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Sample records for alkaline borohydride treatment

  1. Direct use of alcohols and sodium borohydride as fuel in an alkaline fuel cell

    NASA Astrophysics Data System (ADS)

    Verma, A.; Basu, S.

    The performance of an alkaline fuel cell (AFC) was studied at different electrolyte concentrations and temperatures for the direct feeding of methanol, ethanol and sodium borohydride as fuels. Potassium hydroxide is used as the electrolyte in the alkaline fuel cell. The anode was prepared by using Pt black, carbon paper and Nafion dispersion. Nickel mesh was used as the current collector. A standard cathode made of manganese dioxide/carbon paper/Ni-mesh/Teflon dispersion (Electro-Chem-Technic, UK) was used for testing the fuel cell performance. The experimental results showed that the current density increases with increase in KOH concentration. Maximum current densities of 300, 270 and 360 A m -2 were obtained for methanol, ethanol and sodium borohydride as fuel respectively with 3 M KOH electrolyte at 25 °C. The cell performance decreases with further increase in the KOH concentration. The current density of the alkaline fuel cell increases with increase in temperature for all the three fuels. The increase in current density with temperature is not as high as expected for sodium borohydride. These results are explained based on an electrochemical phenomenon and different associated losses.

  2. Alkaline sodium borohydride gel as a hydrogen source for PEMFC or an energy carrier for NaBH 4-air battery

    NASA Astrophysics Data System (ADS)

    Liu, B. H.; Li, Z. P.; Chen, L. L.

    In this preliminary study, we tried to use sodium polyacrylate as the super absorbent polymer to form alkaline NaBH 4 gel and explored its possibilities for borohydride hydrolysis and borohydride electro-oxidation. It was found that the absorption capacity of sodium polyacrylate decreased with increasing NaBH 4 concentration. The formed gel was rather stable in the sealed vessel but tended to slowly decompose in open air. Hydrogen generation from the gel was carried out using CoCl 2 catalyst precursor solutions. Hydrogen generation rate from the alkaline NaBH 4 gel was found to be higher and impurities in hydrogen were less than that from the alkaline NaBH 4 solution. The NaBH 4 gel also successfully powered a NaBH 4-air battery.

  3. Direct synthesis of calcium borohydride

    DOEpatents

    Ronnebro, Ewa Carin Ellinor; Majzoub, Eric H.

    2009-10-27

    A method is disclosed for directly preparing an alkaline earth metal borohydride, i.e. Ca(BH.sub.4).sub.2, from the alkaline earth metal hydride and the alkaline earth metal boride. The borohydride thus prepared is doped with a small portion of a metal chloride catalyst compound, such as RuCl.sub.3, TiCl.sub.3, or a mixture of TiCl.sub.3 and palladium metal. The process provides for mechanically mixing the dry reagents under an inert atmosphere followed by charging the mixed materials with high pressure hydrogen at about 70 MPa while heating the mixture to about 400.degree. C. The method is relatively simple and inexpensive and provides reversible hydride compounds which are free of the usual contamination introduced by prior art wet chemical methods.

  4. Hydrogen generation from catalytic hydrolysis of alkaline sodium borohydride solution using attapulgite clay-supported Co-B catalyst

    NASA Astrophysics Data System (ADS)

    Tian, Hongjing; Guo, Qingjie; Xu, Dongyan

    An attapulgite clay-supported cobalt-boride (Co-B) catalyst used in portable fuel cell fields is prepared in this paper by impregnation-chemical reduction method. The cost of attapulgite clay is much lower compared with some other inert carriers, such as activated carbon and carbon nanotube. Its microstructure and catalytic activity are analyzed in this paper. The effects of NaOH concentration, NaBH 4 concentration, reacting temperature, catalyst loadings and recycle times on the performance of the catalysts in hydrogen production from alkaline NaBH 4 solutions are investigated. Furthermore, characteristics of these catalysts are carried out in SEM, XRD and TEM analysis. The high catalytic activity of the catalyst indicates that it is a promising and practical catalyst. Activation energy of hydrogen generation using such catalysts is estimated to be 56.32 kJ mol -1. In the cycle test, from the 1st cycle to the 9th cycle, the average hydrogen generation rate decreases gradually from 1.27 l min -1 g -1 Co-B to 0.87 l min -1 g -1 Co-B.

  5. Intrinsic borohydride fuel cell/battery hybrid power sources

    NASA Astrophysics Data System (ADS)

    Hong, Jian; Fang, Bin; Wang, Chunsheng; Currie, Kenneth

    The electrochemical oxidation behaviors of NaBH 4 on Zn, Zn-MH, and MH (metal-hydride) electrodes were investigated, and an intrinsic direct borohydride fuel cell (DBFC)/battery hybrid power source using MH (or Zn-MH) as the anode and MnO 2 as the cathode was tested. Borohydride cannot be effectively oxidized on Zn electrodes at the Zn oxidation potential because of the poor electrocatalytic ability of Zn for borohydride oxidation and the high overpotential, even though borohydride has the same oxidation potential of Zn in an alkaline solution. The borohydride can be electrochemically oxidized on Ni and MH electrodes through a 4e reaction at a high overpotential. Simply adding borohydride into an alkaline electrolyte of a Zn/air or MH/air battery can greatly increase the capacity, while an intrinsic DBFC/MH(or Zn)-MnO 2 battery can deliver a higher peak power than regular DBFCs.

  6. Direct synthesis of magnesium borohydride

    DOEpatents

    Ronnebro, Ewa Carin Ellinor [Kennewick, WA; Severa, Godwin [Honolulu, HI; Jensen, Craig M [Kailua, HI

    2012-04-03

    A method is disclosed for directly preparing an alkaline earth metal borohydride, i.e. Mg(BH.sub.4).sub.2, from the alkaline earth metal boride MgB.sub.2 by hydrogenating the MgB.sub.2 at an elevated temperature and pressure. The boride may also be doped with small amounts of a metal chloride catalyst such as TiCl.sub.3 and/or NiCl.sub.2. The process provides for charging MgB.sub.2 with high pressure hydrogen above at least 70 MPa while simultaneously heating the material to about 350.degree. C. to about 400.degree. C. The method is relatively simple and inexpensive and provides a reversible hydride compound having a hydrogen capacity of at least 11 wt %.

  7. Destabilized and catalyzed borohydride for reversible hydrogen storage

    DOEpatents

    Mohtadi, Rana F [Northville, MI; Zidan, Ragaiy [Aiken, SC; Gray, Joshua [Aiken, SC; Stowe, Ashley C [Knoxville, TN; Sivasubramanian, Premkumar [Aiken, SC

    2012-02-28

    A process of forming a hydrogen storage material, including the steps of: providing a borohydride material of the formula: M(BH.sub.4).sub.x where M is an alkali metal or an alkaline earth metal and 1.ltoreq.x.ltoreq.2; providing an alanate material of the formula: M.sub.1(AlH.sub.4).sub.x where M.sub.1 is an alkali metal or an alkaline earth metal and 1.ltoreq.x.ltoreq.2; providing a halide material of the formula: M.sub.2Hal.sub.x where M.sub.2 is an alkali metal, an alkaline earth metal or transition metal and Hal is a halide and 1.ltoreq.x.ltoreq.4; combining the borohydride, alanate and halide materials such that 5 to 50 molar percent from the borohydride material is present forming a reaction product material having a lower hydrogen release temperature than the alanate material.

  8. Method for producing a borohydride

    DOEpatents

    Kong, Peter C.

    2008-09-02

    A method for producing a borohydride is described and which includes the steps of providing a source of borate; providing a material which chemically reduces the source of the borate to produce a borohydride; and reacting the source of borate and the material by supplying heat at a temperature which substantially effects the production of the borohydride.

  9. Method for producing a borohydride

    DOEpatents

    Kong, Peter C.

    2010-06-22

    A method for producing a borohydride is described that includes the steps of providing a source of borate; providing a material that chemically reduces the source of the borate to produce a borohydride; and reacting the source of the borate and the material by supplying heat at a temperature that substantially effects the production of the borohydride.

  10. A composite of borohydride and super absorbent polymer for hydrogen generation

    NASA Astrophysics Data System (ADS)

    Li, Z. P.; Liu, B. H.; Liu, F. F.; Xu, D.

    To develop a hydrogen source for underwater applications, a composite of sodium borohydride and super absorbent polymer (SAP) is prepared by ball milling sodium borohydride powder with SAP powder, and by dehydrating an alkaline borohydride gel. When sodium polyacrylate (NaPAA) is used as the SAP, the resulting composite exhibits a high rate of borohydride hydrolysis for hydrogen generation. A mechanism of hydrogen evolution from the NaBH 4-NaPAA composite is suggested based on structure analysis by X-ray diffraction and scanning electron microscopy. The effects of water and NiCl 2 content in the precursor solution on the hydrogen evolution behavior are investigated and discussed.

  11. ISSUES WITH ALKALINE TREATMENT OF SLUDGE

    EPA Science Inventory

    This presentation begins with a discussion of the use of lime and other alkaline materials from the very earliest times to the present for killing bacteria, viruses and parasites and for controlling odors in wastewaters and sludge. It answers the question "How did EPA arrive at i...

  12. Quaternary ammonium borohydride adsorption in mesoporous silicate MCM-48

    SciTech Connect

    Wolverton, Michael J; Daemen, Luke L; Hartl, Monika A

    2010-01-01

    Inorganic borohydrides have a high gravimetric hydrogen density but release H2 only under energetically unfavorable conditions. Surface chemistry may help in lowering thermodynamic barriers, but inclusion of inorganic borohydrides in porous silica materials has proved hitherto difficult or impossible. We show that borohydrides with a large organic cation are readily adsorbed inside mesoporous silicates, particularly after surface treatment. Thermal analysis reveals that the decomposition thermodynamics of tetraalkylammonium borohydrides are substantially affected by inclusion in MCM-48. Inelastic neutron scattering (INS) data show that the compounds adsorb on the silica surface. Evidence of pore loading is supplemented by DSC/TGA, XRD, FTIR, and BET isotherm measurements. Mass spectrometry shows significant hydrogen release at lower temperature from adsorbed borohydrides in comparison with the bulk borohydrides. INS data measured for partially decomposed samples indicates that the decomposition of the cation and anion is likely simultaneous. Additionally, these data confirm the formation of Si-H bonds on the silica surface upon decomposition of adsorbed tetramethylammonium borohydride.

  13. Chloride substitution in sodium borohydride

    SciTech Connect

    Ravnsbaek, Dorthe B.; Rude, Line H.; Jensen, Torben R.

    2011-07-15

    The dissolution of sodium chloride and sodium borohydride into each other resulting in formation of solid solutions of composition Na(BH{sub 4}){sub 1-x}Cl{sub x} is studied. The dissolution reaction is facilitated by two methods: ball milling or combination of ball milling and annealing at 300 deg. C for three days of NaBH{sub 4}-NaCl samples in molar ratios of 0.5:0.5 and 0.75:0.25. The degree of dissolution is studied by Rietveld refinement of synchrotron radiation powder X-ray diffraction (SR-PXD) data. The results show that dissolution of 10 mol% NaCl into NaBH{sub 4}, forming Na(BH{sub 4}){sub 0.9}Cl{sub 0.1}, takes place during ball milling. A higher degree of dissolution of NaCl in NaBH{sub 4} is obtained by annealing resulting in solid solutions containing up to 57 mol% NaCl, i.e. Na(BH{sub 4}){sub 0.43}Cl{sub 0.57}. In addition, annealing results in dissolution of 10-20 mol% NaBH{sub 4} into NaCl. The mechanism of the dissolution during annealing and the decomposition pathway of the solid solutions are studied by in situ SR-PXD. Furthermore, the stability upon hydrogen release and uptake were studied by Sieverts measurements. - Graphical Abstract: Dissolution of sodium chloride and sodium borohydride into each other resulting in formation of solid solutions of composition Na(BH{sub 4}){sub 1-x}Cl{sub x} is studied. Dissolution is facilitated by two methods: ball milling or annealing at 300 deg. C for three days of NaBH{sub 4}-NaCl samples. Sample compositions and dissolution mechanism are studied by Rietveld refinement of synchrotron radiation powder X-ray diffraction data. Highlights: > Studies of dissolution of sodium chloride and sodium borohydride into each other. > Solid state diffusion facilitated by mechanical and thermal treatments. > Dissolution is more efficiently induced by heating than by mechanical treatment. > Mechanism for dissolution studied by Rietveld refinement of in situ SR-PXD data.

  14. Effects of alkaline treatment for fibroblastic adhesion on titanium

    PubMed Central

    Cuellar-Flores, Miryam; Acosta-Torres, Laura Susana; Martínez-Alvarez, Omar; Sánchez-Trocino, Benjamin; de la Fuente-Hernández, Javier; Garcia-Garduño, Rigoberto; Garcia-Contreras, Rene

    2016-01-01

    Background: The surface energy of titanium (Ti) implants is very important when determining hydrophilicity or hydrophobicity, which is vital in osseointegration. The purpose of this study was to determine how Ti plates with an alkaline treatment (NaOH) affect the adhesion and proliferation of human periodontal ligament fibroblasts (HPLF). Materials and Methods: In vitro experimental study was carried out. Type 1 commercially pure Ti plates were analyzed with atomic force microscopy to evaluate surface roughness. The plates were treated ultrasonically with NaOH at 5 M (pH 13.7) for 45 s. HPLF previously established from periodontal tissue was inoculated on the treated Ti plates. The adhered and proliferated viable cell numbers were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method for 60 min and 24 h, respectively. The data were analyzed using Kruskal–Wallis tests and multiple comparisons of the Mann–Whitney U-test,P value was fixed at 0.05. Results: The mean roughness values equaled 0.04 μm with an almost flat surface and some grooves. The alkaline treatment of Ti plates caused significantly (P < 0.05) more pronounced HPLF adhesion and proliferation compared to untreated Ti plates. Conclusion: The treatment of Ti plates with NaOH enhances cell adhesion and the proliferation of HPLF cells. Clinically, the alkaline treatment of Ti-based implants could be an option to improve and accelerate osseointegration. PMID:28182066

  15. Alkaline peroxide mechanical pulping of wheat straw with enzyme treatment.

    PubMed

    Zhao, Jian; Li, Xuezhi; Qu, Yinbo; Gao, Peiji

    2004-01-01

    Alkaline peroxide mechanical pulping (APMP) of wheat straw with enzyme treatment was studied. Instead of direct enzyme pretreatment on wheat straw, an alternative treatment method was used, in which coarse pulps from refiner defibrated wheat straw rather than wheat straw were pretreated with a crude enzyme containing mainly xylanase, then impregnated with alkaline H2O2 solution and further refined. The optimum conditions of enzyme treatment were xylanase dosage of 10-15 IU/g of oven-dried wheat straw, 90 min, 50-60 degrees C, pulp consistency of 5-10%, and initial pH of 5.0, and those for chemical impregnation were 6% NaOH, 70-80 degrees C, 60-90 min, and 4 to 5% H2O2. Enzyme treatment improved pulpability of wheat straw by the APMP process, and final pulp quality such as brightness, breaking length, and burst index of pulp. Pulp from the APMP process with enzyme treatment could be bleached to a brightness of 70.5% ISO by two-stage H2O2 bleaching sequence with only 4% H2O2, and breaking length of the bleach pulp reached 4470 m

  16. Catalyzed borohydrides for hydrogen storage

    DOEpatents

    Au, Ming [Augusta, GA

    2012-02-28

    A hydrogen storage material and process is provided in which alkali borohydride materials are created which contain effective amounts of catalyst(s) which include transition metal oxides, halides, and chlorides of titanium, zirconium, tin, and combinations of the various catalysts. When the catalysts are added to an alkali borodydride such as a lithium borohydride, the initial hydrogen release point of the resulting mixture is substantially lowered. Additionally, the hydrogen storage material may be rehydrided with weight percent values of hydrogen at least about 9 percent.

  17. Selective fluorescence reaction of indigocarmine stained eosinophil leucocyte granules induced by alkaline reduction of the bound dye to its leuco derivative.

    PubMed

    Stockert, J C; Trigoso, C I

    1994-03-01

    After staining of mammalian blood smears with indigocarmine, eosinophil granules were the unique cell components which stained deeply blue under bright field illumination. Treatment of stained smears with the reducing agent sodium borohydride completely abolished this colour reaction, while under violet-blue exciting light eosinophil granules appeared with bright green fluorescence. Other reducing agents proved less suitable. Spectral analysis of indigocarmine solutions reduced by sodium borohydride showed an emission peak at lambda = 528 nm and confirmed the microscopic observations. These results indicate that the treatment of indigocarmine stained structures with alkaline solutions of strong reducing agents converts the bound dye into its reduced and highly fluorescent leuco derivative.

  18. Hydrogen Generation Via Sodium Borohydride

    NASA Astrophysics Data System (ADS)

    Mohring, Richard M.; Wu, Ying

    2003-07-01

    Along with the technological challenges associated with developing fuel cells and hydrogen burning engines, a major issue that must be addressed to ensure the ultimate success of a hydrogen economy is the ability to store and transport hydrogen effectively. Millennium Cell has developed and patented a proprietary system for storing and generating hydrogen gas called Hydrogen on Demand™. The system releases the hydrogen stored in fuel solutions of sodium borohydride as needed through an easily controllable catalytic process. The fuel itself is water-based, rich in hydrogen content, and non-flammable. It can be stored in plastic containers under no pressure. After the hydrogen from the fuel is consumed, the remaining product, sodium metaborate (chemically similar to borax), can be recycled back into fresh fuel. In this paper, an overview of the Hydrogen on Demand™ technology is presented along with data showing the performance characteristics of practical hydrogen generation systems. A brief discussion of sodium borohydride regeneration chemistry is also provided.

