Carbon Monoxide Production Research Articles

Hybrid Copper Macrocycle/Nickel-Nitrogen Doped Graphite for Aqueous Electrochemical Carbon Dioxide Reduction

Increasing levels of carbon dioxide in the atmosphere has led to adverse effects on the environment due to climate change. These negative effects have stimulated efforts to develop ways to capture carbon dioxide. The issue is what to do with it when it is captured since its current uses are limited. Therefore, identifying catalysts that can reduce carbon dioxide into useful chemicals is a potential solution to this impending problem. Using electrocatalysis could be even more advantageous as it could allow for the use of renewable energy to directly fix carbon. Depending on the final use of the reduced products, whether as fuels or materials, the net effect on carbon dioxide in the atmosphere would be neutral or negative respectively.Combining catalysts that can work together to help make carbon dioxide electrolysis products is the strategy employed in this work. A variety of metal/nitrogen-doped graphite electrocatalysts were screened for their activity for carbon dioxide reduction. These carbon-based metal/nitrogen catalysts primarily produce carbon monoxide from carbon dioxide. For this reason, several different metallized porphyrins and phthalocyanines were tested for their ability to reduce carbon monoxide, as they can be easily attached to the graphitic catalysts. Copper phthalocyanine has been shown to be an effective catalyst for both carbon monoxide and carbon dioxide reduction. Nickel/nitrogen doped graphite when used with copper phthalocyanines has shown promise as a way of increasing the relative amount of two carbon products. So far combining the two catalysts has been shown to increase the amount of ethylene relative to the amount of methane by a factor of six, compared to using the copper phthalocyanine by itself.

High-performance CoII-phthalocyanine-based polymer for practical heterogeneous electrochemical reduction of carbon dioxide

A new bithiophenyl-substituted CoII-phthalocyanine is synthesized and electropolymerized to obtain corresponding polymer films on an indium tin oxide-coated glass and a carbon paper. Formation of the target polymer on substrates is confirmed by Ultraviolet–visible spectrophotometry, Raman spectroscopy and attenuated total reflection-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy analysis, scanning electron microscopy and energy dispersive X-ray spectroscopy. Heterogeneous electrochemical reduction of carbon dioxide (CO2) in a 0.5 M KHCO3 aqueous solution under catalysis of the target polymer coated on the carbon paper gives carbon monoxide (CO) as a major product. Controlled potential electrolysis at a constant potential of –0.66 V vs. reversible hydrogen electrode, corresponding an overpotential of –0.54 V from thermodynamic potential for CO production, for 2 h leads to optimum yield of CO with Faradaic efficiency (FE), turnover number (TON) and turnover frequency (TOF) of 94%, 2.10 × 103 and 0.29 s–1, respectively. Upon 20-h electrolysis with quantitative product monitoring, the target polymer appears to be stable throughout the process and continuously produces CO with the FE, TON and TOF of 72%, 1.24 × 104 and 0.17 s–1, respectively. Spectroelectrochemical study suggests metal-centered mechanism via formation of active reduced species having significant interaction of CoI with CO2. This research demonstrates the use of the synthetically practical CoII-phthalocyanine-based polymeric material as an efficient and stable electrocatalyst for the CO2 reduction.

Synthesis of a copper hydroxystannate modified graphene oxide nanohybrid and its high performance in flexible polyvinyl chloride with simultaneously improved flame retardancy, smoke suppression and mechanical properties

A copper hydroxystannate (CHS) modified graphene oxide (GO) nanohybrid (CGO) was synthesized through one step in-situ technique, and characterized by transmission electronic microscopy, energy dispersive X-ray spectrometry, X-ray diffractometer, etc. Flexible polyvinyl chloride (FPVC) containing CGO demonstrates remarkable mechanical, thermal and flame retardant properties. FPVC with 2 wt% CGO (sample FPVC/2CGO) achieves V0 rating in the UL-94 test with a limiting oxygen index of 26.5%. The cone calorimeter test results exhibit that the peak heat release rate, total smoke release, carbon monoxide production rate and carbon dioxide production rate of sample FPVC/2CGO were reduced by 44.5%, 20.4%, 29.6% and 45.3%, respectively in comparison with the ones of pure FPVC. Moreover, the tensile strength and the elongation at break of sample FPVC/2CGO are higher than the ones of pure FPVC.

