Removal Of Oxygen Research Articles

Effect of trace oxygen on smelter off‐gas reduction desulphurization process over FeSx/γ‐Al2O3 catalysts

AbstractEffects of trace oxygen on iron sulphides‐supported catalysts (FeSx/γ‐Al2O3) were evaluated through smelter off‐gas reduction process for sulphur synthesis. Catalytic performance was evaluated under different oxygen content conditions. The properties of fresh and used catalysts were investigated by means of X‐ray diffraction (XRD), thermogravimetry‐differential thermal analysis (TG‐DTA), X‐ray photoelectron spectroscopy (XPS), and elemental analysis and relationships of active phases and activity were analyzed. The relationship between different active crystal crystals (FeSx, FeS2, Fe, FeO, γ‐Fe2O3) and SO2/O2 adsorption and conversion was investigated. The mechanism of oxygen influence on the FeSx/γ‐Al2O3 surface was given and the lifetime of the catalyst in the reaction atmosphere close to real smelter off‐gas after dust and oxygen removal steps containing trace oxygen (0.5 O2 v/v.%) was explored.

Microcirculation: Current Perspective in Diagnostics, Imaging, and Clinical Applications

This review discusses the pivotal role of microcirculation in maintaining tissue oxygenation and waste removal and highlights its significance in various pathological conditions. It delves into the cellular mechanisms underlying hemodynamic coherence, elucidating the roles of the endothelium, glycocalyx, and erythrocytes in sustaining microcirculatory integrity. Furthermore, the review gives comprehensive information about microcirculatory changes observed in cardiac surgery, sepsis, shock, and COVID-19 disease. Through comprehensive exploration, the review underscores the intricate relationship between microcirculation, disease states, and clinical outcomes, emphasizing the importance of understanding and monitoring microvascular dynamics in critical care settings.

Production of improved quality steel in highscale basic oxygen furnaces using vacuum treatment

The article presents the results of the converter steel technology development using ladle treatment including portion vacuum degassing at vessel UPVS-350 and pouring at continuous casting machine. In order to improve the quality of metal products, steels of grades 3sp, 08sp, 20k, 20sp, 09G2S, 10G2S1D, 09G2S, 08GT, 17G1SU, 17G1S, 17GS, 10HSND, 15HSND, E36, pipe steels of type 09G2FB were treated by vacuum. Steel was smelted in basic oxygen furnaces with a capacity of 350 ton using technical pure oxygen (99,2–99,5% О2). The article shows that with a UPVS-350 vacuum chamber dilution to133 Pa (1 mm Hg), a metal portion weight of 20–40 tons, the number of vacuum ing cycles less than 25 and a circulation coefficient from 2 to 5, a degree of oxygen removal of up to 40%and hydrogen up to 50% can be achieved. There is an improvement in the pouring ability of vacuum treated steel, a decrease in the axial discontinuity (stratification)at the central part of the slabs from 3 to 2–2.5 grades, decrease of the nonmetallic inclusions content in the billets by 0,2–2,3 grade and their distribution in the volume of metal is more uniform. When exhaustion in a vacuum chamber reach of 1–2 mm Hg level, the impact toughness and elongation of steel in crease. For carbon steel, the production of inappropriate quality metal according to the ultrasonic control decreased by about 3 times (from 0,39 to 0,12%), and the total degree of the rejected metal decreased from 1,06 to 0,65%. During vacuuming of 08GT steel using for chemical reactors, there is a more compact and greater uniformity of the ferrite-perlite structure with the value of the actual grain no. 7–9. The internal structure at the liquation central zone of the sheets produced of this steel is also improved

Ladder-Like Polyphenylsilsesquioxane Membranes for Dissolved Oxygen Removal in Liquid–Liquid Membrane Contactors

The main disadvantage of absorption with aqueous alkanolamine solvents is the solvent degradation under process conditions in the presence of oxygen captured from flue gases. In this communication, the direct dissolved oxygen removal from an amine solvent in liquid–liquid membrane contactors is examined. The membranes from ladder-like polyphenylsilsesquioxanes are used for the first time for this process. The membrane deoxygenation is demonstrated in the O2 removal process from monoethanolamine (MEA) into an aqueous solution of Na2SO3. In this case, the O2 removal efficiency reached up to 40% within 1 h.

