H2 Gas Production Research Articles

Laser irradiation of Mg-Al-Zn alloy: Reduced electrochemical kinetics and enhanced performance in simulated body fluid.

As a lightweight metal with mechanical properties similar to natural bone, Mg and its alloys are great prospects for biodegradable, load bearing implants. However, rapid degradation and H2 gas production in physiological media has prevented widespread use of Mg alloys. Surface heterogeneities in the form of intermetallic particles dominate the corrosion response. This research shows that surface homogenization significantly improved the biological corrosion response observed during immersion in simulated body fluid (SBF). The laser processed Mg alloy exhibited a 50% reduction in mass loss and H2 evolution after 24 h of immersion in SBF when compared to the wrought, cast alloy. The laser processed samples exhibited increased wettability as evident from wetting angle studies, further suggesting improved biocompatibility. Electrochemical analysis by potentiodynamic polarization measurements showed that the anodic and cathodic kinetics were reduced following laser processing and are attributed to the surface chemical homogeneity.

Microbial Paper: Cellulose Fiber-based Photo-Absorber Producing Hydrogen Gas from Acetate using Dry-Stabilized Rhodopseudomonas palustris

The microstructure and reactivity of a novel nonwoven cellulose fiber cellular biocomposite (microbial paper) was studied relative to long-term stabilization of potentially any microorganism. Cells were incorporated during the papermaking process as an integral component of a highly porous cellular biocomposite that can be dry stabilized. Hydrogen gas production from acetate via the activity of the nitrogenases in Rhodopseudomonas palustris CGA009, entrapped at a very high concentration, in hand-made microbial paper was sustained for > 1000 h at a rate of 4.0 ± 0.28 mmol H2/m2 h-1 following rehydration. This rate is 2x and 10x greater than previously reported H2 production rates by Rps. palustris latex coatings that were dried on polyester and non-dried formulations applied to the surface of paper, respectively. By vacuum-dewatering and controlled drying steps to the microbial papermaking process and incorporating blends of microfibrillar (MFC), softwood (SW), and hardwood (HW) cellulose fibers, microbial paper films were fabricated that produced H2 gas at 3.94 ± 1.07 mmol H2/m2 h-1 and retain up to 60 mg/m-2 dry cell weight (DCW) of Rps. palustris. The MFC content appears to determine the final cell load and may affect gas/moisture mass transfer properties of the biocomposite.

Development of an Electrolytic Cation Exchange Module for the Simultaneous Extraction of Carbon Dioxide and Hydrogen Gas from Natural Seawater

An electrolytic cation exchange process has been developed to extract large quantities of carbon dioxide (CO2) from natural seawater where it is in the form of bicarbonate and carbonate, and to simultaneously produce H2 gas in quantities and ratios (3:1 H2 to CO2) intended for future synthesis of hydrocarbons. During the early stages of development, optimizing the energy efficiency and CO2 production efficiency of the process is key to its future practical implementation. Both efficiencies are impacted specifically by the amount of time needed to re-establish equilibrium conditions in the module after a polarity reversal. Three electrolytic cation exchange module (E-CEM) configurations were tested and evaluated to determine the parameters that had the most significant effects on shortening the re-equilibration times after polarity reversal. From these evaluations, a new fourth custom E-CEM was designed, built, and tested that lowered seawater pH 65% faster so that carbonate and bicarbonate in the seawater...

Development of a novel process for energy and materials recovery in steelmaking slags

ABSTRACTThis work aims at gathering fundamental knowledge for the development of a novel process for energy (H2 gas) and materials (magnetite Fe3O4) recovery in hot-steelmaking slags by reacting molten steelmaking slag with steam. Thermodynamic simulation was carried out to calculate the accumulated amount of produced H2 gas as a function of the volume of H2O–Ar gas introduced and the precipitated phases of the molten slags during controlled cooling. Laboratory experiments of crystallization behaviours of molten slags during cooling were visualized in situ through a confocal laser scanning microscope, and the cooled slags obtained were characterized by using SEM-EDS and XRD. CCT diagrams for different slags were created showing the slag crystallization/phase transformation at different cooling rates. The recovery ratio of H2 gas and the maximum potential recovery ratio of iron oxide in the oxidized slags were calculated, which concludes that with increasing the slag basicity from 1.0 to 1.5 and 2.0, the recovery ratio of H2 was found to increase from 12.6 to 23.7% and 22.6%, and the maximum potential recovery ratio of iron oxide was found to increase from 18.3 to 34.4% and 32.8% under the investigated conditions.