Reaction Mechanism of In-situ Carbon in Hematite Ore Pellet during Induration

ABSTRACT Carbon is used in the hematite ore pellet as a partial heat source for induration. Apart from this, it has several other roles in the pellet. To achieve the maximum benefit of carbon in pellet quality improvement and energy reduction, a detailed study on the mechanism of C reaction in hematite pellets is required. Although some investigators have reported improvement in pellet properties on using carbon, its detailed analysis is still lacking. For this, the study on the reaction mechanism during induration is essential, which has not been done so far. To alleviate the above knowledge gap, the reaction mechanism of in-situ carbon has been studied through thermodynamic analysis and experimentation in this work. The possibility of evolving carbon monoxide and carbon dioxide during the burning of carbon at the initial stage has been analyzed from the thermodynamic study. The produced carbon monoxide gas may partially reduce the iron oxides in the pellet. This in-situ reduced iron oxide may be beneficial in the sintering of pellets. The possibility of reduction of ferric oxide in pellets followed by its re-oxidation in the final stage has been studied thermodynamically and experimentally. This study helps to understand the mechanism of in-situ carbon reaction during induration and its role in improving the quality of pellets and reducing energy consumption. It is found that the use of carbon enhances diffusion bonding in acidic pellets and both diffusion and slag bonding in basic pellets. The use of 1.5% carbon reduces the induration temperature by 50 K.

Microvascular Stasis Inhibition By Hemopexin in the Townes Mouse Model of Sickle Cell Disease

