Amount Of Hydrogen Gas Research Articles

Quantifying H2 emissions under different nutritional mitigation strategies and its impact on improving the prediction of enteric methane emissions of ruminants

Stoichiometric models that predict methane (CH4) production of ruminants assume that the amount of hydrogen gas (H2) produced during fermentation in the rumen equals the amount of H2 consumed by electron sinks in the rumen and thus that H2 should not be emitted into the environment. However, some studies have demonstrated that H2 emissions occur under practical conditions. In addition, the H2 emissions increase when nutritional mitigation strategies are used. Hence, this study hypothesized that considering H2 emission would improve the prediction of enteric CH4 emission, especially when using mitigation strategies that induce high variation in the H2 emission. The objective of this study was to develop and evaluate the performance of CH4 emission prediction models using H2 emission as an explanatory variable. A database of CH4 and H2 emission (mean treatment data) from ruminants (dairy cattle, growing cattle and sheeps) was built to develop mixed-effects models at three levels of complexity: level 1 - H2 production/yield, DMI, or both; level 2 - level 1 explanatory variables plus chemical composition of the diet (i.e. CP, EE, NDF, OM, or PCO); and level 3 - level 2 explanatory variables plus animal metabolic weight (BW0.75, kg). When all animal categories were grouped, including H2 production improved the performance of CH4 production prediction only in level 1 models for the electron-receptor mitigation strategy, reducing the root mean square of prediction error (RMSPE) by 18 %. For dairy cattle and sheep, dry matter intake was not a significant explanatory variable in level 1 or 2 models. For growing beef cattle, for all mitigation strategies together and the inhibitor-mitigation strategy alone, including H2 production reduced RMSPE by 13 % and 27 %, respectively. Overall, H2 production was included in 60 % of level 1 models and 100 % of level 2 and 3 models, which best predicted CH4 production. Thus, including H2 emission does improve prediction of enteric CH4 emission, especially when mitigation strategies that induce variation in the H2 are used.

Biodegradable Mg Electrodes for Iontophoretic Transdermal Drug Delivery

Biodegradable metals have received limited attention for application in transdermal drug delivery, although metallic microneedles (MNs) and iontophoresis have been thoroughly researched for this purpose. Here, we present Mg as a salient candidate for an MN electrode. Its metallic properties enable the application of voltage to enhance the diffusion of charged drug molecules, while hydrogen gas generated during Mg corrosion prevents its application to electrodes. The Mg MN electrode was fabricated using a nanosecond laser, and the amount of hydrogen gas were measured with applied potential during iontophoresis. Accordingly, an appropriate potential window for iontophoresis was established based on the combined effect of enhanced drug diffusion by applied electric potential and impediment from hydrogen generation. The dye permeation tests of the Mg MN on the porcine skin demonstrated the combined effect of the Mg MN and iontophoresis. The dye migration decreased at higher voltages due to excess hydrogen generation and the corrosion of needle tips, both making the diffusion of charged dye molecules along the Mg MN surface harder. These results demonstrate optimal potential range of Mg MN electrodes for transdermal drug delivery with an electric field and bubble generation during iontophoresis.Graphical

Hidrojen üretimi yoluyla çevre dostu enerji üretiminin incelenmesi

Energy production has become one of the most essential elements determining industry, economy, and international relations in the technological development era we are in. Although globalization can help countries surpass their borders, energy strategies are crucial in shaping these relationships. For this purpose, the resources chosen for energy production should be human and ecosystem-friendly, as well as cost-effective and renewable. The hydrogen is suitable energy carrier. In this study, the hydrogen production was achieved by electrolysis. The Pt anode and Ni modified Ni foam cathode electrodes were used in 1M KOH. The modified electrode surface was monitored by scanning electron microscope (SEM). The X-ray diffractometer (XRD) analysis was achieved for characterization. The amount of hydrogen gas was determined during 1800 seconds. The results showed that Ni modified electrode enhanced the hydrogen performance significantly.

