Removal Of Hydrogen Sulfide Research Articles

Effect of glucose addition on the morphology and activity of ZnO supported on mesoporous zeolite SBA-15 for the removal of hydrogen sulfide

Zinc oxide with its high equilibrium constant for sulfidation, can be utilized to purify H2S-containing gases, but its low kinetics at room temperature limits its sulfur loading capacity. This study use glucose as an organic additive and carbon source to prepare carbon doped ZnO adsorbents with different ZnO loadings (5-20wt%) through initial wet impregnation. It was observed that the sulfur capacity of 15wt% Zn/SBA-15-G (10.9mg/g) was approximately 1.65 times higher than that of 15wt% Zn/SBA-15 (6.6mg/g). This improvement was attributed to the use of glucose, which led to better ZnO dispersion, a narrower distribution of ZnO particle size, and the formation of C-O-Zn bonds that increased the number of hydroxyl groups on the ZnO surface. DFT calculations also indicated that carbon doping could lower the activation energy of the reaction between ZnO and H2S and shorten the reaction pathway. Consequently, the prepared ZnO adsorbent demonstrated enhanced desulfurization efficiency at room temperature. Furthermore, regeneration experiments conducted on the desulfurizer after use revealed that achieving complete regeneration is a challenge.

Integration of Moving Bed Biofilm Reactor (MBBR) and algal PhotoBioReactors (aPBR) for achieving carbon neutrality in wastewater treatment

Carbon neutrality is a primary goal for wastewater treatment plants (WWTPs), as they are responsible for significant greenhouse gas (GHG) emissions as well as unpleasant odour emissions.The paper shows a new modular biotechnology that enables simultaneous treatment of gaseous emissions and biofixation of CO2.A comparative assessment of system performances in removing target pollutants (toluene, p-xylene and hydrogen sulphide) was implemented. Results showed that the highest removal efficiency (RE) was recorded for the toluene, equaling 99.9 ± 0.1 %, for an inlet load (IL) of 9.91 ± 3.44 g m−3 d−1. During the experimental tests regarding hydrogen sulphide removal, the system recorded the highest CO2 assimilation, equal to −3.03 ± 0.93 g m−3 d−1. However, this assimilation rate did not correspond to the maximum volumetric biomass productivity (MVBP), equal to 1.3 g L−1 d−1, recorded with toluene treatment, with a maximum lipid productivity (MLP) of 450 mg L−1 d−1.The results demonstrated the complete adaptability of the investigated system, which can help to fill the gaps in the current technological landscape, providing an innovative biotechnology that can be directly implemented and environmentally sustainable.

TECHNOLOGICAL SOLUTION FOR COMBATING HYDROGEN SULFIDE AT THE FIELD

One of the urgent problems in the production of hydrogen sulfide-containing oils is the problem of increasing the efficiency of hydrogen sulfide removal. Optimization of costs associated with the production, transportation and preparation of oil is very important at the present time. In order to reduce the costs of oil preparation, the use of a differentiated approach to solving the problem of its purification from hydrogen sulfide at the Kashagan field depends on the volumes of oil preparation, the mass fraction of hydrogen sulfide in the oil, the presence of gas near the high-sulfur oil preparation unit (UPVSN) that does not contain hydrogen sulfide, the presence of a gas collection system and the possibility of transporting increased volumes of hydrogen sulfide-containing gas to the sulfur purification unit. Taking these factors into account, it is necessary to identify the maximum values ​​​​of the volume fractions of methane, ethane, nitrogen and carbon dioxide in the composition of the stripping gas, at which the mass of oil will be preserved, as well as the conditions under which it will be purified from hydrogen sulfide in the conditions of the Kashagan field. Studies have shown that with an increase in the oil heating temperature and a decrease in the pressure in the desorption column, the maximum total volume fraction of methane and nitrogen in the mixture in the composition of the stripping gas decreases. A decrease in the mass fraction of hydrogen sulfide in oil below 100 ppm and maintaining the mass yield of oil depending on the proportion of these components in the composition of the stripping gas is possible if the oil temperature and pressure in the column are optimized. An increase in the total volume fraction of methane and nitrogen in the composition of the stripping gas leads to a decrease in its required consumption to achieve a certain efficiency of oil purification from hydrogen sulfide at specified operating parameters of the column.