  19. Barium borohydride chlorides: synthesis, crystal structures and thermal properties.

    PubMed

    Grube, Elisabeth; Olesen, Cathrine H; Ravnsbæk, Dorthe B; Jensen, Torben R

    2016-05-10

    Here we report the synthesis, mechanism of formation, characterization and thermal decomposition of new barium borohydride chlorides prepared by mechanochemistry and thermal treatment of MBH4-BaCl2, M = Li, Na or K in ratios 1 : 1 and 1 : 2. Initially, orthorhombic barium chloride, o-BaCl2 transforms into o-Ba(BH4)xCl2-x, x ∼ 0.15. Excess LiBH4 leads to continued anion substitution and a phase transformation into hexagonal barium borohydride chloride h-Ba(BH4)xCl2-x, which accommodates higher amounts of borohydride, possibly x ∼ 0.85 and resembles h-BaCl2. Thus, two solid solutions are in equilibrium during mechano-chemical treatment of LiBH4-BaCl2 (1 : 1) whereas LiBH4-BaCl2 (2 : 1) converts to h-Ba(BH4)0.85Cl1.15. Upon thermal treatment at T > ∼200 °C, h-Ba(BH4)0.85Cl1.15 transforms into another orthorhombic barium borohydride chloride compound, o-Ba(BH4)0.85Cl1.15, which is structurally similar to o-BaBr2. The samples with M = Na and K have lower reactivity and form o-Ba(BH4)xCl2-x, x ∼ 0.1 and a solid solution of sodium chloride dissolved in solid sodium borohydride, Na(BH4)1-xClx, x = 0.07. The new compounds and reaction mechanisms are investigated by in situ synchrotron radiation powder X-ray diffraction (SR-PXD), Fourier transform infrared spectroscopy (FT-IR) and simultaneous thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), mass spectroscopy (MS) and temperature programmed photographic analysis (TPPA).

  20. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    SciTech Connect

    Delegard, C.H.; Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K.

    1995-05-01

    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes.

  1. Modified lithium borohydrides for reversible hydrogen storage.

    PubMed

    Au, Ming; Jurgensen, Arthur

    2006-04-06

    In an attempt to develop lithium borohydrides as reversible hydrogen storage materials with high hydrogen storage capacities, the feasibility of reducing the dehydrogenation temperature of the lithium borohydride and moderating rehydrogenation conditions was explored. The lithium borohydride was modified by ball milling with metal oxides and metal chlorides as additives. The modified lithium borohydrides released 9 wt % hydrogen starting from 473 K. The dehydrided modified lithium borohydrides absorbed 7-9 wt % hydrogen at 873 K and 7 MPa. The modification with additives reduced the dehydriding starting temperature from 673 to 473 K and moderated the rehydrogenation conditions from 923 K/15 MPa to 873 K/7 MPa. XRD and SEM analysis revealed the formation of an intermediate compound that might play a key role in changing the reaction path, resulting in the lower dehydriding temperature and reversibility. The reversible hydrogen storage capacity of the oxide-modified lithium borohydrides decreased gradually during hydriding/dehydriding cycling. One of the possible reasons for this effect might be the loss of boron during dehydrogenation, but this can be prevented by changing the dehydriding path using appropriate additives. The additives reduced the dehydriding temperature and improved the reversibility, but they also reduced the hydrogen storage capacity. The best compromise can be reached by selecting appropriate additives, optimizing the additive loading, and using new synthesis processes other than ball milling.

  2. Modified borohydrides for reversible hydrogen storage

    SciTech Connect

    Au, Ming

    2005-08-29

    In attempt to develop lithium borohydrides as the reversible hydrogen storage materials with the high capacity, the feasibility to reduce dehydrogenation temperature of the lithium borohydride and moderate rehydrogenation condition has been explored. The commercial available lithium borohydride has been modified by ball milling with metal oxides and metal chlorides as the additives. The modified lithium borohydrides release 9 wt% hydrogen starting from 473K. The dehydrided modified lithium borohydrides absorb 7-9 wt% hydrogen at 873K and 7 MPa. The additive modification reduces dehydriding temperature from 673K to 473K and moderates rehydrogenation conditions to 923K and 15 MPa. XRD and SEM analysis discovered the formation of the intermediate compound TiB{sub 2} that may plays the key role in change the reaction path resulting the lower dehydriding temperature and reversibility. The reversible hydrogen storage capacity of the oxide modified lithium borohydrides decreases gradually during hydriding-dehydriding cycling due to the lost of the boron during dehydrogenation. But, it can be prevented by selecting the suitable additive, forming intermediate boron compounds and changing the reaction path. The additives reduce dehydriding temperature and improve the reversibility, it also reduces the hydrogen storage capacity. The best compromise can be reached by optimization of the additive loading and introducing new process other than ball milling.

  3. Ammine Calcium and Strontium Borohydrides: Syntheses, Structures, and Properties.

    PubMed

    Jepsen, Lars H; Lee, Young-Su; Černý, Radovan; Sarusie, Ram S; Cho, Young Whan; Besenbacher, Flemming; Jensen, Torben R

    2015-10-26

    A new series of solvent- and halide-free ammine strontium metal borohydrides Sr(NH3 )n (BH4 )2 (n=1, 2, and 4) and further investigations of Ca(NH3 )n (BH4 )2 (n=1, 2, 4, and 6) are presented. Crystal structures have been determined by powder XRD and optimized by DFT calculations to evaluate the strength of the dihydrogen bonds. Sr(NH3 )(BH4 )2 (Pbcn) and Sr(NH3 )2 (BH4 )2 (Pnc2) are layered structures, whereas M(NH3 )4 (BH4 )2 (M=Ca and Sr; P21 /c) are molecular structures connected by dihydrogen bonds. Both series of compounds release NH3 gas upon thermal treatment if the partial pressure of ammonia is low. Therefore, the strength of the dihydrogen bonds, the structure of the compounds, and the NH3 /BH4 (-) ratio for M(NH3 )n (BH4 )m have little influence on the composition of the released gasses. The composition of the released gas depends mainly on the thermal stability of the ammine metal borohydride and the corresponding metal borohydride.

  4. [Impacts of alkaline thermal treatment on characteristics of sludge from sewage treatment plant].

    PubMed

    Yang, Shi-Dong; Chen, Xia; Liu, Cao; Xiao, Ben-Yi

    2015-02-01

    Alkaline thermal treatment is an important pretreatment method for sewage sludge. In this paper, in order to optimize the alkaline thermal treatment conditions for sludge pretreatment, four pretreatment parameters ( sludge concentration, pH, temperature and treatment time) were investigated through orthogonal experiments to determine their effects on the sludge disintegration, sludge concentration and sludge morphology of sewage sludge. The experimental results showed that the significance of the four factors on sludge characteristics was in the order of pH > temperature > treatment time > sludge concentration. Additionally, the optimal conditions of the four factors for the release of soluble chemical oxygen demand (SCOD) of unit sludge and decrease of sludge concentration were as follows: 36.55 g x L(-1), pH 12.45, 175 degrees C and 60 min. While the optimal conditions for the decrease of particle size and fractal dimension were 36.55 g x L(-1), pH 12.5, 175 degrees C and 45 min.

  5. Direct borohydride fuel cell using Ni-based composite anodes

    NASA Astrophysics Data System (ADS)

    Ma, Jia; Sahai, Yogeshwar; Buchheit, Rudolph G.

    In this study, nickel-based composite anode catalysts consisting of Ni with either Pd on carbon or Pt on carbon (the ratio of Ni:Pd or Ni:Pt being 25:1) were prepared for use in direct borohydride fuel cells (DBFCs). Cathode catalysts used were 1 mg cm -2 Pt/C or Pd electrodeposited on activated carbon cloth. The oxidants were oxygen, oxygen in air, or acidified hydrogen peroxide. Alkaline solution of sodium borohydride was used as fuel in the cell. High power performance has been achieved by DBFC using non-precious metal, Ni-based composite anodes with relatively low anodic loading (e.g., 270 mW cm -2 for NaBH 4/O 2 fuel cell at 60 °C, 665 mW cm -2 for NaBH 4/H 2O 2 fuel cell at 60 °C). Effects of temperature, oxidant, and anode catalyst loading on the DBFC performance were investigated. The cell was operated for about 100 h and its performance stability was recorded.

  6. Static Compression of Tetramethylammonium Borohydride

    SciTech Connect

    Dalton, Douglas Allen; Somayazulu, M.; Goncharov, Alexander F.; Hemley, Russell J.

    2011-11-15

    Raman spectroscopy and synchrotron X-ray diffraction are used to examine the high-pressure behavior of tetramethylammonium borohydride (TMAB) to 40 GPa at room temperature. The measurements reveal weak pressure-induced structural transitions around 5 and 20 GPa. Rietveld analysis and Le Bail fits of the powder diffraction data based on known structures of tetramethylammonium salts indicate that the transitions are mediated by orientational ordering of the BH{sub 4}{sup -} tetrahedra followed by tilting of the (CH{sub 3}){sub 4}N{sup +} groups. X-ray diffraction patterns obtained during pressure release suggest reversibility with a degree of hysteresis. Changes in the Raman spectrum confirm that these transitions are not accompanied by bonding changes between the two ionic species. At ambient conditions, TMAB does not possess dihydrogen bonding, and Raman data confirms that this feature is not activated upon compression. The pressure-volume equation of state obtained from the diffraction data gives a bulk modulus [K{sub 0} = 5.9(6) GPa, K'{sub 0} = 9.6(4)] slightly lower than that observed for ammonia borane. Raman spectra obtained over the entire pressure range (spanning over 40% densification) indicate that the intramolecular vibrational modes are largely coupled.

  7. Effect of alkaline treatment on the characterization of zalacca midrib wastes fibers

    NASA Astrophysics Data System (ADS)

    Raharjo, Wahyu Purwo; Soenoko, Rudy; Purnowidodo, Anindito; Choiron, Mochammad Agus; Triyono

    2016-03-01

    Nowadays, the need for new materials is urgent due to the scarcity of conventional materials and energy resources. The environmental issue requires materials which are biodegradable. There are many composites, arranged from synthetic fibers and matrix, which cannot be recyclable after their lifetime. In this research, the utilization potency of zalacca midrib wastes for their fibers as composite reinforcement were investigated, especially after the alkaline treatment to improve their characteristics. The influence of alkaline treatment on the density, functional groups of the fiber surface, thermal stability and crystallinity were measured and/or analyzed by linear-density-and-diameter-calculation, FTIR, TGA-DTA and XRD, respectively. The result showed that the zalacca midrib fibers had lower density than synthetic fibers and several natural fibers. Analysis of FTIR spectra indicated that the alkaline treatment of NaOH slightly raised their density because it removed several functional groups which attributed to the hemicellulose and lignin. TGA-DTA analysis indicated that zalacca fibers had good thermal stability until temperature of 220°C and it was improved by alkaline treatment. XRD analysis showed that the crystallinity of zalacca fibers was higher than several natural fibers like rice straw, sorghum stem and wheat straw fibers. Their crystallinity index was higher than wheat straw fiber. The alkaline treatment increases the crystallinity and crystallinity index rather than untreated fibers.

  8. Diborane release and structure distortion in borohydrides.

    PubMed

    Callini, Elsa; Borgschulte, Andreas; Ramirez-Cuesta, Anibal Javier; Züttel, Andreas

    2013-01-21

    Hydrogen desorption from borohydrides is often accompanied by the release of diborane. The amount of diborane released as a byproduct during the decomposition of borohydrides scales inversely with the borohydride stability, which in turn depends on the electronegativity of the corresponding cation. We present a model based on the difference between the symmetric and asymmetric assembly of B(2)H(6) units at the surface. The origin of this reaction is the degree of distortion of the BH(4)(-) anions in the bulk, hitherto depending on the degree of ionization of the cation. A practical measure of the distortion is the range in which the stretching vibration modes appear, which is the difference in the energy of the stretching vibrations of hydrogen atoms with maximum different bonding lengths (Badger's rule). We propose from this relation that the diborane released from the surface of the relatively unstable LiZn(2)(BH(4))(5) is formed from a recombination of BH(2)(δ+) and BH(4)(δ-) units. Ultra high vacuum mass spectroscopy measurements support the presented model and clarify the decomposition of stable borohydrides, such as LiBH(4). The sublimation of borohydrides in UHV competes with their decomposition.

  9. Sodium Borohydride/Hydrogen Peroxide Fuel Cells For Space Application

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Deelo, M. E.; Narayanan, S. R.

    2006-01-01

    This viewgraph presentation examines Sodium Borohydride and Hydrogen Peroxide Fuel Cells as they are applied to space applications. The topics include: 1) Motivation; 2) The Sodium Borohydride Fuel Cell; 3) Sodium Borohydride Fuel Cell Test Stands; 4) Fuel Cell Comparisons; 5) MEA Performance; 6) Anode Polarization; and 7) Electrode Analysis. The benefits of hydrogen peroxide as an oxidant and benefits of sodium borohydride as a fuel are also addressed.

  10. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  11. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  12. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  13. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  14. 40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for...

  15. Experimental data developed to support the selection of a treatment process for West Valley alkaline supernatant

    SciTech Connect

    Bray, L.A.; Holton, L.K.; Myers, T.R.; Richardson, G.M.; Wise, B.M.

    1984-01-01

    At the request of West Valley Nuclear Services Co., Inc., the Pacific Northwest Laboratory (PNL) has studied alternative treatment processes for the alkaline PUREX waste presently being stored in Tank 8D2 at West Valley, New York. Five tasks were completed during FY 1983: (1) simulation and characterization of the alkaline supernatant and sludge from the tank. The radiochemical and chemical distributions between the aqueous and solid phase were determined, and the efficiency of washing sludge with water to remove ions such as Na/sup +/ and SO/sub 4//sup 2 -/ was investigated; (2) evaluation of a sodium tetraphenylboron (Na-TPB) precipitation process to recover cesium (Cs) and a sodium titanate (Na-TiA) sorption process to recover strontium (Sr) and plutonium (Pu) from the West Valley Alkaline supernatant. These processes were previously developed and tested at the US Department of Energy's Savannah River Plant; (3) evaluation of an organic cation-exchange resin (Duolite CS-100) to recover Cs and Pu from the alkaline supernatant followed by an organic macroreticular cation exchange resin (Amberlite IRC-718) to recover Sr; (4) evaluation of an inorganic ion exchanger (Linde Ionsiv IE-95) to recover Cs, Sr, and Pu from the alkaline supernatant; and (5) evaluation of Dowex-1,X8 organic anion exchange resin to recover technetium (Tc) from alkaline supernatant. The findings of these tasks are reported. 21 references, 36 figures, 34 tables.

  16. Coupling alkaline pre-extraction with alkaline-oxidative post-treatment of corn stover to enhance enzymatic hydrolysis and fermentability

    PubMed Central

    2014-01-01

    Background A two-stage chemical pretreatment of corn stover is investigated comprising an NaOH pre-extraction followed by an alkaline hydrogen peroxide (AHP) post-treatment. We propose that conventional one-stage AHP pretreatment can be improved using alkaline pre-extraction, which requires significantly less H2O2 and NaOH. To better understand the potential of this approach, this study investigates several components of this process including alkaline pre-extraction, alkaline and alkaline-oxidative post-treatment, fermentation, and the composition of alkali extracts. Results Mild NaOH pre-extraction of corn stover uses less than 0.1 g NaOH per g corn stover at 80°C. The resulting substrates were highly digestible by cellulolytic enzymes at relatively low enzyme loadings and had a strong susceptibility to drying-induced hydrolysis yield losses. Alkaline pre-extraction was highly selective for lignin removal over xylan removal; xylan removal was relatively minimal (~20%). During alkaline pre-extraction, up to 0.10 g of alkali was consumed per g of corn stover. AHP post-treatment at low oxidant loading (25 mg H2O2 per g pre-extracted biomass) increased glucose hydrolysis yields by 5%, which approached near-theoretical yields. ELISA screening of alkali pre-extraction liquors and the AHP post-treatment liquors demonstrated that xyloglucan and β-glucans likely remained tightly bound in the biomass whereas the majority of the soluble polymeric xylans were glucurono (arabino) xylans and potentially homoxylans. Pectic polysaccharides were depleted in the AHP post-treatment liquor relative to the alkaline pre-extraction liquor. Because the already-low inhibitor content was further decreased in the alkaline pre-extraction, the hydrolysates generated by this two-stage pretreatment were highly fermentable by Saccharomyces cerevisiae strains that were metabolically engineered and evolved for xylose fermentation. Conclusions This work demonstrates that this two

  17. Platinum-rare earth cathodes for direct borohydride-peroxide fuel cells

    NASA Astrophysics Data System (ADS)

    Cardoso, D. S. P.; Santos, D. M. F.; Šljukić, B.; Sequeira, C. A. C.; Macciò, D.; Saccone, A.

    2016-03-01

    Hydrogen peroxide (H2O2) is being actively investigated as an oxidant for direct borohydride fuel cells. Herein, platinum-rare earth (RE = Sm, Dy, Ho) alloys are prepared by arc melting and their activity for hydrogen peroxide reduction reaction (HPRR) is studied in alkaline media. Cyclic voltammetry and chronoamperometry measurements show that Pt-Sm electrode displays the highest catalytic activity for HPRR with the lowest activation energy, followed by Pt-Ho, while Pt-Dy alloys show practically no activity. Laboratory direct borohydride-peroxide fuel cells (DBPFCs) are assembled using these alloys. The DBPFC with Pt-Sm cathode gives the highest peak power density of 85 mW cm-2, which is more than double of that obtained in a DBPFC with Pt electrodes.