Effects of pre-mixed gas composition on combustion characteristics of micro pilot dual fuel (MPDF) in a heavy-duty dual fuel engine

The effects of premixed gas compositions on the combustion characteristics in micro pilot duel fuel (MPDF) conditions were investigated. Propane, hydrogen, and carbon dioxide gases were added to methane gas, and engine experiments were conducted under various premixed gas compositions. A single-cylinder heavy-duty engine with a combustion chamber volume of 1100 mm3 and compression ratio of 17.0 was used. A 55 kW DC dynamometer was used to operate the single-cylinder dual-fuel engine at a constant engine speed. At high propane mixture ratios, knocking combustion occurred, accompanied by intense engine vibrations, owing to the low octane number of propane. Knocking combustion led to an increase in the combustion variation and ringing intensity (which represents the knocking combustion intensity). In contrast, at high ratios of hydrogen, which has a high octane number, knocking combustion was suppressed, and the speed of combustion was lower than that in the case of high propane mixture ratios. The optimum conditions corresponded to a ringing intensity of 3–5 MW/m2. The addition of even a small amount of propane gas enhanced the engine performances in misfiring conditions. In contrast, a considerable amount of hydrogen gas was required to prevent abnormal combustion because of the low density of hydrogen gas. The presence of carbon dioxide effectively stabilized MPDF combustion by suppressing knocking combustion.

Radiolysis of thermally dehydrated gibbsite

Aluminum hydroxide (gibbsite, Al(OH)3) powders and their thermally dehydrated forms were rehydrated and irradiated with gamma rays to examine the effects of the collapse of the crystalline gibbsite structure as it is converted to alumina on the transport of precursors of molecular hydrogen to the surface. The amount of hydrogen gas, H2, production from irradiated gibbsite and its transition phases with adsorbed water increased substantially with increasing temperature for dehydration of the samples, up to a point. The production of H2 for samples without water was considerably lower than the hydrated samples signifying the importance of surface water and the transport of precursors to the surface. EPR spectroscopy showed that the major radiolytic products are trapped electrons and related O− centers. Thermal gravimetric analysis (TGA) measurements of gibbsite dehydration established the temperatures of phase transitions from gibbsite to alumina. Changes to the surface and structure of gibbsite and its transition phases following irradiation were analyzed using nitrogen adsorption, powder X-ray diffraction (pXRD), Raman spectroscopy, electron paramagnetic resonance (EPR), and scanning electron microscopy (SEM). pXRD and Raman spectra showed amorphorization at about 300 °C, coupled to a substantial increase in specific surface area due to increasing porosity.

Using electro- and alum coagulation technologies for treatment of wastewater from fruit juice industry in New Damietta City, Egypt.

Electrocoagulation technology is being increasingly used to treat various types of wastewater over the last several years. This study aimed to investigate the industrial wastewater treatment of a fruit juice factory as an example of food processing industries in New Damietta City, Egypt, by using electrocoagulation technology. This is to solve an environmental problem, represented in the high organic load of these effluents. The electrocoagulation treatment processes were examined by using two electrodes of aluminum (Al) and two electrodes of stainless-steel (SS) and also by using Al as an anode and SS as a cathode. In addition, treatment by alum coagulation was investigated. Results showed that electrocoagulation was more effective than alum coagulation. The use of two combined electrodes of Al as an anode and SS as a cathode resulted in an 83.78% COD removal efficiency, while the use of the alum coagulant yielded 57.57%. Furthermore, total operating cost was calculated, and the amount of hydrogen gas as a subsequent energy alternative was theoretically determined in order to solve the process' power problem.

