Hydrogen Sulfide In Solution Research Articles

The sustainable microwave approach to H2S and RSH activation into Di- and Trisulfides in N-Methylpyrrolidone

A reagent- and waste-free method for the transformation of hydrogen sulfide and thiols with С3-С8 hydrocarbons groups into value-added di- and trisulfides is proposed under the microwave irradiation. The hydrogen sulfide solution in N-methylpyrrolidone was used as the reaction medium to occur the interaction with different thiols. The influence of the microwave irradiation power, duration, the temperature and thiol structure on the yield and ratio of target products has been investigated. It is found that the effective microwave power for activation of H2S and RSH should be at least 200 W, while increasing the reaction temperature reduces the contact time. The maximum values for the yield of di- and trisulfides were obtained at 280 W and 100 °C. High selectivity of trisulfide formation was observed in the case of alkanethiols C3-C5, especially for compounds with isomeric hydrocarbons groups. Differences in the mechanisms of H2S interaction with linear and branched thiols based on the formation of alkylhydropolysulfide intermediates have been identified. The proposed scheme of utilization of H2S and low-molecular-weight thiols into organic polysulfides under microwave irradiation was suggested.

A Novel Turn-On Fluorescent Probe Based on Naphthalimide for Highly Selective and Sensitive Detection of Hydrogen Sulfide in Solution and Gas

A Novel Turn-On Fluorescent Probe Based on Naphthalimide for Highly Selective and Sensitive Detection of Hydrogen Sulfide in Solution and Gas

Improvement mechanism in stress corrosion resistance of the X70 pipeline steel in hydrogen sulfide solution by massive laser shock peening treatment

The effects of massive laser shock peening treatment (MLSPT) on the microstructural evolution and stress corrosion behavior of the X70 pipeline steel in hydrogen sulfide solutions with different concentrations were investigated by residual stress measurement, microstructural observation and slow strain rate tension test. The results revealed that MLSPT generated nanocrystallines, refined martensite-austenite constituent and nanocarbides in the near-surface layer. The combined effects of MLSPT-induced gradient compressive residual stress and refined microstructures significantly improved the stress corrosion crack (SCC) resistance. Furthermore, the influence mechanism of MLSPT on SCC resistance of the X70 pipeline steel was presented in detail.

Amino modified iodinated BODIPY photosensitizer for highly efficient NIR imaging-guided photodynamic therapy with ultralow dose

In PDT, high doses of photosensitizers can lead to prolonged patient photosensitivity and undesired side effects. As a classic fluorescent dye, BODIPY has attracted much attention in optical diagnosis and therapy due to its excellent stability, effective singlet oxygen production, and flexible modification. Herein, we synthesized successfully two organic near-infrared BODIPY derivatives with active groups. NO2-BDPI could be transformed into NH2-BDPI after responding to hydrogen sulfide in solution and brought an apparent color change. And both dyes possessed excellent single oxygen production capacity (ΦΔ = 0.629 for NO2-BDPI and ΦΔ = 0.688 for NH2-BDPI). After being encapsulated with an amphiphilic polypeptide, NH2-BDPI could be assembled into nano–NH2–BDPI particles that own good water solubility and passively tumor-targeting via the enhanced permeability and retention (EPR) effect. Benefiting from the admirable cellular uptake and excellent intracellular ROS generation in vitro, the nano–NH2–BDPI shows splendid PDT effect towards 4T1 and HeLa cells under very low doses (0.24 μM) and NIR power density (660 nm 10 mW/cm2). In vivo experiment, the nano-photosensitizer exhibited highly effective tumor suppression and ablation under a 40 mW/cm2 NIR irradiation. The exploration demonstrated the commendable PDT effect of NH2-BDPI and made it be a potential candidate for further NIR imaging-guided PDT research in clinical application.

Antibrowning effect of commercial and acid-heat coagulated whey on potatoes during refrigerated storage.

