Generation Of Hydrogen Sulfide Research Articles

Development and calibration of a bio-geo-reactive transport model for UHS

The increased share of renewable energy sources will lead to large fluctuations in energy availability and increases energy storage’s significance. Large-scale hydrogen storage in the subsurface may become a vital element of a future sustainable energy system because stored hydrogen becomes an energy carrier available on demand. Large hydrogen amounts can be stored in porous formations such as former gas fields or gas storages, while caverns can contribute with high deliverability. However, the storage of hydrogen induces unique processes in fluid-fluid and rock-fluid interactions (for example, bio- and geochemical reactions), which may affect the efficiency of the storage. In the present study, a mathematical model describing the two-phase multicomponent flow in porous media, including bio- and geochemical reactions, is developed to predict these hydrogen-related processes. The proposed model extends an existing model in the open source simulator DuMux describing the bio-reactive transport process considering methanation and sulfate-reduction by geochemical reactions. Significant attention is placed on the reduction from pyrite-to-pyrrhotite coming with the generation of harmful hydrogen sulfide. This reaction is calibrated by developing a kinetic model in DuMux that mimics the observations of reactor experiments from literature. The developed and calibrated model is afterwards used for simulation runs on field scale to assess the impact on Underground Hydrogen Storage (UHS) operations. The developed kinetic model describes the reduction from pyrite-to-pyrrhotite in agreement with the observations in the literature, whereby particular focus was placed on the hydrogen sulfide production rate. The consecutive implementation of the transport model in DuMux on field scale, including the bio- and geochemical reactions, shows the potential permanent hydrogen losses caused by reactions and temporary ones induced by gas-gas mixing with the initial and cushion gas.

Persulfidation and phosphorylation of transcription factor SlWRKY6 differentially regulate tomato fruit ripening.

Cysteine desulfhydrase (LCD) catalyzes the generation of the signaling molecule hydrogen sulfide (H2S) in plants. In this study, we found that H2S can inhibit tomato (Solanum lycopersicum) fruit ripening and SlWRKY6 undergoes differential protein persulfidation in SlLCD1-overexpressing leaves. Then, further study indicated that SlWRKY6 could be persulfidated by H2S at Cys396. By construction of slwrky6 mutants and SlWRKY6-OE lines, we found that SlWRKY6 positively regulates leaf senescence and fruit ripening by activating the transcription of ripening-related genes STAYGREEN 1 (SlSGR1) and Senescence-Associated Gene 12 (SlSAG12). In addition, SlWRKY6 interacted with kinase SlMAPK4 and was phosphorylated at Ser33. Dual luciferase transient expression assays and electrophoretic mobility shift assays indicated that SlWRKY6 persulfidation attenuated its transcriptional regulation of target genes SlSGR1 and SlSAG12, whereas SlWRKY6 phosphorylation by SlMAPK4 activated the transcription of target genes to promote fruit ripening. Moreover, we provided evidence that SlWRKY6 persulfidation attenuated its SlMAPK4-mediated phosphorylation to inhibit tomato fruit ripening. By transient expression of SlWRKY6, SlWRKY6C396A, SlWRKY6S33A and SlWRKY6S33D in slwrky6 fruits, we found that SlWRKY6 persulfidation attenuated the expression of SlSGR1 and SlSAG12 thereby delaying tomato fruit ripening, while SlWRKY6 phosphorylation increased the expression of target genes. As tomato fruits ripened, endogenous H2S production decreased, while SlMAPK4 expression increased. Therefore, our findings reveal a model in which SlWRKY6 persulfidation due to higher endogenous H2S levels in un-ripened fruit inhibits its ability to activate SlSGR1 and SlSAG12 expression, while SlWRKY6 phosphorylation by SlMAPK4 activates its transcriptional activity, thereby promoting tomato fruit ripening.

Biochemical and structural impact of two novel missense mutations in cystathionine β-synthase gene associated with homocystinuria.

