Papers by Keyword: Hydrogen Sulfide

Abstract: Concrete is a construction material that is extremely widely used in the construction of water management facilities. However, in the presence of hydrogen sulfide in the gas-air operating environment, concrete can undergo extremely aggressive biogenic sulfuric acid corrosion. The paper presents the results of an experimental chemical, physico-chemical and phase study of concrete samples from the surface part of the gravity sewage collector and the primary sump of the city sewage facilities and oil trap at the oil production site. It was proved that all concrete samples were subjected to biogenic sulfuric acid aggression, to the greatest extent – a sample from a city sewage collector.

Abstract: The ecological situation in the world requires the solution of environmental problems associated with the processes of wastewater treatment, hydrogen sulfide pollution of various industrial facilities in order to remove such harmful impurities. The unpleasant odor that appears in industrial and adjacent waste processing areas is a constant concern for the protection of the environment. To solve these problems, it is advisable to use selective sorbents - complex. The introduction of metal ions into complex fibers due to the formation of a coordinated bond between the groups of the metal and the polymer ligand gives high molecular weight complex compounds. The operational and selective properties of the materials based on high-molecular-weight complex compounds can be determined by the type of metal ion introduced into macromolecules, the nature of the polymer chain, and thermodynamic stability. By changing the action of the above factors, complexites can be synthesized for use as highly selective catalysts for various chemical processes. The paper presents data on the catalytic activity of fibers with Cu²⁺, Co²⁺, Ni²⁺ ions with complexing fibers containing carboxyl, amidoxime, hydroxamic groups, using the example of the decomposition of hydrogen peroxide and oxidation of H₂S, Na₂S. An inhibitory effect on the oxidation of fiber functional groups in the pH range 5.5 - 12.5 was revealed. The operational and selective properties of materials based on complexites can be determined by the type of metal ion introduced into the macromolecules, by the nature of the polymer chain. By changing the action of the above factors, complexites can be synthesized to be used as highly selective catalysts for various chemical processes. It was found that the catalytic activity of the complex depends on pH, the stereochemistry of the coordination centers in the fiber matrix and significantly exceeds the activity of model low-molecular-weight complex compounds.

Abstract: The durability of concrete, the material which is widely used for water facilities depends on accumulation in operational environments (drain water, air-gas space) of hydrogen sulfide. Now the mechanism of corrosion destruction of concrete in drainage pipelines is represented as result of biogenous sulphuric acid aggression – influence of the sulphuric acid formed by thionic bacteria. The analysis of data on H₂S concentration in drain waters of various industrial enterprises demonstrates that they create in gaseous operational media H₂S concentration, sufficient for development in aerobic conditions of thionic bacteria. As the results of urban sewer networks inspection have shown, the correlation between concentration of H₂S in aqueous phase and its concentration in air environment, between concentration of H₂S in air environment and the corrosion rate of concrete’s coffering part is observed. Chemical and X-ray crystallography of this concrete showed that in corrosive concrete decreases pH, reaching in some examples of values 1-2, and sulfates collect. In dynamics of corrosion process the exponential growth of concentration in concrete of extremely acidophilic thionic bacteria is noted.

Abstract: Electrical appliances have been suspected to contribute harmful pollutants to the atmosphere hence reducing the quality of outdoor ambient air, this suspicion has given rise to environmentalists carrying out research to determine whether these appliances are pollutant free or not. In the course of this research, carbon monoxide and hydrogen sulfide emissions were assessed from the outdoor part of window air-conditioners. Eight window air-conditioners of four prominent brands labeled as A1, A2, A3 and A4 were identified. The air from the outdoor part of the window air-conditioner was monitored for one hour with readings taken at two minutes intervals using the MSA Altair Xcell 5X Gas Sensor. Raw data of results were obtained for the eight window air-conditioners and they were analysed to obtain the daily, weekly, monthly and yearly contributions of carbon monoxide and hydrogen sulfide to the atmosphere. The yearly contributions of carbon monoxide for each brand was 15360.00 ppm for A1, 15360.00 ppm for A2, 7680.00 ppm for A3 and 5760.00 ppm for A4 while the hydrogen sulfide contributions for each of the brands was 3840.00 ppm for A1, 1920.00 ppm for A2, 0.00 ppm for A3 and 0.00 ppm for A4. From the results obtained, A1window air conditioner had the highest contribution to both carbon monoxide and hydrogen sulfide concentrations in the atmosphere.

Abstract: The goal of this study is to investigate the efficacy of potassium permanganate (KMnO₄) confined in porous carbon for hydrogen sulfide removal. As porous support, carbon was prepared by carbonization process of abundantly biomass source of palm kernel shell (named KATKS). The surface of porous carbon was first modified using hydrogen peroxide oxidation. The confinement process was carried out by an impregnation process. The KMnO₄ contents in porous carbon were varied i.e. 5%, 10%, and 20% w/w (KMnO₄-%/KATKS-Ox). Materials were characterized by N₂-sorption analysis and SEM-EDX. The results showed that KATKS possesses a high specific surface area of ca. 700 m²/g. Due to the impregnation of KMnO₄, the specific surface area of KMnO₄-%/KATKS-Ox decreased to ca. 450 m²/g. SEM-EDX revealed a successful confinement process in which elements of K, Mn, and O were displayed and dispersed on the carbon surface. In the hydrogen sulfide (H₂S) oxidation testing, KMnO₄-20%/KATKS-Ox showed the highest performance of H₂S removal compared to other materials due to the high amount of KMnO₄. KMnO₄-20%/KATKS-Ox could reduce until 98.7% of H₂S. This is remarkably higher than only using bulk KMnO₄ (without confinement) which showed activity of ca. 70% reduction.