Biofuel production from palm oil deoxygenation using nickel-molybdenum on zirconia catalyst using glycerol as a hydrogen donor

The growing demand for renewable energy has generated interest in biofuels as alternatives to fossil fuels. Second-generation biofuels, derived from deoxygenating fats and oils, have garnered a higher level of interest from industry and academia due to their potential for direct replacement of diesel and jet fuels. Palm oil, mostly cultivated in Thailand and composed of C16 and C18 fatty acids, is a primary feedstock sought for biofuel production. Palm oil deoxygenation contains several pathways that may or may not require hydrogen gas. This study aimed to produce biofuels in different fuel ranges, such as gasoline, jet fuel, and diesel, through palm oil deoxygenation using glycerol as a hydrogen source. Glycerol, a low-value byproduct, was used as a hydrogen donor, whereas nickel-molybdenum-supported catalysts were chosen for their high efficiency in deoxygenation and cost-effectiveness. The study investigated the impact of reaction time, temperature, and catalyst activation method on palm oil deoxygenation. Catalyst characterization methods, including XRD, SEM, TEM, XPS, FTIR, TGA, and N2-sorption, were employed to understand the role of catalysts’ activity during palm oil upgrading. Findings indicated that alkane hydrocarbons are the major components in liquid products. The presence of excess H2 in post reaction gaseous phase proves the hydrogen donation capability of glycerol. Increased reaction time and temperature facilitated the removal of oxygen from palm oil. Nickel-molybdenum on zirconia activated by sulfidation demonstrated higher stability than by reduction activation.

Deciphering the Ce3+to Ce4+Evolution: Insight from X-ray Raman Scattering Spectroscopy at Ce N4,5Edges.

Cerium oxide, or ceria, (CeO2) is one of the most studied materials for its wide range of applications in heterogeneous catalysis and energy conversion technologies. The key feature of ceria is the remarkable oxygen storage capacity linked to the switch between Ce4+ and Ce3+ states, in turn creating oxygen vacancies. Changes in the electronic structure occur with oxygen removal from the lattice. Accordingly, the two valence electrons can be accommodated by the reduction of support cations where the electrons can be localized in empty f states of Ce4+ ions nearby.Quantifying the different oxidation states in situ is crucial to understand and model the reaction mechanism. Beside the different techniques to quantify Ce3+ and Ce4+ states, we discuss the use of X-ray Raman Scattering (XRS) spectroscopy as an alternative method. In particular, we show that XRS can observe the oxidation state changes of cerium directly in the bulk of the materials under realistic environmental conditions. The Hilbert++ code is used to simulate the XRS spectra and quantify accurately the Ce3+ and Ce4+ content. These results are compared to those obtained from in situ X-ray Diffraction (XRD) collected in parallel and the differences arising from the two different probes are discussed.

Engineered tools to study endocrine dysfunction of pancreas.

Pancreas, a vital organ with intricate endocrine and exocrine functions, is central to the regulation of the body's glucose levels and digestive processes. Disruptions in its endocrine functions, primarily regulated by islets of Langerhans, can lead to debilitating diseases such as diabetes mellitus. Murine models of pancreatic dysfunction have contributed significantly to the understanding of insulitis, islet-relevant immunological responses, and the optimization of cell therapies. However, genetic differences between mice and humans have severely limited their clinical translational relevance. Recent advancements in tissue engineering and microfabrication have ushered in a new era of in vitro models that offer a promising solution. This paper reviews the state-of-the-art engineered tools designed to study endocrine dysfunction of the pancreas. Islet on a chip devices that allow precise control of various culture conditions and noninvasive readouts of functional outcomes have led to the generation of physiomimetic niches for primary and stem cell derived islets. Live pancreatic slices are a new experimental tool that could more comprehensively recapitulate the complex cellular interplay between the endocrine and exocrine parts of the pancreas. Although a powerful tool, live pancreatic slices require more complex control over their culture parameters such as local oxygenation and continuous removal of digestive enzymes and cellular waste products for maintaining experimental functionality over long term. The combination of islet-immune and slice on chip strategies can guide the path toward the next generation of pancreatic tissue modeling for better understanding and treatment of endocrine pancreatic dysfunctions.