Homocystinuria is a rare disease caused by mutations in the CBS gene that results in a deficiency of cystathionine β-synthase (CBS). CBS is an essential pyridoxal 5'-phosphate (PLP)-dependent enzyme in the transsulfuration pathway, responsible for combining serine with homocysteine to produce cystathionine, whose activity is enhanced by the allosteric regulator S-adenosylmethionine (SAM). CBS also plays a role in generating hydrogen sulfide (H2S), a gaseous signaling molecule with diverse regulatory functions within the vascular, nervous, and immune systems. In this study, we present the clinical and biochemical characterization of two novel CBS missense mutations that do not respond to pyridoxine treatment, namely c.689T > A (L230Q) and 215A > T (K72I), identified in a Chinese patient. We observed that the disease-associated K72I genetic variant had no apparent effects on the spectroscopic and catalytic properties of the full-length enzyme. In contrast, the L230Q variant expressed in Escherichia coli did not fully retain heme and when compared with the wild-type enzyme, it exhibited more significant impairments in both the canonical cystathionine-synthesis and the alternative H2S-producing reactions. This reduced activity is consistent with both in vitro and in silico evidence, which indicates that the L230Q mutation significantly decreases the overall protein's stability, which in turn, may represent the underlying cause of its pathogenicity.

A combination of generated hydrogen sulfide and nitric oxide activity has a potentiated protectant effect against cisplatin induced nephrotoxicity

AimHydrogen sulfide and nitricoxide possess cytoprotective activity and in vivo, they are generated from exogenous sodium hydrosulfide and L-arginine respectively. Cisplatin is a major chemotherapeutic agent used to treat cancer and has a high incidence of nephrotoxicity as a side effect. The study aim was to explore the effects of NaHS and L-arginine or their combination on cisplatin induced nephrotoxicity in rats. MethodsWistar Kyoto rats were given a single intraperitoneal dose of cisplatin (5 mg/kg) followed either by NaHS (56 μmol/kg, i. p.), L-arginine (1.25 g/L in drinking water) or their combination daily for 28-days. Post-mortem plasma, urine and kidney samples were collected for biochemical assays and histopathological analysis. ResultsCisplatin decreased body weights and increased urinary output, while plasma creatinine and urea levels were elevated, but sodium and potassium concentrations were diminished. The renal function parameters, blood urea nitrogen and creatinine clearance, were raised and decreased respectively. Regarding markers of reactive oxygen species, plasma total superoxide dismutase was reduced, whereas malondiadehyde was augmented.Cisplatin also diminished plasma and urinary H2S as well as plasma NO, while NaHS and L-arginine counteracted this activity on both redox-active molecules. Cisplatin cotreatment with NaHS, and/or L-arginine exhibited a reversal of all other measured parameters. ConclusionIn current study, NaHS and L-arginine as monotherapy protected the rats from cisplatin-induced nephrotoxicity but the combination of both worked more effectively suggesting the augmented anti-inflammatory and antioxidative potential of test treatments when administered together.

Метан и сульфитредуцирующие клостридии как показатели экологического состояния пелоидов гиперсоленых озер

The results of field studies of bottom sediments (peloids) of the hypersaline lakes Belyamin, Baskunchak, Elton and flows into Elton the small Smorogda River are presented. The number of sulfite-reducing clostridia (SRC) in bottom sediments was determined and the perfringens titer was calculated. Based on the perfringens titer, the sanitary and microbiological state of bottom sediments was assessed for the possibility of their use for balneological procedures. Based on the perfringens titer, the possibility of using bottom sediments for balneological procedures was assessed. Research has shown that in samples of individual layers of bottom sediments of Lake Baskunchak and the mouth of the Smorogda River, which flows into Lake Elton, the number of vegetative cells of sulfite-reducing clostridia slightly exceeds the standard values for peloids. The ingress of sewage into the peloids of Lake Baskunchak may be due to the settlements of Verkhny Baskunchak, Sredniy Baskunchak and Nizhny Baskunchak located near the lake. Participation of sulfite-reducing clostridia, along with sulfate-reducing bacteria, in the generation of methane and hydrogen sulfide was noted. The possibility of using data on methane content and the amount of SRC to assess the ecological state of peloids is shown.

Inflammatory-stimuli-responsive turn-on NIR fluorogenic theranostic prodrug: adjuvant delivery of diclofenac and hydrogen sulfide attenuates acute inflammatory disorders.

