Low H2S Research Articles

Miro2 sulfhydration by CBS/H2S promotes human trophoblast invasion and migration via regulating mitochondria dynamics

Insufficient cytotrophoblast (CTB) migration and invasion into the maternal myometrium leads to pregnancy related complications like Intra-uterus Growth Restriction (IUGR), and pre-eclampsia (PE). We previously found that hydrogen sulfide (H2S) enhanced CTB migration without knowing the mechanism(s) and the pathophysiological significance. By studying human samples and cell line, we found that H2S levels were lower in PE patients’ plasma; H2S synthetic enzyme cystathionine β-synthetase (CBS) was reduced in PE extravillious invasive trophoblasts. GYY4137 (H2S donor, 1 µM) promoted CBS/H2S translocation onto mitochondria, preserved mitochondria functions, enhanced cell invasion and migration. CBS knockdown hindered the above functions which were rescued by GYY4137, indicating the vital roles of CBS/H2S signal. Disturbance of mitochondria dynamics inhibited cell invasion and migration. The 185 and 504 cysteines of Mitochondrial Rho GTPase 2 (Miro2C185/C504) were highly sulfhydrated by H2S. Knockdown Miro2 or double mutation of Miro2C185/C504 to serine fragmented mitochondria, and inhibited cell invasion and migration which can’t be rescued by H2S. The present study showed that human cytotrophoblast receives low dose H2S regulation; CBS/H2S sustained mitochondria functions via Miro2C185/C504 sulfhydration to enhance cytotrophoblast mobility. These findings established a new regulatory pathway for cytotrophoblast functions, and provided new targets for IUGR and PE.

Case Study: Understanding H2S Occurrence: Bakken Production Using Sulfur Isotopes

_ Souring—or H2S generation—in the Bakken petroleum system (BPS) production is becoming problematic for oil producers and pipeline operators because of the sporadic occurrence and associated economic and HSE impacts. Paradoxically, crude oil produced from the tight Middle Bakken (MB) and underlying Three Forks (TF) reservoirs of the BPS has historically been light (40 °API to 50 °API) with low sulfur content (<0.2 wt.%), typically exhibiting nonexistent to low (<10 parts per million) H2S concentrations. Additionally, neither the MB nor the TF reservoirs have public records indicating the presence of H2S during drillstem tests (DST). However, based on previous work performed by the University of North Dakota Energy & Environmental Research Center (EERC), the frequency of H2S occurrence in BPS wells has increased from 2010 to 2023. Even though the observed H2S increases correlate with larger, multistage well stimulation and completion practices in the BPS, the unclear geographical and temporal trends make the exact mechanisms responsible for souring an open research question. At least five known mechanisms can potentially lead to H2S occurrence in the oil production stream of BPS wells, including: 1. Thermochemical sulfate reduction (TSR) 2. Bacterial sulfate reduction (BSR) 3. Source rock generation 4. Migration from deeper or shallower H2S reservoirs 5. Geochemical mechanisms related to reservoir stimulation work (Table 1). Understanding the mechanisms of H2S generation might reduce the risk of souring in new wells and enable more effective mitigation and management strategies in the wells already producing H2S. Samples Used in the Study This study is focused on oil and gas operations in the North Dakota portion of the Williston Basin and the H2S occurrences in the BPS, which includes two main oil-producing reservoirs: the MB and the TF. In the simplified stratigraphic sequence, the BPS comprises three distinctive lithofacies. From deepest to shallowest, those lithofacies are the Lower Bakken Shale (LBS), the MB reservoir, and the Upper Bakken Shale (UBS). Underlying the BPS is the TF, the upper part of which is the oil-rich TF reservoir, considered part of the BPS. The UBS and LBS are the source rocks for the oil in MB and TF reservoirs and consist of black, organic-rich, siliciclastic mudstones (i.e., shale). Directly overlying the BPS is the Madison Group, a carbonate-dominated Mississippian section that is subdivided into three formations—the Lodgepole (LP), Mission Canyon (MC), and Charles. The Birdbear Formation lies beneath the TF and on top of the Duperow Formation. Both the Duperow and Birdbear Formations produce oil and are dominated by carbonate deposits of shallow marine limestone and dolostones. A sampling program was developed to investigate areas of the BPS with varying levels of souring in the production stream and multiple organic-rich formations representing potential source rocks, including the UBS, LBS, LP, and MC. The samples were collected from locations and formations with different lithologies and maturity levels. Over 70 sour wells were identified for H2S sampling in western North Dakota.