Polymerization of hemoglobin-S (HbS) in the deoxy conformation shortens the lifespan of sickle red blood cells and promotes intravascular and extravascular hemolysis. When sickle red blood cells are lysed intravascularly, HbS is released into the vascular space where it can consume nitric oxide and be oxidized to higher oxidative forms. During these reactions, ferric (Fe3+) HbS is formed, which readily releases heme. The released heme can activate the innate immune pattern recognition receptor toll-like receptor 4 (TLR4) on endothelium, leading to P-selectin expression, NF-ĸB activation, and microvascular stasis in sickle cell disease (SCD) mice with implanted dorsal skin-fold chambers (DSFCs). Heme-induced TLR4 signalling and stasis are blocked by administering hemopexin with the heme. Plasma hemopexin has the highest binding affinity for free heme, rendering it relatively nonreactive and delivering it safely to the liver for endocytosis and degradation by heme oxygenase-1 (HO-1). Due to chronic hemolysis, hemopexin levels are depleted in SCD patients and mice. We previously reported that intravenous hemopexin induces hepatic HO-1 activity and inhibits ongoing, spontaneous stasis in the venules of SCD mice for up to 48 hours. Inhibition of HO-1 activity with tin protoporphyrin (SnPP) and the administration of carbon monoxide (CO) to SnPP-treated mice demonstrated that HO-1 and its reaction product CO play important roles in the protection against stasis. In the current studies, we asked the question how much of the hemopexin-mediated protection is due to preventing heme activation of TLR4 signalling versus induction of HO-1 and CO production. We wondered if hemopexin complexed with heme would be as effective as hemopexin alone in treating a vaso-occlusive crisis (VOC) induced with hemoglobin heme. First, in a stasis prevention model, we intravenously administered different doses of hemopexin in Townes SCD mice with a DSFC one hour prior to a hemoglobin challenge. Briefly, anesthetized mice were placed on an intravital microscopy stage, and 20-24 flowing subcutaneous venules were selected and mapped. After baseline selection of flowing venules and one hour after administration of different doses of hemopexin (0 - 160 mg/kg body weight), microvascular stasis was triggered by infusing hemoglobin (1 µmol/kg). The same vessels were re-examined for stasis (no flow) and percent stasis was calculated. Our results show that hemopexin effectively reduced stasis in a dose responsive manner when delivered one hour prior to the hemoglobin challenge (Figure 1A). Second, we evaluated hemopexin in a VOC acute treatment model by infusing various doses of hemopexin 30 minutes after the intravenous hemoglobin challenge. We found a dose-dependent effect of hemopexin to reduce and resolve microvascular stasis during an acute VOC one hour after hemopexin infusion (Figure 1B). We obtained similar results after inducing stasis with lipopolysaccharide (LPS) or hypoxia-reoxygenation in place of hemoglobin challenge. Third, we evaluated equimolar hemopexin-heme complexes in a VOC acute treatment model by infusing the same doses of hemopexin-heme 40 minutes after the intravenous hemoglobin challenge (1 µmol/kg) to further elucidate the effects of heme scavenging versus HO-1 induction. Our results showed a striking, dose-dependent reduction in stasis, albeit to a detectably lower degree than hemopexin free of heme (Figure 1C). In summary, hemopexin has a dose-dependent effect to prevent and treat vaso-occlusion induced in a mouse model of SCD by hemoglobin, LPS, and hypoxia-reoxygenation. This effect is partially replicated by hemopexin pre-complexed with heme, suggesting that the beneficial effect is not limited to clearance of circulating heme and prevention of TLR4 signalling. The partial effectiveness of hemopexin-heme complex is consistent with our prior published data implicating CO generation by HO-1 as playing a role in the relief of vaso-occlusion by hemopexin. We conclude that hemopexin shows promise for the treatment of VOC. Additional experiments are needed to clarify the activity of hemopexin in clearance-dependent and -independent mechanisms of resolution of vaso-occlusion. Clinical trials of hemopexin are warranted to evaluate its safety, tolerability and potential efficacy in relieving vaso-occlusive pain crisis in patients with SCD. Disclosures Gentinetta: CSL Behring: Current Employment. Vercellotti:CSL Behring: Research Funding. Kato:CSL Behring AG: Current Employment. Brinkman:CSL Behring: Current Employment. Zuercher:CSL Behring AG: Current Employment. Belcher:Mitobridge-Astellas: Consultancy, Research Funding; CSL Behring: Consultancy, Research Funding; Hillhurst Biopharmaceuticals: Consultancy.

Carbon Monoxide Formation during Aerobic Biostabilization of the Organic Fraction of Municipal Solid Waste: The Influence of Technical Parameters in a Full-Scale Treatment System

The present study sought to investigate the formation of carbon monoxide (CO) during aerobic biostabilization (AB) of the organic fraction of municipal solid waste (OFMSW) in forced aerated piles. Understanding the factors influencing CO formation may be important not only for safety, but also for environmental and technical reasons. The objective of the study was to determine the effect of the technical parameters of the piles on the concentration of CO in the process gas during AB of the OFMSW in a full-scale waste treatment system: rate of waste aeration (from 3365 to 12,744 m3∙Mg−1), waste mass loads in the pile (from 391 to 702 Mg), thermal conditions, application of sidewalls as an element of pile bioreactor construction, concentration of O2 and CO2 in the waste piles and the duration of the process from 6 to 9 weeks. The temperature and concentration of O2, CO2, CO, CH4 were measured in each pile at weekly intervals. All six reactors provide stable thermal and aerobic conditions, but the presence of CO was observed, ranging from a few to over 2000 ppm, which demonstrated that ensuring optimum conditions for the process is not sufficient for CO to be eliminated. A moderate, non-linear rise in CO concentration was observed along with a rise in the temperature inside the reactors. Concentrations of CO were not highly correlated with those of O2 or CO2. An increase in waste mass loads increased the CO concentration in waste piles, while application of sidewalls decreased CO concentration. Increasing aeration rate had an influence on CO production, and the highest CO concentrations were noted under air flow rate 5.3 m3·Mg−1·h−1.