Prolonged use of very commonly prescribed non-steroidal anti-inflammatory drugs (NSAIDs) is often associated with undesired side effects, including gastrointestinal ulcers due to the non-selective inhibition of cyclooxygenases. We describe the development of an inflammatory-stimuli-responsive turn-on fluorogenic theranostic prodrug DCF-HS for adjuvant drug delivery. Upon activation by reactive oxygen species (ROS), the prodrug releases diclofenac DCF (active drug) and the NIR fluorophore DCI-NH2 along with carbonyl sulfide (COS). The second activation of COS by the enzyme carbonic anhydrase (CA) generates hydrogen sulfide (H2S). The prodrug was conveniently synthesized using multi-step organic synthesis. The UV-Vis and fluorescence studies revealed the selective reactivity of DCF-HS towards ROS such as H2O2 in the aqueous phase and the desired uncaging of the drug DCF with turn-on NIR fluorescent reporter under physiological conditions. Furthermore, the release of fluorophore DCI-NH2 and drug DCF was confirmed using the reverse phase HPLC method. Compatibility of prodrug activation was studied next in the cellular medium. The prodrug DCF-HS was non-toxic in a representative cancer cell line (HeLa) and a macrophage cell line (RAW 264.7) up to 100 μM concentration, indicating its biocompatibility. The intracellular ROS-mediated activation of the prodrug with the release of NIR dye DCI-NH2 and H2S was investigated in HeLa cells using the H2S-selective probe WSP2. The anti-inflammatory activity of the active drug DCF from the prodrug DCF-HS was studied in the lipopolysaccharide (LPS)-induced macrophage cell line and compared to that of the parent drug DCF using western blot analysis and it was found that the active drug resulted in pronounced inhibition of COX-2 in a dose-dependent manner. Finally, the anti-inflammatory potential of the prodrug and the turn-on fluorescence were validated in the inflammation-induced Wister rat models.

Enhancing antitumor immunity with stimulus-responsive mesoporous silicon in combination with chemotherapy and photothermal therapy.

Due to the immunosuppressive tumor microenvironment (TME) and potential systemic toxicity, chemotherapy often fails to elicit satisfactory anti-tumor responses, so how to activate anti-tumor immunity to improve the therapeutic efficacy remains a challenging problem. Photothermal therapy (PTT) serves as a promising approach to activate anti-tumor immunity by inducing the release of tumor neoantigens in situ. In this study, we designed tetrasulfide bonded mesoporous silicon nanoparticles (MSNs) loaded with the traditional drug doxorubicin (DOX) inside and modified their outer layer with polydopamine (DOX/MSN-4S@PDA) for comprehensive anti-tumor studies in vivo and in vitro. The MSN core contains GSH-sensitive tetrasulfide bonds that enhance DOX release while generating hydrogen sulfide (H2S) to improve the therapeutic efficacy of DOX. The polydopamine (PDA) coating confers acid sensitivity and mild photothermal properties upon exposure to near-infrared (NIR) light, while the addition of hyaluronic acid (HA) to the outermost layer enables targeted delivery to CD44-expressing tumor cells, thereby enhancing drug accumulation at the tumor site and reducing toxic side effects. Our studies demonstrate that DOX/MSN@PDA-HA can reverse the immunosuppressive tumor microenvironment in vivo, inducing potent immunogenic cell death (ICD) of tumor cells and improving anti-tumor efficacy. In addition, DOX/MSN@PDA-HA significantly suppresses tumor metastasis to the lung and liver. In summary, DOX/MSN@PDA-HA exhibits controlled drug release, excellent biocompatibility, and remarkable tumor inhibition capabilities through synergistic chemical/photothermal combined therapy.

Study on the factors of hydrogen sulfide production from lignite bacterial sulfate reduction based on response surface method