Mechanism and kinetics of efficient removal of as from a high arsenic-bearing ZnSO4 solution using ultrasound enhanced oxygen

The traditional lime method for arsenic (As) removal from high arsenic-bearing ZnSO4 solution has disadvantages such as high cost, large amount of wet residue, significant secondary hazards, and long process flow. This study developed a new technology for efficient As removal using ultrasound enhanced oxygen. The effects of zinc roasting dust (ZRD) addition, reaction temperature, oxygen flow rate, and ultrasound power on As removal efficiency were investigated. Under the optimal conditions, the removal rate of As reached 97.90 %. The1O2, O2∙- and •OH radicals generated during the ultrasound-enhanced oxygen process significantly enhance the oxidation efficiency of As(III) and Fe2+. Ultrasound can also refine particle size and improve the removal efficiency of As. Compared with traditional lime method, the reaction time and wet residue amount have been reduced by 40 % and 70.37 %, respectively. Field emission scanning electron microscopy (FE-SEM-EDS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses indicate that As in ZnSO4 solution was primarily removed through by Fe(OH)3 colloidal adsorption and amorphous FeAsO4. Kinetic analysis revealed that the neutralization and As removal process using ZRD under ultrasound and oxygen action conforms to the internal diffusion control model. Ultrasound-enhanced oxygen As removal can reduce the reaction activation energy from 26.94 to 21.02 kJ/mol, effectively lowering the reaction barrier for As removal and demonstrating faster reaction rates under ultrasound conditions. Ultrasound-enhanced oxygen removal of As from high arsenic-bearing ZnSO4 solution provides an efficient and low-cost potential solution for enterprises.

Simultaneous preparation of high-purity Si and eutectic Si-Nd alloy utilizing Nd2O3-containing waste slag and diamond-wire sawing silicon waste

Nd2O3-containing waste slag (NCWS) and diamond-wire sawing silicon waste (DSSW) are important rare earth and Si secondary resources, respectively. Currently, NCWS and DSSW are recycled respectively by at least two different routes, which is not efficient and increases the burden on the environment. The present study proposed a novel technical route for preparing high-purity bulk Si and eutectic Si-Nd alloy simultaneously using NCWS and DSSW as raw materials, depending on the concept of using waste to treat waste. The new technical route has only two steps: initially, raw Si-Nd alloys were obtained by extracting Nd from NCWS utilizing DSSW as a low-cost reductant, and the impurity, oxygen, in the DSSW was effectively removed utilizing NCWS; the highest extraction rate of Nd from NCWS reached 68.3%, and the oxygen removal rate in DSSW was 99.89%; in the subsequent step, the obtained raw Si-Nd alloys were separated and purified to produce high-purity bulk Si (＞99.98%) and eutectic Si-Nd alloy (＞99%) through a physical and clean method-electromagnetic directional crystallization. This novel route is considered effective and environmentally-friendly for the sustainability of rare earth and Si resources, because no gas and liquid wastes discharged throughout the whole route, and two high value products can be prepared simultaneously using two wastes.

Porous transport layer influence on overpotentials in PEM water electrolysis at low anode catalyst loadings

Achieving widespread use of polymer electrolyte membrane water electrolysis (PEMWE) for clean hydrogen generation requires enhancing the efficiency and utilization of low iridium-loaded electrolyzers. Novel porous transport layer (PTL) design and engineering can play a critical role in addressing this challenge. Despite the fact that the PTL is an important component of PEM electrolyzers, it has received little attention, particularly in terms of the mechanistic understanding of the influence of PTL characteristics on overpotentials. Herein, we investigate the impact of the PTL porosity, thickness, and structure on the PEM water electrolyzer performance. We demonstrate that improving the contact between PTL and the catalyst layer by inserting a microporous layer facilitates electron transfer and oxygen removal leading to reduced cell voltage. We observe that this strategy proves particularly effective at low catalyst loadings.