Potato color turns to brown after some process such as peeling, cutting, and slicing. In this research, the effect of acid-heat coagulated whey and commercial whey solutions on the color, polyphenol oxidase, phenylalanine ammonia-lyase activity, malondialdehyde, hydrogen peroxide content of potatoes were compared with pure water (control) immersion and sodium hydrogen sulfide solution. According to color results, there was no significant (P > 0.05) difference was found in the L* and b* values, browning index, and whitening index of the treatment groups. The polyphenol oxidase activity of the sulfide and commercial whey solution groups decreased from the initial values on day 3 then increased over that value. The use of the whey solution in preventing polyphenol oxidase activity showed a similar curve with the use of the sulfide solution. A rapid increase was observed in the malondialdehyde and hydrogen peroxide values of all treatment groups during the first 3-day storage. PRACTICAL APPLICATION: Immersion of potato cubes to whey protein solution prevents the browning and inhibits polyphenol oxidase activity. The browning index of the samples was not affected by the immersing water or whey solutions.

Experimental and theoretical studies of five imidazolium-based ionic liquids as corrosion inhibitors for mild steel in H2S and HCl solutions

In this study, the mild steel corrosion inhibition performance and the corresponding mechanisms of five imidazolium-based ionic liquids (ILs) in hydrogen sulfide (H2S) and hydrochloric acid (HCl) solutions were investigated using electrochemical experiments, weight loss measurement, morphology analysis, and quantum chemical calculation. The results revealed that these ILs inhibited the corrosion of mild steel in H2S and HCl solutions and did not change the corresponding mechanism of the corrosion reaction. The corrosion inhibition ability of these ILs decreased when the temperature increased. 1-Allyl-3-methylimidazolium bromide ([Amim]Br) exhibited the strongest mild steel corrosion inhibition capacity in H2S and HCl solutions. The corrosion inhibition capacity of the ILs can be attributed to their adsorption on metal surfaces, which obeys the Langmuir adsorption isotherm. E HOMO exhibited a higher influence than E LUMO on the corrosion inhibition performance of the imidazolium-based ILs.

Behavioral Analysis of Hydrogen in Metals under the Effect of H2S Corrosion Using a Layer-stripping Micro-hardness Technique

In order to study the distribution behavior of hydrogen in metals under the condition of H2S corrosion, a layer-stripping micro-hardness test was designed to analyze the hydrogen distribution along the depth of hydrogen-charged 45 high-quality structural carbon steel at three different hydrogen sulfide concentrations and four corrosion periods in this study. The results show that there is a terminal solid solubility of hydrogen in the metal for hydrogen sulfide solutions over various concentrations and corrosion periods. A hydrogen-saturated layer is produced by hydrogen diffusing through the metal from an unsaturated state to a fully saturated state. The hydrogen-saturated layer is not affected by the concentration of the corrosion, but its thickness increases as the corrosion period increases. In this way, we established a new hydrogen diffusion model in metals.

In situ determination of polysulfides in alkaline hydrogen sulfide solutions

A method was developed to determine low concentrations of polysulfide ions (Sn2− expressed as zero-valent sulfur) in situ and in the presence of high concentrations (0.5 mol dm−3) of hydrogen sulfide ions, HS−, at pH 14. UV–visible spectrophotometry was used to determine absorbances at 295 and 420 nm using an immersion probe, designed for highly corrosive environments. Three absorbance trends were found, corresponding to three concentration ranges of zero-valent sulfur: low (0–1.2 × 10−3 mol dm−3), medium (1.2–3.6 × 10−3 mol dm−3) and high (3.6–10 × 10−3 mol dm−3). The non-linear dependence of absorbance on concentration over the range studied was due to disproportionation of polysulfides. Determination of these species is well known to be problematic at low concentrations due to the effects of adventitious oxygen in solution, meta-stability and speciation of polysulfide species: S22− – S82−. Oxygen concentrations must be minimised in the inert gas used to de-oxygenate sulfide solutions and for the same reason, their contact with atmospheric oxygen should be minimised. During potentiostatic oxidation of alkaline solutions containing HS− ions in the anolyte of electrochemical reactors incorporating cation-permeable membranes, temporal changes in anolyte absorbance and charge were used to estimate polysulfide concentrations. Charge yields for sulfide to polysulfide oxidation were close to unity, confirming the utility of the technique developed. Molar attenuation coefficients of the predominant polysulfide ions S32− at 420 nm and S42− at 295 nm were also estimated as 289 and 3609 dm3 mol−1 cm−1, respectively, and comparable to values of (190, 206) and (3420, 3690) dm3 mol−1 cm−1 reported previously.