Bacterial sulfate reduction (BSR) is one of the key factors leading to the anomalous accumulation of hydrogen sulphide in coal mines. Environmental factors such as temperature and pH play a crucial role in the metabolism and degradation of coal by sulfate-reducing bacteria (SRB). In this study, coal samples were selected from Shengli Coal Mine, and SRB strains were isolated and purified from mine water using a dilution spread-plate anaerobic cultivation method. Based on single-factor experiments and response surface methodology (RSM), the impact of temperature, pH, oxidation–reduction potential (ORP), chemical oxygen demand to sulfate ratio (COD/SO42−) on the generation of hydrogen sulphide during brown coal BSR was analyzed. The results showed that the anaerobic degradation of coal by SRB was inhibited by either too high or too low a temperature to produce hydrogen sulfide, and the greatest production of hydrogen sulfide occurred at a temperature of about 30 °C; The greatest production of hydrogen sulfide occurred at an initial ambient pH of 7.5; COD/SO42− ratio of around 2.0 is most conducive to hydrogen sulphide generation; the lower ORP value is more favorable for hydrogen sulfide generation. The optimal conditions obtained by RSM were: temperature of 30.37 °C, pH of 7.64 and COD/SO42− of 1.96. Under these conditions, the hydrogen sulfide concentration was 56.79 mg/L, the pH value was 8.40, the ORP value was −274 mV, and the SO42− utilization rate was 58.04%. The RSM results showed that temperature, ambient pH and COD/SO42− had a significant effect on hydrogen sulfide production, and the degree of effect was: ambient pH > temperature > COD/SO42−.

Proteome Profiling of the Dystrophic mdx Mice Diaphragm.

Mdx mice with a spontaneous mutation in exon 23 of the Dmd gene represent the most common model to investigate the pathophysiology of Duchenne muscular dystrophy (DMD). The disease, caused by the lack of functional dystrophin, is characterized by irreversible impairment of muscle functions, with the diaphragm affected earlier and more severely than other skeletal muscles. We applied a label-free (LF) method and the more thorough tandem mass tag (TMT)-based method to analyze differentially expressed proteins in the diaphragm of 6-week-old mdx mice. The comparison of both methods revealed 88 commonly changed proteins. A more in-depth analysis of the TMT-based method showed 953 significantly changed proteins, with 867 increased and 86 decreased in dystrophic animals (q-value < 0.05, fold-change threshold: 1.5). Consequently, several dysregulated processes were demonstrated, including the immune response, fibrosis, translation, and programmed cell death. Interestingly, in the dystrophic diaphragm, we found a significant decrease in the expression of enzymes generating hydrogen sulfide (H2S), suggesting that alterations in the metabolism of this gaseous mediator could modulate DMD progression, which could be a potential target for pharmacological intervention.

Suppression of Hydrogen Sulfide Generation via the Coexistence of Anaerobic Sludge and Goethite-Rich Limonite/Polyethersulfone Composite Fibers.

Limonite-polyethersulfone (PES) composite fibers were prepared by the wet spinning method to suppress hydrogen sulfide (H2S) generation from anaerobic microbial sludge. The H2S adsorption of the prepared limonite composite fibers followed the Langmuir type, with a maximum adsorption capacity of 3.7-4.4 g H2S/g, indicating mesopore adsorption. The in vitro H2S fermentation environment with anaerobic microbial sludge with the coexistence of limonite composite fibers exhibited suppression of H2S generation. The coexistence of limonite composite fibers also suppressed the amount of CO generation produced by microbial fermentation, so the fibers also affected the metabolism of anaerobic microorganisms. During the anaerobic digestion process, particularly at 672-840 h (28-35 days), the mesopores of limonite in the composite fibers disappeared and changed to macropore adsorption, and the reaction of limonite with hydrogen sulfide produced pyrite (FeS2) and iron sulfate (Fe2(SO4)3) as products, which remained in the fiber with conversion efficiencies of 6.8 and 32.4%, respectively. The in vitro hydrogen disulfide action of limonite composite fibers was found to be able to suppress the generated environment of about 300 ppm to about 0.4 ppm.

New insight into effects of waste scrap iron on sludge anaerobic digestion: Performances, microbial community, and potential metabolic functions