Study of Hybrid Autonomous Power System Modelling Via Multi-Agents Strategy

In this paper, a design of a Hybrid autonomous Power System is proposed and detailed. The studied system integrates several components as solar energy source, Energy Recovery system based on a proton membrane exchange fuel cell system and two energy storage components, namely, (1) Energy Storage based on H2 gas production, and (2) an Ultra-capacitor storage device. The system is controlled through an energy management Unit which aims to ensure the smooth operation system to be against any unexpected fluctuation. The modelling of the system relies on the application of a multi-agent strategy whose good effects on the performance of the system is evaluated and demonstrated by the obtained simulation results. The improvement of the system performance is proved through a comparison with the conventional strategies. The system that relies on multi-agents control approach seems to be more reliable and promising in term of effectiveness and fast response.

Obesity Is Inversely Related to Hydrogen-Producing Small Intestinal Bacterial Overgrowth in Non-Constipation Irritable Bowel Syndrome

There have been inconsistent findings on the association of obesity and non-constipation irritable bowel syndrome (IBS). Small intestinal bacterial overgrowth (SIBO) with hydrogen (H2) gas forming-microflora causes non-constipation IBS. But, the effect of H2 producing SIBO on obesity in non-constipation IBS patients has not been studied yet. The aim of this study was to investigate the association between obesity and SIBO in non-constipation IBS patients. We reviewed the charts of patients who showed IBS symptoms along with the documented results of their lactulose hydrogen breath test (LHBT) for SIBO. Multivariate models were used to assess the association between obesity and SIBO. Four-hundred fifty-eight patients were retrospectively included in the study. Of the 485 IBS patients, 158 (30.7%) subjects had positive results for LHBT. Subjects without SIBO showed significantly higher levels of body mass index (24.8 vs. 23.3; P < 0.001) and waist circumference (86.5 vs. 82.7; P < 0.001) as compared to subjects with SIBO. In multivariate analysis, the odds ratios of SIBO were 0.396 (P = 0.018) for obesity and 0.482 (P = 0.021) for abdominal obesity. This is the first human study to demonstrate that obesity is inversely related to SIBO with H2 gas production in non-constipation IBS patients.

Production of Bio-Hydrogen Gas and Other Metabolic Gases by Anaerobic Bacteria Grown on Molasses

The study had aimed to characterize the production of hydrogen gases by anaerobic bacteria. One isolate was found in sheep ruminal fluid and four isolates were obtained from the activated sludge. These isolates were identified by microscopic methods and by rRNA sequences. One ruminal bacterium was identified as Escherichia coli, and it was found that these isolates from activated sludge were related to Clostridium botulinum, C. perfringens and C. difficile. One strain could not be assigned to any species but was similar to C. botulinum. Growth and production of the metabolic gases with molasses as sole carbon source were measured during the anaerobic cultivation by Micro-Oxymax (Columbus Instruments, Columbus, OH, U.S.A.) gas analyzer. One of the most available saccharidic waste products is molasses. The growth on molasses as carbon source was done to test the production of H2. It was found that all tested Clostridium isolates (AK 1-4, AK 1-5, AK 1-9 and AK 1-12) and E. coli isolate (No 2- 24) had utilized molasses as carbon source monitored by production of CO2 gas. All these strains produced H2 gas, and CO gas in concentration range 102 μmol L–1, and H2S gas in concentrations lower by one order of magnitude. Kinetics of evolution of these gases was different suggesting that they are produced by independent processes. Results show that metabolic gases are produced mainly in the exponential phase of growth.

Iron removal, energy consumption and operating cost of electrocoagulation of drinking water using a new flow column reactor

The goal of this project was to remove iron from drinking water using a new electrocoagulation (EC) cell. In this research, a flow column has been employed in the designing of a new electrocoagulation reactor (FCER) to achieve the planned target. Where, the water being treated flows through the perforated disc electrodes, thereby effectively mixing and aerating the water being treated. As a result, the stirring and aerating devices that until now have been widely used in the electrocoagulation reactors are unnecessary.The obtained results indicated that FCER reduced the iron concentration from 20 to 0.3 mg/L within 20 min of electrolysis at initial pH of 6, inter-electrode distance (ID) of 5 mm, current density (CD) of 1.5 mA/cm2, and minimum operating cost of 0.22 US $/m3. Additionally, it was found that FCER produces H2 gas enough to generate energy of 10.14 kW/m3.Statistically, it was found that the relationship between iron removal and operating parameters could be modelled with R2 of 0.86, and the influence of operating parameters on iron removal followed the order: C0>t>CD>pH. Finally, the SEM (scanning electron microscopy) images showed a large number of irregularities on the surface of anode due to the generation of aluminium hydroxides.