Evidence of Local Corrosion of Bimetallic Cu–Sn Catalysts and Its Effects on the Selectivity of Electrochemical CO2 Reduction

The electrochemical carbon dioxide (CO2) reduction is a promising method for carbon recycling. Bimetallic catalysts have been extensively developed for the selective production of carbon monoxide (...

Phase-Selective Epitaxial Growth of Heterophase Nanostructures on Unconventional 2H-Pd Nanoparticles.

Heterostructured, including heterophase, noble-metal nanomaterials have attracted much interest due to their promising applications in diverse fields. However, great challenges still remain in the rational synthesis of well-defined noble-metal heterophase nanostructures. Herein, we report the preparation of Pd nanoparticles with an unconventional hexagonal close-packed (2H type) phase, referred to as 2H-Pd nanoparticles, via a controlled phase transformation of amorphous Pd nanoparticles. Impressively, by using the 2H-Pd nanoparticles as seeds, Au nanomaterials with different crystal phases epitaxially grow on the specific exposed facets of the 2H-Pd, i.e., face-centered cubic (fcc) Au (fcc-Au) on the (002)h facets of 2H-Pd while 2H-Au on the other exposed facets, to achieve well-defined fcc-2H-fcc heterophase Pd@Au core-shell nanorods. Moreover, through such unique facet-directed crystal-phase-selective epitaxial growth, a series of unconventional fcc-2H-fcc heterophase core-shell nanostructures, including Pd@Ag, Pd@Pt, Pd@PtNi, and Pd@PtCo, have also been prepared. Impressively, the fcc-2H-fcc heterophase Pd@Au nanorods show excellent performance toward the electrochemical carbon dioxide reduction reaction (CO2RR) for production of carbon monoxide with Faradaic efficiencies of over 90% in an exceptionally wide applied potential window from -0.9 to -0.4 V (versus the reversible hydrogen electrode), which is among the best reported CO2RR catalysts in H-type electrochemical cells.

Creating MXene/reduced graphene oxide hybrid towards highly fire safe thermoplastic polyurethane nanocomposites

Developing highly effective flame retardant polymeric materials with the release of low toxic fumes during burning still keep a huge challenge. In this work, we demonstrated successful synthesis of titanium carbide-reduced graphene oxide (Ti3C2Tx-rGO) hybrid via hydrogen bonding induced assembly of Ti3C2Tx and rGO, which was utilized to improve the thermal and fire safe performances of thermoplastic polyurethane elastomer (TPU). The results indicated that the Ti3C2Tx-rGO hybrid showed a strong adhesion and good compatibility with TPU host. Furthermore, as-prepared Ti3C2Tx-rGO hybrid was homogeneously dispersed in the TPU matrix due to the mutual intercalation of rGO and Ti3C2Tx preventing the re-aggregation. The thermal stability of TPU was dramatically improved after the introduction of Ti3C2Tx-rGO. With addition of 2.0 wt% Ti3C2Tx-rGO, the peak of smoke production rate and total smoke release of TPU nanocomposite were remarkably decreased by 81.2% and 54.0%, respectively. In addition, the TPU/Ti3C2Tx-rGO-2.0 showed distinct reductions in the peak of carbon monoxide production rate (54.1%) and total carbon monoxide yield (46.2%). The physical barrier effect, the catalytic charring of Ti3C2Tx-rGO hybrid and the chemical transformation of Ti3C2Tx were responsible for the excellent fire resistance of TPU/Ti3C2Tx-rGO systems. This work provides a novel strategy to significantly reduce the fire hazards of TPU, thus broadening its industrial applications.