The effect of milling time on formation of magnesium-activated carbon composites as hydrogen absorbing materials

Hydrogen is a potential environmentally friendly fuel, but it has problems in terms of storage. Hydrogen storage using magnesium (Mg) and activated carbon (AC) is an effective and safe alternative because it can store hydrogen in a large enough capacity. This research was conducted to study the potential of Mg-AC material with addition of cobalt as catalyst in storing hydrogen by studying the effect of milling time and weight ratio of Mg-AC on the characteristics of the composites and the amount of hydrogen gas that can be adsorbed. Composites were formed using mechanical milling method using Fritsch 6 Planetary Ball Mill. The prepared composites were characterized using the X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR), Scanning Electron Microscopy (SEM) and Thermal Gravimetric Analysis (TGA). XRD analysis showed that MgH2 compound was formed starting from 3 hr of milling time. The results of FTIR characterization showed that more C-H groups were formed with increasing milling time. The SEM graphs show that the longer milling time, the more evenly the distribution of particles in the Mg-AC composite and forming more nano particles. Meanwhile, the TGA analysis showed that with the addition of 5% AC, 10% and 15% then a weight reduction reached 9.6%, 10.6% and 14.2%, respectively.

Evaluation of various corn variety kernels for hydrogen gas production by APR

The present study was designed to evaluate gasification performances of various corn kernel varieties (field corn, non-genetically modified (non-GMO) field corn, yellow field corn, white field corn and popcorn) for hydrogen gas production by aqueous-phase reforming (APR) using activated carbon supported platinum catalyst.Corn kernels were solubilized in 200°C-subcritical water medium under 13.79 MPa CO2 pressure before use. The hydrolysates obtained from hydrolysis process were rich in total organic carbons (TOC) with a 5200–5850 mg/L concentration range. There were significant differences among varieties in terms of overall solubilization. However, hydrolysates from different corn varieties produced the same amount of hydrogen gas with a yield of 130 mL/g corn on average. The gas chromatography-mass spectrometry (GC-MS) analysis of corn hydrolysates showed considerable decreases in the peak areas after APR compared to initial hydrolysates. These decreases indicate consuming most of the corresponding organics in the gasification process. Evaluation of gasification results based on carbon balance showed that only small fractions of organic carbons converted to carbon-containing gaseous products (CO and CO2) and remaining carbons were precipitated as ungasified solid residue. Thus, gas mixtures produced from corn kernel hydrolysates were mostly composed of hydrogen as found in gas analysis.

Cathodic hydrogen production by simultaneous oxidation of methyl red and 2,4-dichlorophenoxyacetate in aqueous solutions using PbO2, Sb-doped SnO2 and Si/BDD anodes. Part 2: hydrogen production.

In this work, results concerning hydrogen gas production during the oxidation of methyl red (MR) and sodium 2,4-dichlorophenoxyacetate (2,4-DNa), is presented, emphasizing not only the amount of hydrogen gas that was produced but also the kinetic and efficiency parameters involved in this process. For this purpose, a two-compartment electrochemical cell was used with a Nafion® membrane as separator in order to collect H2 without other chemical species (only with traces of water vapor). Under these experimental conditions, it was possible to guarantee the purity of the H2 collected. The electrochemical oxidation of MR and 2,4-DNa solutions was carried out by applying 30 mA cm−2 at 298 K, using different non-active anodes (Si/BDD, Pb/PbO2, or Sb-doped SnO2) and different cathodes (Pt mesh, 316-type stainless-steel, or Pt–10%Rh) in order to investigate the effect of the electrocatalytic materials and experimental conditions. Thus, the H2 produced was measured as a function of the electrolysis time and compared with the values estimated by Faraday's law. The results showed that the hydrogen production rate r(H2) is independent of the nature of the anodic material, although an important effect on the oxygen production was observed on the BDD anode by using sulfuric acid as supporting electrolyte. The effect was discussed through the formation of sulphate-oxidizing species (SO4−˙ and S2O82−) which interfere in the oxygen production step on BDD anodes. The use of different cathodes showed small changes in the hydrogen production rate r(H2), which were basically associated with the differences in hydrogen adsorption energy prior to its evolution. The results were discussed in light of the existing literature.