Computational Study on Reduction Potential of [CoP4N2(OH2)2]2+ as a Super-Efficient Catalyst in Electrochemical Hydrogen Evolution

Hydrogen is considered as a unique choice for future world’s resources. The important parameter in the process of hydrogen production is the value of reduction potential for the used catalyst, in direct contact with consumed energy in process. The application of computational methods to design and modify molecular catalysts is highly regarded. This study sought to explore Density Functional Theory (DFT), employing an effective core potential basis set (LanL2DZ) for metals, as an applicable method used to calculate molecular geometries and electronic structures of the redox forms of two new super-efficient catalysts, CoP4N2 and FeP4N2. The reduction potential related to CoP4N2 catalyst in the presence of water solvent is measured using a reference isodesmic reaction. The calculated data revealed that obtained theoretical value for the reduction potential of catalyst, -0.58V, is in an excellent agreement with its experimental value, -0.50 V. The results confirmed that water molecules coordinated with Co or Fe core in catalyst structure play the main role in H2 gas production.

(Invited) Development of Nitride Photocatalysts for Artificial Photosynthesis

Nitride semiconductors are attractive materials not only for energy-saving devices such as LEDs and LDs but also for clean-energy production systems. Nitride photocatalysts are possible to generate “clean hydrogen” from water and to produce hydrocarbon from CO2, so-called artificial photosynthesis. Energy conversion from light energy to these clean energies are efficient by using nitride photocatalysts. Efficient LEDs in regions of UV, blue, green are based on nitride semiconductors since nitrides have direct bandgap. Direct bandgap also causes efficient photo-absorption. InGaN alloys have a potential of photo-absorption devices such as solar cells and photocatalysts because their bandgaps cover 0.65-3.42 eV. The energy range is the same with photon energy of 362-1900 nm in wavelength. InGaN seems to be possible to utilize solar light efficiently. On the other hand, nitrides are, generally, chemically stable. Chemical stability gives us a hint that semiconductors in solution seem to be possible. Based on these situations, I invented nitride photocatalysts [K. Ohkawa, Japanese Patent 3730142 (2001)]. Nitride photocatalysts are possible to produce “clean hydrogen” from water using light energy [K. Fujii, T. Karasawa, and K. Ohkawa, Jpn. J. Appl. Phys. 44, L543 (2005); M. Ono and K. Ohkawa et al., J. Chem. Phys. 126, 054708 (2007); K. Ohkawa et al., Jpn. J. Appl. Phys. 52, 08JH04 (2013)]. Nitride photocatalysts can reduce CO2 which causes the global warming into “renewable energy” such as HCOOH, CH4 and C2H4 and C2H5OH [S. Yotsuhashi, K. Ohkawa et al., Appl. Phys. Express 4, 117101 (2011); M. Deguchi, K. Ohkawa et al., Jpn. J. Appl. Phys. 52, 08JF07 (2013)]. Concerning HCOOH production, our recent energy conversion efficiency reached 0.97% which is greater than average of global biological photosynthetic one [T. Sekimoto, K. Ohkawa et al., Appl. Phys. Lett. 106, 073902 (2015)]. Nitride photoelectrodes consist of uid-InGaN photo-absorption layer/n+-GaN conductive layer/sapphire or GaN substrate. These structures were grown by metalorganic vapor-phase epitaxy. We used a nitride photoelectrode as a working electrode, a Pt wire as a counterelectrode. These electrodes are connected with a metal wire through their Ohmic contacts. These working- and counter-electrodes are immersed into electrolyte such as 1 M NaOH. We irradiated light from a Xe-lamp or a solar simulator on the nitride photoelectrode. Photoabsorption is happen in the InGaN layer mainly, and absorbed photons create electron-hole pairs. The uid-InGaN is slightly n-type and its surface band bends to the upper energy side at the surface. The band bending causes electron-hole separation. Holes are emitted from InGaN and/or NiO co-catalyst surface, and oxidize water (produce O2 gas). Separated electrons go out from the Ohmic contact to the Pt counterelectrode, and reduce water (produce H2 gas). In case of InGaN with Eg=3.16 eV and a Xe lamp, applied bias photon-to-current efficiency (ABPE) was as high as 4.6% at 0.48 V between the nitride photoelectrode and Pt wire. Decreasing InGaN bandgap, photoabsorption is enhanced then we will realize higher ABPE. Since we are possible to grow high-quality high-In-content InGaN layers, we will get more “clean hydrogen” using nitride photocatalysis phenomenon.