2D electrodeposition assembly of Cu/Cu2O nanoarrays for low temperature H2S sensing

Ultra-sensitive hydrogen sulfide (H2S) detection technology at low temperatures provides critical support for the application of one-time alert systems under extreme conditions, ensuring reliable monitoring of H2S in low-temperature environments and enhancing safety and practicability. In this study, we developed a novel low-temperature H2S sensor based on Cu/Cu2O nanoarrays, prepared through a combination of 2D electrodeposition in situ assembly and the hydrothermal method. The heterointerface between Cu nanowires and Cu2O nanocubes presents a high barrier, which can be modulated to zero through the formation of continuous CuxS conductive channels via the vulcanization reaction, thereby achieving excellent sensitivity and selectivity towards H2S at low temperatures. At freezing temperatures and low H2S concentrations (≤20 ppm), the sensors show ideal recovery and reasonable sensitivity (R=150 to 10 ppm H2S at 0 °C). However, the response significantly increases (R=5624 at 10 ppm H2S at 50 °C) and recovery is lost under reversed conditions. First-principles calculations have confirmed that the enhanced H2S adsorption at the heterointerface is the primary reason for the robust response observed at 0 °C. Experimental results demonstrate that the Cu/Cu2O nanoarrays were capable of rapid detection of H2S at low temperatures through modulation of heterointerface barriers.

Prepared gold-modified hollow nanosphere Co3O4/rGO composites for low concentration H2S gas detection

In this paper, Au-modified Co3O4 hollow nanospheres/graphene composites (Au-Co3O4/rGO) were synthesized for the first time through a novel “one-pot cooking” method at ambient temperature. The hollow nanospheres exhibited a particle size of approximately 10–15 nm, while the modified Au nanoparticles were about 4–5 nm in diameter. A high-efficiency and high response H2S gas sensor was constructed based on Au-Co3O4/rGO ternary composites. The effects of different Au modifying mass ratios on the H2S gas-sensitive performance of the composites were systematically investigated. At an operational temperature of 92 °C, the Au-Co3O4/rGO sensor, incorporating an Au loading mass ratio of 1.3 wt%, exhibited a response value of 175.4 for H2S at 100 ppm, a recovery time of 30 s, and a detection limit reaching as low as 10 ppb. This response was tripled compared to the undoped Co3O4/rGO sensor. At the same time, the H2S sensing mechanism by Au-Co3O4/rGO was discussed in detail.

Resistance-driven low power H2S sensors based on MWCNT@CuO heterojunction

Resistance-driven low power H2S sensors based on MWCNT@CuO heterojunction

GOLD ENRICHMENT MECHANISM IN MID-OCEAN RIDGE HYDROTHERMAL SYSTEMS: AN EXAMPLE FROM THE LONGQI HYDROTHERMAL FIELD ON THE ULTRASLOW-SPREADING SOUTHWEST INDIAN RIDGE