Empirical modeling of H2S removal from biogas by chemical absorption in electrochemically prepared solutions containing iron ions

AbstractFor the energy use of biogas, it is important to remove hydrogen sulfide (H2S) as it is highly corrosive. Chemical absorption is a technology that has proven to be effective for H2S removal. Based on the principle of this technology, the objective of this research was to evaluate the removal of H2S from biogas via chemical absorption using solutions containing Iron III ions (Fe3+). These solutions were produced electrochemically based on experimental designs that had pH and electrolysis time as independent variables, as well as the solution deactivation time as a response variable. The Fe3+ ion solutions were prepared in the laboratory and subsequently used in biogas purification tests, which were carried out using biogas from a poultry slaughtering agro‐industry biodigester. The results indicated a good performance of the solutions for H2S removal when compared with distilled water. It was possible to observe that better results for the deactivation time can be found when higher pH values are used in the solutions, within the range applied in this study. The solution prepared under pH 7.4 and electrolysis time of 22.1 min provided a deactivation time 83% greater than water one. In addition, it was possible to find a significant mathematical model that describes the solution deactivation time as a function of pH.

Optimum Tuning for the High-efficiency Removal of Malodorous Gas Containing Hydrogen Sulphide Using Biological Treatment

Hydrogen sulfide, as the main pollutant causing stench, has always been one of the main problems in environmental protection. In order to promote the practical application, a pilot study was carried out in this work on the biological treatment of hydrogen sulfide malodorous gas by the combined process of biological drip filtration on the basis of our previous laboratory-scale experiments. After enlarging the reactor in pilot experiment, various factors affecting the deodorization efficiency are compared in pilot scale and laboratory scale, and the optimum pilot condition are obtained. Furthermore, the mechanism of biological deodorization is analyzed. Based on the results of the comparison between the previous laboratory-scale and the pilot-scale of this work, possible bottlenecks and challenges of biological deodorization technology from pilot to industrial application are discussed. The technical approach proposed in this work provides an economical and efficient feasible scheme for biological deodorization in the industrial practice.

CFD modeling of H2S removal from liquid sulfur in a pilot-scale gas-liquid contactor

Removal of hydrogen sulfide (H2S) from liquid sulfur is essential to product quality and safe operation in sulfur processing recovery. This paper presents computational fluid dynamics (CFD) models of sulfur degassing performance in a pilot-scale gas-liquid contactor. Two mass transfer models with and without considering the decomposition of hydrogen polysulfide (H2Sx) to H2S are established. They are then used to explore the effects of various operating parameters, including residence time, injected liquid sulfur flow rate, impeller type, and agitation speed, on degassing efficiency. Results show that the relative errors between calculation and experimental data are within ±6.2 %. Furthermore, the impeller geometry is optimized, and the efficiencies of three degasser shapes are compared using the verified CFD tool. The optimized impeller structure can increase degassing efficiency by about 9 % compared to the original one. The CFD model can be further improved to guide the design and scale-up of diverse H2S degassers.

Hydrogen sulphide removal from raw biogas using novel coconut husk and sugarcane bagasse composite biochar adsorbent

Abstract The presence of water, hydrogen sulfide (H2S), ammonia, oxygen, nitrogen, and siloxanes in biogas is not desirable for thermal and electrical applications through the engine route. H2S adversely affects engines and fuel cells by causing corrosion on metal components, poisoning catalytic converters, and accelerating wear and tear, compromising performance and longevity. To meet specific quality requirements for diverse applications such as heating, combined heat and power generation, vehicle fuel, and fuel cells, biogas must undergo cleaning and upgrading processes. Using biochar to remove H2S in biogas is a comparatively new technique and can be a promising option for small-scale, decentralized units. Current research primarily investigates the potential of biochar derived from coconut husk (CH) and sugarcane bagasse (SB) for effectively removing H2S from raw biogas within an experimental framework. The selection of a composite material consisting of equal parts CH and SB was based on available literature and material accessibility. The integrated methodology provided comprehensive insights into the performance of biochars in biogas purification. Morphological analysis elucidated the role of pore structure in facilitating H2S removal, while CHNS analysis highlighted the influence of elemental composition on biochar reactivity. Additionally, pH studies underscored the potential for biochar application to mitigate biogas acidity. According to the findings, the biochar from the combination of CH and SB exhibited a removal efficiency of 77.60% for H2S in raw biogas.