Thermal Decomposition of Donor‐Stabilized Phosphinoborane PH2BH2NMe3: A Tensimetry Study

The thermal decomposition of PH2BH2·NMe3 (1) in closed system was studied by static tensimetry with membrane null‐manometer. Compound 1 is unstable already at room temperature and partially decomposes with the release of gaseous trimethylamine and nonvolatile polymeric material. Storage of 1 at 311 K for 53 days results in evolution of small amounts of hydrogen and phosphine. At temperatures up to 329 K, PH3 evolution and BH3NMe3 adduct formation is observed after 3 days, and above 387 K, considerable amount of hydrogen gas is released. The data obtained indicate that the pyrolysis of 1 in the closed system may result in the enrichment of the condensed phase with boron due to phosphine loss.

Expired Atenolol Drug: A Nontoxic Corrosion Inhibitor for Al in 3 M HCl Pickling Environment

Corrosion protection of expired Atenolol drug on the Al in the 3[Formula: see text]M HCl was investigated through the weight loss, gasometric, Tafel plot, impedance, atomic absorption spectroscopy (AAS), quantum chemical, scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies. The addition of different concentrations of expired Atenolol drug enhances the protection efficiency. Gasometric technique was performed in order to study the variation in the amount of hydrogen gas in the presence and absence of the inhibitor. The potentiodynamic polarization plots show that the expired Atenolol drug acts as a mixed type. Data of impedance studies show that the charge transfer process controls the corrosion of Al in the 3[Formula: see text]M HCl medium. The SEM and AFM results explore that the expired Atenolol drug is a powerful corrosion inhibitor for the Al in HCl solution.

Assessment of the degradation rates and effectiveness of different coated Mg-Zn-Ca alloy scaffolds for in vivo repair of critical-size bone defects

Surgical repair of bone defects remains challenging, and the search for alternative procedures is ongoing. Devices made of Mg for bone repair have received much attention owing to their good biocompatibility and mechanical properties. We developed a new type of scaffold made of a Mg-Zn-Ca alloy with a shape that mimics cortical bone and can be filled with morselized bone. We evaluated its durability and efficacy in a rabbit ulna-defect model. Three types of scaffold-surface coating were evaluated: group A, no coating; group B, a 10-μm microarc oxidation coating; group C, a hydrothermal duplex composite coating; and group D, an empty-defect control. X-ray and micro-computed tomography(micro-CT) images were acquired over 12 weeks to assess ulnar repair. A mechanical stress test indicated that bone repair within each group improved significantly over time (P < 0.01). The degradation behavior of the different scaffolds was assessed by micro-CT and quantified according to the amount of hydrogen gas generated; these measurements indicated that the group C scaffold better resisted corrosion than did the other scaffold types (P < 0.05). Calcein fluorescence and histology revealed that greater mineral densities and better bone responses were achieved for groups B and C than for group A, with group C providing the best response. In conclusion, our Mg-Zn-Ca-alloy scaffold effectively aided bone repair. The group C scaffold exhibited the best corrosion resistance and osteogenesis properties, making it a candidate scaffold for repair of bone defects.

A novel zinc(II) complex containing square pyramidal, octahedral and tetrahedral geometries on the same polymeric chain constructed from pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole

In this study, a novel Zn(II) complex of pyrazine-2,3-dicarboxylic acid and 1-vinylimidazole was synthesized and fully characterized by elemental analysis, IR spectroscopy, thermal analysis, X-ray powder diffraction, and X-ray single crystal techniques. The X-ray single crystal data revealed that the polymeric coordination complex crystallizes in the monoclinic system with C2 space group and shows a peculiar feature as having the Zn(II) ions with four (tetrahedral), five (square pyramidal) and six (octahedral) coordination numbers on the same polymeric chain. In the complex, the pyrazine-2,3-dicarboxylato ligand acts as a bridging ligand via the ring nitrogen atoms and the carboxyl oxygen atoms while the 1-vinylimidazole ligand coordinates to the metal ion as monodentate via the ring nitrogen atom. In addition, the surface area and hydrogen adsorption studies were carried out and it was found that the complex has a small BET surface area but it can adsorb considerable amount of hydrogen gas at different pressures. Further, the accessible surface area and free volume of the Zn(II) complex were calculated at a Connolly diameter of 0.8 Å by the Grand Canonical Monte Carlo simulation. Synopsis A novel Zn(II) complex including square pyramidal, octahedral and tetrahedral geometries on the same polymeric chain was synthesized using pyrazine-2,3-dicarboxylic acid as a bridging ligand and 1-vinylimidazole as a second ligand, structurally characterized by spectroscopy, thermal analysis and crystallography studies, and investigated for hydrogen adsorption performance.