Improved flame-retardant properties of polydimethylsiloxane/multi-walled carbon nanotube nanocomposites

The flame-retardant properties of polydimethylsiloxane (PDMS)/oxidised multi-walled carbon nanotubes (MWCNT–COOH) nanocomposite films were dispersed using a nonionic acrylate copolymer surfactant. The nanocomposite films were prepared by spin coating and characterised using SEM, quasi-elastic cold-neutron scattering, TGA–FTIR, cone calorimetry, and LOI. The PDMS/surfactant/MWCNT–COOH (PSM) nanocomposite displayed superior flame-retardant performance compared to materials containing only surfactant or MWCNT–COOH. The peak heat release rate, the peak smoke production rate, total smoke release rate, carbon monoxide, and carbon dioxide production from PSM were 42, 47, 18, 28, and 47% less than the PDMS control. The LOI results for PSM exhibited a value of 32% with respect to 25% for the PDMS. PSM suppresses the smoke emission and inhibits penetration of the air reacting with the gas volatiles of the material. These new nanocomposites provide a valuable improvement in flame-retardant capabilities by physical barrier effect compared to other PDMS polymer materials.

Hydrogen production by supercritical water gasification of coal: A reaction kinetic model including nitrogen and sulfur elements

Researches on reaction kinetics and mechanism are crucial to the application of hydrogen production technology by supercritical water gasification of coal from experiment to industrialization. Based on the migration mechanisms of nitrogen and sulfur in the process, this paper developed a general model including nitrogen and sulfur to study the generation path, consumption path and reaction rate of the gasification products. The parameters of the kinetic model were obtained by fitting the experimental data of the gasification products, and the activation energy of each reaction was obtained by the Arrhenius equation. By comparing the reaction rates among the various reactions, the reaction steps for controlling the production or digestion of the product could be obtained. The main source of ammonia production was pyrolysis of coal followed by steam reforming reaction of fixed carbon. The rate of ammonia contribution from ammonia synthesis was extremely low and could be ignored. The consumption path of ammonia was the decomposition reaction of ammonia though its rate was also slow. The pyrolysis reaction of coal was the main source of hydrogen sulfide, followed by the steam reforming reaction of fixed carbon. The difference of the concentration and reactivity between organic sulfur and inorganic sulfur caused the difference in the generation source of hydrogen sulfide in early and late stage of the gasification. The kinetic model can predict not only the production of hydrogen, methane, carbon dioxide, carbon monoxide, ammonia and hydrogen sulfide under different operating conditions, but also the products for different coal types, which may provide a theoretical basis for the targeted regulation of nitrogen and sulfur elements in supercritical water.

Thermogravimetric Analysis–Fourier Transform Infrared Spectroscopy Study on the Effect of Extraction Pretreatment on the Pyrolysis Properties of Eucalyptus Wood Waste

Eucalyptus wood is one of the important hardwood resources with attractive properties of rapid growth and good quality, which are widely used for the manufacture of wood-based boards, furniture, pulp and paper, and so on. In order to explore the potential of sawdust waste from the eucalyptus wood furniture factory as a bioenergy feedstock, its pyrolysis properties after different solvent extractions were examined using thermogravimetric analysis coupled with Fourier transform infrared spectrometry. The mass ratio of extractives in eucalyptus wood sawdust by benzene–alcohol, hot water, and sodium hydroxide solution was 4.25, 9.68, and 16.11%, respectively. After extraction, the thermal decomposition process of eucalyptus wood was promoted with a higher weight loss rate, lower activation energy, and lower residue content compared to the raw sample without pretreatment, and the promotion level was positively correlated to the strength of extracting solvent. CO2, CO, CH4, H2O, acids, aldehydes, aromatics, ethers, and alcohols were identified as the important intermediates in pyrolysis vapors, which can be tuned by different extraction pretreatments. In terms of typical gas products, benzene–alcohol enhanced the release of carbon dioxide, and hot water enhanced the water generation from dehydration reactions and slightly increased the production of carbon monoxide, while sodium hydroxide promoted the formation of methane at the early stage under 280 °C and later stage over 460 °C during the pyrolysis of eucalyptus wood. It is believed that the extraction pretreatment can not only obtain the bioactive extractive products but also benefit the pyrolysis process by lowering the energy barrier and tuning the composition of pyrolysis products.