Activation of NO with microwave irradiation for low temperature direct decomposition

Direct decomposition of nitric oxide (NO) on metal oxides under microwave (MW) irradiation was investigated and it was found that the most metal oxides show higher NO decomposition activity than that in the conventional electric furnace heating at low temperature. Among the examined oxides, it was found that TiO2, CeO2, ZrO2, and Y2O3 show about 95 % or higher NO conversion at 573 K, and both N2 and O2 are formed with almost equimolar amount. In particular, ZrO2 exhibited high and stable NO decomposition activity more than 25 h. In this study, the influence of coexisting gases on NO decomposition activity on ZrO2 under microwave heating was further investigated and the direct decomposition of NO can be proceeded even in the presence of 5 % O2, 5 % CO2, or humidified condition. Mechanism of high NO decomposition activity under MW irradiation was also studied and it was found that removal of oxygen from the catalyst was much increased under MW irradiation because of direct activation of oxygen and also direct activation of NO which is also suggested by pulse reaction.

Polystyrene infused with functionalized reduced graphene oxide as a reusable oil sorbent

Adsorption has been reported to be optimal among oil spill cleanup methods due to its simplicity, low capital and operational cost, high removal efficiency and environmental friendliness. However, its continuous usage has been linked to generation of enormous waste, after oil spill cleanup, to which use of reusable oil sorbents has been proposed as a possible solution. Synthetic organic oil sorbents have high mechanical properties compared to other categories of oil sorbents, but they suffer low adsorptive capacities. To address this problem, among other nanoparticles, rGO have been infused in polymeric materials to produce composite oil sorbents characterized with high adsorptive capacities. In this research, surface modified rGO was infused in waste expanded polystyrene, to produce electrospun PS/FrGO composite sorbents by solution blending and electrospinning method. Adsorptive capacities of produced composites were evaluated in four oil samples. Functionalization of rGO was found to cause removal of residual oxygen containing functional groups such as hydroxyl (–OH), and resulted in more hydrophobic surface. Infusion of FrGO, in waste expanded polystyrene resulted into composites with increased surface area, from 71.50 m2/g for pure PS20 to 353.45 m2/g, 429.18 m2/g, 456.14 m2/g for PS20 infused with 1, 2 and 4wt% of FrGO. Increase in oil sorption capacities of the composite, observed in four oil samples corresponds to improved surface area. Produced composites show good recyclability in the four oil samples, at least up to the third sorption cycle.Graphical

Sustainable Aviation Fuel Molecules from (Hemi)Cellulose: Computational Insights into Synthesis Routes, Fuel Properties, and Process Chemistry Metrics.

Production of sustainable aviation fuels (SAFs) can significantly reduce the aviation industry's carbon footprint. Current pathways that produce SAFs in significant volumes from ethanol and fatty acids can be costly, have a relatively high carbon intensity (CI), and impose sustainability challenges. There is a need for a diversified approach to reduce costs and utilize more sustainable feedstocks effectively. Here, we map out catalytic synthesis routes to convert furanics derived from the (hemi)cellulosic biomass to alkanes and cycloalkanes using automated network generation with RING and semiempirical thermochemistry calculations. We find >100 energy-dense C8-C16 alkane and cycloalkane SAF candidates over 300 synthesis routes; the top three are 2-methyl heptane, ethyl cyclohexane, and propyl cyclohexane, although these are relatively short. The shortest, least endothermic process chemistry involves C-C coupling, oxygen removal, and hydrogen addition, with dehydracyclization of the heterocyclic oxygens in the furan ring being the most endothermic step. The global warming potential due to hydrogen use and byproduct CO2 is typically 0.7-1 kg CO2/kg SAF product; the least CO2 emitting routes entail making larger molecules with fewer ketonization, hydrogenation, and hydrodeoxygenation steps. The large number of SAF candidates highlights the rich potential of furanics as a source of SAF molecules. However, the structural dissimilarity between reactants and target products precludes pathways with fewer than six synthetic steps, thus necessitating intensified processes, integrating multiple reaction steps in multifunctional catalytic reactors.