Experimental study and numerical simulation on the SSCC in FV520B stainless steel exposed to H2S+Cl− Environment

Constant displacement loading tests using wedge opening loading specimens were carried out in aqueous hydrogen sulfide solution containing sodium chloride to investigate the susceptibility of stress corrosion cracking (SCC) of FV520B precipitation hardening martensitic stainless steel. Results of the SCC tests indicated that the stress corrosion critical stress intensity factor (KISCC) dramatically decreased in the corrosion medium investigated and decreased with the increasing of H2S concentration. Microstructures of fracture surfaces were analyzed using a scanning electron microscope (SEM) with an energy dispersive X-ray spectroscopy (EDS). The fracture surface was typical of sulfide stress corrosion fracture. In addition, large amount of intermittent arc-crack on the side surfaces around the tip of main crack formed even no main crack propagated.A sequentially coupling finite element analysis (FEA) program was utilized to simulate the stress field and calculate the diffused hydrogen concentration distribution of specimen exposed to the corrosion medium investigated. The FEA results indicated that corrosion pit affected the stress and diffusion hydrogen distribution around the corrosion pit where large stress gradients formed. Side surface cracks initiated from those corrosion pits and propagated under the synergy of stress and hydrogen. The effect of the corrosion pit on hydrostatic stress distribution was limited in superficial zone near the side surface, thus side surface cracks propagated along the hoop direction rather than along the direction of specimen thickness. Based on the morphology observation and FEA results, it can be concluded that the SCC mechanism of FV520B steel was hydrogen embrittlement mainly and combination of anodic dissolution. Simultaneously, corrosion pitting was the precondition of side surface crack formation while the stress induced hydrogen diffusion was the dominant factor.

STUDY OF CORROSION RATE AND FEATURES OF NANOCTRUCTURED ALUMINUM ALLOY SAMPLES IN HYDROGEN SULFIDE MEDIUM

The study determines corrosion rate and covers corrosion damage specifics of AK4-1 aluminum alloy samples in the NACE hydrogen sulfide solution. The alloy was studied in an ultrafine state as compared to the coarse-grained state obtained after standard T6 treatment (hardening + ageing). The alloy was nanostructured by equal-channel angular pressing (ECAP). It was shown that the alloy corrosion rate after ECAP was 1,9 times higher than after T6 treatment. Thus, general corrosion occurred in the alloy after ECAP, while in the T6 state pit corrosion occurred in the alloy in addition to general corrosion. The corrosive effect had a greater impact on surface roughness of samples made of AK4-1 alloy after ECAP as compared to samples after T6 treatment.

Static Crack Resistance of 20 and 30KhMA Steels in a Nace Solution

We study the crack resistance of 20 and 30KhМА steels in a NACE hydrogen-sulfide solution under static and repeated static stresses and found their threshold stress intensity factors. A conclusion is made that these steels almost satisfy the criteria of their applicability in hydrogen-sulfide media accepted in the engineering practice.

The corrosion behavior of hard W–C system chemical vapor deposition layers in HCl and H2S aqueous solutions

The results of a study of anticorrosion performance of low carbon containing tungsten-based hard chemical vapor deposition (CVD) coatings with microhardness from 5 to 17 GPa are presented in this work. Their high corrosion resistance in hydrochloric acid and hydrogen sulfide solutions is noted, as their corrosion rate does not exceed 6 μm per year in hydrochloric acid solution and 15 μm per year in hydrochloric acid solution saturated with hydrogen. The open circuit potentials correspond to tungsten (VI) oxide formation so the corrosion process supposedly runs in passive state. Taking into account the low porosity of the CVD layers, which is lower than 0.02%, these coatings are promising for application as anticorrosion wear-resistant coatings for chemical and oil and gas apparatus responsible units.

