Papers by Keyword: Hydrogen Sulfide

Abstract: This contribution revisits recent results regarding the selective detection of the trace gases hydrogen sulfide, nitrogen oxide, and nitrogen dioxide using cupric oxide (CuO). It demonstrates how the variation of the surface temperature may be used to learn about basic material parameters as well as control the surface reactions. In contrast to commonly employed modulation schemes that continuously vary the temperature we use a steady-state approach in order to extract information about gas matrices. Our results highlight the potential for incorporating laboratory results regarding surface processes in pattern recognition schemes to improve the performance of these algorithms. We propose to implement the findings into temperature modulation schemes in order to allow for adding highly gas specific elements to the algorithms deployed.

Abstract: This research introduces method of processing zinc obtained from waste of used zinc-carbon battery to be used as biogas desulfurizer. The zinc is processed by using Natrium Chloride (NaCl) . The zinc-carbon battery consist of carbon rod as positive terminal and zinc case container as negative terminal. The electrolyte is ammonium chloride mixed with carbon powder. In the Waste of used zinc carbon battery, the zinc case is found still remind and have a potential to be used as desulfurizer. The zinc was taken out from the used battery and chopped to become small piece. About 100 gram of chopped zinc was immersed in various concentration of NaCl (25 gr/l, 50 gr/l, 75 gr/l, and 100 gr/l) at 70°C for 4 hours. The bubble of air introduce in to the solution. The zinc then was taken out from the solution, drying and compacted as a billet with diameter 5 cm and thickness about 2 cm. The billet was installed inside the pipe and 50 liter biogas with flow rate 3 liter/minute is let flown in to the desulfurizer. The Hydrogen sulfide before and after pass the desulfurizer were measured. It is found that the desulfuriser in all variation of concentration of NaCl is working well to elimination H2S to zero level.

Abstract: H₂S gas would pose a threat to coal mine safety. This article from the biodegradation, microbial sulfate reduction, thermal decomposition chemistry, chemical sulfate reduction and magmatic 5 aspects to analyze the formation mechanism of hydrogen sulfide gas in coal mine, a coal mine combined with field data, analysis of hydrogen sulfide gas in the coal mining the transport mechanisms. Research for the comprehensive management of coal mine hydrogen sulfide gas has certain significance.

Abstract: Sulfur cycling based on biological oxidation of sulfide to sulfate involves sulfur-oxidizing reducing microbial communities associated with sulfide which normally oxidize sulfide in acidic environment to sulfate. The chemolithotrophic sulfur oxidizing bacteria (SOB) usually use organic and/ or inorganic sulfide initially oxidizing and subsequently released sulfate under aerobic or subaerobic condition. This study was to understand SOB community isolated from coal mine treating plant at Mae Moh, Lampang and their potentials in hydrogen sulfide (H₂S) removal. In this result, with common heterotrophic medium supplemented with glucose 10 mg/ L and sulfur 0.001%, the cultured SOB were successfully cultivated based on most probable number method. Their activity showed an increase in sulfate concentration over time correspondent to an increase in culturable SOB communities. The SOB community could also develop their own microbial niches in the present of continuously aerated H₂S in the medium at 30-40°C during 7 day incubation. They could remove H₂S between 200-500 ppm from wastewater. These sulfur oxidized H₂S contaminated in wastewater treatment facilities or drainage. Their species will be further isolated and characterized by molecular analysis.

Abstract: First principle calculation is performed to investigate structural and electronic properties of strained silicene (silicon analogue of graphene) when absorbing the hydrogen sulfide molecule gas. Two configuration of silicene-H₂S system, center and hollow configuration, is checked under 0% (pure), 5%, and 10% uniaxial engineering strain. We report that the silicene-H₂S system in center configuration has larger binding energy compare to the silicene-H₂S system in hollow configuration. The results show that H₂S is physisorbed on silicene. In this work, we also find the change of band gap energy (~60 meV) is appearing when H₂S interacted with silicene in center configuration, whereas the band gap energy of silicene has no change when interacted with H₂S in hollow configuration.