Abstract In mid-ocean ridge (MOR) hydrothermal systems, the gold grade of sea-floor massive sulfides (SMSs) is negatively correlated with the spreading rate of the ridge. Previous investigations have addressed the distribution of gold in sulfides from hydrothermal fields hosted by ultramafic rocks. In contrast, the gold enrichment mechanisms in sulfides from hydrothermal fields hosted by mafic rocks in ultraslow-spreading ridge environments are less well constrained. The basalt-hosted Longqi hydrothermal field, located on the classic ultraslow-spreading Southwest Indian Ridge, provides an opportunity to examine gold enrichment mechanisms in such an environment. Two ore-forming stages are identified in chimney fragments: anhydrite + barite + colloidal/porous pyrite (Py1) + marcasite + fine-grained sphalerite (stage 1); euhedral-subhedral pyrite (Py2) + coarse-grained sphalerite + chalcopyrite + isocubanite (stage 2). Py1 is usually overgrown by marcasite, which is in turn enclosed by Py2. Py2 coexists with coarse-grained sphalerite and chalcopyrite. Abundant native gold nanoparticles occur in Py1 or at the transition zone between Py1 and Py2. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis suggests that Py1 contains higher Mo, V, Sn, and Pb and lower As, Co/Ni, and Se/Tl values compared to Py2. In situ LA-multicollector (MC)-ICP-MS analyses show that Py1 has a higher mean δ34S (+7.1‰) value than Py2 (+6.6‰). Sulfur primarily derives from MORB and seawater sulfate, of which the proportion of sulfur from seawater sulfate is between 20.5 and 47.6%. Textures, mineral assemblages, and trace element contents of sulfides indicate that the degree of mixing between hydrothermal fluids and seawater decreases as the chimney grows and is accompanied by a gradual increase in temperature. Based on data compiled from 41 hydrothermal fields hosted by basalt, the large range of sulfide δ34S from slow- and ultraslow-spreading MORs may be attributed to the wide range of sulfur sources (e.g., leaching from MOR basalt, thermochemical reduction of seawater sulfate, magma degassing, and bacterial activity), fluid-basalt interaction, and redox state (CH4/CO2 ratios). Prolonged fluid-basalt interaction and the type of chimneys, such as beehive chimneys, may lead to higher gold grades in hydrothermal fields. Moreover, low H2S content may be an important contributor to gold enrichment in basalt-hosted SMS deposits in ultraslow-spreading MOR environments.

Elucidating the effect of H2S on the syngas autotrophic fermentation: Focusing on functional microorganisms and metabolic pathway

As an impurity of syngas, hydrogen sulfide (H2S) has adverse effect of on syngas fermentation, but its inhibitory threshold and mechanism are still not clear. Here in, the present study systematically investigated the insight mechanism of H2S on syngas fermentation pathways via evaluating the key enzymatic activities, genes expression and functional microorganisms. Results showed that the inhibitory threshold of H2S on syngas fermentation was 200 ppm, reflected by a significant decrease of syngas consumption rate and volatile fatty acids (VFAs) production. However, low concentration of H2S (20–100 ppm) had a promotion effect on syngas fermentation and the highest of VFAs concentration of 2.8 g/L was observed at 50 ppm H2S. Low H2S concentrations improved the percent of lately apoptotic cells, but 200 ppm H2S led to most of cells at early apoptotic status. At the presence of H2S, the enzymatic activities (i.e., CODH and FDH) and functional genes (i.e., fhs and acsE) encoding the methyl branch were significantly decreased, while the expression of genes encoding the carbonyl branch (i.e., acsA) up-regulated. The down-regulated of genes encoding the acetogenic pathway (i.e., codh) proved the enhancement of reductive acetate production pathway. Moreover, the functional bacteria of Terrisporobacter and Acetobacter that involved in the methyl branch, showed significant decrease at the presence of H2S. Hence, H2S stress led to the changes of metabolic pathway from methyl branch to carbonyl branch. The proliferation of sulfur metabolizer (i.e., Mesotoga and SBR1031) explained the improvement of VFAs production at low H2S concentrations.

Mucosal organs exhibit distinct response signatures to hydrogen sulphide in Atlantic salmon (Salmo salar)