Research on hydrogen sulfide removal from water using a hydroejector

The war in Ukraine has significantly impacted the country's water resources, leading to deteriorated water quality, threats to drinking water supplies, and long-term environmental issues. Intensive pollution of surface water sources has necessitated increased use of groundwater for drinking purposes. The quality of groundwater in Ukraine varies greatly, often containing concentrations of iron, manganese, hardness salts, and hydrogen sulfide that exceed acceptable limits. Hydrogen sulfide concentrations in different regions range from 1 to over 20 mg/dm³, far exceeding the permissible limit of 0.05 mg/dm³ for drinking water. In the southern regions of Ukraine, such as Kherson, Mykolaiv, and Odesa oblasts, hydrogen sulfide levels exceed the norm by more than 100 times. Existing water purification methods for hydrogen sulfide require the construction of expensive aeration facilities with various loadings, biological reactors, and oxidation filters, which entail significant capital and operational costs. Moreover, these facilities do not always ensure the desired water quality. Therefore, developing new methods and technologies aimed at intensifying hydrogen sulfide removal from water, along with various devices and structures for their implementation, is a pressing issue related to supplying the population with quality water. Among the developed approaches, the use of aeration as an independent method for purification is notable; however, it is used for low hydrogen sulfide concentrations and is most effective at low water pH levels. This article presents the results of experimental studies on the purification of groundwater from hydrogen sulfide by aeration using a hydroejector. Optimal parameters for the hydrogen sulfide removal process, depending on its concentration and water pH, were determined. The effectiveness of water purification using the hydroejector was substantiated and investigated. The key operational parameters of the hydroejector were established.

Removal of Carbon Dioxide and Hydrogen Sulfide from Natural Gas Using a Hybrid Solvent of Monoethanolamine and N-Methyl 2-Pyrrolidone.

The main goal of traditional methods for sweetening natural gas (NG) is to remove hydrogen sulfide (H2S) and significantly lower carbon dioxide (CO2). However, when NG processes are integrated into the carbon capture and storage (CCS) framework, there is potential for synergy between these two technologies. A steady-state model utilizing a hybrid solvent consisting of N-methyl-2-pyrrolidone (NMP) and monoethanolamine (MEA) has been developed to successfully anticipate the CO2 and H2S capture process from NG. The model was tested against important variables affecting process performance. This article specifically explores the impact of operational parameters such as lean amine temperature, absorber pressure, and amine flow rate on the concentrations of CO2 and H2S in the sweet gas and reboiler duty. The result shows that hybrid solvents (MEA + NMP) perform better in removing acid gases and reducing reboiler duty than conventional chemical solvent MEA. The primary purpose is to meet product requirements while consuming the least energy possible, which is in line with any process plant's efficiency goals.

Co-Hydrothermal Carbonization of Sewage Sludge and Waste Pickling Acid to Produce a Novel Adsorbent for Hydrogen Sulfide Removal From Biogas

Co-Hydrothermal Carbonization of Sewage Sludge and Waste Pickling Acid to Produce a Novel Adsorbent for Hydrogen Sulfide Removal From Biogas

Influence of oxidation–reduction potential and pH on polysulfide concentrations and chain lengths in the biological desulfurization process under haloalkaline conditions

Biological desulfurization under haloalkaline conditions has been applied worldwide to remove hydrogen sulfide (H2S) from sour gas steams. The process relies on sulfide-oxidizing bacteria (SOB) to oxidize H2S to elemental sulfur (S8), which can then be recovered and reused. Recently, a dual-reactor biological desulfurization system was implemented where an anaerobic (sulfidic) bioreactor was incorporated as an addition to a micro-oxic bioreactor, allowing for higher S8 selectivity by limiting by-product formation. The highly sulfidic bioreactor environment enabled the SOB to remove (poly)sulfides (Sx2−) in the absence of oxygen, with Sx2− speculated as a main substrate in the removal pathway, thus making it vital to understand its role in the process. The SOB are influenced by the oxidation–reduction potential (ORP) set-point of the micro-oxic bioreactor as it is used to control the product of oxidation (S8 vs. SO42−), while the uptake of Sx2− by SOB has been qualitatively linked to pH. Therefore, to quantify these effects, this work determined the concentration and speciation of Sx2− in the biological desulfurization process under various pH values and ORP set-points. The total Sx2− concentrations in the sulfidic zone increased at elevated pH (8.9) compared to low pH (< 8.0), with on average 3.3 ± 1.0 mM-S more Sx2−. Chain lengths varied, with S72− only doubling in concentration while S52− increased 9 fold, which is in contrast with observations from abiotic systems. Changes to the ORP set-point of the micro-oxic reactor did not produce substantial changes in Sx2− concentration in the sulfidic zone. This illustrates that the reduction degree of the SOB in the micro-oxic bioreactor does not enhance their ability to interact with Sx2− in the sulfidic bioreactor. This increased understanding of how both pH and ORP affect changes in Sx2− concentration and chain length can lead to improved efficiency and design of the dual-reactor biological desulfurization process.