Thermodynamic Consideration of the Direct Removal of Oxygen from Titanium by Utilizing Metallothermic Reduction of Rare Earth Metal Halides

As the demand for titanium (Ti) continues to grow, so too does the use of Ti scrap, underscoring the need for innovative techniques for the efficient removal of oxygen (O) impurities from Ti scrap. Despite the immense challenge of directly removing oxygen from Ti–O solid solutions and the current lack of industrially applicable deoxidation methods, the current work explores a groundbreaking approach to address this issue. The thermodynamic analysis of a new technique for eliminating oxygen dissolved in solid Ti was conducted, leveraging the deoxidation properties of rare earth metals (REMs) such as Sc, Y, and La. This cutting-edge method relies on the in-situ production of REMs through the metallothermic reduction of REM halides. It was shown that Sc or Y metal can be synthesized via the reduction of ScCl3 by Mg or YCl3 by Li or Na, respectively. Ti with oxygen concentrations below 100 mass ppm can be obtained by leveraging the deoxidation properties of the Sc and Y metals produced in situ during the metallothermic reduction process, which contribute to deoxidation through their subsequent oxychloride-forming reactions. Employing REM halides in tandem with Li, Na, and Mg enables the efficient removal of oxygen impurities from Ti, even though these reactive metals have only weak deoxidation properties for Ti on their own. Remarkably, the proposed technique achieves oxygen concentrations significantly lower than those obtained using Ca metal as a deoxidant. In the future, this pioneering deoxidation method could be used to reduce CO2 emissions and energy consumption during Ti production while promoting resource circulation as a key technology for Ti recycling.

Atomistic Insights Into the Surface Dynamics of Ni(111) During Reverse Water gas Shift Reaction

AbstractThe conversion of CO2‐H2 mixtures on Ni‐based catalysts can proceed through either the reverse water gas shift reaction (RWGS) path to produce CO or the CO2 methanation path to produce CH4. The balance between these competing reactions depends on both the reaction conditions and catalyst structure. In this study, using surface‐sensitive infrared and ambient pressure X‐ray photoelectron spectroscopies, we investigate the effect of reaction conditions on the interaction between CO2 and H2 on a Ni(111) model catalyst. Our findings highlight the occurrence of RWGS, involving direct dissociation of CO2 to CO and atomic oxygen, followed by oxygen reacting with hydrogen to form H2O, and CO and H2O desorption. Hydrogen affects the distribution of CO between hollow and top sites by displacing oxygen from the energetically preferred hollow sites. The overall balance between oxygen production from CO2 dissociation and oxygen removal by hydrogen governs the oxygen coverage and consequently the distribution of CO between top and hollow sites. This balance is significantly influenced by the reaction temperature and the H2/CO2 partial pressures.

Venovenous extracorporeal membrane oxygenation (VV-ECMO) for severe acute respiratory distress syndrome (ARDS) in adults—a single-center experience

BackgroundThe survival benefit of venovenous extracorporeal membrane oxygenation (VV-ECMO) in adult patients with severe acute respiratory distress syndrome (ARDS) remains controversial. This study aimed to investigate the efficiency and potential prognostic factors of VV-ECMO for severe ARDS in adults by evaluating our institutional experience and results.Materials and methodsThis research studied ARDS patients receiving VV-ECMO between June 2011 and May 2023. The inclusion criteria were PaO2/FiO2 < 100 mmHg at FiO2 of 1.0. Retrospective data was analyzed to identify factors associated with successful ECMO weaning and hospital discharge survival.ResultsA total of 18 patients were included in this study, with 7 cases (38.9%) successfully weaned from ECMO and 5 cases (27.8%) surviving hospital discharge. The overall complication rate was 77.8%. After treatment with VV ECMO, there were statistically significant improvements in both PaO2 and PaCO2 (P < 0.05). Patients in the successful weaning group had a lower pTB value, less accumulative volume of sodium bicarbonate during ECMO, and lower accumulative volume of intravenous immunoglobulin in the hospital compared to the unsuccessful weaning group (all P < 0.05). Furthermore, compared to the non-survivors, the survivors had less severe acidosis, higher mean arterial pressure before ECMO, a lower level of pCr, and a lower pTB value during ECMO (all P < 0.05).ConclusionECMO can effectively promote oxygenation and carbon dioxide (CO2) removal in patients with severe ARDS. Early initiation of ECMO with appropriate management could benefit in reducing comorbidities and mortality.