Hydrogen sulphide (H2S) is considered an immunotoxicant, and its presence in the water can influence the mucosal barrier functions of fish. However, there is a significant knowledge gap on how fish mucosa responds to low environmental H2S levels. The present study investigated the consequences of prolonged exposure to sub-lethal levels of H2S on the mucosal defences of Atlantic salmon (Salmo salar). Fish were continuously exposed to two levels of H2S (low: 0.05 µM; and high: 0.12 µM) for 12 days. Unexposed fish served as control. Molecular and histological profiling focused on the changes in the skin, gills and olfactory rosette. In addition, metabolomics and proteomics were performed on the skin and gill mucus. The gene expression profile indicated that the gills and olfactory rosette were more sensitive to H2S than the skin. The olfactory rosette showed a dose-dependent response, but not the gills. Genes related to stress responses were triggered at mucosal sites by H2S. Moreover, H2S elicited strong inflammatory responses, particularly in the gills. All mucosal organs demonstrated the key molecular repertoire for sulphide detoxification, but their temporal and spatial expression was not substantially affected by sub-lethal H2S levels. Mucosal barrier integrity was not considerably affected by H2S. Mucus metabolomes of the skin and gills were unaffected, but a matrix-dependent response was identified. Comparing the high-concentration group's skin and gills mucus metabolomes identified altered amino acid biosynthesis and metabolism pathways. The skin and gill mucus exhibited distinct proteomic profiles. Enrichment analysis revealed that proteins related to immunity and metabolism were affected in both mucus matrices. The present study expands our knowledge of the defence mechanisms against H2S at mucosal sites in Atlantic salmon. The findings offer insights into the health and welfare consequences of sub-lethal H2S, which can be incorporated into the risk assessment protocols in salmon land-based farms.

Exploring chemical disposal options for non-condensable gasses in geothermal power plants: A case study of Kızıldere geothermal field (Türkiye)

Geothermal power plants are among the most important renewable energy power plants owing to their high-capacity factors and integrated utilization possibilities. Currently, these power plants utilize geothermal fluid to generate electricity. Although their emissions are lower than those of conventional power plants, gasses such as CO2 and H2S are released into the air from the cooling towers, particularly in flash-type geothermal power plantsTo reduce the emission of CO2 gas released from geothermal power plants, reinjection studies have mainly been carried out around the world. These types of studies require extensive analysis of underground fracture systems, detailed geosciences, and the reservoir studies. However, these studies are considered risky and expensive for most plant operators because possible changes in underground fracture systems may affect the productivity of geothermal production zones. In terms of the environmental impact, hydrogen sulfide is a more harmful gas than CO2. Effective H2S removal methods cannot be widely used, except in areas with extremely high concentrations, because they commonly incur significant costs for plant operators. Effective H2S removal methods are not widely available except for geothermal sites with high concentrations. The fact that local limit values can be exceeded in geothermal power plants with relatively low H2S concentrations, such as geothermal power plants in Türkiye, pushes plant operators to find new low-cost solutions due to high operation costs. For this reason, a treatment method that can be applied at every site and whose cost is not too high has not yet been put forward. However, NaOH is used for this purpose in geothermal fields such as steam-dominated Geyser field to increase the pH values in geothermal wells, which has been producing for a long time.In this study, field tests were carried out with five different chemicals and pure water to examine the reduction of non-condensable gasses in a geothermal power plant located in the Kızıldere (Denizli, Türkiye) geothermal field, one of the most important geothermal fields in the world. According to this, the capture of these gasses is technically possible using chemical methods, with a performance of up to 70 % observed in CO2 gas capture.However, although it is possible to capture 70 % of non-condensable gasses with such chemical methods, the consumable cost of the operation is quite high.

Exposure to sublethal levels of H2S does not influence the short-term growth or feed utilization in post-smolt Atlantic salmon (Salmo salar) during restrictive feeding

Hydrogen sulfide (H2S) related mass mortality events in land-based recirculating aquaculture systems (RAS) are associated with the sudden release of substantial amounts of H2S, resulting in acutely toxic exposure. However, the production and release of H2S can also occur at slower constant rates, leading to continuous exposure to sublethal H2S concentrations, the effects of which are unknown. Here, we examined growth rates, feed conversion ratios, and apparent nutrient digestibility in post-smolt Atlantic salmon, following a 10-day exposure to one of two sublethal concentrations of H2S, compared against a control group. The H2S concentrations of the low exposure (LE) and moderate exposure (ME) groups throughout the trial were 1.8 ± 0.8 μg/L and 4.1 ± 1.9 μg/L, respectively. Neither exposure regime affected growth, feed utilization, or the apparent nutrient digestibility. The results suggest that Atlantic salmon tolerate exposure to sublethal H2S concentrations for 10 days, without a discernible effect on the production performance. For aquaculture systems, specifically RAS, this means that while higher concentrations of H2S should be strictly avoided, the presence of low H2S concentrations for a limited period might not be detrimental to fish welfare or production. The RAS environment is complex, and the potential combined effects of H2S and factors pertinent to RAS may influence fish performance differently in a production setting.