  18. Treatment of Alkaline Cr(VI)-Contaminated Leachate with an Alkaliphilic Metal-Reducing Bacterium

    PubMed Central

    Watts, Mathew P.; Khijniak, Tatiana V.; Boothman, Christopher

    2015-01-01

    Chromium in its toxic Cr(VI) valence state is a common contaminant particularly associated with alkaline environments. A well-publicized case of this occurred in Glasgow, United Kingdom, where poorly controlled disposal of a cementitious industrial by-product, chromite ore processing residue (COPR), has resulted in extensive contamination by Cr(VI)-contaminated alkaline leachates. In the search for viable bioremediation treatments for Cr(VI), a variety of bacteria that are capable of reduction of the toxic and highly soluble Cr(VI) to the relatively nontoxic and less mobile Cr(III) oxidation state, predominantly under circumneutral pH conditions, have been isolated. Recently, however, alkaliphilic bacteria that have the potential to reduce Cr(VI) under alkaline conditions have been identified. This study focuses on the application of a metal-reducing bacterium to the remediation of alkaline Cr(VI)-contaminated leachates from COPR. This bacterium, belonging to the Halomonas genus, was found to exhibit growth concomitant to Cr(VI) reduction under alkaline conditions (pH 10). Bacterial cells were able to rapidly remove high concentrations of aqueous Cr(VI) (2.5 mM) under anaerobic conditions, up to a starting pH of 11. Cr(VI) reduction rates were controlled by pH, with slower removal observed at pH 11, compared to pH 10, while no removal was observed at pH 12. The reduction of aqueous Cr(VI) resulted in the precipitation of Cr(III) biominerals, which were characterized using transmission electron microscopy and energy-dispersive X-ray analysis (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The effectiveness of this haloalkaliphilic bacterium for Cr(VI) reduction at high pH suggests potential for its use as an in situ treatment of COPR and other alkaline Cr(VI)-contaminated environments. PMID:26048926

  19. Treatment of Alkaline Cr(VI)-Contaminated Leachate with an Alkaliphilic Metal-Reducing Bacterium.

    PubMed

    Watts, Mathew P; Khijniak, Tatiana V; Boothman, Christopher; Lloyd, Jonathan R

    2015-08-15

    Chromium in its toxic Cr(VI) valence state is a common contaminant particularly associated with alkaline environments. A well-publicized case of this occurred in Glasgow, United Kingdom, where poorly controlled disposal of a cementitious industrial by-product, chromite ore processing residue (COPR), has resulted in extensive contamination by Cr(VI)-contaminated alkaline leachates. In the search for viable bioremediation treatments for Cr(VI), a variety of bacteria that are capable of reduction of the toxic and highly soluble Cr(VI) to the relatively nontoxic and less mobile Cr(III) oxidation state, predominantly under circumneutral pH conditions, have been isolated. Recently, however, alkaliphilic bacteria that have the potential to reduce Cr(VI) under alkaline conditions have been identified. This study focuses on the application of a metal-reducing bacterium to the remediation of alkaline Cr(VI)-contaminated leachates from COPR. This bacterium, belonging to the Halomonas genus, was found to exhibit growth concomitant to Cr(VI) reduction under alkaline conditions (pH 10). Bacterial cells were able to rapidly remove high concentrations of aqueous Cr(VI) (2.5 mM) under anaerobic conditions, up to a starting pH of 11. Cr(VI) reduction rates were controlled by pH, with slower removal observed at pH 11, compared to pH 10, while no removal was observed at pH 12. The reduction of aqueous Cr(VI) resulted in the precipitation of Cr(III) biominerals, which were characterized using transmission electron microscopy and energy-dispersive X-ray analysis (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The effectiveness of this haloalkaliphilic bacterium for Cr(VI) reduction at high pH suggests potential for its use as an in situ treatment of COPR and other alkaline Cr(VI)-contaminated environments.

  20. Synthesis of Borohydride and Catalytic Dehydrogenation by Hydrogel Based Catalyst

    NASA Astrophysics Data System (ADS)

    Boynuegri, Tugba Akkas; Karabulut, Ahmet F.; Guru, Metin

    2016-08-01

    This paper deals with the synthesis of calcium borohydride (Ca(BH4)2) as hydrogen storage material. Calcium chloride salt (CaCl2), magnesium hydride (MgH2), and boron oxide (B2O3) were used as reactants in the mechanochemical synthesis of Ca(BH4)2. The mechanochemical reaction was carried out by means of Spex type ball milling without applying high pressure and temperature. Parametric studies have been established at different reaction times and for different amounts of reactants at a constant ball to powder ratio (BPR) 4:1. The best combination was determined by Fourier Transform Infrared (FT-IR) analysis. According to the FT-IR analysis, reaction time, the first reaction parameter, was found as 1600 min. After the reaction time was fixed at 1600 min, the difference of the B-H peak areas was dependent on the amount of reactant MgH2 that was investigated. The amount of the reactant (MgH2), the second reaction parameter, was measured to be 2.85 times more than the stoichiometric amount of MgH2. According to our previous studies, BPR was selected as 4:1 for all experiments. Samples were prepared in a glove box under argon atmosphere but the time that elapsed for FT-IR analysis highly affected B-H bonds. B-H peak areas clearly decreased with time because of negative effect of ambient atmosphere. A catalyst was prepared by absorbing cobalt fluoride (CoF2) in poly (acrylamide-co-acrylic acid) hydrogel matrices type and its catalytic dehydrogenation performance that has been characterized by the catalytic reaction of sodium borohydride's known hydrogen capacity in an alkaline medium. The metal amount of hydrogel catalyst was determined as 135.82 mg Co by Atomic Absorption Spectroscopy (AAS). The specific dehydrogenation capacity of the Co active compound in the catalyst thanks to catalytic dehydrogenation of commercial sodium borohydride was measured as 1.66 mL H2/mg Co.

  1. Treatment of cotton with an alkaline Bacillus spp cellulase: activity towards crystalline cellulose.

    PubMed

    Caparrós, Cristina; López, Carmen; Torrell, Marc; Lant, Neil; Smets, Johan; Cavaco-Paulo, Artur

    2012-02-01

    We analysed the influence of several enzymatic treatment processes using an alkaline cellulase enzyme from Bacillus spp. on the sorption properties of cotton fabrics. Although cellulases are commonly applied in detergent formulations due to their anti-redeposition and depilling benefits, determining the mechanism of action of alkaline cellulases on cotton fibres requires a deeper understanding of the morphology and structure of cotton fibres in terms of fibre cleaning. The accessibility of cellulose fibres was studied by evaluating the iodine sorption value and by fluorescent-labelled enzyme microscopy; the surface morphology of fabrics was analysed by scanning microscopy. The action of enzyme hydrolysis over short time periods can produce fibrillation on cotton fibre surface without any release of cellulosic material. The results indicate that several short consecutive treatments were more effective in increasing the fibre accessibility than one long treatment. In addition, no detectable hydrolytic activity, in terms of reducing sugar production, was found.

  2. Comparative study of low-energy ultrasonic and alkaline treatment on biosludge from secondary industrial wastewater treatment.

    PubMed

    Li, Dongzhe; Tan, Youming; Zhou, Yan; Pathak, Santosh; Sendjaja, Antonius Yudi; Abdul Majid, Maszenan; Chowdhury, Prannoy; Ng, Wun Jern

    2015-01-01

    In this study, low-energy ultrasonic (3 and 6 kJ/g volatile solids of feed biomass (FB) which was lower than the heat value of the FB), alkaline, and ultrasonic-alkaline pretreatments were applied on FB, a biosludge from secondary industrial wastewater treatment. Biochemical methane potential (BMP), particle size distribution, Biomass Stress Index (BSI™), soluble chemical oxygen demand (SCOD), protein, carbohydrate, and size-exclusion chromatography (SEC) fingerprints were used to comparatively study the mechanisms of these pretreatment methods. The results indicated that low-energy ultrasonication and alkali exhibited significantly different impacts on the FB. After ultrasonication with energy input of 6 kJ/g-VS, the average particle size of FB was reduced from 102.6 to 19.4 µm. However, ultrasonication had no obvious effect on microbial cells rupture, solubilization of protein and carbohydrate, and SEC fingerprint. Consequently, low-energy ultrasonication could not enhance methane generation. However, after alkaline pretreatment with dosage of 0.3 g-NaOH/g-VS, SCOD, soluble protein, and soluble carbohydrate concentration of FB increased from 0.66, 0.00, 0.07 to 2.83, 0.83, 0.47 g/L, respectively. At the same time, BSI™ increased from 5.3% to 96.8%, and the SEC fingerprint changed significantly. Consequently, the methane generation in the BMP test increased from 68.9 to 135.0 mL. Ultrasonic-alkaline pretreatment was similar to alkaline pretreatment in terms of methane generation. Based on this study, alkaline pretreatment is recommended over both low-energy ultrasonic and low-energy ultrasonic-alkaline pretreatment to enhance the biodegradability of FB.

  3. MODIFIED BOROHYDRIDES FOR REVERSIBLE HYDROGEN STORAGE

    SciTech Connect

    Au, Ming

    2006-05-10

    This paper reports the results in the effort to destabilize lithium borohydride for reversible hydrogen storage. A number of metals, metal hydrides, metal chlorides and complex hydrides were selected and evaluated as the destabilization agents for reducing dehydriding temperature and generating dehydriding-rehydriding reversibility. It is found that some additives are effective. The Raman spectroscopic analysis shows the change of B-H binding nature.

  4. BIMETALLIC LITHIUM BOROHYDRIDES TOWARD REVERSIBLE HYDROGEN STORAGE

    SciTech Connect

    Au, M.

    2010-10-21

    Borohydrides such as LiBH{sub 4} have been studied as candidates for hydrogen storage because of their high hydrogen contents (18.4 wt% for LiBH{sub 4}). Limited success has been made in reducing the dehydrogenation temperature by adding reactants such as metals, metal oxides and metal halides. However, full rehydrogenation has not been realized because of multi-step decomposition processes and the stable intermediate species produced. It is suggested that adding second cation in LiBH{sub 4} may reduce the binding energy of B-H. The second cation may also provide the pathway for full rehydrogenation. In this work, several bimetallic borohydrides were synthesized using wet chemistry, high pressure reactive ball milling and sintering processes. The investigation found that the thermodynamic stability was reduced, but the full rehydrogenation is still a challenge. Although our experiments show the partial reversibility of the bimetallic borohydrides, it was not sustainable during dehydriding-rehydriding cycles because of the accumulation of hydrogen inert species.

  5. Inactivation of Geobacillus stearothermophilus spores by alkaline hydrolysis applied to medical waste treatment.

    PubMed

    Pinho, Sílvia C; Nunes, Olga C; Lobo-da-Cunha, Alexandre; Almeida, Manuel F

    2015-09-15

    Although alkaline hydrolysis treatment emerges as an alternative disinfection/sterilization method for medical waste, information on its effects on the inactivation of biological indicators is scarce. The effects of alkaline treatment on the resistance of Geobacillus stearothermophilus spores were investigated and the influence of temperature (80 °C, 100 °C and 110 °C) and NaOH concentration was evaluated. In addition, spore inactivation in the presence of animal tissues and discarded medical components, used as surrogate of medical waste, was also assessed. The effectiveness of the alkaline treatment was carried out by determination of survival curves and D-values. No significant differences were seen in D-values obtained at 80 °C and 100 °C for NaOH concentrations of 0.5 M and 0.75 M. The D-values obtained at 110 °C (2.3-0.5 min) were approximately 3 times lower than those at 100 °C (8.8-1.6 min). Independent of the presence of animal tissues and discarded medical components, 6 log10 reduction times varied between 66 and 5 min at 100 °C-0.1 M NaOH and 110 °C-1 M NaOH, respectively. The alkaline treatment may be used in future as a disinfection or sterilization alternative method for contaminated waste.

  6. Evaluation of anode (electro)catalytic materials for the direct borohydride fuel cell: Methods and benchmarks

    NASA Astrophysics Data System (ADS)

    Olu, Pierre-Yves; Job, Nathalie; Chatenet, Marian

    2016-09-01

    In this paper, different methods are discussed for the evaluation of the potential of a given catalyst, in view of an application as a direct borohydride fuel cell DBFC anode material. Characterizations results in DBFC configuration are notably analyzed at the light of important experimental variables which influence the performances of the DBFC. However, in many practical DBFC-oriented studies, these various experimental variables prevent one to isolate the influence of the anode catalyst on the cell performances. Thus, the electrochemical three-electrode cell is a widely-employed and useful tool to isolate the DBFC anode catalyst and to investigate its electrocatalytic activity towards the borohydride oxidation reaction (BOR) in the absence of other limitations. This article reviews selected results for different types of catalysts in electrochemical cell containing a sodium borohydride alkaline electrolyte. In particular, propositions of common experimental conditions and benchmarks are given for practical evaluation of the electrocatalytic activity towards the BOR in three-electrode cell configuration. The major issue of gaseous hydrogen generation and escape upon DBFC operation is also addressed through a comprehensive review of various results depending on the anode composition. At last, preliminary concerns are raised about the stability of potential anode catalysts upon DBFC operation.

  7. Tailoring the properties of ammine metal borohydrides for solid-state hydrogen storage.

    PubMed

    Jepsen, Lars H; Ley, Morten B; Filinchuk, Yaroslav; Besenbacher, Flemming; Jensen, Torben R

    2015-04-24

    A series of halide-free ammine manganese borohydrides, Mn(BH4 )2 ⋅nNH3 , n=1, 2, 3, and 6, a new bimetallic compound Li2 Mn(BH4 )4 ⋅6NH3 , and the first ammine metal borohydride solid solution Mg1-x Mnx (BH4 )2 ⋅6NH3 are presented. Four new crystal structures have been determined by synchrotron radiation powder X-ray diffraction and the thermal decomposition is systematically investigated for all the new compounds. The solid-gas reaction between Mn(BH4 )2 and NH3 provides Mn(BH4 )2 ⋅6NH3 . The number of NH3 per Mn has been varied by mechanochemical treatment of Mn(BH4 )2 ⋅6NH3 -Mn(BH4 )2 mixtures giving rise to increased hydrogen purity for n/m≤1 for M(BH4 )m ⋅nNH3 . The structures of Mg(BH4 )2 ⋅3NH3 and Li2 Mg(BH4 )4 ⋅6NH3 have been revisited and new structural models are presented. Finally, we demonstrate that ammonia destabilizes metal borohydrides with low electronegativity of the metal (χp <∼1.6), while metal borohydrides with high electronegativity (χp >∼1.6) are generally stabilized.

  8. Physicochemical Properties of Defatted Rambutan (Nephelium lappaceum) Seed Flour after Alkaline Treatment.

    PubMed

    Eiamwat, Jirawat; Wanlapa, Sorada; Kampruengdet, Sukit

    2016-03-31

    Rambutan seeds were subjected to SC-CO₂ extraction at 35 MPa, 45 °C to obtain defatted rambutan seed flour. Its physicochemical properties before and after treatment with alkali solution using 0.075 N NaOH were investigated. Alkali-treated flour had a significant increment in bulk density, swelling power, water adsorption capacity, emulsion capacity and stability but a reduction in turbidity, solubility and oil absorption capacity. Pasting measurements showed peak viscosity, breakdown, setback and final viscosity increased significantly for the alkali-treated flour, while pasting temperature decreased. The alkaline treatment decreased the least gelation concentration, but increased the apparent viscosity.

  9. Metal borohydrides and derivatives - synthesis, structure and properties.

    PubMed

    Paskevicius, Mark; Jepsen, Lars H; Schouwink, Pascal; Černý, Radovan; Ravnsbæk, Dorthe B; Filinchuk, Yaroslav; Dornheim, Martin; Besenbacher, Flemming; Jensen, Torben R

    2017-03-06

    A wide variety of metal borohydrides, MBH4, have been discovered and characterized during the past decade, revealing an extremely rich chemistry including fascinating structural flexibility and a wide range of compositions and physical properties. Metal borohydrides receive increasing interest within the energy storage field due to their extremely high hydrogen density and possible uses in batteries as solid state ion conductors. Recently, new types of physical properties have been explored in lanthanide-bearing borohydrides related to solid state phosphors and magnetic refrigeration. Two major classes of metal borohydride derivatives have also been discovered: anion-substituted compounds where the complex borohydride anion, BH4(-), is replaced by another anion, i.e. a halide or amide ion; and metal borohydrides modified with neutral molecules, such as NH3, NH3BH3, N2H4, etc. Here, we review new synthetic strategies along with structural, physical and chemical properties for metal borohydrides, revealing a number of new trends correlating composition, structure, bonding and thermal properties. These new trends provide general knowledge and may contribute to the design and discovery of new metal borohydrides with tailored properties towards the rational design of novel functional materials. This review also demonstrates that there is still room for discovering new combinations of light elements including boron and hydrogen, leading to complex hydrides with extreme flexibility in composition, structure and properties.

  10. Fungal treatment of cornstalks enhances the delignification and xylan loss during mild alkaline pretreatment and enzymatic digestibility of glucan.

    PubMed

    Yu, Hongbo; Du, Wanqing; Zhang, Ji; Ma, Fuying; Zhang, Xiaoyu; Zhong, Weixin

    2010-09-01

    Fungal treatment with Irpex lacteus was used to enhance the delignification and xylan loss during mild alkaline pretreatment and subsequent enzymatic conversion in this research. The 15-day bio-treatment can modify the lignin structure and increase losses of lignin (from 75.67% to 80.00%) and xylan (from 40.68% to 51.37%) during alkaline pretreatment, making the enzymatic conversion more efficient. The high digestibility of glucan can be obtained after the bio-treatment and alkaline pretreatment at near room-temperature (30 degrees C), and the maximum digestibility increased 14% in comparison with that after the sole alkaline pretreatment. The bio-treatment enhanced delignification and glucan digestibility more significantly when the alkaline pretreatment was performed at lower severity. Additionally, Nuclei Growth model with a time-dependent rate constant can describe well the delignification and xylan loss. Results indicated that the bio-treatment increased the rate constant of initial reaction, but accelerated the decline of rate constant during alkaline pretreatment.

  11. Sodium borohydride based hybrid power system

    NASA Astrophysics Data System (ADS)

    Richardson, Bradley S.; Birdwell, Joseph F.; Pin, François G.; Jansen, John F.; Lind, Randall F.

    Sodium borohydride's properties make it a good source of hydrogen for use with a fuel cell for an on-demand system that is easily controllable and has no idle costs. Previous work, as described in the literature, indicated that ruthenium (Ru) is an efficient catalyst for generating hydrogen from sodium borohydride. Tests were conducted to evaluate catalyst loading with the results of these tests indicating that the hydrolysis rate is affected by the loading of the catalyst. It was also apparent that the substrate surface is not completely occupied by Ru at the lower loadings, and that increased loadings are needed to optimize the reaction rate. A differential rate test with a fixed bed reactor was also conducted. It was observed that temperature has a significant effect on the rate of reaction. Feed rate also affected the rate of reaction with lower feed rates (longer residence time in the reactor) having higher reaction rates. A bench-top hybrid system was also developed and tested. This test bed demonstrated how a system based on a chemically generated hydrogen-fed proton exchange membrane fuel cell could be integrated with batteries to provide a hybrid power system that can meet the demands of a highly varying electrical load up to four times the rated output of the fuel cell.