Experimental study on stress corrosion crack propagation rate of FV520B in carbon dioxide and hydrogen sulfide solution

FV520B steel is a kind of precipitation hardening Martensitic stainless steel, it has high-strength, good plasticity and good corrosion resistance. Stress corrosion cracking (SCC) is one of the main corrosion failure mode for FV520B in industrial transportation of natural gas operation. For a better understanding the effect on SCC of FV520B, the improved wedge opening loading (WOL) specimens and constant displacement loading methods were employed in experimental research in carbon dioxide and hydrogen sulfide solution. The test results showed that the crack propagation rate is 1.941×10−7–5.748×10−7mm/s, the stress intensity factor KISCC is not more than 36.83MPa m. The rate increases with the increasing of the crack opening displacement. Under the condition of different initial loading, KISCC generally shows a decreasing tendency with the increase in H2S concentration, and the crack propagation rate showed an increasing trend substantially. For the enrichment of sulfur ion in the crack tip induced the generation of pitting corrosion, promoting the surrounding metal formed the corrosion micro batteries, the pit defects gradually extended and connected with the adjacent pit to form a small crack, leading to further propagation till cracking happened. Fracture microscopic morphology displayed typical brittle fracture phenomena, accompanying with trans-granular cracking, river shape and sector, many second cracks on the fracture surface.

Nanostructured hard coatings: the key to safe operation of equipment in extreme conditions

Two main classes of hard coatings based on tungsten and tungsten carbides prepared by chemical gas-phase sedimentation are considered in this work. The coatings possess high hardness (11–40 GPa) and thickness (12–100 µm). Results on abrasive and corrosion resistance in solutions of hydrogen sulfide, inorganic acids, and other aggressive environment are presented. All these coatings are promising for use in extremely severe conditions of abrasive, corrosion, and erosive wear owing to a unique combination of chemical stability, hardness, viscosity, and crackand impact-resistance.

Anti-corrosion behavior of thiadiazole derivatives for silver strip in hydrogen sulfide solutions

Purpose– This paper aims to evaluate the inhibition efficiency of thiadiazole derivatives, such as 2,5-dimercapto-1,3,4-thiadiazole (DMTD), 5-methly-2-mercapto-1,3,4-thiadiazole (MMTD) and 2,5-dithiododecyl-1,3,4-thiadiazole (DDTD), in 50 mg/L hydrogen sulfide for silver strip.Design/methodology/approach– Evaluation was carried out by corrosion-inhibiting test, electrochemical measurement and surface analysis techniques. 3D surface profiler, atom force microscopy, scanning electron microscopy and energy-dispersive X-ray analysis were applied and finally confirmed the existence of the adsorbed film.Findings– The electrochemical measurement showed that the inhibition efficiency increases with increasing inhibitor concentration in 50 mg/L hydrogen sulfide solution, while the corrosion rate and the corrosion current decrease. Weight-gained measurements also indicated that inhibitor decreases the corrosion rate in the studied solution. The adsorption of DMTD and MMTD on the silver surface obeys Temkin’s adsorption isotherm, but the adsorption of DDTD follows Langmuir’s adsorption isotherm. That means that the inhibition mechanism is different between DMTD, MMTD and DDTD. The ΔG0advalues of DMTD, MMTD and DDTD were −37.47, −37.29 and −38.69 kJ/mol, respectively. It showed that there was an adsorption bond between silver surface and inhibitor, and the adsorption belongs to chemical adsorption.Originality/value– The inhibitors have an excellent inhibition efficiency, and the best inhibition efficiency is 91.76 per cent. Inhibitors can effectively inhibit metal corrosion in the oil and gas.

A BODIPY-based turn-on fluorescent probe for the selective detection of hydrogen sulfide in solution and in cells

A new turn-on fluorescent probe, incorporating 7-nitrobenzoxadiazole (NBD) ether group into a BODIPY molecule, was synthesized and studied for the detection of H2S and biothiols in aqueous solution and in living cells. The design was based on thiol-induced thiolysis of the NBD ether bond and followed by the cleavage and the release of free meso-(4-hydroxybenzyl)-substituted BODIPY fluorophore. The BODIPY-based probe displayed highly sensitive and selective fluorescence enhancement respond to H2S over competing biothiols such as cysteine (Cys) and glutathione (GSH), mainly due to the weak reactivity of biothiols toward the probe. There was a good linearity between the fluorescence intensity and the concentrations of H2S in the range of 1–200µM with a detection limit of 2.6µM. The proposed reaction mechanism was confirmed by mass spectrometry and optical spectroscopy, and the mechanism of turn-on fluorescent response was further determinated by the density functional theory (DFT) calculations using Gaussian 03 program. Moreover, the probe was successfully applied for the fluorescence imaging of H2S in HeLa cells under physiological conditions (pH 7.4).