The binding energy distribution of H2S: why it is not the major sulphur reservoir of the interstellar ices

Abstract Despite hydrogen sulfide (H2S) has been predicted to be the major reservoir of S-bearing species on the icy mantles of interstellar grains, no solid H2S has been detected so far. A crucial parameter that governs whether or not a species remains frozen onto the grain mantles is its binding energy (BE). We present a new computational study of the H2S BE on a large amorphous water ice surface, constituted by 200 water molecules. The resulting H2S BE distribution ranges from 57 K (0.5 kJ/mol) to 2406 K (20.0 kJ/mol), with the average μ = 984 K (8.2 kJ/mol). We discuss the reasons why the low bound of the newly computed BE distribution, which testifies to the very weak interaction of H2S with the ice surface, has never been found by previous theoretical or experimental works before. In addition, the low H2S BEs may also explain why frozen H2S is not detected in interstellar ices. Following previous molecular dynamics studies that show that the energy of reactions occurring on ice surfaces is quickly absorbed by the water molecules of the ice and conservatively assuming that 10% of the HS + H → H2S formation energy (-369.5 kJ/mol) is left to the newly formed H2S, its energy is more than twice the largest BE and 5 times the average BE and, hence, H2S will most likely leave the water surface.

Cu-MOF-derived Cu nanoparticles decorated porous N-doped biochar for low-temperature H2S desulfurization

Hydrogen sulfide (H2S) is a highly toxic and corrosive gas that poses significant risks to human health and the environment. Therefore, the development of an adsorbent capable of efficiently purifying H2S at room temperature remains a challenging task. In this study, a novel composite adsorbent with a specific surface area of 434 m2·g−1 was fabricated by modifying porous N-doped biochar with Cu nanoparticles (Cu/NBC) derived from Cu-MOFs for low-temperature desulfurization of H2S. The effect of pyrolysis temperature and the doping ratio of Cu-MOFs to biochar on the desulfurization performance of H2S for the as-prepared Cu/NBC was comprehensively investigated. Experimental results indicated that the desulfurization capability of the optimized Cu/NBC-600-1 adsorbent (synthesized at a pyrolysis temperature of 600 °C and a doping ratio of 1:1) was significantly affected by the desulfurization conditions, and the optimal conditions were determined to be at 25 °C, with 20 % oxygen content and 70 % relative humidity. Under the optimized conditions, the Cu/NBC-600-1 adsorbent exhibited a high H2S removal capacity of 158.28 mg·g−1, which was about 3.8 times higher than that of the pristine N-doped biochar. The desulfurization mechanism of the Cu/NBC composite was demonstrated to involve reactive adsorption and catalytic oxidation, resulting in the formation of elemental sulfur and copper sulfides as the main products. This study not only provides a promising approach to modify porous biochar with MOF derivatives, but also offers an effective strategy to remove low concentration H2S at room temperature.

Biodesulfurization of landfill biogas by a pilot-scale bioscrubber: Operational limits and microbial analysis.

Biogas serves as a crucial renewable energy vector to ensure a more sustainable energy future. However, the presence of hydrogen sulfide (H2S) limits its application in various sectors, emphasizing the importance of effective H2S removal techniques for maximizing its potential. In the present study, the limits of a pilot-scale bioscrubber for biogas desulfurization was study in a real scenario. An increase in the superficial liquid velocity resulted in significant improvements in the H2S removal efficiency, increasing from 76 ± 8% (elimination capacity of 6.2 ± 0.5 gS-H2S m−3 h−1) to 97.7 ± 0.5% (elimination capacity of 8 ± 1 gS-H2S m−3 h−1) as the superficial liquid velocity increased from 50 ± 3 m h−1 to 200 ± 8 m h−1. A USL of 161.4 ± 0.5 m h−1 was able to achieve outlet H2S concentrations as low as 3 ± 1 ppmv (H2S removal efficiency of 97 ± 1%) for 7 days. High superficial liquid velocity favoured the aerobic H2S oxidation reducing the nitrate demand. The maximum EC reached throughout the operation was 50.8 ± 0.6 gS-H2S m−3 h−1 (H2S removal efficiency of 96 ± 1%) and a sulfur production of 60%. Studies in batch flocculation experiments showed sulfur removal rates up to 97.6 ± 0.9% with a cationic flocculant dose of 75 mg L−1. Microbial analysis revealed that the predominant genus with sulfo-oxidant capacity during periods of low H2S inlet load was Thioalkalispira-sulfurivermis (61–69%), while in periods of higher H2S inlet load, family Arcobacteraceae was the most prevalent (11%).