Abstract: The purpose of this study was to absorb the hydrogen sulfide (H₂S) produced by biogas system for local community six absorbents, namely activated carbon, shredded rusty iron and iron oxide-based clay with 4 different size distributions that were tested by employing Completely Randomized Design (CRD). The results showed that iron oxide-based clay from a groundwater supply with smallest size (8.73 mm in diameter) was the most effective absorbent in removing the H₂S judging by security level of biogas users and security level of the engine of 368 and 406 minutes, respectively. However, the security level of the engine of the smallest iron oxide was not significantly different from that of medium size (12 mm in diameter) in 325 minutes. For the durability of absorbent determined from H₂S was less than 500 ppm, the iron oxide with the smallest size was also effective with the best removal (506 minutes) but was not significantly different from those of the medium size (491 minutes) and the mixed size (435 minutes). Therefore, the smallest iron oxide-based clay was selected for the technology transfer to rubber tree farmers and fishermen in the south of Thailand.

Abstract: This research work is focuses on understanding the characteristics of modified nitrogen-enriched palm shell activated carbon (N-PSAC) that undergo different microwave (MW) operating parameters towards efficient H₂S removal. The nitrogen functional groups were tailored onto PSAC micropore structures through impregnation of urea onto palm shell activated carbon (PSAC). The effect of MW heating variables (heating temperature, N₂ flow rate, heating time and amount of adsorbent) on N-PSAC adsorbent was investigated and analyzed with respect to H₂S adsorption capacity.One factor at a time (OFAT) approach was used to produce an efficient N-PSAC adsorbent, where theH₂S breakthrough capacity (measured at 5% of H₂S outlet concentration) attained was in the range of 98.71 – 211.35 mg/g.It was found that MW heating variables contribute a significant impactto the modification of N-PSAC adsorbent in catering the H₂S emission.

Abstract: In this article we have used new anticorrosion investigating techniques and studied new polarization resistance aspects of anticorrosion mechanism of cucurbit [n] urils and thioglycolurils based inhibitors in aggressive acid and alkaline containing chloride mediums. Results suggest that the active complex of inhibitor with iron is non-soluble and stable in aggressive mediums.

Abstract: Biogas derived from anaerobic digestion of biological wastes has been extensively used for heating purposes and/or electricity generation. Presence of hydrogen sulfide (H₂S) in biogas affects engine performance adversely, thus reducing H₂S content is a valuable part in practical application before utilizing biogas. Adsorptive separation is very appealing due to being an economical and effective method including the use of iron oxide based adsorbents. Pelletization of iron oxide adsorbents has never been reported among the adsorbents described to date. Therefore, H₂S capture in two iron oxides (ferric oxide (Fe₂O₃) and magnetite (Fe₃O₄)) was experimentally investigated to determine technical feasibility of shaping pellets based on active iron oxide sorbent in removing H₂S from a simulated gas stream (0.35 vol.% H₂S balanced in N₂). Many factors affecting the behavior of gas adsorption such as gas in-flow rate, adsorption temperature, binder loadings and textural characteristics were considered. The pellet strengths were also undertaken using a bulk crushing strength analyzer. The results indicated that higher temperature favors the diffusion of H₂S molecules from the surface into the bulk of iron oxides. The H₂S-sorption capacity of Fe₃O₄ sorbent was higher than that of Fe₂O₃ sorbent corresponding with the different pore volume and surface area in each adsorbent. With the same active Fe₃O₄, the extruded pellet produced with starch binder showed the excellent H₂S uptake and crushing resistance. The higher gas in-flow rate had positive impact to contacting efficiency and mass transfer of solid and gas phase. The adsorbed H₂S gas can be readily desorbed from the pellets with the desorption temperature below 60°C and the H₂S-sorption capacity was consistent over repeated cycles. The pellets can be reused several times for consecutive adsorption/desorption cycles, without loss of performance in a large-scale reactor and therefore represent serious candidates for use in commercial absorbers.

Abstract: Biogas typically refers to a mixture of primarily flammable gases produced from organic matters by means of anaerobic fermentation. Since the abundance and renewability of biomasses, biogas deserves the potential of being as an alternative to fossil energy. However, biogas may contain hydrogen sulfide which will damage the facilities, hazardous to the environment and to living beings. The objective of this study is to develop a water scrubbing system to remove hydrogen sulfide from biogas. The efficiency of hydrogen sulfide scrubbing is assured by injecting biogas into circulating water through a diffuser. The diffuser makes the passing biogas into numerous bubbles. The study carried out on combinations of various water circulation flow rates and biogas volumetric flow rates. Experimental results showed that the performance of hydrogen sulfide removal decreases as a result of increasing scrubbing time. The removal efficiency could be maintained at 47.7% with adequate additional fresh water of 10 ℓ /min. The system requires only simple operation and is cost effective and hence it is suitable for small-scale pig farms in waste processing.