Enhancing hydrogen sulphide removal efficiency: A DFT study on selected functionalized graphene-based materials

In response to the escalating demand for cleaner energy sources, this study investigates the potential of carefully selected functionalized graphene-based materials for enhancing hydrogen sulphide (H2S) removal in fuel streams, utilizing semi-empirical and density functional theory (DFT) calculations for molecular-level insights. A particular focus is placed on aliphatic methyl (-CH), alcohol (-COH), carboxylate (-COO), carbonyl (-CO), and acid (-COOH) -functionalized graphene, aiming to bridge gaps between desulphurization methods and graphene applications, specifically targeting H2S removal. Through extensive computational analyses, the research unravels the intricate interactions between chosen functionalized graphene materials and sulfur compounds like H2S, emphasizing mechanisms contributing to improved desulphurization efficiency. Our study's analysis highlights the superior performance of carboxylate (-COO)-functionalized graphene, mainly through dissociative adsorption mechanisms. The study systematically evaluates the influence of selected functional groups on adsorption activity, emphasizing the significance of dissociation. Overall, this research advances desulphurization strategies and underscores the potential of functionalized graphene in sustainable energy solutions.

Performance assessment of activated carbon thermally modified with iron in the desulfurization of biogas in a static batch system supported by headspace gas chromatography

A static batch arrangement composed of anti-leak vials coupled to gas chromatography is proposed as a complementary system for performance assessment of biogas desulfurization by adsorption. For testing, a modified commercial activated carbon produced by controlled thermal treatment in the presence of iron(III) species improved biogas desulfurization. The adsorbents showed a superior hydrogen sulfide removal compared to ordinary one. Pseudo-first-order, pseudo-second-order, and Bangham’s kinetic models were used to fit experimental data. All studied samples followed pseudo-first-order model, indicating the predominance of physisorption, and Bangham’s model, confirming that the micropores structure played an important role for gases diffusion and adsorbent capacity. Additionally, the materials were characterized by N2 adsorption–desorption, X-ray diffraction, infrared spectroscopy, scanning electron microscopy and energy-dispersive spectroscopy. The thermal treatment associated with iron impregnation caused significant modifications in the surface of the materials, and the iron species showed two main benefits: an expressive increase in the specific area and the formation of specific adsorption sites for hydrogen sulfide removal. The results reinforce the advantages of iron-modified adsorbents in relation to their non-modified counterparts. The analytical methodology based on the confinement of multiple gases contributes to improving the understanding of the hydrogen sulfide adsorption process using pressure swing adsorption technology.Graphical

Simultaneous absorption of H2S, MM and COS into a novel SRSG absorbent using a rotating packed bed

In industries, many gases are required to remove hydrogen sulfide (H2S) and organic sulfur. However, it is still a huge challenge to achieve the efficient and simultaneous removal using a single process. Herein, a novel simultaneous removal sulfide gas (SRSG) absorbent is developed to simultaneously absorb H2S, methyl mercaptan (MM) and carbonyl sulfide (COS). The absorption mechanism between the SRSG absorbent and H2S, MM, COS is explored by quantum chemistry calculations (QCC) and controlled experiments in a rotating packed bed (RPB). Results indicate that the interaction between SRSG and H2S, MM belongs to physical absorption while COS absorption in SRSG obeys two molecule reaction mechanism. Furthermore, the effect of different operating conditions, including rotating speed (N), liquid flow rate (L), gas–liquid ratio (G/L) and temperature (T), on the absorption efficiencies (η) and gas volumetric mass transfer coefficient (KGa) of H2S, MM and COS is systematically investigated. It can be found that both η and KGa are dependent on those operating conditions. The optimal η value for H2S, MM and COS is up to 99.99%, 100%, 100%, respectively. Moreover, nondimensional equations for Sherwood number (Sh) are established, and the calculated and experimental values of Sh(H2S), Sh(MM) and Sh(COS) are in agreement with a deviation within ±13%, ±13%, and ±20%, respectively. These results will provide a valuable potential technique for simultaneously removing acidic gas components from industrial gases.