The low sludge degradation efficiency and hydrogen sulfide (H2S) generation impair the development of sludge anaerobic digestion. This study explored the effects of waste scrap iron (WSI) addition on methane (CH4) production and H2S control in sludge anaerobic digestion. The maximum cumulative CH4 yield of 205.02 mL/g VSS was obtained at the WSI dosage of 0.7 g/g VSS, which increased by 21.34 % compared to that of control without WSI addition. The increase in CH4 yield was attributed to the enhancement of sludge degradation and soluble organic conversion. Meanwhile, the cumulative H2S yield reduced by 62.00 % compared to that of control. The pH value and content of insoluble sulfide precipitate increased with the increase in WSI dosage, which were two main reasons for H2S control. Microbial community results indicated that relative abundance of unclassified_f_Clostridiaceae_1, Bacteroides, vadinBC27_wastewater-sludge_group, Clostridium_sensu-stricto-1, Macellibacteroides, and hydrogenotrophic methanogens increased with WSI addition, meaning that WSI addition promoted syntrophic interaction between key bacteria and hydrogenotrophic methanogens. Gene prediction analysis demonstrated that WSI addition promoted microbial proliferation and respiration, carbohydrate and amino acid metabolism, and activity of butyrate kinase, acetate kinase, pyruvate ferredoxin oxidoreductase, and coenzyme F420 hydrogenase. In view of the enhancement of ABC transporters, lipopolysaccharide biosynthesis, quorum sensing, two-component systems, and ribosome metabolic pathway, it could be considered that WSI addition promoted information recognition and substance exchange among microorganisms, increasing microbial metabolic activity of anaerobic system.

Synthesis of Sulfur-35-Labeled Trisulfides and GYY-4137 as Donors of Radioactive Hydrogen Sulfide.

Hydrogen sulfide has emerged as a key gasotransmitter in humans and in plants, and the addition of exogenous hydrogen sulfide has many beneficial effects in vivo and in vitro. A challenge in investigating the effect of exogenous hydrogen sulfide is tracking the location of exogenous hydrogen sulfide on an organism and cellular level. In this article, we report the synthesis of three key chemicals (cysteine trisulfide, glutathione trisulfide, and GYY-4137) that release radiolabeled 35S as hydrogen sulfide. The synthesis started with the reduction of Na235SO4 mixed with Na2SO4 to generate hydrogen sulfide gas that was trapped with aq NaOH to yield radiolabeled Na2S. The Na2S was converted in one step to GYY-4137 at 65% yield. It was also converted to bis(tributyltin) sulfide that readily reacted with N-bromophthalimide to yield a monosulfur transfer reagent. Trisulfides were synthesized by reaction with the monosulfur transfer reagent and the corresponding thiols. The levels of radioactivity of the final products could be varied on a per gram basis to alter the radioactivity for applications that require different loadings of hydrogen sulfide donors.

Utilizing Electricity-Producing Bacteria Flora to Mitigate Hydrogen Sulfide Generation in Sewers through an Electron-Pathway Enabled Conductive Concrete

This study aims to demonstrate the effectiveness of using biological oxidation for hydrogen sulfide (H2S) control. A long-term experiment was conducted using a rod-shaped electrode made of highly conductive concrete, which provided an electron pathway for H2S mitigation. Bacterial flora analysis was conducted using PCR-DGGE and metagenomic analysis by next-generation sequencing to identify electricity-producing bacteria. Results showed that H2S was effectively mitigated, and electricity-producing bacteria, including Geobacter sp. and Pelobacter sp., were found around the inner surface of the anode. The study found that highly conductive concrete can create an electron pathway for biological oxidation of H2S. Oxygen from the air layer near the surface of the water can act as an electron acceptor, even under anaerobic conditions, enabling effective H2S control in sewer systems.

Hydrogen sulphide synthesis in GtoPdb v.2023.1

Hydrogen sulfide is a gasotransmitter, with similarities to nitric oxide and carbon monoxide. Although the enzymes indicated below have multiple enzymatic activities, the focus here is the generation of hydrogen sulphide (H2S) and the enzymatic characteristics are described accordingly. Cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) are pyridoxal phosphate (PLP)-dependent enzymes. 3-mercaptopyruvate sulfurtransferase (3-MPST) functions to generate H2S; only CAT is PLP-dependent, while 3-MPST is not. Thus, this third pathway is sometimes referred to as PLP-independent. CBS and CSE are predominantly cytosolic enzymes, while 3-MPST is found both in the cytosol and the mitochondria. For an authoritative review on the pharmacological modulation of H2S levels, see Szabo and Papapetropoulos, 2017 [8].

The Impact of Drugs on Hydrogen Sulfide Homeostasis in Mammals.