Relationships between hyperinsulinaemia, magnesium, vitamin D, thrombosis and COVID-19: rationale for clinical management.

Risk factors for COVID-19 patients with poorer outcomes include pre-existing conditions: obesity, type 2 diabetes mellitus, cardiovascular disease (CVD), heart failure, hypertension, low oxygen saturation capacity, cancer, elevated: ferritin, C reactive protein (CRP) and D-dimer. A common denominator, hyperinsulinaemia, provides a plausible mechanism of action, underlying CVD, hypertension and strokes, all conditions typified with thrombi. The underlying science provides a theoretical management algorithm for the frontline practitioners.Vitamin D activation requires magnesium. Hyperinsulinaemia promotes: magnesium depletion via increased renal excretion, reduced intracellular levels, lowers vitamin D status via sequestration into adipocytes and hydroxylation activation inhibition. Hyperinsulinaemia mediates thrombi development via: fibrinolysis inhibition, anticoagulation production dysregulation, increasing reactive oxygen species, decreased antioxidant capacity via nicotinamide adenine dinucleotide depletion, haem oxidation and catabolism, producing carbon monoxide, increasing deep vein thrombosis risk and pulmonary emboli. Increased haem-synthesis demand upregulates carbon dioxide production, decreasing oxygen saturation capacity. Hyperinsulinaemia decreases cholesterol sulfurylation to cholesterol sulfate, as low vitamin D regulation due to magnesium depletion and/or vitamin D sequestration and/or diminished activation capacity decreases sulfotransferase enzyme SULT2B1b activity, consequently decreasing plasma membrane negative charge between red blood cells, platelets and endothelial cells, thus increasing agglutination and thrombosis.Patients with COVID-19 admitted with hyperglycaemia and/or hyperinsulinaemia should be placed on a restricted refined carbohydrate diet, with limited use of intravenous dextrose solutions. Degree/level of restriction is determined by serial testing of blood glucose, insulin and ketones. Supplemental magnesium, vitamin D and zinc should be administered. By implementing refined carbohydrate restriction, three primary risk factors, hyperinsulinaemia, hyperglycaemia and hypertension, that increase inflammation, coagulation and thrombosis risk are rapidly managed.

Ligand-Directed Approach to Activity-Based Sensing: Developing Palladacycle Fluorescent Probes That Enable Endogenous Carbon Monoxide Detection.

Carbon monoxide (CO) is an emerging gasotransmitter and reactive carbon species with broad anti-inflammatory, cytoprotective, and neurotransmitter functions along with therapeutic potential for the treatment of cardiovascular diseases. The study of CO chemistry in biology and medicine relative to other prominent gasotransmitters such as NO and H2S remains challenging, in large part due to limitations in available tools for the direct visualization of this transient and freely diffusing small molecule in complex living systems. Here we report a ligand-directed activity-based sensing (ABS) approach to CO detection through palladium-mediated carbonylation chemistry. Specifically, the design and synthesis of a series of ABS probes with systematic alterations in the palladium-ligand environment (e.g., sp3-S, sp3-N, sp2-N) establish structure-activity relationships for palladacycles to confer selective reactivity with CO under physiological conditions. These fundamental studies led to the development of an optimized probe, termed Carbon Monoxide Probe-3 Ester Pyridine (COP-3E-Py), which enables imaging of CO release in live cell and brain settings, including monitoring of endogenous CO production that triggers presynaptic dopamine release in fly brains. This work provides a unique tool for studying CO in living systems and establishes the utility of a synthetic methods approach to activity-based sensing using principles of organometallic chemistry.