Numerical investigation of boiler waterwall corrosion by integrated tube temperature prediction and sulfur evolution model

High temperature corrosion has become one of the leading causes of boiler waterwall tube failures because of the wide application of air-staged combustion in coal-fired boilers. High temperature corrosion is strongly affected by the H2S concentration and wall tube temperature distributions in the furnace. Particularly, the corrosion rate increases exponentially with the increase of tube temperature. However, by far most of the numerical studies on high temperature corrosion only considered the effects of H2S concentration while the critical effects of tube temperature were overlooked. Thus, this paper presents a comprehensive corrosion model that incorporates the key effects of both tube temperature and H2S concentration. Specifically, the tube temperature is predicted by a coupled combustion and hydrodynamic model that integrates the critical effects of both the boiler gas flow and steam flow on waterwall tube temperature. The H2S concentration is predicted by a sulfur evolution model describing the devolatilization process of coal sulfur species and their subsequent gaseous reactions. The tube temperature prediction model and H2S evolution model provide all the key parameters for accurate prediction of boiler waterwall corrosion. The corrosion model is applied to a 350 MW supercritical wall-fired boiler. The results show that the tube temperature varies significantly over the boiler waterwall, and hence, has significant impacts on the distribution of wall tube corrosion. Particularly, local high tube temperature zones could form on the waterwall areas of relatively low H2S concentration leading to substantially higher tube corrosion rates than the adjacent wall areas. The results demonstrate the importance of incorporating both the wall tube temperature and H2S concentration in the prediction of boiler waterwall corrosion.

A sensitive CsBr/Cs3Bi2Br3I6 heterostructure perovskite gas sensor for H2S detection at room temperature with high stability

In this paper, a new all inorganic lead-free perovskite gas sensor based on CsBr/Cs3Bi2Br3I6 composite was prepared to detect low concentrations H2S gas at room temperature (23 ℃). A two-step method of evaporation and subsequent spraying process was adopted, which makes the vertical growing Cs3Bi2Br3I6 nanoplates uniformly coating on the surface of the CsBr microspheres and forming a heterogeneous structure based conductive path way. The gas sensing test results indicate that the sensor shows good selectivity and reliable repeatability for H2S detection with long-term stability over 60 days, and the lowest concentration detected is 0.5 ppm. The sensor shows satisfactory stability in the range of relative humidity from 44 to 83 %. The in-situ diffuse reflectance infrared Fourier transformations spectroscopy (DRIFTs) results confirm the formation and enhancement process of SO asymmetric telescopic vibration peak due to the introduction of H2S gas, supporting the synergistic mechanism of adsorption-desorption and dynamic defect passivation.

The Effects of Trace H2S Levels on the Structure of Surface Scales in CO2 Corrosion