Thermal spring water drinking attenuates dextran-sulfate-sodium-induced colitis in mice.

The present study investigates the effect of oral consumption of hydrogen sulfide-containing Harkány thermal spring water, as well as sodium hydrogen sulfide (NaHS) solution on experimental colitis. Colitis was induced by 2% dextran sulfate sodium (DSS) in the drinking water of C57BL/6 mice for 7 days. Some animal groups drank Harkány thermal spring water or water supplemented with 21.68 mg/L NaHS. General signs of colitis, myeloperoxidase (MPO) enzyme activity of colon samples, histological features of colitis and function of the enteric nervous system were assessed. Oral administration of Harkány thermal spring water significantly attenuated general signs of colitis, MPO enzyme activity of colon samples and detrimental effect of colitis on the function of the enteric nervous system, but not histological signs of colitis. These findings could be reproduced using NaHS solution with additional significantly diminished histological damage. We conclude that oral treatment with Harkány thermal spring water relieves various aspects of DSS-evoked colitis in mice. This effect is most likely to be mediated by hydrogen sulfide content of the Harkány water. Our data might promote complementary utilization of sulfurous thermal spring water in the therapy of inflammatory bowel disease.

Chemoselective reduction and self-immolation based FRET probes for detecting hydrogen sulfide in solution and in cells.

Hydrogen sulfide (H2S) has been regarded as the third gaseous transmitter. Based on the mechanism of chemoselective azido reduction and self-immolation, five fluorescence resonance energy transfer (FRET) probes for the detection of H2S were designed and synthesized. The effect of functional substitution of the self-immolative moiety on azido reduction and quinone-methide rearrangement were investigated. Their fluorescence responses and chemoselectivity for H2S detection were evaluated in solutions and in cells. This strategy may provide a general route for designing H2S probes with many commercially available FRET pairs.

Stress Corrosion Cracking Behavior of 35CrMo Steel in Acidic Hydrogen Sulfide Solutions

The combination of electrochemical corrosion technologies were performed to study corrosion of 35CrMo steel in H2S solution with various pH values by simulate the low concentrations of hydrogen sulfide environment of oilfield in the pit. Stress corrosion cracking(SCC) of 35CrMo steel in acidic hydrogen sulfide solutions with various pH values and temperature was investigated by U-bent specimen immersing test and slow strain rate tensile test. It is shown that 35CrMo steel exhibits a high susceptibility to SCC in acidic hydrogen sulfide solutions. The susceptibility and corrosion increases by decreasing the pH value of the solution. The susceptibility varied seriously with the change of pH value. The decrease of pH would accelerate the cathodic process greatly, leading to the increase of corrosion rate and hydrogen charging current density, resulting the local anodic dissolution and hydrogen embrittlement effect more significant. The different susceptibility to SCC of 35CrMo steel in 15-90 ℃, Maximum susceptibility in 35 ℃ and 90 ℃. The SCC mechanism of 35CrMo steel is hydrogen embrittlement(HE) mainly and combination of anodic dissolution(AD) in acidic hydrogen sulfide solutions.

Microstructure and corrosion behavior of TiC/Ti(CN)/TiN multilayer CVD coatings on high strength steels

Titanium carbide/titanium carbonitride/titanium nitride (TiC/Ti(CN)/TiN) multilayer coatings are prepared on the surface of three high-strength steels (35CrMo, 42CrMo, and 40CrNiMo) by chemical vapor deposition method. The fracture morphology, elemental distribution, phase composition, micro-hardness, and adhesion of the multilayer film are analyzed. The hydrogen sulfide stress corrosion resistance of the coating is evaluated by the National Association of Corrosion Engineers saturated hydrogen sulfide solution immersion test. A test simulating the environment of the natural gas wells with high temperature and pressure in Luojiazhai in Sichuan is also performed. The results show that the multilayer coatings have dense structures, ∼11μm thickness, 24.5±2.0GPa nano-hardness, and ∼70N adhesion. The corrosion sample also shows no brittle failure induced by stress corrosion after treatment with the coating. Gravimetric analysis shows that the deposition of TiC/Ti(CN)/TiN multilayer coatings results in a corrosion rate reduction of at least 50 times compared with the high-strength steel substrate. A preliminary analysis on this phenomenon is conducted.