  12. Summary technical report on the electrochemical treatment of alkaline nuclear wastes

    SciTech Connect

    Hobbs, D.T.

    1994-07-30

    This report summarizes the laboratory studies investigating the electrolytic treatment of alkaline solutions carried out under the direction of the Savannah River Technology Center from 1985-1992. Electrolytic treatment has been demonstrated at the laboratory scale to be feasible for the destruction of nitrate and nitrite and the removal of radioactive species such as {sup 99}Tc and {sup 106}Ru from Savannah River Site (SRS) decontaminated salt solution and other alkaline wastes. The reaction rate and current efficiency for the removal of these species are dependent on cell configuration, electrode material, nature of electrode surface, waste composition, current density, and temperature. Nitrogen, ammonia, and nitrous oxide have been identified as the nitrogen-containing reaction products from the electrochemical reduction of nitrate and nitrite under alkaline conditions. The reaction mechanism for the reduction is very complex. Voltammetric studies indicated that the electrode reactions involve surface phenomena and are not necessarily mass transfer controlled. In an undivided cell, results suggest an electrocatalytic role for oxygen via the generation of the superoxide anion. In general, more efficient reduction of nitrite and nitrate occurs at cathode materials with higher overpotentials for hydrogen evolution. Nitrate and nitrite destruction has also been demonstrated in engineering-scale flow reactors. In flow reactors, the nitrate/nitrite destruction efficiency is improved with an increase in the current density, temperature, and when the cell is operated in a divided cell configuration. Nafion{reg_sign} cation exchange membranes have exhibited good stability and consistent performance as separators in the divided-cell tests. The membranes were also shown to be unaffected by radiation at doses approximating four years of cell operation in treating decontaminated salt solution.

  13. Application of alkaline treatment for sludge decrement and humic acid recovery.

    PubMed

    Li, Huan; Jin, Yiying; Nie, Yongfeng

    2009-12-01

    A new method was introduced to reduce waste activated sludge and extract humic acid for liquid fertilizer. Sludge was disintegrated with NaOH (0.4 g/g dry solid, 8 h) and then centrifuged to obtain the supernatant. The residual sludge was then dewatered, while the supernatant was used to extract humic acid with an ultrafiltration membrane. The results showed that the alkaline treatment dissolved more than half of the sludge organic matter, which was composed of 24% humic acid by mass. After the supernatant was concentrated 20 times using a membrane with a molecular weight cutoff of 1000, the retentate contained 94.5% of the dissolved organics and could be used to produce humic acid fertilizer. Additionally, only 26% of the NaOH was consumed and the residual NaOH in the permeate flux could be reused. Due to the removal of water and organics, the dewatered sludge could be reduced by 60% when compared to samples that did not receive the alkaline treatment.

  14. High volume hydrogen production from the hydrolysis of sodium borohydride using a cobalt catalyst supported on a honeycomb matrix

    NASA Astrophysics Data System (ADS)

    Marchionni, Andrea; Bevilacqua, Manuela; Filippi, Jonathan; Folliero, Maria G.; Innocenti, Massimo; Lavacchi, Alessandro; Miller, Hamish A.; Pagliaro, Maria V.; Vizza, Francesco

    2015-12-01

    Hydrogen storage and distribution will be two very important aspects of any renewable energy infrastructure that uses hydrogen as energy vector. The chemical storage of hydrogen in compounds like sodium borohydride (NaBH4) could play an important role in overcoming current difficulties associated with these aspects. Sodium borohydride is a very attractive material due to its high hydrogen content. In this paper, we describe a reactor where a stable cobalt based catalyst supported on a commercial Cordierite Honeycomb Monolith (CHM) is employed for the hydrolysis of alkaline stabilized NaBH4 (SBH) aqueous solutions. The apparatus is able to operate at up to 5 bar and 130 °C, providing a hydrogen generation rate of up to 32 L min-1.

  15. Investigation on application of homogeneous and heterogeneous catalysis for alkaline waste treatment

    SciTech Connect

    Shilov, V.P.; Bessonov, A.A.; Garnov, A.Y.; Gelis, A.V.

    1997-09-01

    The stabilization of neptunium(IV) in alkaline solution by chemical reductants under various conditions was studied. Testing showed that neptunium(V) is slowly reduced to Np(IV) by V(IV) at room temperature in alkaline solutions. Increasing temperature accelerates reduction. Complete reduction of 2 x 10{sup -4} M Np(V) occurs in three hours at 80{degrees}C in 1 M NaOH with 0.02 M VOSO{sub 4-}. Under similar conditions, but in 5 M NaOH, only 15 to 20% of the Np(V) was reduced in 5 hours. In all cases, about 98 % of the initial neptunium was found in the precipitate. Thus V(IV) acts both as a reductant and as a precipitation carrier. Tests showed Np(V) reduction by hydrazine hydrate could be catalyzed by Pd(II). Reduction increased with temperature and catalyst concentration and decreased with hydroxide concentration. Reduction of Np(V) also takes place in 1 M NaOH solutions containing 1 M sodium formate and palladium. Increasing temperature accelerates reduction; with three hours` treatment in 5 M NaOH solution at 90{degrees}C, about 95 % of the initial 2 x 10{sup -4} M neptunium(V) is transformed to Np(IV). Organic complexants and organic acid anions hinder the decontamination of alkaline solutions from neptunium and plutonium by coprecipitation with d-element hydroxides (the Method of Appearing Reagents). It was found that ethylenediaminetetraacetate (EDTA) and N-(2-hydroxyethyl) ethylenediaminetriacetate (HEDTA) are decomposed by H{sub 2}O{sub 2} in alkaline solution in the presence of cobalt compounds with heating and by Na2S208 at moderate temperatures. Citrate, glycolate, and oxalate are decomposed by Na{sub 2}S{sub 2}O{sub 8} with heating. Oxidant amounts must be increased when NaNO{sub 2} also is present in solution. 8 refs., 25 figs., 16 tabs.

  16. Environmentally safe treatment of black liquor with Comamonas sp. B-9 under high-alkaline conditions.

    PubMed

    Zheng, Yu; Chai, Liyuan; Yang, Zhihui; Chen, Yuehui; Shi, Yan; Wang, Yangyang

    2014-02-01

    The strain Comamonas sp. B-9 was isolated from steeping fluid of erosive bamboo slips derived from Kingdom Wu during the Three-Kingdoms Dynasty of ancient China (A.D. 220-280). It could be used to treat black liquor (BL) with high-alkaline pH and with an initial chemical oxygen demand (COD) of 18,000-25,000 mg L(-1) , without the addition of other carbon and nitrogen sources. The results revealed that Comamonas sp. B-9 was capable of reducing the COD, color, and lignin content of BL by up to 56.8, 35.3, and 43.5%, respectively. High levels of laccase, manganese peroxidase, cellulase, and xylanase enzymatic activities were also observed, and these enzymes could play an important role in the biotreatment of BL. Further, GC-MS analysis showed that most of the compounds detected in BL after biotreatment with Comamonas sp. B-9 were diminished, while 4-methyl benzaldehyde, 3,4,5-trihydroxybenzoic acid ethyl ester, and 4-hydroxy-3,5-dimethoxy benzaldehyde were produced as metabolites. The presented results indicate that Comamonas sp. B-9 has potential application for the treatment of wastewaters from pulp and paper processing with high COD load under high-alkaline conditions.

  17. Structural elucidation of sorghum lignins from an integrated biorefinery process based on hydrothermal and alkaline treatments.

    PubMed

    Sun, Shao-Long; Wen, Jia-Long; Ma, Ming-Guo; Sun, Run-Cang

    2014-08-13

    An integrated process based on hydrothermal pretreatment (HTP) (i.e., 110-230 °C, 0.5-2.0 h) and alkaline post-treatment (2% NaOH at 90 °C for 2.0 h) has been performed for the production of xylooligosaccharide, lignin, and digestible substrate from sweet sorghum stems. The yield, purity, dissociation mechanisms, structural features, and structural transformations of alkali lignins obtained from the integrated process were investigated. It was found that the HTP process facilitated the subsequent alkaline delignification, releasing lignin with the highest yield (79.3%) and purity from the HTP residue obtained at 190 °C for 0.5 h. All of the results indicated that the cleavage of the β-O-4 linkages and degradation of β-β and β-5 linkages occurred under the harsh HTP conditions. Depolymerization and condensation reactions simultaneously occurred at higher temperatures (≥ 170 °C). Moreover, the thermostability of lignin was positively related to its molecular weight, but was also affected by the inherent structures, such as β-O-4 linkages and condensed units. These findings will enhance the understanding of structural transformations of the lignins during the integrated process and maximize the potential utilizations of the lignins in a current biorefinery process.

  18. Textbook Errors, 136: The Reducing Action of Sodium Borohydride.

    ERIC Educational Resources Information Center

    Todd, David

    1979-01-01

    This column generally relates errors which have been discovered in textbooks. The error discussed in this issue is the prevalence of erroneous ideas in organic chemistry textbooks, related to the chemistry of sodium borohydride. (Author/SA)

  19. Catalytic polymeric electrodes for direct borohydride fuel cells

    NASA Astrophysics Data System (ADS)

    Bayatsarmadi, Bita; Peters, Alice; Talemi, Pejman

    2016-08-01

    The direct borohydride fuel cell (DBFC) is a new class of fuel cells that produces non-toxic by-products and has a potential for a high voltage and high energy density. A major challenge in developing efficient DBFCs is the development of an efficient, stable, and economic catalyst for the oxidation of borohydride. In this paper, we report the use of conducting polymer Poly(3,4-ethylenedioxythiophene) (PEDOT) as electrocatalysts in DBFC. PEDOT electrodes prepared by vacuum phase polymerization exhibited electrocatalytic behavior towards oxidation of borohydride and reduction of hydrogen peroxide. Spectroscopic analysis of samples showed that PEDOT can act as an interface for electron transfer from borohydride ions. Comparing the polarization curves of DBFCs with PEDOT coated on graphite electrodes and cells with bare graphite electrodes, demonstrated higher voltage, maximum power density, and stability.

  20. Alkaline hydrothermal conversion of fly ash filtrates into zeolites 2: utilization in wastewater treatment.

    PubMed

    Somerset, Vernon; Petrik, Leslie; Iwuoha, Emmanuel

    2005-01-01

    Filtrates were collected using a codisposal reaction wherein fly ash was reacted with acid mine drainage. These codisposal filtrates were then analyzed by X-ray Fluorescence spectrometry for quantitative determination of the SiO2 and Al2O3 content. Alkaline hydrothermal zeolite synthesis was then applied to the filtrates to convert the fly ash material into zeolites. The zeolites formed under the experimental conditions were faujasite, sodalite, and zeolite A. The use of the fly ash-derived zeolites and a commercial zeolite was explored in wastewater decontamination experiments as it was applied to acid mine drainage in different dosages. The concentrations of Ni, Zn, Cd, As, and Pb metal ions in the treated wastewater were investigated. The results of the treatment of the acid mine drainage with the prepared fly ash zeolites showed that the concentrations of Ni, Zn, Cd, and Hg were decreased as the zeolite dosages of the fly ash zeolite (FAZ1) increased.

  1. Method of recycling lithium borate to lithium borohydride through diborane

    DOEpatents

    Filby, Evan E.

    1976-01-01

    This invention provides a method for the recycling of lithium borate to lithium borohydride which can be reacted with water to generate hydrogen for utilization as a fuel. The lithium borate by-product of the hydrogen generation reaction is reacted with hydrogen chloride and water to produce boric acid and lithium chloride. The boric acid and lithium chloride are converted to lithium borohydride through a diborane intermediate to complete the recycle scheme.

  2. [Chemical structure of bioethanol lignin by low-temperature alkaline catalytic hydrothermal treatment].

    PubMed

    Liu, Xiao-Huan; Zhang, Ming-Ming; Wang, Ji-Fu; Xu, Yu-Zhi; Wang, Chun-Peng; Chu, Fu-Xiang

    2013-11-01

    In order to improve the reaction activity of bioethanol lignin, we investigated the activation of bioethanol lignin by a hydrothermal treatment method. Catalytic hydrothermal treatment of bioethanol lignin was performed at 180 degrees C for 3 h in the presence of alkaline solutions (NaOH, Na2 CO3, KOH and K2 CO3), the change in bioethanol lignin structures was studied comparatively by FTIR, 1H NMR,GPC and elemental analysis. FTIR spectra showed that after alkali hydrothermal treatment, the band at 1 375 cm(-1) attributed to the phenolic hydroxyl groups increased, and the band intensity at 1 116 cm(-1) attributed to the ether bond decreased. On the other hand, the band at 1 597 and 1 511 cm(-1) attributed to aromatic skeletal vibration remained almost unchanged. 1H NMR spectra showed that after alkali hydrothermal treatment, the number of aromatic methoxyl is increased, and based on the increment of the content of phenolic hydroxyl, the catalytic activity can be ranked as follows: KOH > NaOH > K2 CO3 > Na2 CO3. Especially for KOH, the increment of the content of phenolic hydroxyl was 170%, because the ion radius of potassium cation is bigger than sodium cation, so the potassium cations more easily formed cation adducts with lignin. GPC results showed that the molecular weight of alkali hydrothermal treatment lignin decreased and the molecular distribution got wider. Elemental analysis showed that hydrothermal treatment could break the interlinkage between lignin and protein, which can reduce the protein content and increase the purity of lignin, meanwhile, the content of O and H both decreased,while C fell, indicating that the bioethanol lignin had suffered a decarbonylation reaction. This is the most benefit of the lignin as a substitute for phenol.

  3. The borohydride oxidation reaction on La-Ni-based hydrogen-storage alloys.

    PubMed

    Paschoalino, Waldemir J; Thompson, Stephen J; Russell, Andrea E; Ticianelli, Edson A

    2014-07-21

    This work provides insights into the processes involved in the borohydride oxidation reaction (BOR) in alkaline media on metal hydride alloys formed by LaNi(4.7)Sn(0.2)Cu(0.1) and LaNi(4.78)Al(0.22) with and without deposited Pt, Pd, and Au. The results confirm the occurrence of hydrolysis of the borohydride ions when the materials are exposed to BH(4)(-) and a continuous hydriding of the alloys during BH(4)(-) oxidation measurements at low current densities. The activity for the direct BOR is low in both bare metal hydride alloys, but the rate of the BH(4)(-) hydrolysis and the hydrogen-storage capacity are higher, while the rate of H diffusion is slower for bare LaNi(4.78) Al(0.22). The addition of Pt and Pd to both alloys results in an increase of the BH(4)(-) hydrolysis, but the H(2) formed is rapidly oxidized at the Pt-modified catalysts. In the case of Au modification, a small increase in the BH(4)(-) hydrolysis is observed as compared to the bare alloys. The presence of Au and Pd also leads to a reduction of the rates of alloy hydriding/de-hydriding.

  4. High performance and eco-friendly chitosan hydrogel membrane electrolytes for direct borohydride fuel cells

    NASA Astrophysics Data System (ADS)

    Choudhury, Nurul A.; Ma, Jia; Sahai, Yogeshwar

    2012-07-01

    Novel, cost-effective, and environmentally benign polymer electrolyte membranes (PEMs) consisting of ionically cross-linked chitosan (CS) hydrogel is reported for direct borohydride fuel cells (DBFCs). The membranes have been prepared by ionic cross-linking of CS with sulfate and hydrogen phosphate salts of sodium. Use of Na2SO4 and Na2HPO4 as cross-linking agents in the preparation of ionically cross-linked CS hydrogel membrane electrolytes (ICCSHMEs) not only enhances cost-effectiveness but also environmental friendliness of fuel cell technologies. The DBFCs have been assembled with a composite of nickel and carbon-supported palladium as anode catalyst, carbon-supported platinum as cathode catalyst and ICCSHMEs as electrolytes-cum-separators. The DBFCs have been studied by using an aqueous alkaline solution of sodium borohydride as fuel in flowing mode using a peristaltic pump and oxygen as oxidant. A maximum peak power density of about 810 mW cm-2 has been achieved for the DBFC employing Na2HPO4-based ICCSHME and operating at a cell temperature of 70 °C.

  5. Electrocatalytic performance of Pt-Dy alloys for direct borohydride fuel cells

    NASA Astrophysics Data System (ADS)

    Šljukić, Biljana; Milikić, Jadranka; Santos, Diogo M. F.; Sequeira, César A. C.; Macciò, Daniele; Saccone, Adriana

    2014-12-01

    The electrochemical oxidation of sodium borohydride (NaBH4) is systematically studied on platinum-dysprosium (Pt-Dy) alloys in alkaline media with respect to application in direct borohydride fuel cells (DBFCs). Using several different techniques, namely cyclic voltammetry, chronoamperometry and chronopotentiometry, reaction parameters are evaluated for NaBH4 electrooxidation in 2 M NaOH supporting electrolyte. The values obtained for the number of electrons exchanged are comparable for the two alloys and close to 2.5. Dependence of Pt-Dy alloys activity for NaBH4 oxidation on the electrolyte composition and temperature is also investigated. Test fuel cell is assembled using Pt-Dy alloy as anode, reaching peak power density of 298 mW cm-2 at current density of 595 mA cm-2 and cell potential of 0.5 V at 25 °C. Pt-Dy alloys exhibit comparable behavior with pure Pt electrode at room temperature, while at higher temperature they exhibit improved Coulombic efficiency, with the advantage of significantly lower price.

  6. Process for production of a borohydride compound

    DOEpatents

    Allen, Nathan Tait; Butterick, III, Robert; Chin, Arthur Achhing; Millar, Dean Michael; Molzahn, David Craig

    2014-08-19

    A process for production of a borohydride compound M(BH.sub.4).sub.y. The process has three steps. The first step combines a compound of formula (R.sup.1O).sub.yM with aluminum, hydrogen and a metallic catalyst containing at least one metal selected from the group consisting of titanium, zirconium, hafnium, niobium, vanadium, tantalum and iron to produce a compound of formula M(AlH.sub.3OR.sup.1).sub.y, wherein R.sup.1 is phenyl or phenyl substituted by at least one alkyl or alkoxy group; M is an alkali metal, Be or Mg; and y is one or two; wherein the catalyst is present at a level of at least 200 ppm based on weight of aluminum. The second step combines the compound of formula M(AlH.sub.3OR.sup.1).sub.y with a borate, boroxine or borazine compound to produce M(BH.sub.4).sub.y and a byproduct mixture containing alkali metal and aluminum aryloxides. The third step separates M(BH.sub.4).sub.y from the byproduct mixture.