Preparation and stability of zinc‐based mesoporous sorbent modified with aluminium for high temperature coal gas desulphurization

AbstractZinc‐based sorbents with ordered mesoporous structure were modified with aluminium and the key factors in the preparation were optimized based on the results of desulphurization tests performed in a fixed‐bed reactor with simulated coal gas. It was shown that the sorbents for hydrogen sulphide removal reached an optimum sulphur capacity of 9.14% when prepared under conditions of 10.0 crystalline pH, 30:1 Si:Al molar ratio, 0.32:1 Zn:Si molar ratio, and 1:3 Zn:TAA molar ratio. The sorbent without aluminium was synthesized synchronously as a comparison sample to investigate the effect of aluminium addition on the desulphurization properties. The surface acidity of the sorbents is enhanced by the addition of aluminium, and the sulphur capacity of the aluminium‐doped sorbent is consequently lower compared to that of aluminium‐free sorbent. Nevertheless, the aluminium‐doped sorbent shows a significant advantage in stability of performance over multiple desulphurization–regeneration cycles and reaches an 81% retention rate of sulphur capacity after five desulphurization, while the aluminium‐free sorbent is only 51% in contrast. The characterization results manifest that aluminium enters the carrier skeleton and increases the wall thickness, which alleviates the collapse of the carrier pore channels and the agglomeration of the active components during the desulphurization process. Stable pore structures and highly dispersed active components facilitate the mass transfer in the reaction process after multiple desulphurization. As a result, the aluminium‐doped sorbent exhibits better performance stability in high temperature coal gas desulphurization.

Titanium dioxide–supported mercury photocatalysts for oxidative removal of hydrogen sulfide from the air using a portable air purification unit

Photocatalytic removal of gaseous hydrogen sulfide (H2S) has been studied through the control of key process variables using a prototype air purifier (AP) fabricated with titanium dioxide (TiO2)-supported mercury. The performance of Hg/TiO2 systems, prepared with different Hg mass proportions over TiO2 (such as 0.1%, 1%, 2%, and 5%), is measured against 5 ppm H2S at 160 L min-1 under UV irradiation. Accordingly, their removal efficiency (RE) values after 360 s are 40.3%, 74.8%, 99.3%, and 99.9%, respectively (relative to 33.5% of AP (TiO2)). An AP with a 2% Hg/TiO2 unit achieves a clean air delivery rate of 32 L min-1 with kinetic reaction rate (r (at 10% RE)) of 0.774 mmol h-1 g-1, quantum yield of 2.19E-02 molecules photon-1, and space-time yield of 1.46E-04 molecules photon-1 mg-1. The superior photocatalytic performance of Hg/TiO2 is supported by superoxide anion and hydroxyl radicals formed in dry air and humid nitrogen (N2) environments, respectively. A density functional theory simulation suggests that the presence of oxygen vacancies should promote the disparities in the electronic structure to subsequently affect the reaction pathways and energetics. The presence of moisture enhances the robust formation of a mercury-OH bond to favorably yield β-mercury sulfide from H2S.

Hydrogen sulfide removal from biogas using biomass-derived naturally alkaline biochars: performance analysis and kinetics

Hydrogen sulfide removal from biogas using biomass-derived naturally alkaline biochars: performance analysis and kinetics

Sequential hydrotalcite precipitation, microbial sulfate reduction and in situ hydrogen sulfide removal for neutral mine drainage treatment