The Oxygen Evolution Reaction at Transition Metal Oxide (TMO) Films in Alkaline Media

Alkaline water electrolysis produces H2 gas, which can be used as a fuel in H2/O2 fuel cells to generate power. The most energy intensive step in water electrolysis is the evolution of O2 due to the large anodic overpotential of the Oxygen Evolution Reaction (OER).1 Thus, understanding and optimizing electrocatalysts for OER remains one of the grand challenges for both physical electrochemistry and energy science. For the OER in alkaline media, the best performing electrocatalysts are thermally prepared RuO2 and IrO2, which exhibit the lowest OER overpotentials to date, but these oxides are expensive and somewhat unstable in alkaline media, rendering them impractical and uneconomical.1 First row Transition Metal Oxides (TMO), e.g. Mn, Ni, Co or Fe, show great promise as alternative materials for OER, as they exhibit low overpotentials and high stability at lower costs than those of RuO2 or IrO2. However, mechanistic studies of OER at TMO electrodes in alkaline media have been sparse and the nature of catalytic sites and the mechanism leading to O2 evolution are not well understood.2 In this work, pure and mixed Ni/Fe materials were electrochemically deposited on Ti supports to fabricate inexpensive electrocatalysts. Their potential as OER catalysts was elucidated in NaOH electrolyte with different amounts of Fe impurities; 1 ppb, 5 ppb and 102 ppb, as determined by Inductive Coupled Plasma (ICP) spectroscopy. The results indicate that the electrocatalytic activity of the materials depends on the ratio of Ni/Fe and the concentration of Fe impurities in the electrolyte. Most of the mixed catalysts show improved OER performances compared to the pure Ni and Fe oxide materials with respect to overpotential at 10 mA cm-2, Figure 1(a), Tafel slope values and Turnover Frequencies (TOF) numbers. Interestingly, the pure and mixed Ni/Fe materials in the NaOH electrolyte containing 5 ppb Fe impurities exhibited lower overpotentials at 10mA cm-2 compared to the same material in the NaOH containing 1 ppb and 100 ppb, Figure 1(a). This is thought to be due to the substitution of the Fe ions in the electrolyte for the Ni atoms in the material lattice, improving the OER performance.3 Pure and mixed manganese and ruthenium oxides were also examined in this work. The OER catalytic activity of pure manganese oxide compounds displaying overpotentials between 0.74 - 0.49 V at a current density of 10 mA cm-2. Furthermore, when combined with other compounds this overpotential value further decreases.4 However, mechanistic studies of the OER at thermally prepared DSA® type MnxOy electrodes in alkaline media have been sparse.2 Several of the mixed Mn/Ru electrode materials in this study were found to exhibit significantly improved OER activity and stability when compared with pure RuO2films, Figure 1(b), while lowering the cost of producing the catalyst.5 These Mn/Ru materials could therefore offer a competitive low-cost alternative to the already commercially available OER catalysts. The composition, morphology and structure of all the aforementioned materials are thoroughly characterised by X-Ray Photoelectron Spectroscopy (XPS), Raman spectroscopy and Scanning Electron Microscopy–Energy Dispersive X-Ray (SEM-EDX). Finally, the Ni/Fe and Mn/Ru oxides will be a compared under cost and OER performance, to help identify the most economic and practical OER catalyst in this work. Acknowledgements We would like to thank Science Foundation Ireland (SFI) under the Grant Number SFI/10/IN.1/I2969. References (1) Lyons, M. E. G.; Doyle, R. L.; Fernandez, D.; Godwin, I. J.; Browne, M. P.; Rovetta, A. Electrochem. Commun. 2014, 45, 56-59. (2) Fernández, J. L.; Gennero De Chialvo, M. R.; Chialvo, A. C. J. Appl. Electrochem. 2002, 32, 513-520. (3) Klaus, S.; Louie, M. W.; Trotochaud, L.; Bell, A. T. The Journal of Physical Chemistry C 2015, 119, 18303-18316. (4) Gao, M.-R.; Xu, Y.-F.; Jiang, J.; Zheng, Y.-R.; Yu, S.-H. J. Am. Chem. Soc. 2012, 134, 2930-2933. (5) Browne, M. P.; Nolan, H.; Duesberg, G. S.; Colavita, P. E.; Lyons, M. E. G. ACS Catalysis 2016. Figure 1