  7. Synergistic Effect of Atmospheric Pressure Plasma Pre-Treatment on Alkaline Etching of Polyethylene Terephthalate Fabrics and Films

    NASA Astrophysics Data System (ADS)

    A. Elabid Amel, E.; Guo, Ying; Shi, Jianjun; Ding, Ke; Zhang, Jing

    2016-04-01

    Dyeing of PET materials by traditional methods presents several problems. Plasma technology has received enormous attention as a solution for the environmental problems related with textile surface modifications, and there has been a rapid development and commercialization of plasma technology over the past decade. In this work, the synergistic effect of atmospheric pressure plasma on alkaline etching and deep coloring of dyeing properties on polyethylene terephthalate (PET) fabrics and films was investigated. The topographical changes of the PET surface were investigated by atomic force microscopy (AFM) images, which revealed a smooth surface morphology of the untreated sample whereas a high surface roughness for the plasma and/or alkaline treated samples. The effects of atmospheric pressure plasma on alkaline etching of the structure and properties of PET were investigated by means of differential scanning calorimetry (DSC), the main objective of performing DSC was to investigate the effect of the plasma pre-treatment on the Tg and Tm. Using a tensile strength tester YG065H and following a standard procedure the maximum force and elongation at maximum force of PET materials was investigated. Oxygen and argon plasma pre-treatment was found to increase the PET fabric weight loss rate. The color strength of PET fabrics was increased by various plasma pre-treatment times. The penetration of plasma and alkaline reactive species deep into the PET structure results in better dyeability and leaves a significant effect on the K/S values of the plasma pre-treated PET. It indicated that plasma pre-treatment has a great synergistic effect with the alkaline treatment of PET.

  8. Thermal treatment for recovery of manganese and zinc from zinc-carbon and alkaline spent batteries

    SciTech Connect

    Belardi, G.; Lavecchia, R.; Medici, F.; Piga, L.

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer We separated Zn from Mn in zinc-carbon and alkaline batteries after removal of Hg. Black-Right-Pointing-Pointer Almost total removal of Hg is achieved at low temperature in air. Black-Right-Pointing-Pointer Nitrogen atmosphere is needed to reduce zinc and to permit its volatilization. Black-Right-Pointing-Pointer A high grade Zn concentrate was obtained with a high recovery at 1000-1200 Degree-Sign C. Black-Right-Pointing-Pointer The grade of Mn in the residue was enhanced with complete recovery. - Abstract: The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357 Degree-Sign C and 906 Degree-Sign C the boiling point of mercury and zinc and 1564 Degree-Sign C the melting point of Mn{sub 2}O{sub 3}. Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400 Degree-Sign C and 10 min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000 Degree-Sign C and 30 min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at

  9. Treatment of a high-strength sulphate-rich alkaline leachate using an anaerobic filter

    SciTech Connect

    Wang, Z.; Banks, C.J.

    2007-07-01

    The research looks at the feasibility of treating an alkaline sulphate-rich leachate arising from the co-disposal of municipal solid waste with cement kiln dust by means of an anaerobic filter (AF). This type of leachate with a high sulphate concentration is commonly prohibited for discharge to sewer and requires an on-site treatment solution. The AF used had a working volume of 4 l and contained reticulated polyurethane foam as the biomass support material. The filters were operated over a 152 day experimental period during which the COD loading onto the filter was increased from 0.76 to 7.63 kg COD m{sup -3} d{sup -1}. In the early stages of operation at low loading, soluble sulphides accumulated that inhibited methanogenic activity. This was restored by dosing FeCl{sub 3} to the reactor. The continued dosing allowed efficient COD removal of between 75% and 90% until the nominal retention time in the reactor was 3 days, at which point reactor performance declined significantly. The main mechanism for COD removal was by sulphate-reducing bacteria, which also resulted in up to 88% sulphate removal from the leachate. The average methane generation rate was 0.10 l g{sup -1} COD removed. The results indicate the potential for using this approach as a pre-treatment that could significantly reduce the COD load to a second stage treatment process, but problems associated with the implementation of the technology at a larger scale have been identified.

  10. Alkaline phosphatase as a treatment of sepsis-associated acute kidney injury.

    PubMed

    Peters, Esther; van Elsas, Andrea; Heemskerk, Suzanne; Jonk, Luigi; van der Hoeven, Johannes; Arend, Jacques; Masereeuw, Rosalinde; Pickkers, Peter

    2013-01-01

    Currently there are no pharmacological therapies licensed to treat sepsis-associated acute kidney injury (AKI). Considering the high incidence and mortality of sepsis-associated AKI, there is an urgent medical need to develop effective pharmacological interventions. Two phase II clinical trials recently demonstrated beneficial effects of the enzyme alkaline phosphatase (AP). In critically ill patients with sepsis-associated AKI, treatment with AP reduced the urinary excretion of tubular injury biomarkers and plasma markers of inflammation, which was associated with improvement of renal function. The dephosphorylating enzyme, AP, is endogenously present in the renal proximal tubule apical membrane but becomes depleted during ischemia-induced AKI, thereby possibly contributing to further renal damage. The exact mechanism of action of AP in AKI is unknown, but might be related to detoxification of circulating lipopolysaccharide and other proinflammatory mediators that lose their proinflammatory effects after dephosphorylation. Alternatively, tissue damage associated with systemic inflammation might be attenuated by an AP-mediated effect on adenosine metabolism. Adenosine is a signaling molecule that has been shown to protect the body from inflammation-induced tissue injury, which is derived through dephosphorylation of ATP. In this Perspectives article, we discuss the clinical activity of AP and its putative molecular modes of action, and we speculate on its use to treat and possibly prevent sepsis-associated AKI.

  11. Influence of alkalinity and VFAs on the performance of an UASB reactor with recirculation for the treatment of Tequila vinasses.

    PubMed

    López-López, Alberto; León-Becerril, Elizabeth; Rosales-Contreras, María Elena; Villegas-García, Edgardo

    2015-01-01

    The main problem linked to the stability of upflow anaerobic sludge blanket (UASB) reactors during the treatment of Tequila vinasse is the high acidity and the null alkalinity present in this effluent. This research evaluates the effect of alkalinity and volatile fatty acids (VFAs) concentration on the performance of an UASB reactor with recirculation of the effluent for removing organic matter and biogas production from Tequila vinasses. Recirculation of the effluent reduces the impact of VFAs and organic matter concentration present in the influent, inducing the stability of the reactor. The UASB reactor was operated during 235 days at organic loading rates from 2.5 to 20.0 kg m(-3) d(-1), attaining a removal efficiency of COD greater than 75% with a methane yield of 335 ml CH4 g(-1) COD at SPT, maintaining a ratio of VFAs/Alk ≤ 0.5. Therefore, an optimal ratio of VFAs/Alk was established for the system operating in stable conditions for the treatment of Tequila vinasses. Under these conditions, the alkalinity was recuperated by the system itself, without the addition of external alkalinity.

  12. Thermal treatment for recovery of manganese and zinc from zinc-carbon and alkaline spent batteries.

    PubMed

    Belardi, G; Lavecchia, R; Medici, F; Piga, L

    2012-10-01

    The aim of this paper is the recovery of manganese and zinc from a mixture of zinc-carbon and alkaline spent batteries, containing 40.9% of Mn and 30.1% of Zn, after preliminary physical treatment followed by removal of mercury. Separation of the metals has been carried out on the basis of their different boiling points, being 357°C and 906°C the boiling point of mercury and zinc and 1564°C the melting point of Mn(2)O(3). Characterization by chemical analysis, TGA/DTA and X-ray powder diffraction of the mixture has been carried out after comminution sieving and shaking table treatment to remove the anodic collectors and most of chlorides contained in the mixture. The mixture has been roasted at various temperatures and resident times in a flow of air to set the best conditions to remove mercury that were 400°C and 10 min. After that, the flow of air has been turned into a nitrogen one (inert atmosphere) and the temperatures raised, thus permitting the zinc oxide to be reduced to metallic zinc by the carbon present in the original mixture and recovered after volatilization as a high grade concentrate, while manganese was left in the residue. The recovery and the grade of the two metals, at 1000°C and 30 min residence time, were 84% and 100% for zinc and 85% and 63% for manganese, respectively. The recovery of zinc increased to 99% with a grade of 97% at 1200°C and 30 min residence time, while the recovery and grade of manganese were 86% and 87%, respectively, at that temperature. Moreover, the chlorinated compounds that could form by the combustion of the plastics contained in the spent batteries, are destroyed at the temperature required by the process.

  13. Effects of hydrazine addition on gas evolution and performance of the direct borohydride fuel cell

    NASA Astrophysics Data System (ADS)

    Qin, H. Y.; Liu, Z. X.; Yin, W. X.; Zhu, J. K.; Li, Z. P.

    A fuel cell configuration using alkaline NaBH 4-N 2H 4 solutions as the fuel is suggested. Gas evolution behaviors and cell performances of alkaline NaBH 4-N 2H 4 solutions on different catalysts have been studied. It is found that gas evolution behaviors are influenced by the applied anodic catalysts and the concentration of NaBH 4 and N 2H 4. NaBH 4 is mainly electro-oxidized on Pd but N 2H 4 is mainly electro-oxidized on Ni and surface-treated Zr-Ni alloy when using NaBH 4-N 2H 4 solutions as the fuel and a composite of Pd, Ni and surface-treated Zr-Ni alloy as the anodic catalyst. The cyclic voltammetry results show that electrochemical oxidation potential of NaBH 4 is higher than that of N 2H 4. Adding hydrazine into alkaline sodium borohydride solutions can suppress gas evolution and improve the cell performance of the DBFC. The performances of fuel cells using NaBH 4-N 2H 4 solutions are comparable to that of fuel cell using N 2H 4 solution.

  14. The production of glucose from corn stalk using hydrothermal process with pre-treatment ultrasound assisted alkaline

    NASA Astrophysics Data System (ADS)

    Yolanda, Dora; Prasutiyo, Indry; Trisanti, P. N.; Sumarno

    2015-12-01

    The production of glucose from corn stalk by using subcritical hydrothermal technology is studied in this work. Ultrasound-assisted alkaline delignification methods are used as pre-treatment. The corn stalk powder were pretreated with ultrasound-assisted alkaline (NaOH 2% w/w, solid to liquid ratio 1:22 w/v) at room temperature and 30 minutes. After pre-treatment, solid residue and liquid fractions are separated by filtration. Pretreated solids are further submitted to hydrothermal process for glucose production. Hydrothermal process was carried out at 100 Bar and 120°C in various times. The solid product was characterized by SEM and XRD. And liquid product was analysis using DNS method to determine percentage of glucose. From XRD analysis showed that crystallinity of material was lower than delignification product.

  15. Fractionation of bagasse into cellulose, hemicelluloses, and lignin with ionic liquid treatment followed by alkaline extraction.

    PubMed

    Lan, Wu; Liu, Chuan-Fu; Sun, Run-Cang

    2011-08-24

    Lignocellulose materials are potentially valuable resources for transformation into biofuels and bioproducts. However, their complicated structures make it difficult to fractionate them into cellulose, hemicelluloses, and lignin, which limits their utilization and economical conversion into value-added products. This study proposes a novel and feasible fractionation method based on complete dissolution of bagasse in 1-butyl-3-methylimidazolium chloride ([C(4)mim]Cl) followed by precipitation in acetone/water (9:1, v/v) and extraction with 3% NaOH solution. The ionic liquid [C(4)mim]Cl was easily recycled after concentration and treatment with acetonitrile. (1)H NMR analysis confirmed that there was no obvious difference between the recycled [C(4)mim]Cl and fresh material. Bagasse was fractionated with this method to 36.78% cellulose, 26.04% hemicelluloses, and 10.51% lignin, accounting for 47.17 and 33.85% of the original polysaccharides and 54.62% of the original lignin, respectively. The physicochemical properties of the isolated fractions were characterized by chemical analysis, high-performance anion exchange chromatography (HPAEC), gel permeation chromatography (GPC), Fourier transform infrared (FT-IR), and (1)H and 2D (13)C-(1)H correlation (HSQC) nuclear magnetic resonance spectroscopy. The results showed that the acetone-soluble lignin and alkaline lignin fractions had structures similar to those of milled wood lignin (MWL). The easy extraction of the noncellulose components from homogeneous bagasse solution and amorphous regenerated materials resulted in the relatively high purity of cellulosic fraction (>92%). The hemicellulosic fraction was mainly 4-O-methyl-D-glucuronoxylans with some α-L-arabinofuranosyl units substituted at C-2 and C-3.

  16. Roles of alkaline phosphatase and labile internal mineral in matrix vesicle-mediated calcification. Effect of selective release of membrane-bound alkaline phosphatase and treatment with isosmotic pH 6 buffer.

    PubMed

    Register, T C; McLean, F M; Low, M G; Wuthier, R E

    1986-07-15

    The roles of alkaline phosphatase and labile internal mineral in matrix vesicle-mediated mineralization have been studied by selectively releasing the enzyme from a wide variety of matrix vesicle preparations using treatment with a bacterial phosphatidylinositol-specific phospholipase C and by demineralization of the vesicles using isosmotic pH 6 buffer. Following depletion of 50-90% of the alkaline phosphatase activity or treatment with citrate buffer, the vesicles were tested for their ability to accumulate 45Ca2+ and 32Pi from a synthetic cartilage lymph. Removal of alkaline phosphatase by phospholipase C treatment caused two principal effects, depending on the matrix vesicle preparation. In rapidly mineralizing vesicle fractions which did not require organic phosphate esters (Po) to accumulate mineral ions, release of alkaline phosphatase had only a minor effect. In slowly mineralizing vesicles preparations or those dependent on Po substrates for mineral ion uptake, release of alkaline phosphatase caused significant loss of mineralizing activity. The activity of rapidly calcifying vesicles was shown to be dependent on the presence of labile internal mineral, as demonstrated by major loss in activity when the vesicles were decalcified by various treatments. Ion uptake by demineralized vesicles or those fractionated on sucrose step gradients required Po and was significantly decreased by alkaline phosphatase depletion. Uptake of Pi, however, was not coupled with hydrolysis of the Po substrate. These findings argue against a direct role for alkaline phosphatase as a porter in matrix vesicle Pi uptake, contrary to previous postulates. The results emphasize the importance of internal labile mineral in rapid uptake of mineral ions by matrix vesicles.

  17. Alkaline phosphatase: a possible treatment for sepsis-associated acute kidney injury in critically ill patients.

    PubMed

    Peters, Esther; Heemskerk, Suzanne; Masereeuw, Rosalinde; Pickkers, Peter

    2014-06-01

    Acute kidney injury (AKI) is a common disease in the intensive care unit and accounts for high morbidity and mortality. Sepsis, the predominant cause of AKI in this setting, involves a complex pathogenesis in which renal inflammation and hypoxia are believed to play an important role. A new therapy should be aimed at targeting both these processes, and the enzyme alkaline phosphatase, with its dual mode of action, might be a promising candidate. First, alkaline phosphatase is able to reduce inflammation through dephosphorylation and thereby detoxification of endotoxin (lipopolysaccharide), which is an important mediator of sepsis. Second, adenosine triphosphate, released during cellular stress caused by inflammation and hypoxia, has detrimental effects but can be converted by alkaline phosphatase into adenosine with anti-inflammatory and tissue-protective effects. These postulated beneficial effects of alkaline phosphatase have been confirmed in animal experiments and two phase 2a clinical trials showing that kidney function improved in critically ill patients with sepsis-associated AKI. Because renal inflammation and hypoxia also are observed commonly in AKI induced by other causes, it would be of interest to investigate the therapeutic effect of alkaline phosphatase in these nephropathies as well.

  18. Pre-treatment serum lactate dehydrogenase and alkaline phosphatase as predictors of metastases in extremity osteosarcoma

    PubMed Central

    Marais, Leonard C.; Bertie, Julia; Rodseth, Reitze; Sartorius, Benn; Ferreira, Nando

    2015-01-01

    Background The prognosis of patients with metastatic osteosarcoma remains poor. However, the chance of survival can be improved by surgical resection of all metastases. In this study we investigate the value of serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in predicting the presence of metastatic disease at time of diagnosis. Methods Sixty-one patients with histologically confirmed conventional osteosarcoma of the extremity were included in the study. Only 19.7% of cases presented without evidence of systemic spread of the disease. Pre-treatment serum ALP and LDH were analysed in patients with and without skeletal or pulmonary metastases. Results Serum LDH and ALP levels were not significantly different in patients with or without pulmonary metastases (p=0.88 and p=0.47, respectively). The serum LDH and ALP levels did however differ significantly in patients with or without skeletal metastases (p<0.001 and p=0.02, respectively). The optimal breakpoint for serum LDH as a marker of skeletal metastases was 849 IU/L (AUC 0.839; Sensitivity=0.88; Specificity=0.73). LDH >454 IU/L equated to 100% sensitivity for detected bone metastases (positive diagnostic likelihood ratio (DLR)=1.32). With a cut-off of 76 IU/L a sensitivity of 100% was reached for serum ALP predicting the presence of skeletal metastases (positive DLR=1.1). In a multivariate analysis both LDH ≥850 IU/L (odds ratio [OR]=9; 95% confidence interval (CI) 1.8–44.3) and ALP ≥280 IU/L (OR=10.3; 95% CI 2.1–50.5) were predictive of skeletal metastases. LDH however lost its significance in a multivariate model which included pre-treatment tumour volume. Conclusion In cases of osteosarcoma with LDH >850 IU/L and/or ALP >280 IU/L it may be prudent to consider more sensitive staging investigations for detection of skeletal metastases. Further research is required to determine the value and the most sensitive cut-off points of serum ALP and LDH in the prediction of skeletal metastases. PMID

  19. Electromembrane recycling of highly mineralized alkaline blowdown water from evaporative water treatment plants at thermal power stations

    NASA Astrophysics Data System (ADS)

    Chichirova, N. D.; Chichirov, A. A.; Lyapin, A. I.; Minibaev, A. I.; Silov, I. Yu.; Tolmachev, L. I.