The CO2 corrosion of carbon steel is very strongly influenced by the formation of surface scales of corrosion products. Hence, the structure and composition of those scales has been the subject of much research. For oxygen-free brines in contact with gaseous CO2 at partial pressures up to ~50 bar, and temperatures up to ~120 °C, the formed scales are generally found to consist of a mixture of Fe3C (cementite) and FeCO3 (siderite). In simulated oil and gas production brines, the siderite incorporates Ca and Mg, while DeMarco et al [1] identified the scales that form over short times at ambient temperature as a mixture of Fe2(OH2)CO3 and Fe2O2CO3.Williams and colleagues [2-7] carried out detailed studies of the scales formed in solutions of moderate chloride content (0.5 – 1 M), saturated with CO2 at ~ 1 bar, pH adjusted to ~ 6.5 and at temperatures of ~ 80 °C. For the solutions containing only sodium chloride, siderite (FeCO3) was the major phase in the scale, though chukanovite (Fe2(OH)2CO3) was also present in some cases. With the addition of magnesium chloride, both siderite and chukanovite were always found in the scale, while there was no evidence of magnesium incorporation until the bulk concentration of MgCl2 was ~ 0.1 M. Considering the effect of low-level Cr and Mo alloying, it was found in the base sodium chloride solutions that mixed siderite/chukanovite scales were formed, but the scale became thinner and the chukanovite-to-siderite ratio decreased with alloy content. Even for alloys with 3.5 wt% Cr there was no evidence of discrete Cr (hydr)oxide layers within the scale. However, the addition of trace levels of H2S (∼ 0.5 μM) produced more significant changes. First, only chukanovite and FeS (mackinawite) were now found in the scale, with no siderite. Second, for the unalloyed steel and for alloys with 1 wt% Cr and up to 0.7% Mo, the scales were highly porous. Finally, for the 3.5wt% Cr alloy, a non-porous, protective layer was formed, about 200–600 nm thick.In this paper, we utilize ab-initio techniques to investigate the effects of very low level H2S on carbonate scale formation. In the past DFT has been used to understand the various aspects of corrosion and the design of corrosion inhibitors for various conditions [9-11]. We have used similar approach for studying the H2S adsorption on siderite and chukanovite surfaces, considering the experimental observation by Hassan et al [2], that trace amounts of H2S result in chukanovite over siderite. Initial studies show that there is a 0.7 eV higher interaction energy (more thermodynamically favorable) for H2S adsorption on chukanovite compared to siderite. This may imply the possibility that H2S could encourage chukanovite formation over siderite formation in aqueous environments.We further investigate this possibility using DFT to understand the mechanism that leads to formation of chukanovite. We aim to use implicit solvation in order to bring the effect of water in the vicinity. We further use the cluster approach within DFT, to explain the effect that alloying has on the scale formation. We take a bare Fe cluster and replace one of its atoms with an alloying element and study the electronic structure in the presence of H2S and CO2. The potential energy surface gets modified for a H2S—Fe interaction in the presence of Ni. We expect that this work would help us to have a deeper understanding of how alloying can impact or rather initiate certain kind of scale formation over others.

A mixed-potential gas sensor with heterojunctions based on Co3O4/ZnO/Y2O3 nanocomposite for low concentration H2S detection

This study aimed to develop a H2S gas sensor based on gadolinia-doped ceria (GDC) solid electrolyte and Co3O4/ZnO/Y2O3 ternary nanocomposite. Heterojunctions were formed inside the Co3O4/ZnO/Y2O3 ternary nanocomposite sensing material due to the difference of work function, which effectively adjusted the oxygen vacancy concentration, improved the electrocatalytic activity of the material, and reduced the working temperature. The response showed a piecewise linear correlation with the concentration of H2S, and its sensitivity for 0.2–2 ppm and 2–10 ppm H2S was −6.4 and −36.35 mV/decade, respectively. Furthermore, the sensor exhibited good stability, repeatability, and selectivity to H2S. This study showed that the GDC-based mixed potential sensor with Co3O4/ZnO/Y2O3-SE could be used as a potential sensor for detecting low concentration of H2S.

Genesis and source of natural gas in Well Mitan-1 of Ordovician Majiagou Formation, middle-eastern Ordos Basin, China