Mammalian cells and tissues have the capacity to generate hydrogen sulfide gas (H2S) via catabolic routes involving cysteine metabolism. H2S acts on cell signaling cascades that are necessary in many biochemical and physiological roles important in the heart, brain, liver, kidney, urogenital tract, and cardiovascular and immune systems of mammals. Diminished levels of this molecule are observed in several pathophysiological conditions including heart disease, diabetes, obesity, and immune function. Interestingly, in the last two decades, it has become apparent that some commonly prescribed pharmacological drugs can impact the expression and activities of enzymes responsible for hydrogen sulfide production in cells and tissues. Therefore, the current review provides an overview of the studies that catalogue key drugs and their impact on hydrogen sulfide production in mammals.

Bilayer dressing based on aerogel/electrospun mats with self-catalytic hydrogen sulfide generation and enhanced antioxidant ability.

Hydrogen sulfide (H2S) releasing wound dressings have attracted much attention for their ability to promote cell proliferation, stimulate angiogenesis, and resist inflammation. Mimicking the skin structure, a bilayer wound dressing based on aerogel/mats with H2S release capability was designed and fabricated. A bio-macromolecular H2S donor based on a keratin-TA conjugate (KTC) was first synthesized through a thiol-disulfide exchange reaction. As an inner layer, KTC was then loaded into a gelatin hydrogel with large pores to absorb the wound exudates and generate H2S self-catalytically. Subsequently, polyurethane was electrospun with glutathione (GSH) to be used as an outer layer with small pores, which provided mechanical support, supplied GSH, and prevented bacterial invasion. The bilayer dressing was capable of generating H2S self-catalytically, achieving a controlled and sustained release. The dressing could also promote cell proliferation and migration. In addition, the dress possessed enhanced antioxidant ability and reactive oxygen species (ROS) scavenging capability. The bilayer dressing on promoting wound healing was investigated in a full-thickness excisional cutaneous wound model in rats. The results demonstrated that it could reduce inflammation, promote vascularization, and facilitate hair follicle regeneration, thereby accelerating wound healing. Overall, the bilayer dressing has great potential applications in the field of the wound dressing.

Generation and Physiology of Hydrogen Sulfide and Reactive Sulfur Species in Bacteria.

Sulfur is not only one of the most abundant elements on the Earth, but it is also essential to all living organisms. As life likely began and evolved in a hydrogen sulfide (H2S)-rich environment, sulfur metabolism represents an early form of energy generation via various reactions in prokaryotes and has driven the sulfur biogeochemical cycle since. It has long been known that H2S is toxic to cells at high concentrations, but now this gaseous molecule, at the physiological level, is recognized as a signaling molecule and a regulator of critical biological processes. Recently, many metabolites of H2S, collectively called reactive sulfur species (RSS), have been gradually appreciated as having similar or divergent regulatory roles compared with H2S in living organisms, especially mammals. In prokaryotes, even in bacteria, investigations into generation and physiology of RSS remain preliminary and an understanding of the relevant biological processes is still in its infancy. Despite this, recent and exciting advances in the fields are many. Here, we discuss abiotic and biotic generation of H2S/RSS, sulfur-transforming enzymes and their functioning mechanisms, and their physiological roles as well as the sensing and regulation of H2S/RSS.

CTH G1208T and MTHFR A1298C polymorphisms are associated with a higher risk of a first myocardial infarction with fatal outcome among women.

Cystathionine-gamma-lyase (CSE) in the transsulfuration pathway generates hydrogen sulfide (H2S), suggested regulating cardiovascular function. The G1208T polymorphism in the CTH gene, rs1021737, has, in addition toMTHFR, been found to increase homocysteine, related to myocardial infarction (MI) risk. This study aimed, for the first time, to investigate the associations of the polymorphisms CTH G1208T, MTHFR C677T, and A1298C with the prospective risk of developing a fatal or non-fatal first MI. This case-referent study included 545 cases later developing a first-ever MI and 1,054 referents from the Northern Sweden Health and Disease Study. Fatal MI was defined as death within 28days after MI symptoms. Women, but not men, had a positive association between fatal MI and the CTH G1208T, odds ratio [95% confidence interval] 3.14 [1.16-8.54] for heterozygotes, and the dominant model 3.22 [1.22-8.51], and for the MTHFR A1298C heterozygotes 3.24 [1.26-8.34] and the dominant model 2.63 [1.06-6.50]. The MTHFR C677T polymorphism was not related to MI. This study indicates that the minor alleles of CTH G1208T and MTHFR A1298C polymorphisms are associated with a higher risk for a fatal MI among women but not for non-fatal MI. No association was found in men.