New Test Setup for On‐Site Testing of Gas Cleaning Catalysts

AbstractA new catalyst test setup on miniplant‐scale was planned and built. The setup enables the use of real process gases in the environment of a steel mill or related application and the utilization of synthetic gases with a wide range of gas compositions including trace compounds to investigate the operational limits of gas cleaning catalysts. First investigations focus on oxygen removal from real coke oven gas (COG). The concept not only addresses effects of scale and heat management but also emphasizes the use of real process gases for application‐oriented catalyst development in industrial settings.

Numerical Investigation of the Performance of a Proton Exchange Membrane Water Electrolyzer under Various Outlet Manifold Structure Conditions.

The oxygen discharge process significantly affects the electrochemical performance of a proton exchange membrane water electrolyzer (PEMWE), which requires an optimal structure of the flow field implemented in the bipolar plate (BP) component. In this study, we numerically investigated the two-phase (liquid water and oxygen) flow in the PEMWE's channel region with different outlet manifold structures utilizing the volume of fluid (VOF) model. Then, the oxygen volume fraction at the liquid/gas diffusion layer (L/GDL) surface, i.e., the interface of the channel and L/GDL, obtained by the liquid water and oxygen flow model was incorporated into a three-dimensional (3D) PEMWE model, which made it possible to predict the influence of the outlet manifold structure on the multiple transfers inside the whole electrolyzer as well as the electrochemical performance. The results indicate that the existence of oxygen in the flow field significantly decreased the electrolyzer voltage at a fixed operation current density and deteriorated the uniform distribution of the oxygen amount, current density (corresponding to the electrochemical reaction rate) and temperature in the membrane electrode assembly (MEA), indicating that the rapid oxygen removal from the flow field is preferred in the operation of the electrolyzer. Moreover, slight increases in the width of the outlet manifold were helpful in relieving the oxygen accumulation in the anode CL and, hence, improved the electrolyzer performance with more uniform distribution characteristics.

Improving the Oxygen Removal Process in a Chamber Using Computational Fluid Dynamics Simulations for Pest Control Applications

Improving the Oxygen Removal Process in a Chamber Using Computational Fluid Dynamics Simulations for Pest Control Applications

The activity of thermostable NiO/CeO2 heterointerface structure toward low-temperature catalytic CO–NO reaction

Abstract The surface grafting of NiO onto CeO2 nanocrystallites generates heterointerface structures, providing efficient active sites for CO–NO reactions toward forming N2 and CO2. In this study, we investigated the effects of high-temperature thermal aging on the activity and nanostructure of the NiO/CeO2 catalyst. After thermal aging at 900°C, the catalyst retained a high catalytic activity, whereas the reference catalysts lost theirs owing to considerable solid-state reactions and sintering. The as-prepared fresh NiO/CeO2 catalyst (calcined at 600°C) contained high dispersions of NiO species in CeO2 crystallites. Conversely, the thermally aged catalyst comprised grown NiO and CeO2 crystallites were allowed to contact intimately to form thermostable interfaces, where the perimeter in the vicinity provided the Ni2+-incorporated CeO2 surface for removing and filling the oxygen species in the catalytic cycle toward facilitating CO–NO reactions. Based on in situ Fourier-transform infrared and parallel isotopic reaction analyses, we confirmed the following as possible pathways: (i) the removal of the surface oxygen by the adsorbed CO to form an oxygen vacancy (VO), (ii) the interaction between the adsorbed NO with VO, and (iii) the N–O bond cleavage and the reaction with CO to form isocyanate, followed by the reaction with NO to produce N2.