The Well Mitan-1 has achieved a major breakthrough in the exploration of Ordovician subsalt natural gas in the mid-eastern Ordos Basin, demonstrating a high-yield industrial gas flow in fourth member of the Majiagou Formation of Ordovician (O1m4). Despite this success, there are ongoing disputes regarding the origin of the natural gas found in Well Mitan-1. Measured results show that the natural gas in Well Mitan-1 is mainly composed of alkane gas (95.18 %). The gas drying coefficient (C1/C1-5) is measured at 0.947, and the H2S content is 3.49 %, with a small amount of N2 and CO2 in the non-hydrocarbon gas. The carbon isotopic compositions of methane, ethane, and propane in the natural gas are −45.5 ‰, −26.4 ‰, and −24.3 ‰, respectively. Based on the regional geological background, the characteristics of potential source rocks and the geochemical characteristics of natural gas, it is considered that the natural gas in Well Mitan-1 is self-generated and self-accumulated oil-associated gas in Ordovician subsalt carbonate rocks. However, certain geochemical anomalies, such as the lighter methane carbon isotope value (δ13C1) and coal-type gas characteristics in ethane carbon isotope (δ13C2), raise questions. Further insights from thermal simulation experiments on hydrocarbon generation and the analysis of residual gas in rocks suggest a close relationship between the special geochemical characteristics of Well Mitan-1 and the presence of gypsum rocks. The ubiquitous gypsum rock serves a dual purpose: acting as an effective caprock, facilitating the retention of early-generated natural gas, and promoting the generation of heavy hydrocarbon gases (C2+) and H2S. The relatively low H2S content (less than 5 %) and higher C2+ content indicate that thermochemical sulfate reduction (TSR), if present, is not strong enough to significantly impact methane. The δ13C2 is identified as a potentially sensitive parameter for identifying TSR.

Exogenous hydrogen sulfide attenuates hyperoxia effects on neonatal mouse airways.

Supplemental O2 remains a necessary intervention for many premature infants (<34 wk gestation). Even moderate hyperoxia (<60% O2) poses a risk for subsequent airway disease, thereby predisposing premature infants to pediatric asthma involving chronic inflammation, airway hyperresponsiveness (AHR), airway remodeling, and airflow obstruction. Moderate hyperoxia promotes AHR via effects on airway smooth muscle (ASM), a cell type that also contributes to impaired bronchodilation and remodeling (proliferation, altered extracellular matrix). Understanding mechanisms by which O2 initiates long-term airway changes in prematurity is critical for therapeutic advancements for wheezing disorders and asthma in babies and children. Immature or dysfunctional antioxidant systems in the underdeveloped lungs of premature infants thereby heightens susceptibility to oxidative stress from O2. The novel gasotransmitter hydrogen sulfide (H2S) is involved in antioxidant defense and has vasodilatory effects with oxidative stress. We previously showed that exogenous H2S exhibits bronchodilatory effects in human developing airway in the context of hyperoxia exposure. Here, we proposed that exogenous H2S would attenuate effects of O2 on airway contractility, thickness, and remodeling in mice exposed to hyperoxia during the neonatal period. Using functional [flexiVent; precision-cut lung slices (PCLS)] and structural (histology; immunofluorescence) analyses, we show that H2S donors mitigate the effects of O2 on developing airway structure and function, with moderate O2 and H2S effects on developing mouse airways showing a sex difference. Our study demonstrates the potential applicability of low-dose H2S toward alleviating the detrimental effects of hyperoxia on the premature lung.NEW & NOTEWORTHY Chronic airway disease is a short- and long-term consequence of premature birth. Understanding effects of O2 exposure during the perinatal period is key to identify targetable mechanisms that initiate and sustain adverse airway changes. Our findings show a beneficial effect of exogenous H2S on developing mouse airway structure and function with notable sex differences. H2S donors alleviate effects of O2 on airway hyperreactivity, contractility, airway smooth muscle thickness, and extracellular matrix deposition.

Influence of Ni on corrosion and trench formation of low alloy steel in low H2S content sour corrosion environments

AbstractThe influence of Ni content on corrosion and trench formation of low alloy steel in a low H2S containing sour corrosion environment was investigated. The results show that Ni decreases the total amount of corrosion by forming a passive film containing Ni components, such as NiS and Ni3S2 on the steel surface as a result of long‐term corrosion and suppressing the anodic dissolution reaction, while increasing the trench depth. It was also identified that the Ni content had a more dominant effect on trench formation in steel regardless of the tested sour environments with 0.01 bar H2S gas (pH 4.0) and 0.001 M Na2S2O3 (pH 2.7) in this study. Based on the experimental findings, the mechanism of trenching propagation by Ni was discussed from the viewpoint of changes in surface film properties and associated difference of corrosion resistance between trench‐tip and bulk surface due to the variation in Ni content.