Abstract: Hydrogen sulfide is a common composition of natural gas. It is an important problem to develop suitable natural gas desulfurization technology for the present situation of China. Now, a novel process of H₂S abatement from gas streams has been investigated for chemical absorption of H₂S using a weak alkaline solution followed by the oxidation of the absorbed sulfide to elemental sulfur by naturally occurring microorganisms and alkaline solution regeneration for recycle and reuse in the process. This method is currently attracting more and more interests of researchers, because it requires little equipment, is inexpensive and produces only elemental sulfur, thus minimizing the production of pollutants. The biological oxidation process of the absorbed sulfides to elemental sulfur by Thiobacillus thioparus TYY-1 was studied in an airlift-loop reactor (effective volume=20L).Two efficiency factors including hydraulic remain time and the air aeration quantity were inspected. The air aeration quantity is key influence factor of desulfuration rate and elemental sulfur production rate. The investigation demonstrated that the optimum hydraulic remain time was 4—6h under the influent concentration of S^2- for 200 mg/L, and the best treatment effect of aeration was obtained at 120 —160L/h. With these conditions after 20 days of operation, the result showed superior performance of the bioreactor for desulfuration rate and elemental sulfur production rate, the conversion products were mainly sulfur and the production rate of SO₄^2- was low. The removal efficiency of sulfide was more than 99.5% while the maximum yield of sulfur was 88% approximately.

Abstract: Hydrogen sulfide is a typical toxic, inflammable gas. The detection of H₂S is crucial in the areas of oil, natural gas and so on. However, studies on H₂S gas sensors at room temperature were seldom reported. In this study, Quartz crystal microbalance (QCM) sensors have been utilized, and PVP film were prepared on the QCM by airbrush method with different airbrush volume for H₂S detection. The results showed that the PVP film with airbrush volume 0.2ml exhibited a better sensing response to H₂S gas. Besides, sensitive characteristics parameters, i.e. selectivity, stability, linearity and sensitivity of prepared sensors were studied for comparison. The relative sensing mechanism associated with SEM pictures was studied as well.

Abstract: Using the first principles method, which is based on the density function theory (DFT), the structures and electronic properties for different concentration of H₂S are adsorbed on the Fe (100) surface, and their molecular orbital and absorption energies were calculated with the generalized gradient approximation. The results show that, whether one or two molecules of H₂S adsorpted Fe (100) surface, adsorption of single molecules Fe (100) surface partial density of states between pure Fe (100) and two molecules, and the total density of states is mainly composed of 3d electronic contribution.

Abstract: The rapid and precise detection of hydrogen sulfide (H₂S) has great significance due to its high toxicity. In this work, the response properties of multiple-walled carbon nanotubes (MWNTs) and MWNTs-HAuCl₄ to H₂S at room temperature were compared. Scanning electron microscopy (SEM) technique was used to characterize MWNTs and MWNTs-HAuCl4 films. It was found that sensors with MWNTs-HAuCl₄ exhibited much higher response value. On the other hand, sensors with MWNTs were observed to have faster response time and better recovery properties.

Abstract: This project carries out the research on influence factors of wells producing hydrogen sulfide in connection with the actual situation of producing hydrogen sulfide in Qi-40 steam drive process. Experimental studies have shown that: A. temperature is the main external factors of produce hydrogen sulfide, It will produce hydrogen sulfide when temperature is above 100°C, hydrogen sulfide content increase about 300ppm in average when the temperature increase per 20°C; hydrogen sulfide content will be in the greatest increase when temperature at the range of 160°C~180°C; the rate of increase in the levels of hydrogen sulfide will significantly reduce when temperature above 180 °C.B. Adding Chemical agent with surface activity can inhibit the release of hydrogen sulfide. C. Adding acid chemical agent will make the content of hydrogen sulfide increase. The experimental study also investigated hydrogen sulfide prevention measures.