This study proposed and examined a new process flowsheet for treating neutral mine drainage (NMD) from an open-pit gold mine. The process consisted of three sequential stages: (1) in situ hydrotalcite (HT) precipitation; (2) low-cost carbon substrate driven microbial sulfate reduction; and (3) ferrosol reactive barrier for removing biogenic dissolved hydrogen sulfide (H2S). For concept validation, laboratory-scale columns were established and operated for a 140-days period with key process performance parameters regularly measured. At the end, solids recovered from various depths of the ferrosol column were analysed for elemental composition and mineral phases. Prokaryotic microbial communities in various process locations were characterised using 16S rRNA gene sequencing. Results showed that the Stage 1 HT-treatment substantially removed a range of elements (As, B, Ba, Ca, F, Zn, Si, and U) in the NMD, but not nitrate or sulfate. The Stage 2 sulfate reducing bioreactor (SRB) packed with 70 % (v/v) Eucalyptus woodchip, 1 % (w/v) ground (<1 mm) dried Typha biomass, and 10 % (w/v) NMD-pond sediment facilitated complete nitrate removal and stable sulfate removal of ca. 50 % (50 g-SO4 m−3 d−1), with an average H2S generation rate of 10 g-H2S m−3d−1. The H2S-removal performance of the Stage 3 ferrosol column was compared with a synthetic amorphous Fe-oxyhydroxide-amended sand control column. Although both columns facilitated excellent (95–100 %) H2S removal, the control column only enabled a further ca. 10 % sulfate reduction, giving an overall sulfate removal of 56 %. In contrast, the ferrosol enabled an extra 99.9 % sulfate reduction in the SRB effluent, leading to a near complete sulfate removal. Overall, the process successfully eliminated a range of metal/metalloid contaminants, nitrate, sulfate (2500 mg-SO4 L−1 in the NMD to <10 mg-SO4 L−1 in the final effluent) and H2S (>95 % removal). Further optimisation is required to minimise release of ferrous iron from the ferrosol barrier into the final effluent.

Zinc Oxide Nanoclusters Encapsulated in MFI Zeolite as a Highly Stable Adsorbent for the Ultradeep Removal of Hydrogen Sulfide.

Often, trace impurities in a feed stream will cause failures in industrial applications. The efficient removal of such a trace impurity from industrial steams, however, is a daunting challenge due to the extremely small driving force for mass transfer. The issue lies in an activity-stability dilemma, that is, an ultrafine adsorbent that offers a high exposure of active sites is favorable for capturing species of a low concentration, but free-standing adsorptive species are susceptible to rapidly aggregating in working conditions, thus losing their intrinsic high activity. Confining ultrafine adsorbents in a porous matrix is a feasible solution to address this activity-stability dilemma. We herein demonstrate a proof of concept by encapsulating ZnO nanoclusters into a pure-silica MFI zeolite (ZnO@silicalite-1) for the ultradeep removal of H2S, a critical need in the purification of hydrogen for fuel cells. The Zn species and their interaction with silicalite-1 were thoroughly investigated by a collection of characterization techniques such as HADDF-STEM, UV-visible spectroscopy, DRIFTS, and 1H MAS NMR. The results show that the zeolite offers rich silanol defects, which enable the guest nanoclusters to be highly dispersed and anchored in the silicious matrix. The nanoclusters are present in two forms, Zn(OH)+ and ZnO, depending on the varying degrees of interaction with the silanol defects. The ultrafine nanoclusters exhibit an excellent desulfurization performance in terms of the adsorption rate and utilization. Furthermore, the ZnO@silicalite-1 adsorbents are remarkably stable against sintering at high temperatures, thus maintaining a high activity in multiple adsorption-regeneration cycles. The results demonstrate that the encapsulation of active metal oxide species into zeolite is a promising strategy to develop fast responsive and highly stable adsorbents for the ultradeep removal of trace impurities.

From microbial heterogeneity to evolutionary insights: A strain-resolved metagenomic study of H2S-induced changes in anaerobic biofilms

The hidden layers of genomic diversity in microbiota of biotechnological interest have been only partially explored and a deeper investigation that overcome species level resolution is needed. CO2-fixating microbiota are prone to such evaluation as case study. A lab-scale trickle-bed reactor was employed to successfully achieve simultaneous biomethanation and desulfurization on artificial biogas and sulfur-rich biogas, and oxygen supplementation was also implemented. Under microaerophilic conditions, hydrogen sulfide removal efficiency of 81% and methane content of 95% were achieved. Methanobacterium sp. DTU45 emerged as predominant, and its metabolic function was tied to community-wide dynamics in sulfur catabolism. Genomic evolution was investigated in Gammaproteobacteria sp. DTU53, identified as the main contributor to microaerophilic desulfurization. Positive selection of variants in the hydrogen sulfide oxidation pathway was discovered and amino acid variants were localized on the sulfide entrance channel for sulfide:quinone oxidoreductase. Upon oxygen supplementation strain selection was the primary mechanism driving microbial adaptation, rather than a shift in species dominance. Selective pressure determined the emergence of new strains for example on Gammaproteobacteria sp. DTU53, providing in depth evidence of functional redundancy within the microbiome.