Toward Inexpensive Photocatalytic Hydrogen Evolution: A Nickel Sulfide Catalyst Supported on a High-Stability Metal-Organic Framework.

Few-atom clusters composed of nickel and sulfur have been successfully installed into the Zr(IV)-based metal-organic framework (MOF) NU-1000 via ALD-like chemistry (ALD = atomic layer deposition). X-ray photoelectron spectroscopy and Raman spectroscopy are used to determine that primarily Ni(2+) and S(2-) sites are deposited within the MOF. In a pH 7 buffered aqueous solution, the porous catalyst is able to produce H2 gas at a rate of 3.1 mmol g(-1) h(-1) upon UV irradiation, whereas no H2 is generated by irradiating bare NU-1000. Upon visible light irradiation, little H2 generation was observed; however, with the addition of an organic dye, rose bengal, NiS-AIM can catalyze the production of H2 at an enhanced rate of 4.8 mmol g(-1) h(-1). These results indicate that ALD in MOFs (AIM) can engender reactivity within high surface area supports for applications in the solar fuels field.

Changes in the Photosystem II complex associated with hydrogen formation in sulfur deprived Chlamydomonas reinhardtii

Redox properties of the acceptor side of Photosystem II were studied during H2 gas production in cells of Chlamydomonas reinhardtii. Flash-induced variable fluorescence changes and thermoluminescence measurements were performed in wild type and Stm6 mutant cells during different stages of sulfur (S)-deprivation. Analysis of the fluorescence decay kinetics indicated that the forward electron transfer on the acceptor side of Photosystem II was dramatically slowed down during the O2 evolution and O2 consumption stages and was completely blocked in the anaerobic stage of S-deprivation, thus, indicating a complete reduction of the PQ-pool. During the H2 formation stage, the forward electron transfer kinetics in the μsec and msec time scale re-appeared indicating partially restored electron flow from QA− to QB and the PQ-pool. Thermoluminescese measurements fully confirmed the fluorescence kinetic analysis. Activation of hydrogenase in the H2 formation stage is responsible for re-oxidation of the PQ pool and reactivation of the electron flow which was found to be faster and more efficient on the Stm6 mutant due to the higher amount of functionally preserved Photosystem II.

Effect of Cr(VI) concentration on gas and particle production during iron oxidation in aqueous solutions containing Cl− ions

ABSTRACTZero-valent iron (ZVI) is commonly used as a medium in permeable reactive barriers (PRBs) because of its high reducing ability. The generation of H2 gas in PRBs, however, can decrease the permeability of PRBs and reduce the contact area between the PRB and contaminated groundwater. This study investigated the effect of the initial Cr(VI) concentration ([Cr(VI)init]) in aqueous solutions containing Cl− ions on the generation of H2 gas. ZVI chips were reacted in reactors with 0.5-M NaCl solutions with [Cr(VI)init] ranging between 51 and 303 mg/L. The initial pH was set at 3. The oxidation of ZVI chips by Cr(VI) in aqueous solutions containing Cl− ions produced H2 gas and particles (Fe(III)–Cr(III)(oxy)hydroxides). The Cr(VI) removal from aqueous solutions increased as the [Cr(VI)init] increased, as did H2 gas generation. The positive effect of [Cr(VI)init] on H2 gas generation might be due to an increase in the redox potential gradient as [Cr(VI)init] increases. This increased gradient would enhance H+ ion penetration through the passive film (Fe(III)–Cr(III)(oxy)hydroxides), which formed on the ZVI surface, by diffusion from the solution to pits beneath the passive film.

Essential Genes Predicted in the Genome of Rubrivivax gelatinosus.