    2016-12-01

    Thermal power stations (TPS) are the main source of highly mineralized effluents affecting the environment. An analysis of their water systems demonstrates that alkaline effluents prevail at TPSs. Extraction of an alkali from highly mineralized effluents can make the recycling of effluents economically feasible. A method is proposed of electromembrane recycling of liquid alkaline highly mineralized wastes from TPSs. The process includes electromembrane apparatuses of two types, namely, a diffusion dialysis extractor (DDE) intended for extraction of the alkali from a highly mineralized solution having a complex composition and an electrodialysis concentrator for increasing the concentration of the extracted solution to a value suitable for use in water treatment plants at TPSs. For implementation of the first process (i.e. the extraction of alkali from alkaline-salt solution) various membranes from various manufacturers were studied: CM-PAD and AM-PAD (Ralex, Czechia), MK-40, MA-40, MA-41, MA-414, and MB-2 (OOO OKhK "Shchekinoazot", Russia), AR103-QDF and CR61-CMP (Ionies Inc., USA). The experiments demonstrate that the acceptable degree of separation of the alkali and the salt is achieved in a pair of cation-exchange membranes with the efficiency of separation being higher without an electric field. The highest efficiency was attained with Russian-made membranes (MK-40, OOO OKhK "Shchekinoazot"). A full scale experiment on recycling of highly-mineralized blowdown water from the evaporating water treatment system at the Kazan cogeneration power station No. 3 (TETs-3) was performed in a pilot unit consisting of two electromembrane apparatuses made by UAB "Membraninės Technologijos LT". In the experiments every ton of blowdown water yielded 0.1 t of concentrated alkaline solution with an alkali content of up to 4 wt % and 0.9 t of the softened salt solution suitable for the reuse in the TPS cycle. The power rate is 6 kWh / ton of blowdown water.

  20. Combination of Successive Alkalinity Producing System (SAPS) and Aeration for Passive Treatment of Highly Acidic Mine Drainage

    NASA Astrophysics Data System (ADS)

    Oh, C.; Ji, S.

    2015-12-01

    Passive treatment system has been widely used for remediation of mine drainage since its advantage of low installation and maintenance cost. The system, however, has also a disadvantage in assuring remediation and management efficiency if the drainage is highly acidic mine drainage. To remediate acid mine drainage (AMD) especially showing high acidity, passive treatment system which consists of successive alkalinity producing system (SAPS) and subsequent aeration pond was proposed and its mechanisms and efficiency was evaluated in this research. Target AMD was obtained from Waryong coal mine and showed typical characteristics of AMD having high metal concentration and low pH (acidity > 300 mg/L as CaCO3). Four experimental cases were conducted; untreated, treated with SAPS, treated with aeration, treated with SAPS and aeration to compare role and mechanism of each unit. Between organic matter and limestone layer which constitute SAPS, the former eliminated most of Fe(III) and Al in the AMD so that the latter was kept from being clogged by precipitates. Net acidity of the AMD rapidly decreased by supplement of alkalinity at the limestone layer. A primary function of SAPS, producing alkalinity constantly without clogging, was attained due to addition a portion of limestone particle into the organic matter layer. The discharge from SAPS had low ORP and DO values because of an anaerobic environment formed at the organic matter layer although its alkalinity was increased. This water quality was unfavorable for Fe(II) to be oxidized. Installation of aeration pond after SAPS, therefore, could be effective way of enhancing oxidation rate of Fe(II). Among the experimental cases, the combination of SAPS and aeration pond was only able to remediate the AMD. This concluded that to remediate highly acidic mine drainage with passive treatment system, three critical conditions were required; pre-precipitation of Fe(III) and Al at organic matter layer in SAPS, constant alkalinity

  1. Improved bioconversion of poplar by synergistic treatments with white-rot fungus Trametes velutina D10149 pretreatment and alkaline fractionation.

    PubMed

    Yang, Haiyan; Wang, Kun; Wang, Wei; Sun, Run-Cang

    2013-02-01

    Successive treatments with fungus and alkali were proposed to reduce the recalcitrance and improved the enzymatic digestibility of triploid poplar. Biopretreatment with Trametes velutina D10149 for 0, 4, 8, 12 and 16weeks gradually degraded hemicelluloses and lignin, and improved the digestibility of cellulose from 4.0% to 19.5% with the increasing dry mass loss of lignocelluloses from 15.5% to 53.4%. Combining with alkaline fractionation, biopretreatment for 4weeks significantly enhanced the availability of cellulose and achieved a maximum glucose yield (38.8% of the original cellulose) with a dry mass loss of 24.4%. The BET surface area of lignocelluloses increased from 1.7 to 10.6m(2)/g after combination of 8weeks biopretreatment and alkaline fractionation. Moreover, alkaline fractionation removed amorphous and low molecular components, which incurred a higher crystalline index and narrower molecular weight distribution of residual carbohydrates in synergistically treated samples as compared to biopretreated samples.

  2. Volatile Fatty Acids Production from Codigestion of Food Waste and Sewage Sludge Based on β-Cyclodextrins and Alkaline Treatments.

    PubMed

    Yang, Xue; Liu, Xiang; Chen, Si; Liu, Guangmin; Wu, Shuyan; Wan, Chunli

    2016-01-01

    Volatile fatty acids (VFAs) are preferred valuable resources, which can be produced from anaerobic digestion process. This study presents a novel technology using β-cyclodextrins (β-CD) pretreatment integrated alkaline method to enhance VFAs production from codigestion of food waste and sewage sludge. Experiment results showed that optimized ratio of food waste to sewage sludge was 3 : 2 because it provided adequate organic substance and seed microorganisms. Based on this optimized ratio, the integrated treatment of alkaline pH 10 and β-CD addition (0.2 g/g TS) performed the best enhancement on VFAs production, and the maximum VFAs production was 8631.7 mg/L which was 6.13, 1.38, and 1.57 times higher than that of control, initial pH 10, and 0.2 g β-CD/g TS treatment, respectively. Furthermore, the hydrolysis rate of protein and polysaccharides was greatly improved in integration treatment, which was 1.18-3.45 times higher than that of other tests. Though the VFAs production and hydrolysis of polymeric organics were highly enhanced, the primary bacterial communities with different treatments did not show substantial differences.

  3. Volatile Fatty Acids Production from Codigestion of Food Waste and Sewage Sludge Based on β-Cyclodextrins and Alkaline Treatments

    PubMed Central

    Yang, Xue; Liu, Xiang; Chen, Si; Wu, Shuyan

    2016-01-01

    Volatile fatty acids (VFAs) are preferred valuable resources, which can be produced from anaerobic digestion process. This study presents a novel technology using β-cyclodextrins (β-CD) pretreatment integrated alkaline method to enhance VFAs production from codigestion of food waste and sewage sludge. Experiment results showed that optimized ratio of food waste to sewage sludge was 3 : 2 because it provided adequate organic substance and seed microorganisms. Based on this optimized ratio, the integrated treatment of alkaline pH 10 and β-CD addition (0.2 g/g TS) performed the best enhancement on VFAs production, and the maximum VFAs production was 8631.7 mg/L which was 6.13, 1.38, and 1.57 times higher than that of control, initial pH 10, and 0.2 g β-CD/g TS treatment, respectively. Furthermore, the hydrolysis rate of protein and polysaccharides was greatly improved in integration treatment, which was 1.18–3.45 times higher than that of other tests. Though the VFAs production and hydrolysis of polymeric organics were highly enhanced, the primary bacterial communities with different treatments did not show substantial differences. PMID:28096735

  4. Bacterial treatment of alkaline cement kiln dust using Bacillus halodurans strain KG1

    PubMed Central

    Kunal; Rajor, Anita; Siddique, Rafat

    2016-01-01

    This study was conducted to isolate an acid-producing, alkaliphilic bacterium to reduce the alkalinity of cement industry waste (cement kiln dust). Gram-positive isolate KG1 grew well at pH values of 6–12, temperatures of 28–50 °C, and NaCl concentrations of 0–16% and thus was further screened for its potential to reduce the pH of an alkaline medium. Phenotypic characteristics of the KG1 isolate were consistent with those of the genus Bacillus, and the highest level of 16S rRNA gene sequence similarity was found with Bacillus halodurans strain DSM 497 (94.7%). On the basis of its phenotypic characteristics and genotypic distinctiveness from other phylogenetic neighbors belonging to alkaliphilic Bacillus species, the isolated strain was designated B. halodurans strain KG1, with GenBank accession number JQ307184 (= NCIM 5439). Isolate KG1 reduced the alkalinity (by 83.64%) and the chloride content (by 86.96%) of cement kiln dust and showed a potential to be used in the cement industry for a variety of applications. PMID:26887220

  5. Bacterial treatment of alkaline cement kiln dust using Bacillus halodurans strain KG1.

    PubMed

    Kunal; Rajor, Anita; Siddique, Rafat

    2016-01-01

    This study was conducted to isolate an acid-producing, alkaliphilic bacterium to reduce the alkalinity of cement industry waste (cement kiln dust). Gram-positive isolate KG1 grew well at pH values of 6-12, temperatures of 28-50°C, and NaCl concentrations of 0-16% and thus was further screened for its potential to reduce the pH of an alkaline medium. Phenotypic characteristics of the KG1 isolate were consistent with those of the genus Bacillus, and the highest level of 16S rRNA gene sequence similarity was found with Bacillus halodurans strain DSM 497 (94.7%). On the basis of its phenotypic characteristics and genotypic distinctiveness from other phylogenetic neighbors belonging to alkaliphilic Bacillus species, the isolated strain was designated B. halodurans strain KG1, with GenBank accession number JQ307184 (= NCIM 5439). Isolate KG1 reduced the alkalinity (by 83.64%) and the chloride content (by 86.96%) of cement kiln dust and showed a potential to be used in the cement industry for a variety of applications.

  6. Kinetics of Ru-catalyzed sodium borohydride hydrolysis

    NASA Astrophysics Data System (ADS)

    Zhang, J. S.; Delgass, W. N.; Fisher, T. S.; Gore, J. P.

    Chemical hydrides have been identified as a potential medium for on-board hydrogen storage, one of the most challenging technical barriers to the prospective transition from gasoline to hydrogen-powered vehicles. Systematic study of the feasibility of the sodium borohydride systems, and chemical-hydride systems more generally, requires detailed kinetic studies of the reaction for use in reactor modeling and system-level experiments. This work reports an experimental study of the kinetics of sodium borohydride hydrolysis with a Ru-on-carbon catalyst and a Langmuir-Hinshelwood kinetic model developed based on experimental data. The model assumes that the reaction consists of two important steps: the equilibrated adsorption of sodium borohydride on the surface of the catalyst and the reaction of the adsorbed species. The model successfully captures both the reaction's zero-order behavior at low temperatures and the first-order behavior at higher temperatures. Reaction rate constants at different temperatures are determined from the experimental data, and the activation energy is found to be 66.9 kJ mol -1 from an Arrhenius plot.

  7. Method of Manufacturing Micro-Disperse Particles of Sodium Borohydride

    DOEpatents

    Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester. Alan P.; Bell, Nelson S.

    2008-09-23

    A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

  8. Method of generating hydrogen gas from sodium borohydride

    DOEpatents

    Kravitz, Stanley H.; Hecht, Andrew M.; Sylwester, Alan P.; Bell, Nelson S.

    2007-12-11

    A compact solid source of hydrogen gas, where the gas is generated by contacting water with micro-disperse particles of sodium borohydride in the presence of a catalyst, such as cobalt or ruthenium. The micro-disperse particles can have a substantially uniform diameter of 1-10 microns, and preferably about 3-5 microns. Ruthenium or cobalt catalytic nanoparticles can be incorporated in the micro-disperse particles of sodium borohydride, which allows a rapid and complete reaction to occur without the problems associated with caking and scaling of the surface by the reactant product sodium metaborate. A closed loop water management system can be used to recycle wastewater from a PEM fuel cell to supply water for reacting with the micro-disperse particles of sodium borohydride in a compact hydrogen gas generator. Capillary forces can wick water from a water reservoir into a packed bed of micro-disperse fuel particles, eliminating the need for using an active pump.

  9. Characterization of Lithium Borohydride using Neutron Scattering Techniques

    NASA Astrophysics Data System (ADS)

    Hartman, Michael; Rush, Jack; Udovic, Terry

    2006-03-01

    Lithium borohydride, LiBH4, is a complex metal hydride that shows great promise as a hydrogen storage medium with a volumetric hydrogen density of 122 kg H/m^3 and a gravimetric hydrogen density of 18.5 wt. %. While numerous NMR, Raman, and infrared investigations have been reported in the literature, neutron scattering investigations of LiBH4 have been limited due to the large neutron absorption cross-section of naturally occurring lithium and boron. We have recently synthesized an isotopically-enriched lithium borohydride, containing ^7Li and ^11B, which eliminates the large neutron absorption cross-section that arises from the presence of ^6Li and ^10B. The results of powder neutron diffraction, inelastic neutron scattering, and quasi-elastic neutron scattering investigations on the ^7Li^11BH4 material are presented. These measurements provide a fundamental understanding of the behavior of hydrogen within lithium borohydride, and they provide a basis to understand changes concomitant with the introduction of catalytic or destabilizing compounds.

  10. Metal borohydride formation from aluminium boride and metal hydrides.

    PubMed

    Møller, Kasper T; Fogh, Alexander S; Paskevicius, Mark; Skibsted, Jørgen; Jensen, Torben R

    2016-10-05

    Metal borides are often decomposition products from metal borohydrides and thus play a role in the reverse reaction where hydrogen is absorbed. In this work, aluminium boride, AlB2, has been investigated as a boron source for the formation of borohydrides under hydrogen pressures of p(H2) = 100 or 600 bar at elevated temperatures (350 or 400 °C). The systems AlB2-MHx (M = Li, Na, Mg, Ca) have been investigated, producing LiBH4, NaBH4 and Ca(BH4)2, whereas the formation of Mg(BH4)2 was not observed at T = 400 °C and p(H2) = 600 bar. The formation of the metal borohydrides is confirmed by powder X-ray diffraction and infrared spectroscopy and the fraction of boron in AlB2 and M(BH4)x is determined quantitatively by (11)B MAS NMR. Hydrogenation for 12 h at T = 350-400 °C and p(H2) = 600 bar leads to the formation of substantial amounts of LiBH4 (38.6 mol%), NaBH4 (83.0 mol%) and Ca(BH4)2 (43.6 mol%).

  11. Alkaline Hydrolysis is an Effective Treatment Technology for RDX-Contaminated Groundwater

    SciTech Connect

    Hqang, Snagchul; Felt, Deborah R.; Bouwer, Edward J.; Brooks, Michael C.; Larson, Steven L.; Davis, Jeffrey L.

    2003-03-26

    Kinetics and treatability of alkaline hydrolysis were investigated in batch reactor and continuous flow-stirred tank reactor (CFSTR) for remediating groundwater contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The batch system (pH 11 to 13, RDX 1 to 10 mg/L) achieved pseudo first-order RDX transformation rates in the range of 0.2 to 47.5 min-1, corresponding to 57.8 to 0.2 hrs of half-life period, respectively. In the CFSTR system (pH 11 to 11.9, HRT 0.54 to 2 days), the best alkaline RDX transformation was achieved a 99% RDX removal with the longest HRT and the highest reaction pH. Formate ({approx}2 M/M RDXremoved) and nitrite ({approx}0.2 M/M RDXremoved) were produced as the major hydrolysates, indicative of a simultaneous transformation mechanism by RDX ring cleavage and ring nitrogen elimination. The net OH- demand was found to be 1.5, 390 and 130 M OH-/M RDXremoved at the pH of 11.9, 11.5 and 11.0, respectively, in the CFSTR system.

  12. Plasma membranes modified by plasma treatment or deposition as solid electrolytes for potential application in solid alkaline fuel cells.

    PubMed

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-07-30

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane.

  13. Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

    PubMed Central

    Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

    2012-01-01

    In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane. PMID:24958295

  14. Preparation by alkaline treatment and detailed characterisation of empty hepatitis B virus core particles for vaccine and gene therapy applications

    NASA Astrophysics Data System (ADS)

    Strods, Arnis; Ose, Velta; Bogans, Janis; Cielens, Indulis; Kalnins, Gints; Radovica, Ilze; Kazaks, Andris; Pumpens, Paul; Renhofa, Regina

    2015-06-01

    Hepatitis B virus (HBV) core (HBc) virus-like particles (VLPs) are one of the most powerful protein engineering tools utilised to expose immunological epitopes and/or cell-targeting signals and for the packaging of genetic material and immune stimulatory sequences. Although HBc VLPs and their numerous derivatives are produced in highly efficient bacterial and yeast expression systems, the existing purification and packaging protocols are not sufficiently optimised and standardised. Here, a simple alkaline treatment method was employed for the complete removal of internal RNA from bacteria- and yeast-produced HBc VLPs and for the conversion of these VLPs into empty particles, without any damage to the VLP structure. The empty HBc VLPs were able to effectively package the added DNA and RNA sequences. Furthermore, the alkaline hydrolysis technology appeared efficient for the purification and packaging of four different HBc variants carrying lysine residues on the HBc VLP spikes. Utilising the introduced lysine residues and the intrinsic aspartic and glutamic acid residues exposed on the tips of the HBc spikes for chemical coupling of the chosen peptide and/or nucleic acid sequences ensured a standard and easy protocol for the further development of versatile HBc VLP-based vaccine and gene therapy applications.

  15. Preparation by alkaline treatment and detailed characterisation of empty hepatitis B virus core particles for vaccine and gene therapy applications.

