorphous porous materials. The rankings were observed to be XGBoost > GBDT > RF > CatBoost.

Application of Response Surface Methodology (RSM) For Optimization of Hydrogen Sulphide Adsorption Using Coconut Shell Activated Carbon Xerogel: Effect of Adsorption Pressure and Hydrogen Sulphide Flowrate

Application of Response Surface Methodology (RSM) For Optimization of Hydrogen Sulphide Adsorption Using Coconut Shell Activated Carbon Xerogel: Effect of Adsorption Pressure and Hydrogen Sulphide Flowrate

Methane Storage and Purification of Natural Gas in Metal-Organic Frameworks.

Natural gas, primarily composed of methane (CH4), represent an excellent choice for a potentially sustainable renewable energy transition. However, the process of compressing and liquefying CH4 for transport and storage typically results in significant energy losses. In addition, in order to optimize its efficacy as a fuel, the CH4 content of natural gas needs to be increased to a level of at least 97 % to ensure its quality and efficiency in various applications. Metal-organic frameworks (MOFs) represent a novel category of porous materials that possess exceptional capability in modifying pore size and chemical environment, making them ideally suited for the storage of CH4 and the adsorption of propane (C3H8), ethane (C2H6), carbon dioxide (CO2), nitrogen (N2), and hydrogen sulfide (H2S) to facilitate the purification process of CH4 from natural gas. In this paper, we systematically summarize the mechanism by which MOF materials facilitate the storage of CH4 and the purification of CH4 from natural gas, leveraging the structural characteristics inherent to MOF materials. The focus of further research should also be directed towards the investigation of CH4 storage by flexible MOFs, the resolution of the trade-off dilemma, and the commercial application of MOFs.

Reactive adsorption and catalytic oxidation of gaseous hydrogen sulfide using a prototype air purifier built with bismuth-doped titanium dioxide

A prototype air purifier (AP) module has been constructed using bismuth-doped titanium dioxide (Bix-P25: x(%) as Bi/Ti molar ratios of 1.1, 2.1, 3.3, 5.3, and 8.7). The reactive adsorption property of Bix-P25 materials is evaluated against H2S gas at a recirculation rate of 160 L min−1 in a 17 L closed chamber. The AP (Bi5.3-P25) exhibits superior performance against 10 ppm H2S in dry air under dark conditions (i.e., without light irradiation), with a removal efficiency (XH2S)= 99% in 5 mins, reaction kinetic rate (r (at X = 10%))= 7.3 mmol h−1g−1, and partition coefficient= 0.18 mol kg−1 Pa−1. As such, its superiority is evident over the reference AP (P25) filter with XH2S < 10%. The clean air delivery rate (CADR) of AP (Bi5.3-P25) increases noticeably from 9.9 to 17.8 L min−1 with increasing relative humidity (RH) from 0 to 80%, respectively. In contrast, the CADR decreases from 9.9 to 5.8 L min−1 as the H2S increases from 10 to 20 ppm. According to density functional theory (DFT), the presence of H2O vapor enhances the hydroxylation of Bix-P25 surface to promote H2S mineralization through the formation of TiS3 (i.e., thermodynamic reaction of S atom with the catalytic surface). Complete removal of H2S on the Bi5.3-P25 surface is also confirmed consistently through gas chromatography-mass spectrometry (GC-MS), in-situ diffuse reflection infrared spectroscopy (in-situ DRIFTS), and elemental analysis (EA). This work represents the first utilization of Bix-P25 materials fabricated on an AP platform toward the desulfurization of H2S at room temperature (RT). The practical utility of Bix-P25 is overall validated by its eminent role in reactive adsorption and catalytic oxidation (RACO) of H2S from the air.

Optimization for the Effects of Coconut Shell Activated Carbon Xerogel Weight and Temperature on the Hydrogen Sulphide Adsorption Using Response Surface Methodology

Optimization for the Effects of Coconut Shell Activated Carbon Xerogel Weight and Temperature on the Hydrogen Sulphide Adsorption Using Response Surface Methodology

Measuring Mass Transfer of n-Hexane and 2-Chloroethyl Ethyl Sulfide in Sorbent/Polymer Fiber Composites Using a Volumetric Adsorption Apparatus.

The integration of metal-organic frameworks (MOFs) into composite systems serves as an effective strategy to increase the processability of these materials. Notably, MOF/fiber composites have shown much promise as protective equipment for the capture and remediation of chemical warfare agents. However, the practical application of these composites requires an understanding of their mass transport properties, as both mass transfer resistance at the surface and diffusion within the materials can impact the efficacy of these materials. In this work, we synthesized composite fibers of MOF-808 and amidoxime-functionalized polymers of intrinsic microporosity (PIM-1-AX) and measured the adsorption and mass transport behavior of n-hexane and 2-chloroethyl ethyl sulfide (CEES), a sulfur mustard simulant. We developed a new Fickian diffusion model for cylindrical shapes to fit the dynamic adsorption data obtained from a commercial volumetric adsorption apparatus and found that mass transport behavior in composite fibers closely resembled that in the pure PIM fibers, regardless of MOF loading. Moreover, we found that n-hexane adsorption mirrors that of CEES, indicating that it could be used as a structural mimic for future adsorption studies of the sulfur mustard simulant. These preliminary insights and the new model introduced in this work lay the groundwork for the design of next-generation composite materials for practical applications.