Rubrivivax gelatinosus is a betaproteobacterium with impressive metabolic diversity. It is capable of phototrophy, chemotrophy, two different mechanisms of sugar metabolism, fermentation, and H2 gas production. To identify core essential genes, R. gelatinosus was subjected to saturating transposon mutagenesis and high-throughput sequencing (TnSeq) analysis using nutrient-rich, aerobic conditions. Results revealed that virtually no primary metabolic genes are essential to the organism and that genomic redundancy only explains a portion of the nonessentiality, but some biosynthetic pathways are still essential under nutrient-rich conditions. Different essentialities of different portions of the Pho regulatory pathway suggest that overexpression of the regulon is toxic and hint at a larger connection between phosphate regulation and cellular health. Lastly, various essentialities of different tRNAs hint at a more complex situation than would be expected for such a core process. These results expand upon research regarding cross-organism gene essentiality and further enrich the study of purple nonsulfur bacteria. Microbial genomic data are increasing at a tremendous rate, but physiological characterization of those data lags far behind. One mechanism of high-throughput physiological characterization is TnSeq, which uses high-volume transposon mutagenesis and high-throughput sequencing to identify all of the essential genes in a given organism's genome. Here TnSeq was used to identify essential genes in the metabolically versatile betaproteobacterium Rubrivivax gelatinosus The results presented here add to the growing TnSeq field and also reveal important aspects of R. gelatinosus physiology, which are applicable to researchers working on metabolically flexible organisms.

Valorization of Waste Lipids through Hydrothermal Catalytic Conversion to Liquid Hydrocarbon Fuels with in Situ Hydrogen Production

We demonstrate hydrothermal (300 °C, 10 MPa) catalytic conversion of real waste lipids (e.g., waste vegetable oil, sewer trap grease) to liquid hydrocarbon fuels without net need for external chemical inputs (e.g., H2 gas, methanol). A supported bimetallic catalyst (Pt–Re/C; 5 wt % of each metal) previously shown to catalyze both aqueous phase reforming of glycerol (a triacylglyceride lipid hydrolysis coproduct) to H2 gas and conversion of oleic and stearic acid, model unsaturated and saturated fatty acids, to linear alkanes was applied to process real waste lipid feedstocks in water. For reactions conducted with an initially inert headspace gas (N2), waste vegetable oil (WVO) was fully converted into linear hydrocarbons (C15–C17) and other hydrolyzed byproducts within 4.5 h, and H2 gas production was observed. Addition of H2 to the initial reactor headspace accelerated conversion, but net H2 production was still observed, in agreement with results obtained for aqueous mixtures containing model fatty acids and glycerol. Conversion to liquid hydrocarbons with net H2 production was also observed for a range of other waste lipid feedstocks (animal fat residuals, sewer trap grease, dry distiller’s grain oil, coffee oil residual). These findings demonstrate potential for valorization of waste lipids through conversion to hydrocarbons that are more compatible with current petroleum-based liquid fuels than the biodiesel and biogas products of conventional waste lipid processing technologies.

An unprecedented one-step synthesis of octahedral Cu(ii)-bis(iminoquinone) complexes and their reactivity with NaBH4.

A new non-innocent ligand, H2L(AP(o-NO2-OPh)), was synthesized. The ligand H2L(AP(o-NO2-OPh)) reacted with 0.5 equivalents of CuCl2·2H2O and provided the corresponding mononuclear four-coordinate [Cu(ii)-bis(iminosemiquinone)] complex (1). Interestingly, the ligand upon reacting with 2 equivalents of CuCl2·2H2O in the presence of Et3N and air provided the corresponding trans-dichloride-bound six-coordinate mononuclear Cu(ii)-complex (2) in one step. To extend the validity of the newly developed one-step synthesis of the trans-dichloride-bound Cu(ii)-bis(iminoquinone) complex using a non-innocent ligand and 2 equivalents of CuCl2·2H2O, the previously reported non-innocent ligand H2L(AP) was further examined. Thus the formed trans-dichloride-bound Cu(ii)-bis(iminoquinone) complex was designated as complex 3. The complexes were characterized by IR, mass, UV-Vis/NIR, X-band EPR, and X-ray single crystal diffraction techniques. Molecular structure analysis confirmed that in 1 the oxidation state of the coordinating ligands was [L(ISQ(o-NO2-OPh))](1-), i.e., one-electron oxidized iminosemiquinone. In 2 and 3·CH2Cl2, both the coordinated-ligands were present in their two-electron oxidized iminoquinone form. The iminoquinone-complex formation was found to proceed with the generation of CuCl salt. X-band EPR spectrum measurement confirmed that both the iminoquinone-complexes were paramagnetic and the unpaired electron was located at the 3dx(2)-y(2) orbital of Cu(ii) ions. When the Cu(ii)-bis(iminoquinone) complex 3 was subjected to react with NaBH4 in dry CH3CN, H2 gas was formed along with the generation of the corresponding Cu(ii)-bis(iminosemiquinone) complex. GC analyses were performed for the identification of H2 gas.