The interplay between microbial reservoir souring and barite scale formation in hydrocarbon reservoirs

The injection of seawater into a hydrocarbon reservoir (seawater flooding) as a secondary or tertiary oil recovery method is associated with two possibly significant challenges. First, the formation and deposition of various types of scale may happen due to incompatibility between the injection seawater and formation brine. Especially, the addition of sulfate ions may trigger the formation of various types of sulfate scales (e.g., barium sulfate, strontium sulfate, and calcium sulfate). Second, microbial reservoir souring may happen due to the activation of Sulfate Reducing Bacteria (SRBs), which reduce sulfate ions to hydrogen sulfide. This is mainly a result of a drop in temperature in the reservoir, the addition of sulfate from the seawater to the reservoir, and the presence of Dissolved Organic Carbon (DOC) coming from reservoir hydrocarbon. Since both these processes include the consumption of sulfate ions, a competition is expected to happen between them. Especially, there is a concern about whether an efficient mitigation strategy for souring (e.g., nitrate treatment) will result in less consumption of sulfate ions and in turn more formation of sulfate scales. This study tests this theory and investigates the effect of souring intensity and mitigation on the severity of barite scale formation inside the reservoir. In this study, a non-isothermal multi-component bio-chemical model to simultaneously simulate both the processes is developed. Several simulation cases in one and two dimensions are investigated in different conditions in order to study the effect of three influential parameters, namely sulfate ion concentration in the injection sweater, the DOC content of the reservoir hydrocarbon, and injection flow rate on barite scale formation, microbial reservoir souring, nitrate treatment, and the interplay among them. The results show that the effect of barite scale formation on reservoir souring is small (a maximum of 4 percent reduction in the total generated hydrogen sulfide) whereas reservoir souring and nitrate treatment significantly influence barite formation. Depending on the case, the presence of souring can cause a complete removal of barite scale especially around the production well (positive effect) or a maximum of 8 times increase in barite scale amount around the production well (negative effect). Moreover, in all cases, with a more efficient nitrate treatment, although less hydrogen sulfide is generated inside the reservoir (up to a full removal of souring), the generation zone moves closer to the production well. Therefore, an insufficient nitrate treatment may cause an earlier hydrogen sulfide production from the production well (up to twice as early). Several other trends observed in the set of results are also presented in this paper.

Synergistic strategy constructed hydrogel-aerogel biphase gel (HAB-gel) with self-negative-pressure exudate absorption, M2 macrophage‐polarized and antibacterial for chronic wound treatment

Chronic wound healing is a major and unmet challenge, due to contamination of exudate, bacterial infection and non-healing symptoms, having become urgent an problem to be solved. Developing multifunctional dressings capable of efficiently absorbing exudate by forming self-micro-negative pressure, effectively antibacterial and inducing immune regulation, would be a promising strategy for wound healing. Herein, the hydrogel-aerogel biphase gel (HAB-gel) dressing consisted of PVA grafted with PAM and bio-based polyurethane was prepared to generate synergistic therapeutic effects through removing exudates, antibacterial properties and immune regulation. The PVA grafted with PAMs features generating self-negative pressure to absorb deep exudate by aerogel phase, providing a comfortable microenvironment for wound healing, moreover, the capacities of liquid absorption and retention are enhanced by hydrogel phase, preventing wounds from exudate contamination. The incorporation of β-cyclodextrin (β-CD) in the constructed polyurethane (LPU) endows the HAB-gel materials with excellent antibacterial properties after being loaded with polyhexamethylene biguanidine (PHMB). Furthermore, the HAB-gel dressing can accelerate the macrophage polarization into anti-inflammatory M2 via the hydrogen sulfide (H2S) generation, angiogenesis promotion and collagen deposition in periwound tissue. Overall, this novel strategy for synergistic treatment of chronic wounds, provides a promising method for the management of tissue regeneration disorders.