Rendimiento del motor y análisis de emisiones utilizando biodiésel de Neem y Jatropha

This paper presents the production of biodiesel from indigenous species of Jatropha curcas and Neem (Azadirachta indica) oils, then its engine performance and emission characteristics of B10 blends measured at 1000 rpm. Biodiesel production yields were found 90% and 68% by weight from Jatropha curcas and Neem (Azadirachta indica), respectively. Three prepared biodiesel blends were 10% Neem biodiesel (NB10), 10% Jatropha biodiesel (JB10) and 5% Jatropha + 5% Neem biodiesels (NJB10). The engine emission test showed less carbon monoxide production from NB10 (94 +- 2.15 ppm), followed by JB10 (100+- 2.44ppm) and NJB10 (121 +- 3.65ppm) as compared to diesel (135+- 2.18ppm). However, the carbon dioxide emissions were found higher due to the better combustion characteristics of biodiesel blends as NB10 (3.21%), JB10 (3.06%) and NJB10 (2.53%) than diesel (2.13%) by volume. The reduced amounts of sulphur dioxide (SO2) emissions were found with blended biodiesel fuel in comparison to mineral diesel. Nitrogen dioxide (NO2) emissions were 5 ppm from diesel at 73 C exhaust temperature, while it was increased by using blended biodiesel, to 8 ppm with NB10 due to higher exhaust temperatures 85;33 C. The measured engine power and torque produced from the blended biodiesel samples were slightly lower than the conventional diesel by 12% and 7.7%, respectively. The experimental results showed that an engine performance and emission characteristic of Neem biodiesel (NB10) was better as compared to other biodiesel blends.

Simulation and modeling of hydrogen production and power from wheat straw biomass at supercritical condition through Aspen Plus and ANN approaches

In this study, the effects of temperature, flow rates of water, and biomass on the production of hydrogen, methane, and carbon monoxide in the presence of supercritical water were investigated. The wheat straw was used as biomass in the process. The hydrothermal gasification method was applied in a Gibbs reactor to produce the gases. The results revealed that with increasing temperature, the conversion of the hydrogen and carbon monoxide gases increased while that of the methane gas decreased. In addition, the flow rate of water had a significant role in producing the hydrogen gas. Finally, power was generated in a turbine for optimal use of the output gases. Aspen Plus software simulated the process. Moreover, to compare and test the Aspen Plus outputs, an artificial neural network (ANN) was developed. The Aspen Plus evaluated the experimental data with a good agreement but was limited to using default model. The ANN approach overcame the problem by making different weights and biases. The hydrogen gas as desired product was attained at 32.7 kg/h at a temperature of 700 °C, flow rates of water 2000 kg/h, and biomass of 1500 kg/h. The thermodynamic analyses determined the efficiencies of the energy and exergy as 17.2% and 22.1%, respectively.

Flame-responsive aryl ether nitrile structure towards multiple fire hazards suppression of thermoplastic polyester

Multiple fire hazards (heat, smoke, dripping) caused by thermoplastic polymers pose integrated risks. Halogen or phosphorus flame-retardants tend to increase toxic, smoke or dripping hazards due to their flame-retardant mechanism. The physical blending flame-retardants into matrixes also presents a migration dilemma with causing potential environmental threats. Herein, we propose a novel multi-hazards inhibition strategy by chemical-incorporating aryl ether nitrile structures into poly(ethylene terephthalate)(PET), which is a typical thermoplastic polymer and a major contributor of multiple fire hazards. Through flame-responsive cyclotrimerization and aliphatic fragment capture, the flammability risks and multi-hazards (heat, smoke, toxicity, dripping) are significantly suppressed. The limiting oxygen index of the modified PET increases from 21.0 to 31.0. The peak of heat release, total smoke release, and carbon monoxide production decrease by 49.0 %, 31.1 %, and 52.6 %, respectively. The dripping hazards are eliminated, and the UL-94 rating reaches to V-0 level with no dripping production. Hence, this state-of-art strategy supplies a new approach for the fire hazards suppression of thermoplastic polymers.