Corrosion Studies of Carbon Steel in 3% NaCl Solution in Presence of Expired Ceftin: Investigation of Environmental Friendly Corrosion Inhibitor

In this investigation, the application of the Ceftin drug on the prevention of the corrosion of carbon steel in 3 % NaCl solution was examined through weight loss (mass loss), gasometric and atomic absorption spectroscopy techniques. The effectiveness of the Ceftin drug as corrosion inhibitor for carbon steel was proved by weight loss, gasometric and atomic absorption spectroscopy results. The increase in the Ceftin drug concentration decreases the carbon steel weight loss in the 3 % NaCl solution, which is due to the formation of invisible thick layer on the carbon steel in the 3 % NaCl solution. The increase in the contact time decreases the corrosion inhibition property of expired Ceftin drug. Gasometric studies show that, the amount of hydrogen gas evolved decreases with rise in the concentration of 3 % NaCl solution. The results of atomic absorption spectroscopy well support the weight loss (mass loss) and gasometric results.

Deposition of high-electron-mobility transparent conducting zinc oxide thin films by DC magnetron sputtering in gas mixture of argon and hydrogen

Transparent conducting zinc oxide thin films having high electron-mobility are deposited on glass substrates by DC magnetron sputtering in gas mixture of argon and hydrogen at room temperature. Introducing a little amount of hydrogen gas into sputtering Ar gas can remarkedly improve the electron mobility in ZnO thin films. With gas flow rate ratios of hydrogen to argon range from 7.2 % to 19.2 %, ZnO films with hydrogen (ZnO:H) have stable and low resistivity of 6.6×10-4 Ω.cm. At H2/Ar flow rate ratio 7.2 %, electron Hall mobility in ZnO:H film reaches a maximum value of 61 cm2.V-1.s-1. This value is much higher than the one of 23 cm2.V-1.s-1 in pure ZnO films under the same deposition condition. Morever, electron density of 1.51020 cm-3 in ZnO:H films is also higher than the one of 6×1019 cm-3 in pure ZnO films. XRD and FESEM show that the average crystallinegrain size in ZnO:H films are larger than the one in pure ZnO films. The 600-nm-thick ZnO:H films (substrate included) have average transmission of 83 % in the wide wavelength range of 380-1100 nm and low sheet resistance of 11 /square.

Thermodynamics of H2O Splitting and H2 Formation at the Cu(110)–Water Interface

We used density functional theory to investigate the sequential oxidation of the (110) surface of fcc copper triggered by the dehydrogenation of molecularly adsorbed water—the reactions studied did not involve any oxygen besides that present in the water molecules. According to the obtained Gibbs free energies, the formation of half a monolayer of HO and the corresponding amount of hydrogen gas is spontaneous (ΔrG° < 0) starting from a monolayer of adsorbed water at Cu(110). The subsequent dehydrogenation steps necessary to ultimately form one monolayer of O atoms are nonspontaneous (ΔrG° > 0). We present a computationally efficient approach which shows good accuracy for determining the solvation energy of the Cu(110) surface, deviating only by 0.014 eV from literature data. The solvation effect imparts additional stabilization to several oxygen-containing species adsorbed at the Cu(110) surface. Additionally, we investigated the effect of an overlayer of water molecules at the surface where the dehydrogenation of H2O takes place. We found that even though the Gibbs free energy changes associated with the first steps of dehydrogenation of H2O at the Cu surface do not differ substantially from those without an additional water layer, subsequent dehydrogenation steps are favored by as much as 1.6 eV. In view of these results we discuss the importance of the hydrogen-bonding network—formed when an overlayer of H2O is present—in determining the reactivity of surface species. Additionally, we found a considerable effect of the second water layer on the surface relaxation, which differs significantly from the case where no second water layer is present. The hydrogen-bonding network has an important role in affecting the chemistry of the surface species but also in stabilizing the surface itself, which in turn affects the surface relaxation. These findings shed additional light on the modeling of surface processes in solution, which have implications for corrosion science and catalysis.