    PubMed

    Strods, Arnis; Ose, Velta; Bogans, Janis; Cielens, Indulis; Kalnins, Gints; Radovica, Ilze; Kazaks, Andris; Pumpens, Paul; Renhofa, Regina

    2015-06-26

    Hepatitis B virus (HBV) core (HBc) virus-like particles (VLPs) are one of the most powerful protein engineering tools utilised to expose immunological epitopes and/or cell-targeting signals and for the packaging of genetic material and immune stimulatory sequences. Although HBc VLPs and their numerous derivatives are produced in highly efficient bacterial and yeast expression systems, the existing purification and packaging protocols are not sufficiently optimised and standardised. Here, a simple alkaline treatment method was employed for the complete removal of internal RNA from bacteria- and yeast-produced HBc VLPs and for the conversion of these VLPs into empty particles, without any damage to the VLP structure. The empty HBc VLPs were able to effectively package the added DNA and RNA sequences. Furthermore, the alkaline hydrolysis technology appeared efficient for the purification and packaging of four different HBc variants carrying lysine residues on the HBc VLP spikes. Utilising the introduced lysine residues and the intrinsic aspartic and glutamic acid residues exposed on the tips of the HBc spikes for chemical coupling of the chosen peptide and/or nucleic acid sequences ensured a standard and easy protocol for the further development of versatile HBc VLP-based vaccine and gene therapy applications.

  16. Effect of alkalinity on nitrite accumulation in treatment of coal chemical industry wastewater using moving bed biofilm reactor.

    PubMed

    Hou, Baolin; Han, Hongjun; Jia, Shengyong; Zhuang, Haifeng; Zhao, Qian; Xu, Peng

    2014-05-01

    Nitrogen removal via nitrite (the nitrite pathway) is more suitable for carbon-limited industrial wastewater. Partial nitrification to nitrite is the primary step to achieve nitrogen removal via nitrite. The effect of alkalinity on nitrite accumulation in a continuous process was investigated by progressively increasing the alkalinity dosage ratio (amount of alkalinity to ammonia ratio, mol/mol). There is a close relationship among alkalinity, pH and the state of matter present in aqueous solution. When alkalinity was insufficient (compared to the theoretical alkalinity amount), ammonia removal efficiency increased first and then decreased at each alkalinity dosage ratio, with an abrupt removal efficiency peak. Generally, ammonia removal efficiency rose with increasing alkalinity dosage ratio. Ammonia removal efficiency reached to 88% from 23% when alkalinity addition was sufficient. Nitrite accumulation could be achieved by inhibiting nitrite oxidizing bacteria (NOB) by free ammonia (FA) in the early period and free nitrous acid in the later period of nitrification when alkalinity was not adequate. Only FA worked to inhibit the activity of NOB when alkalinity addition was sufficient.

  17. Volatile fatty acids production from anaerobic treatment of cassava waste water: effect of temperature and alkalinity.

    PubMed

    Hasan, Salah Din Mahmud; Giongo, Citieli; Fiorese, Mônica Lady; Gomes, Simone Damasceno; Ferrari, Tatiane Caroline; Savoldi, Tarcio Enrico

    2015-01-01

    The production of volatile fatty acids (VFAs), intermediates in the anaerobic degradation process of organic matter from waste water, was evaluated in this work. A batch reactor was used to investigate the effect of temperature, and alkalinity in the production of VFAs, from the fermentation of industrial cassava waste water. Peak production of total volatile fatty acids (TVFAs) was observed in the first two days of acidogenesis. A central composite design was performed, and the highest yield (3400 mg L(-1) of TVFA) was obtained with 30°C and 3 g L(-1) of sodium bicarbonate. The peak of VFA was in 45 h (pH 5.9) with a predominance of acetic (63%) and butyric acid (22%), followed by propionic acid (12%). Decreases in amounts of cyanide (12.9%) and chemical oxygen demand (21.6%) were observed, in addition to the production of biogas (0.53 cm(3) h(-1)). The process was validated experimentally and 3400 g L(-1) of TVFA were obtained with a low relative standard deviation.

  18. In situ spectroscopic ellipsometry during electrochemical treatment of zinc in alkaline carbonate electrolyte

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Erbe, Andreas

    2013-01-01

    In situ spectroscopic ellipsometry (SE, 297-820 nm, 4.4-1.5 eV) during electrochemical oxidation/reduction of zinc in alkaline carbonate electrolyte was performed using a specially designed optical-electrochemical cell. The growth and shrinkage of the interfacial layer on Zn was analysed on the basis of Lekner's first order perturbation theory. For non-absorbing thin films on metal surfaces, an algorithm has been derived to extract the thickness of a surface film directly from ellipsometric data without the need of optical modelling. During cyclic voltammetry (CV), a rapid decrease/increase in the layer thickness in the reduction/oxidation peak has been found. In the potential regime where the surface is oxide-covered, the layer thickness increases/decreases linearly with potential in anodic/cathodic scans. The density of the interfacial region in this regime is constant. During chronoamperometric experiments, a fast correlating jump in thickness was found after potential jumps. An ageing of the films is observed in the absorption spectrum (from the ellipsometric parameter Ψ), which shows changes until ≈ 30 min after potential jumps. Analysis of the current transients points to continuous dissolution of Zn.

  19. Laboratory Studies of Hydrogen Gas Generation Using the Cobalt Chloride Catalyzed Sodium Borohydride-Water Reaction

    DTIC Science & Technology

    2015-07-01

    TECHNICAL REPORT 2082 July 2015 Laboratory Studies of Hydrogen Gas Generation Using the Cobalt Chloride Catalyzed Sodium ...describes experiments to generate hydrogen gas using the cobalt chloride catalyzed sodium borohydride-water reaction. Space and Naval Warfare Systems...to inflate LTAs. Of the metal hydrides, we chose to explore the sodium borohydride chemistry. We chose this chemistry because of its energy density

  20. The surgical treatment of chronic gastric atony following Roux-Y diversion for alkaline reflux gastritis

    SciTech Connect

    Vogel, S.B.; Woodward, E.R.

    1989-06-01

    Symptoms of severe nausea, vomiting, abdominal pain, and frequent bezoars, as well as objective gastric retention, can occur following Roux-Y biliary diversion for alkaline reflux gastritis. Medical therapy and prokinetic drugs have proven ineffective. This review evaluates 37 patients who underwent further gastric resection from 1979 to 1987 to improve gastric emptying and resolve symptoms. Fifteen patients underwent perioperative radionuclide solid-food gastric emptying studies. Seventy-three per cent (27 of 37 patients) of the patients who underwent further gastric resection (70% to 95%) had a satisfactory postoperative response. Twenty patients were graded Visick 1 or 2 and 7 Visick-3 patients, although much improved, still had some symptoms of gastroparesis. Twenty-seven per cent (10 of 37 patients) failed to improve and underwent completion total gastrectomy. Overall, 70% of this group had almost complete resolution of their symptoms. Three of 10 patients were considered ''failures'' due to postprandial pain in 1 and early vasomotor dumping in 2. Of the 10 patients who failed initial revisional surgery, 7 underwent a 70% to 80% subtotal gastric resection (STG) and 3 patients underwent 85% to 95% extensive resection (EXT.G.). Of the 15 patients who underwent perioperative radionuclide evaluation, a mean two-hour gastric retention of 61.4% +/- 4% (SEM) decreased to 25% +/- 4% following further gastric resection. Eight patients were in the STG group and seven patients were in the EXT.G group. Following STG, mean two-hour gastric retention of 58.2% +/- 3.5% decreased to 38% +/- 3% (p less than 0.05). In seven patients who underwent EXT.G, mean two-hour retention of 65% +/- 4% decreased to 10% +/- 2.5% (p less than 0.005). EXT.G resulted in normal gastric emptying and few late failures.

  1. Alkaline phosphatase level in gingival crevicular fluid during treatment with Quad-Helix.

    PubMed

    Delli Mauri, A; Petrini, M; Vitale, D; Tecco, S; Festa, F; Barbato, E; Spoto, G

    2015-01-01

    The aim of this work is to assess the level of the human alkaline phosphatase enzyme (ALP) during palatal expansion with Quad-Helix (QH) appliance. A total of twenty-two orthodontic patients characterized by contraction of the upper jaw, that needed application of a QH in order to treat their condition, were included in this study. Gingival crevicular fluid (GCF) was collected at four different times: before cementation (T0), after two weeks (T1), after four weeks (T2) and after one year (T3) from application of QH. In each patient maxillary first molars, right (UM-right) and left (UM-left), which were connected with bands to QH, were used for testing; first lower molars were used as Controls (LM-right, LM-left). Data show that ALP level in tension sites was proportional to the average increase of the inter-molar distance; on the contrary, the enzymatic level in compression sites was characterized by an inverse trend. The only exception to this phenomenon was recorded after one year (T3), when the increase of ALP level in both sites of tension and compression was ascribed to a mild inflammation due to bacterial plaque accumulation. The level of ALP in control sites was constant for the whole period of observation. The described ALP fluctuations in accordance with the inter-molar distance increment, shows that the main action of QH on bone remodelling was exerted during the fourth week (T2); for this reason, the monitoring of this enzyme could be used as a marker of effective function of the QH appliance.

  2. Passive aerobic treatment of net-alkaline, iron-laden drainage from a flooded underground anthracite mine, Pennsylvania, USA

    USGS Publications Warehouse

    Cravotta, C.A.

    2007-01-01

    This report evaluates the results of a continuous 4.5-day laboratory aeration experiment and the first year of passive, aerobic treatment of abandoned mine drainage (AMD) from a typical flooded underground anthracite mine in eastern Pennsylvania, USA. During 1991-2006, the AMD source, locally known as the Otto Discharge, had flows from 20 to 270 L/s (median 92 L/s) and water quality that was consistently suboxic (median 0.9 mg/L O2) and circumneutral (pH ??? 6.0; net alkalinity >10) with moderate concentrations of dissolved iron and manganese and low concentrations of dissolved aluminum (medians of 11, 2.2, and <0.2 mg/L, respectively). In 2001, the laboratory aeration experiment demonstrated rapid oxidation of ferrous iron (Fe 2+) without supplemental alkalinity; the initial Fe2+ concentration of 16.4 mg/L decreased to less than 0.5 mg/L within 24 h; pH values increased rapidly from 5.8 to 7.2, ultimately attaining a steady-state value of 7.5. The increased pH coincided with a rapid decrease in the partial pressure of carbon dioxide (PCO2) from an initial value of 10 -1.1atm to a steady-state value of 10-3.1atm. From these results, a staged aerobic treatment system was conceptualized consisting of a 2 m deep pond with innovative aeration and recirculation to promote rapid oxidation of Fe2+, two 0.3 m deep wetlands to facilitate iron solids removal, and a supplemental oxic limestone drain for dissolved manganese and trace-metal removal. The system was constructed, but without the aeration mechanism, and began operation in June 2005. During the first 12 months of operation, estimated detention times in the treatment system ranged from 9 to 38 h. However, in contrast with 80-100% removal of Fe2+ over similar elapsed times during the laboratory aeration experiment, the treatment system typically removed less than 35% of the influent Fe2+. Although concentrations of dissolved CO2 decreased progressively within the treatment system, the PCO2 values for treated effluent

  3. Isotopic Exchange in Porous and Dense Magnesium Borohydride.

    PubMed

    Zavorotynska, Olena; Deledda, Stefano; Li, Guanqiao; Matsuo, Motoaki; Orimo, Shin-ichi; Hauback, Bjørn C

    2015-09-01

    Magnesium borohydride (Mg(BH4)2) is one of the most promising complex hydrides presently studied for energy-related applications. Many of its properties depend on the stability of the BH4(-) anion. The BH4(-) stability was investigated with respect to H→D exchange. In situ Raman measurements on high-surface-area porous Mg(BH4 )2 in 0.3 MPa D2 have shown that the isotopic exchange at appreciable rates occurs already at 373 K. This is the lowest exchange temperature observed in stable borohydrides. Gas-solid isotopic exchange follows the BH4(-) +D˙ →BH3D(-) +H˙ mechanism at least at the initial reaction steps. Ex situ deuteration of porous Mg(BH4)2 and its dense-phase polymorph indicates that the intrinsic porosity of the hydride is the key behind the high isotopic exchange rates. It implies that the solid-state H(D) diffusion is considerably slower than the gas-solid H→D exchange reaction at the surface and it is a rate-limiting steps for hydrogen desorption and absorption in Mg(BH4)2.

  4. Arsenic in an Alkaline AMD Treatment Sludge: Characterization and Stability Under Prolonged Anoxic Conditions

    SciTech Connect

    Beauchemin, S.; Fiset, J; Poirier, G; Ablett, J

    2010-01-01

    Lime treatment of acid mine drainage (AMD) generates large volumes of neutralization sludge that are often stored under water covers. The sludge consists mainly of calcite, gypsum and a widespread ferrihydrite-like Fe phase with several associated species of metal(loid) contaminants. The long-term stability of metal(loid)s in this chemically ill-defined material remains unknown. In this study, the stability and speciation of As in AMD sludge subjected to prolonged anoxic conditions is determined. The total As concentration in the sludge is 300 mg kg{sup -1}. In the laboratory, three distinct water cover treatments were imposed on the sludge to induce different redox conditions (100%N{sub 2}, 100%N{sub 2} + glucose, 95%N{sub 2}:5%H{sub 2}). These treatments were compared against a control of oxidized, water-saturated sludge. Electron micro-probe (EMP) analysis and spatially resolved synchrotron X-ray fluorescence (SXRF) results indicate that As is dominantly associated with Fe in the sludge. In all treatments and throughout the experiment, measured concentrations of dissolved As were less than 5 {micro}g L{sup -1}. Dissolved Mn concentration in the N{sub 2} + glucose treatment increased significantly compared to other treatments. Manganese and As K-edge X-ray absorption near edge structure spectroscopy (XANES) analyses showed that Mn was the redox-active element in the solid-phase, while As was stable. Arsenic(V) was still the dominant species in all water-covered sludges after 9 months of anoxic treatments. In contrast, Mn(IV) in the original sludge was partially reduced into Mn(II) in all water-covered sludges. The effect was most pronounced in the N{sub 2} + glucose treatment, suggesting microbial reduction. Micro-scale SXRF and XANES analysis of the treated sludge showed that Mn(II) accumulated in areas already enriched in Fe and As. Overall, the study shows that AMD sludges remain stable under prolonged anoxic conditions. External sources of chemical reductants

  5. Investigation of nanostructured platinum-nickel supported on the titanium surface as electrocatalysts for alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Tamašauskaitė-Tamašiūnaitė, L.; Balčiūnaitė, A.; Vaiciukevičienė, A.; Selskis, A.; Pakštas, V.

    2012-06-01

    This study involves the formation of nanostructured platinum-nickel supported on the titanium surface catalysts using the galvanic displacement technique and investigation of their electrocatalytic activity toward the oxidation of borohydride, methanol and ethanol in an alkaline media by cyclic voltammetry and chronoamperometry. Scanning electron microscopy, Energy Dispersive X-ray Spectroscopy and X-ray diffraction were used to characterize the surface structure, composition and morphology. The nanoPt(Ni)/Ti and nanoPt/Ti catalysts exhibited a higher catalytic efficiency to the oxidation of borohydride, ethanol and methanol as compared with that of pure Pt.

  6. Consequences of alkaline treatment for the ultrastructure of the acetylcholine-receptor-rich membranes from Torpedo marmorata electric organ

    PubMed Central

    1981-01-01

    After fixation with glutaraldehyde and impregnation with tannic acid, the membrane that underlies the nerve terminals in Torpedo marmorata electroplaque presents a typical asymmetric triple-layered structure with an unusual thickness; in addition, it is coated with electron- dense material on its inner, cytoplasmic face. Filamentous structures are frequently found attached to these "subsynaptic densities." The organization of the subsynaptic membrane is partly preserved after homogenization of the electric organ and purification of acetylcholine- receptor (AchR)-rich membrane fragments. In vitro treatment at pH 11 and 4 degrees C of these AchR-rich membranes releases an extrinsic protein of 43,000 mol wt and at the same time causes the complete disappearance of the cytoplasmic condensations. Freeze-etching of native membrane fragments discloses remnants of the ribbonlike organization of the AchR rosettes. This organization disappears ater alkaline treatment and is replaced by a network which is not observed after rapid freezing and, therefore, most likely results from the lateral redistribution of the AchR rosettes during condition of slow freezing. A dispersion of the AchR rosettes in the plane of the membrane also occurs after fusion of the pH 11-treated fragments with phospholipid vesicles. These results are interpreted in terms of a structural stabilization and immobilization of the AchR by the 43,000- Mr protein binding to the inner face of the subsynaptic membrane. PMID:7287814

  7. Lignin preparation from oil palm empty fruit bunches by sequential acid/alkaline treatment--A biorefinery approach.

    PubMed

    Medina, Jesus David Coral; Woiciechowski, Adenise; Zandona Filho, Arion; Noseda, Miguel D; Kaur, Brar Satinder; Soccol, Carlos Ricardo

    2015-10-01

    Lignin is an important raw material for the sustainable biorefineries and also the forerunner of high-value added products, such as biocomposite for chemical, pharmaceutical and cement industries. Oil palm empty fruit bunches (OPEFB) were used for lignin preparation by successive treatment with 1% (w/w) H2SO4 at 121°C for 60 min and 2.5% NaOH at 121°C for 80 min resulting in the high lignin yield of 28.89%, corresponding to 68.82% of the original lignin. The lignin obtained was characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The results indicated a lignin with molecular masses ramping from 4500 kDa to 12,580 kDa. FTIR and NMR of these lignins showed more syringyl and p-hydroxyphenyl than guaiacyl units. Moderate acid/alkaline treatment provided lignin with high industrial potential and acid hydrolyzates rich in fermentable sugars and highly porous cellulosic fibers.

  8. Modification of chemical reactivity of enzymatic hydrolysis lignin by ultrasound treatment in dilute alkaline solutions.

    PubMed

    Ma, Zhuoming; Li, Shujun; Fang, Guizhen; Patil, Nikhil; Yan, Ning

    2016-12-01

    In this study, we have explored various ultrasound treatment conditions for structural modification of enzymatic hydrolysis lignin (EHL) for enhanced chemical reactivity. The key structural modifications were characterized by using a combination of analytical methods, including, Fourier Transform-Infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance ((1)H NMR), Gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), and Folin-Ciocalteu (F-C) method. Chemical reactivity of the modified EHL samples was determined by both 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and their reactivity towards formaldehyde. It was observed that the modified EHL had a higher phenolic hydroxyl group content, a lower molecular weight, a higher reactivity towards formaldehyde, and a greater antioxidant property. The higher reactivity demonstrated by the samples after treatment suggesting that ultrasound is a promising method for modifying enzymatic hydrolysis lignin for value-added applications.