Two Faces of Heme Catabolic Pathway in Newborns: A Potential Role of Bilirubin and Carbon Monoxide in Neonatal Inflammatory Diseases.

In an infant's body, all the systems undergo significant changes in order to adapt to the new, extrauterine environment and challenges which it poses. Fragile homeostasis can be easily disrupted as the defensive mechanisms are yet imperfect. The activity of antioxidant enzymes, i.e., superoxide dismutase, catalase, and glutathione peroxidase, is low; therefore, neonates are especially vulnerable to oxidative stress. Free radical burden significantly contributes to neonatal illnesses such as sepsis, retinopathy of premature, necrotizing enterocolitis, bronchopulmonary dysplasia, or leukomalacia. However, newborns have an important ally—an inducible heme oxygenase-1 (HO-1) which expression rises rapidly in response to stress stimuli. HO-1 activity leads to production of carbon monoxide (CO), free iron ion, and biliverdin; the latter is promptly reduced to bilirubin. Although CO and bilirubin used to be considered noxious by-products, new interesting properties of those compounds are being revealed. Bilirubin proved to be an efficient free radicals scavenger and modulator of immune responses. CO affects a vast range of processes such as vasodilatation, platelet aggregation, and inflammatory reactions. Recently, developed nanoparticles consisting of PEGylated bilirubin as well as several kinds of molecules releasing CO have been successfully tested on animal models of inflammatory diseases. This paper focuses on the role of heme metabolites and their potential utility in prevention and treatment of neonatal diseases.

Experimental study on the causes and critical conditions of toxic gases in hydraulically fractured oil wells

ABSTRACT Hydraulic fracturing is the most preferred oil well stimulation technology worldwide. In fractured oil wells, toxic gases (hydrogen sulfide and carbon monoxide) present a problem when the produced water is reclaimed as base fluid for fracturing. These gases can cause equipment corrosion, environment pollution, and adversely affect the operational personnel’s health. Extant research focuses on toxic gases produced at high temperatures (>200 °C). Therefore, this paper examines the causes and critical conditions for toxic gas formation in fractured wells in conventional reservoirs at low temperatures (<160 °C) through a series of laboratory experiments that include bacterial culture and heating experiments. The results show that for temperature in the range 40–60 °C, the presence of sulfate-reducing bacteria in the produced water is the main cause of hydrogen sulfide production in fractured wells. However, when the temperature is higher than 102 °C, the sulfur compounds (potassium persulfate and sodium sulfite) in the fracturing fluid and crude oil can produce hydrogen sulfide by thermochemical sulfate reduction. In addition, when the temperature is higher than 75 °C, oxygenated compounds (aldehydes) in crude oil can produce carbon monoxide by decarbonylation. Both processes can occur simultaneously when the temperature is higher than 102 °C. This paper is of great significance in controlling the formation of toxic gases in fractured wells.

Standard Electrode Potentials for Electrochemical Hydrogen Production, Carbon Dioxide Reduction, and Oxygen Reduction Reactions in N,N-Dimethylacetamide

Four standard electrode potentials versus the standard hydrogen electrode (SHE) are reported in a polar aprotic solvent, N,N-dimethylacetamide (DMA) at 298 K: (1) −0.319 ± 0.033 V for a H2 production; (2) −0.415 ± 0.033 V and −1.195 ± 0.033 V for CO2 reductions to produce carbon monoxide (CO) in the absence and presence of water, respectively; and (3) +0.918 ± 0.033 V for an O2 reduction (ORR) or O2 evolution (OER) reactions. These potentials were estimated based on measurements of absolute (and conventional) acidity constants for several Brønsted acids in DMA including CO2 with water ([H2O] = 1.1 M) of which absolute pKa is 18.6 ± 0.2 in reference to aqueous proton at standard states. The standard Gibbs transfer energy of proton was calculated to be −31 ± 3 kJ/mol from water to DMA at 298 K.