Hydrogen and syn gas production via CO2 dry reforming of methane over Mg/La promoted Co–Ni/MSU-S catalyst

A series of xMg/La yCozNi/MSU-S catalysts were prepared by a sol–gel method and characterized by means of N2-physisorption, FT-IR, H2-TPR, CO2-TPD, H2-TPD, XRD, HRTEM, TG/DSC and O2-TPO techniques. The catalytic performance of the catalysts was evaluated for H2 and syn gas production at different temperatures at atmospheric pressure. The effect of reaction temperature, catalyst composition and performance of the catalyst were investigated during CO2 dry reforming reaction at 700–800 °C with GHSV of 2.4 × 104 mL/g−1 h−1. The results indicated that upon La, Mg and Co promotion, the Ni nanoparticles are highly dispersed on the mesoporous walls of MSU-S via strong interaction between metal ions and the HO–Si-groups of MSU-S. The presence of La2O3 in xLayCozNi/MSU-S results in enhancement of initial catalytic activity as compared to xMgyCozNi/MSU-S. It revealed that 3 La 2Co 7Ni/MSU-S performed the best with highest CH4 and CO2 conversion showing outstanding catalytic activity, greater stability and low coking for 50 h during 75 h time on stream at 750 °C.

BIOHYDROGEN PRODUCTION FROM FERMENTATION OF SWEET SORHGUM (SORGHUM BIOCULAR L) BY INTEROBACTER AEROGENES ADH-43 IN THE PACKED-BED REACTOR

Hydrogen gas (H2) is one of a clean energy because its combustion produces only water vapor and heat, and leaves no carbon emissions. H2 gas is an energy future that promises both from the aspect of social, economic, or environmental. One of potential raw material for H2 gas production is Sweet sorghum (Sorghum bicolor). It is an annual plant native of tropical adaptive in hot and dry season. Moreover, it has a high biomass production , it also can adapt to extreme and sub-tropical regions. The objective of this experimental work was to produce gas H2 using sweet sorghum at packed-bed reactor by Enterobacter aerogenes ADH-43 and to get optimum dilution rate in order to increase gas H2 production. The reactor used is a packed bed with a working volume of 450 mL and total volume of 900 mL, height 60 cm with a diameter of 4 cm. The reactor is equipped with a coat of water associated with water heating to the temperature maintained at 37 ° C ± 1 oC. It also linked to the flask containing the Ca (OH) 2 which serves to capture the CO2 gas produced, so expect only the H2 gas. Batch experiments were performed in the beginning, the fresh sorghum medium was fed into the reactor before two hours of the stationary phase in order to achieve continuous culture. The steady state condition showed that that optimum dilution rate was 0.15 h-1 with H2 gasproduction 81.50 mmol/L.h and yield 0.87 mol H2/mol total sugar.

Bioeffects of micron-size magnesium particles on inflammatory cells and bone turnover in vivo and in vitro.

Magnesium (Mg) is a promising biodegradable metal offering many potential advantages over current scaffold technologies. Many studies have reported on the corrosion characteristics the Mg and its bioeffects in vitro and in vivo, but there are few studies on the biological effects of the corrosive products of Mg - the micron-size Mg particles (MgMPs). In this study, the effects of size-selected commercial MgMPs on bone turnover and macrophages were investigated in vivo and in vitro. We found that MgMPs were susceptible to engulfment by macrophages, leading to cell lysis, likely resulting from H2 gas production. We also found that the inflammatory cytokines IL-1, IL-6, and TNF-α were induced more strongly by titanium particles (TiMPs) group than by either MgMPs or control. Examination of the expression of bone remodeling markers revealed that MgMPs are beneficial for bone regeneration. Micro-CT scanning indicated that, 30 days postimplantation, unlike TiMPs, MgMPs had no adverse effect on either bone quality or quantity. We have investigated the bioeffects of micron-size MgMPs in vivo and in vitro, and our results indicate that MgMPs may promote bone regeneration without inducing inflammation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 923-931, 2016.