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

Activated carbon (AC) serves as extensively researched adsorbents, with numerous established methods for their preparation. This study originated from the hypothesis that compressing a hydrocarbon substance to create a densely compacted pellet, known as pelletizing, would enhance the development of porous features of the resulting AC. The anticipated enhancement is attributed to the rise in spatial proximity amidst HEC polymer chains within the bulk of the pellet, which facilitates aromatization both in extent and functionality. 2-Hydroxyethyl cellulose (HEC) pellets were prepared by adjusting the duration of load holding, aiming to increase the packing density of HEC polymer chains via creeping. The BET analysis of the resulting AC samples demonstrates the efficacy of compression on HEC pellets in enhancing their porous properties. The FE-SEM study revealed diverse AC surface morphologies that are associated with a set of specific pelletizing conditions. The 13C NMR spectroscopy for carbon skeletons, FT-IR spectroscopy for organic functionality, and XPS spectroscopy for surface composition collectively report the leverage of compression treatment before pyrolyzing HEC pellets. Furthermore, the assessment of hydrogen sulfide adsorption by the resulting AC samples revealed distinctive breakthrough curves, providing validation for the proposed compression effect.

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

A DFT study of the adsorption of fouling molecules (metal sulfides and hydroxides) onto TiZrO4 ceramic membranes

Ceramic membrane fouling is a constraint in the treatment of acid mine drainage (AMD), leading to a decrease in efficiency over time. Here, it is described via first-principles calculations the physical and chemical phenomena occurring on the surface of TiZrO4 filtration membranes due to the adsorption of eight potential fouling compounds [CuS, FeS, Fe2S3, CaS, Al(OH)3, Fe(OH)3, Fe(OH)2, and Cu(OH)2]. The interaction of these fouling molecules was performed onto nanostructured TiZrO4 surfaces with several pores representing the filtration membranes employed in the treatment of AMD. The adsorption energies reveal that the adsorption is feasible with all the fouling molecules studied, and it is strongly related to the molecular polarity of the adsorbate. Consequently, the adsorption of metal sulfides is more feasible than hydroxides with adsorption orders of CaS>FeS>CuS>Fe2S3, and Al(OH)3>Fe-hydroxides>Cu(OH)2. The outcomes suggest that the metal sulfide adsorption depends on the adsorbate intrinsic polarity, solvent effects, adsorbate van der Waals radius, and membrane surface topology, while the adsorption of hydroxides is less influenced by the last two factors. Density-based binding and energy decomposition analyses indicate strong electrostatic attractions and covalent bonds at the adsorbate-membrane interface supporting the chemical fouling onto ceramic filtration membranes. According to our theoretical results and the elevated concentration of Cu and Fe in AMD, we propose that FeS and CuS are mainly responsible for the fouling onto TiZrO4 membrane surfaces. These results offer valuable information on the adsorption phenomena at TiZrO4 membrane surfaces, which can be useful for metallurgy, industrial water treatment, food industry, biotechnology, and pharmaceutical applications.

Ultrafast and highly efficient Cd(II) and Pb(II) removal by magnetic adsorbents derived from gypsum and corncob: Performances and mechanisms

The utilization of gypsum and biomass in environmental remediation has become a novel approach to promote waste recycling. Generally, raw waste materials exhibit limited adsorption capacity for heavy metal ions (HMIs) and often result in poor solid–liquid separation. In this study, through co-pyrolysis with corncob waste, titanium gypsum (TiG) was transformed into magnetic adsorbents (GCx, where x denotes the proportion of corncob in the gypsum–corncob mixture) for the removal of Cd(II) and Pb(II). GC10, the optimal adsorbent, which was composed primarily of anhydrite, calcium sulfide, and magnetic Fe3O4, exhibited significantly faster adsorption kinetics (rate constant k1 was 218 times and 9 times of raw TiG for Cd(II) and Pb(II)) and higher adsorption capacity (Qe exceeded 200 mg/g for Cd(II) and 400 mg/g for Pb(II)) than raw TiG and previous adsorbents. Cd(II) removal was more profoundly inhibited in a Cd(II) + Pb(II) binary system, suggesting that GC10 showed better selectivity for Pb(II). Moreover, GC10 could be easily separated from purified water for further recovery, due to its high saturation magnetization value (6.3 emu/g). The superior removal capabilities of GC10 were due to adsorption and surface precipitation of metal sulfides and metal sulfates on the adsorbent surface. Overall, these waste-derived magnetic adsorbents provide a novel and sustainable approach to waste recycling and the deep purification of multiple HMIs.

Synergistic effect between amorphous ZrO2 modified support and Pd catalyst: Unveiling superlative sulfur resistance and exquisite catalytic hydrogenation performance

The presence of sulfides in the reaction system can seriously affect the stability and activity of the catalysts. In this paper, we compare the impact of introducing varying amounts of the metal oxide ZrO2 on the hydrogenation activity and sulfur resistance of Pd-based catalysts. The study examined the effect of calcination temperature for catalysts and various organic sulfide types on their catalytic performance. We employed multiple techniques to characterize the catalysts, including physical adsorption, TEM, XRD, XPS, H2-TPD, NH3-TPD, and Py-IR. The results revealed that the catalysts achieved 99.9 % conversion and exhibited 99.5 % selectivity towards 4-ethyltoluene when the Pd and Zr molar ratio was 1:5. Furthermore, they could withstand the presence of toxicants for over 10 cycles. The main reason for the difference in activity and stability between catalysts lies in introducing ZrO2 as a promoter. This introduction increases the number of acidic sites and enhances the electronic effect, thereby facilitating the cleavage of H2 by Pd0. The synergistic effect between Pd and ZrO2 decreases the strength of S-Me, impedes sulfide adsorption, and improves the sulfur resistance stability of the catalyst. This work demonstrates that ZrO2-modified Pd-based catalysts have great potential in the anti-sulfur system of olefin hydrogenation.

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.