Synthesis and Characterization of Hematite Nanoparticles as Active Photocatalyst for Water Splitting Application

This paper highlights on the hydrogen production through photocatalytic activity by using hematite nanoparticles synthesized from self-combustion method based on different stirring period. The morphologies and microstructures of the nanostructures were determined using Field-Emission Scanning Electron Microscope (FESEM), X-Ray Diffractometer (XRD) and Particle Size Analyser (PSA). Besides that, surface area analyser was used to determine the BET surface area of the hematite samples. The hematite nanocatalyst as-synthesized are proven to be rhombohedral crystalline hematite (α-Fe2O3) with particle diameters ranging from 60-140 nm. The BET specific surface area of hematite samples increased from 5.437 to 7.6425 m2/g with increasing stirring period from 1 to 4 weeks. This caused the amount of hydrogen gas produced from photocatalytic water splitting to increase as well.

Carbon nanotube diameter tuning using hydrogen amount and temperature on SiO2/Si substrates

Carbon nanotubes (CNTs) were grown on thin iron (Fe) films on SiO2/Si substrates by chemical vapor deposition (CVD) at four different hydrogen (H2)/methane (CH4) ratios at temperatures ranging from 925 to 1000°C. The effects of temperature and the amount of hydrogen gas on the mean diameter at increasing temperature were examined. We demonstrated that the mean diameter and its distribution depend not only on temperature but also on the H2 amount. We showed that increasing H2 amount strongly affects the structure of CNTs, especially at high growth temperature; the mean diameter at 1000°C reduced from about 383 to 34 nm by increasing H2 amount from 24 to 50 sccm. We observed that at high temperature growth the mean diameter was decreasing very fast initially with increasing H2 amount suggesting the dominance of H2 over the growth temperature. A decrease in the slope of diameter vs. H2 amount with further increment in H2 amount implied that the temperature was, then, deciding the CNT diameter through catalyst particle coarsening. The statistical analysis presented implies that the H2 amount has to be adjusted according to the growth temperature for given CH4 amount to keep CNT diameter under control, and the large diameter distributions at high temperature and high H2 amount can be associated with the large variation in the catalyst particle sizes.

Photocatalytic hydrogen production enhanced by laser ablation in water–methanol mixture containing titanium(IV) oxide and graphite silica

Abstract Photocatalytic hydrogen production from methanol aqueous solution containing mixture of titanium dioxide (TiO 2 ) and graphite silica (GS) was enhanced by laser ablation in liquid. It was found that the amount of hydrogen gas evolved in lased GS–TiO 2 was less than that in raw GS–TiO 2 mixture. However, the amount of hydrogen gas with the mixture of raw TiO 2 and lased GS was two times as large as that of the raw GS–TiO 2 mixture. This enhancement effect may be attributed to increase in the reaction surface area by the fine-subdivided GS particles and the aggregation of lased GS and raw TiO 2 .

Hybridized synergy effect among TiO2, Pt and graphite silica on photocatalytic hydrogen production from water–methanol solution

Abstract The photocatalytic production of hydrogen gas from aqueous methanol solution was performed using powdered mixtures of graphite silica (GS) and platinized TiO 2 (Pt/TiO 2 ) or those of GS, Pt and TiO 2 . The addition of GS to Pt/TiO 2 resulted in the decrease of the amount of H 2 gas, whereas the addition of GS to mixtures of TiO 2 and Pt led to the incremental production of H 2 gas. This effect is attributed to the aggregation of GS, TiO 2 and Pt in suspension. The new additional electron transfer process of TiO 2 → Pt → GS caused the increment of the amount of hydrogen gas.