  9. Development of a pH/alkalinity treatment model for applications of the lampricide TFM to streams tributary to the Great Lakes

    USGS Publications Warehouse

    Bills, Terry D.; Boogaard, Michael A.; Johnson, David A.; Brege, Dorance C.; Scholefield, Ronald J.; Westman, R. Wayne; Stephens, Brian E.

    2003-01-01

    It has long been known that the toxicity of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is influenced by chemical and physical properties of water. As the pH, conductivity, and alkalinity of water increase, greater concentrations of TFM are required to kill sea lamprey (Petromyzon marinus) larvae. Consequently, the concentration of TFM required for effective treatment varies among streams. Brown trout (Salmo trutta) and sea lamprey larvae were exposed to a series of TFM concentrations in a continuous-flow diluter for 12 h. Twenty five exposures were conducted at various water alkalinities and pHs that treatment personnel encounter during lampricide treatments. Survival/mortality data were analyzed for lampricide concentrations that produced 50 and 99.9% mortality (LC50 and LC99.9) for sea lamprey larvae and 25 and 50% mortality (LC25 and LC50) for brown trout. Linear regression analyses were performed for each set of tests for each selected alkalinity by comparing the 12-h post exposure LC99.9 sea lamprey data and LC25 brown trout data at each pH. Mortality data from on-site toxicity tests conducted by lampricide control personnel were compared to predicted values from the pH/alkalinity prediction model. Of the 31 tests examined, 27 resulted in the LC100s (lowest TFM concentration where 100% mortality of sea lamprey was observed after 12 h of exposure) falling within 0.2 mg/L of the predicted sea lamprey minimum lethal (LC99.9) range. The pH/alkalinity prediction model provides managers with an operational tool that reduces the amount of TFM required for effective treatment while minimizing the impact on non-target organisms.

  10. A simple borohydride/GC method for measuring sparteine metabolites in man.

    PubMed Central

    Inaba, T; Vinks, A; Otton, S V

    1986-01-01

    A simple borohydride/GC method was developed for phenotyping sparteine oxidation in man. The major metabolites of sparteine found in human urine, 2- and 5-dehydrosparteine, were converted quantitatively back to sparteine by sodium borohydride reduction. The amount of sparteine metabolites can be estimated from the difference of sparteine concentrations between the borohydride-treated and untreated urine samples. The coefficient of variation of this assay was estimated from repeated analyses to be +/- 3% within a day (intra-assay) and +/- 8% between days (inter-assay). PMID:3718806

  11. Pre-treatment serum alkaline phosphatase and lactate dehydrogenase as prognostic factors in triple negative breast cancer

    PubMed Central

    Chen, Bo; Dai, Danian; Tang, Hailin; Chen, Xi; Ai, Xiaohong; Huang, Xiaojia; Wei, Weidong; Xie, Xiaoming

    2016-01-01

    Background: Serum parameters as prognostic parameters are studied widely. We aim to examine the prognostic significance of the serum alkaline phosphatase (ALP) level and lactate dehydrogenase (LDH) level in triple negative breast cancer (TNBC). Methods: Total of 253 TNBC patients from Sun Yat-sen University Cancer Center who underwent treatment between January 2004 and December 2009 was conducted in this retrospective study. Before treatment serum ALP and LDH levels were routinely measured. We use the receiver operating characteristic (ROC) curve analysis to estimate the cutoff value of serum ALP and LDH levels. The Kaplan-Meier method and multivariable Cox regression analysis were used for Disease free survival (DFS) and overall survival (OS) assessed. Results: The ROC curves determined that the optimum cutoff point for ALP and LDH were 66.5u/L and 160.5u/L, respectively. The elevated ALP and LDH were both significantly associated with decreased DFS and OS (both P < 0.001). In addition, the entire cohort was stratified into three subgroups basis of ALP levels and LDH levels. TNBC Patients who with ALP >66.5 u/L and LDH >160.5u/L had the worst DFS and OS (both P < 0.001). In TNBC patients, univariate and multivariate Cox regression analyses conformed ALP and LDH were independent unfavorable prognostic factors for DFS and OS. Conclusions: The serum levels of ALP and LDH before treatment are independent prognostic parameters and may serve as complement to help predict survival in TNBC. PMID:27994669

  12. Complex metal borohydrides: multifunctional materials for energy storage and conversion.

    PubMed

    Mohtadi, Rana; Remhof, Arndt; Jena, Puru

    2016-09-07

    With the limited supply of fossil fuels and their adverse effect on the climate and the environment, it has become a global priority to seek alternate sources of energy that are clean, abundant, and sustainable. While sources such as solar, wind, and hydrogen can meet the world's energy demand, considerable challenges remain to find materials that can store and/or convert energy efficiently. This topical review focuses on one such class of materials, namely, multi-functional complex metal borohydrides that not only have the ability to store sufficient amount of hydrogen to meet the needs of the transportation industry, but also can be used for a new generation of metal ion batteries and solar cells. We discuss the material challenges in all these areas and review the progress that has been made to address them, the issues that still need to be resolved and the outlook for the future.

  13. Complex metal borohydrides: multifunctional materials for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Mohtadi, Rana; Remhof, Arndt; Jena, Puru

    2016-09-01

    With the limited supply of fossil fuels and their adverse effect on the climate and the environment, it has become a global priority to seek alternate sources of energy that are clean, abundant, and sustainable. While sources such as solar, wind, and hydrogen can meet the world’s energy demand, considerable challenges remain to find materials that can store and/or convert energy efficiently. This topical review focuses on one such class of materials, namely, multi-functional complex metal borohydrides that not only have the ability to store sufficient amount of hydrogen to meet the needs of the transportation industry, but also can be used for a new generation of metal ion batteries and solar cells. We discuss the material challenges in all these areas and review the progress that has been made to address them, the issues that still need to be resolved and the outlook for the future.

  14. New insights on the mechanism of palladium-catalyzed hydrolysis of sodium borohydride from 11B NMR measurements.

    PubMed

    Guella, G; Zanchetta, C; Patton, B; Miotello, A

    2006-08-31

    To gain insight on the mechanistic aspects of the palladium-catalyzed hydrolysis of NaBH(4) in alkaline media, the kinetics of the reaction has been investigated by (11)B NMR (nuclear magnetic resonance) measurements taken at different times during the reaction course. Working with BH(4)(-) concentration in the range 0.05-0.1 M and with a [substrate]/[catalyst] molar ratio of 0.03-0.11, hydrolysis has been found to follow a first-order kinetic dependence from concentration of both the substrate and the catalyst (Pd/C 10 wt %). We followed the reaction of NaBH(4) and its perdeuterated analogue NaBD(4) in H(2)O, in D(2)O and H(2)O/D(2)O mixtures. When the process was carried out in D(2)O, deuterium incorporation in BH(4)(-) afforded BH(4)(-)(n)D(n)(-) (n = 1, 2, 3, 4) species, and a competition between hydrolysis and hydrogen/deuterium exchange processes was observed. By fitting the kinetics NMR data by nonlinear least-squares regression techniques, the rate constants of the elementary steps involved in the palladium-catalyzed borohydride hydrolysis have been evaluated. Such a regression analysis was performed on a reaction scheme wherein the starting reactant BH(4)(-) is allowed both to reversibly exchange hydrogen with deuterium atoms of D(2)O and to irreversibly hydrolyze into borohydroxy species B(OD)(4)(-). In contrast to acid-catalyzed hydrolysis of sodium borohydride, our results indicate that in the palladium-catalyzed process the rate constants of the exchange processes are higher than those of the corresponding hydrolysis reactions.

  15. Investigation of platinum and palladium as potential anodic catalysts for direct borohydride and ammonia borane fuel cells

    NASA Astrophysics Data System (ADS)

    Olu, Pierre-Yves; Deschamps, Fabien; Caldarella, Giuseppe; Chatenet, Marian; Job, Nathalie

    2015-11-01

    Platinum and palladium are investigated as anodic catalysts for direct borohydride and direct ammonia borane fuel cells (DBFC and DABFC). Half-cell characterizations performed at 25 °C using NH3BH3 or NaBH4 alkaline electrolytes demonstrate the lowest open-circuit potential and highest electrocatalytic activity for the NH3BH3 alkaline electrolyte for Pd and Pt rotating disk electrodes, respectively. Voltammograms performed in fuel cell configuration at 25 °C confirm this trend: the highest open circuit voltage (1.05 V) and peak power density (181 mW·cm-2) are monitored for DABFC using Pd/C and Pt/C anodes, respectively. Increasing the temperature heightens the peak power density (that reaches 420 mW·cm-2 at 60 °C for DBFC using Pt/C anodes), but strongly generates gas from the fuel hydrolysis, hindering the overall fuel cells performances. The anode texture strongly influences the fuel cell performances, highlighting: (i) that an open anode texture is required to efficiently circulate the anolyte and (ii) the difficulty to compare potential anodic catalysts characterized using different fuel cell setups within the literature. Furthermore, TEM imaging of Pt/C and Pd/C catalysts prior/post DBFC and DABFC operation shows fast degradation of the carbon-supported nanoparticles.

  16. Oxidation behavior of Cr(III) during thermal treatment of chromium hydroxide in the presence of alkali and alkaline earth metal chlorides.

    PubMed

    Mao, Linqiang; Gao, Bingying; Deng, Ning; Liu, Lu; Cui, Hao

    2016-02-01

    The oxidation behavior of Cr(III) during the thermal treatment of chromium hydroxide in the presence of alkali and alkaline earth metal chlorides (NaCl, KCl, MgCl2, and CaCl2) was investigated. The amounts of Cr(III) oxidized at various temperatures and heating times were determined, and the Cr-containing species in the residues were characterized. During the transformation of chromium hydroxide to Cr2O3 at 300 °C approximately 5% of the Cr(III) was oxidized to form intermediate compounds containing Cr(VI) (i.e., CrO3), but these intermediates were reduced to Cr2O3 when the temperature was above 400 °C. Alkali and alkaline earth metals significantly promoted the oxidation of Cr(III) during the thermal drying process. Two pathways were involved in the influences the alkali and alkaline earth metals had on the formation of Cr(VI). In pathway I, the alkali and alkaline earth metals were found to act as electron transfer agents and to interfere with the dehydration process, causing more intermediate Cr(VI)-containing compounds (which were identified as being CrO3 and Cr5O12) to be formed. The reduction of intermediate compounds to Cr2O3 was also found to be hindered in pathway I. In pathway II, the alkali and alkaline earth metals were found to contribute to the oxidation of Cr(III) to form chromates. The results showed that the presence of alkali and alkaline earth metals significantly increases the degree to which Cr(III) is oxidized during the thermal drying of chromium-containing sludge.

  17. Effect of Treatment pH on the End Products of the Alkaline Hydrolysis of TNT and RDX

    DTIC Science & Technology

    2007-06-01

    Comparison of final TOC of TNT alkaline hydrolysis solutions at three pHs........................19 Table 7. Results of ion chromatographic analysis ...25 Table 12. Results of ion chromatographic analysis of unlabeled RDX solutions following extended alkaline hydrolysis at three...8330 explo- sives analysis TOC IC Lime Control ERDC/EL TR-07-4 7 3 Materials and Methods Chemicals Chemicals used in this study included

  18. Nanoconfinement in activated mesoporous carbon of calcium borohydride for improved reversible hydrogen storage.

    PubMed

    Comănescu, Cezar; Capurso, Giovanni; Maddalena, Amedeo

    2012-09-28

    Mesoporous carbon frameworks were synthesized using the soft-template method. Ca(BH(4))(2) was incorporated into activated mesoporous carbon by the incipient wetness method. The activation of mesoporous carbon was necessary to optimize the surface area and pore size. Thermal programmed absorption measurements showed that the confinement of this borohydride into carbon nanoscaffolds improved its reversible capacity (relative to the reactive portion) and performance of hydrogen storage compared to unsupported borohydride. Hydrogen release from the supported hydride started at a temperature as low as 100 °C and the dehydrogenation rate was fast compared to the bulk borohydride. In addition, the hydrogen pressure necessary to regenerate the borohydride from the dehydrogenation products was reduced.

  19. Degradation of azo dye methyl red by alkaliphilic, halotolerant Nesterenkonia lacusekhoensis EMLA3: application in alkaline and salt-rich dyeing effluent treatment.

    PubMed

    Bhattacharya, Amrik; Goyal, Nidhi; Gupta, Anshu

    2017-03-02

    Effluents from textile industries are highly colored due to vast use of various azo dyes and color is the first visual indicator of pollution. Biological treatment of textile effluent is often hampered due to the alkaline pH and high salinity; a common characteristic of many textile industrial wastewaters. Considering this, the present study explores the potential of a newly isolated halotolerant and alkaliphilic bacterium Nesterenkonia lacusekhoensis EMLA3 for degradation of methyl red (MR) dye under alkaline condition. Strain EMLA3 showed 97% degradation of 50 mg L(-1) MR after 16 h at initial pH of 11.5 in nutrient medium. Dye degradation by the isolate is supported by the formation of low-molecular weight metabolites as divulge through GC-MS & FTIR studies Optimum dye degradation was observed in the pH range of 8.0-11.5 and temperature range of 30-35 °C. Significant MR degrading activity of the strain could be achieved in the presence of very high salt level (100-120 g L(-1) NaCl) and in co-presence of different heavy metals. Application of strain to alkaline pH, salt, and heavy metals laden-textile effluent resulted in overall 83% dye removal from the effluent after 120 h of treatment under static condition. Furthermore, the property of microbe to drop-down the pH of wastewater from 11.5 to 8.60 after treatment also lowers the need of additional neutralization treatment. The entire study thus comes out with novel application of N. lacusekhoensis-a less explored extremophilic bacterium-for treatment of alkaline and salt-rich azo dye-containing wastewaters.

  20. Electrocatalysis of borohydride oxidation: a review of density functional theory approach combined with experimental validation

    NASA Astrophysics Data System (ADS)

    Sison Escaño, Mary Clare; Lacdao Arevalo, Ryan; Gyenge, Elod; Kasai, Hideaki

    2014-09-01

    The electrocatalysis of borohydride oxidation is a complex, up-to-eight-electron transfer process, which is essential for development of efficient direct borohydride fuel cells. Here we review the progress achieved by density functional theory (DFT) calculations in explaining the adsorption of BH4- on various catalyst surfaces, with implications for electrocatalyst screening and selection. Wherever possible, we correlate the theoretical predictions with experimental findings, in order to validate the proposed models and to identify potential directions for further advancements.

  1. Method of recycling lithium borate to lithium borohydride through methyl borate

    DOEpatents

    Filby, Evan E.

    1977-01-01

    This invention provides a method for the recycling of lithium borate to lithium borohydride which can be reacted with water to generate hydrogen for utilization as a fuel. The lithium borate by-product of the hydrogen generation reaction is reacted with hydrogen chloride and water to produce boric acid and lithium chloride. The boric acid and lithium chloride are converted to lithium borohydride through a methyl borate intermediate to complete the recycle scheme.

  2. The crystal chemistry of inorganic metal borohydrides and their relation to metal oxides.

    PubMed

    Černý, Radovan; Schouwink, Pascal

    2015-12-01

    The crystal structures of inorganic homoleptic metal borohydrides are analysed with respect to their structural prototypes found amongst metal oxides in the inorganic databases such as Pearson's Crystal Data [Villars & Cenzual (2015). Pearson's Crystal Data. Crystal Structure Database for Inorganic Compounds, Release 2014/2015, ASM International, Materials Park, Ohio, USA]. The coordination polyhedra around the cations and the borohydride anion are determined, and constitute the basis of the structural systematics underlying metal borohydride chemistry in various frameworks and variants of ionic packing, including complex anions and the packing of neutral molecules in the crystal. Underlying nets are determined by topology analysis using the program TOPOS [Blatov (2006). IUCr CompComm. Newsl. 7, 4-38]. It is found that the Pauling rules for ionic crystals apply to all non-molecular borohydride crystal structures, and that the latter can often be derived by simple deformation of the close-packed anionic lattices c.c.p. and h.c.p., by partially removing anions and filling tetrahedral or octahedral sites. The deviation from an ideal close packing is facilitated in metal borohydrides with respect to the oxide due to geometrical and electronic considerations of the BH4(-) anion (tetrahedral shape, polarizability). This review on crystal chemistry of borohydrides and their similarity to oxides is a contribution which should serve materials engineers as a roadmap to design new materials, synthetic chemists in their search for promising compounds to be prepared, and materials scientists in understanding the properties of novel materials.

  3. Sulfur-oxidizing autotrophic and mixotrophic denitrification processes for drinking water treatment: elimination of excess sulfate production and alkalinity requirement.

    PubMed

    Sahinkaya, Erkan; Dursun, Nesrin

    2012-09-01

    This study evaluated the elimination of alkalinity need and excess sulfate generation of sulfur-based autotrophic denitrification process by stimulating simultaneous autotrophic and heterotrophic (mixotrophic) denitrification process in a column bioreactor by methanol supplementation. Also, denitrification performances of sulfur-based autotrophic and mixotrophic processes were compared. In autotrophic process, acidity produced by denitrifying sulfur-oxidizing bacteria was neutralized by the external NaHCO(3) supplementation. After stimulating mixotrophic denitrification process, the alkalinity need of the autotrophic process was satisfied by the alkalinity produced by heterotrophic denitrifiers. Decreasing and lastly eliminating the external alkalinity supplementation did not adversely affect the process performance. Complete denitrification of 75 mg L(-1) NO(3)-N under mixotrophic conditions at 4 h hydraulic retention time was achieved without external alkalinity supplementation and with effluent sulfate concentration lower than the drinking water guideline value of 250 mg L(-1). The denitrification rate of mixotrophic process (0.45 g NO(3)-N L(-1) d(-1)) was higher than that of autotrophic one (0.3 g NO(3)-N L(-1) d(-1)). Batch studies showed that the sulfur-based autotrophic nitrate reduction rate increased with increasing initial nitrate concentration and transient accumulation of nitrite was observed.

  4. The effects on DNA migration of altering parameters in the comet assay protocol such as agarose density, electrophoresis conditions and durations of the enzyme or the alkaline treatments.

    PubMed

    Ersson, Clara; Möller, Lennart

    2011-11-01

    The single cell gel electrophoresis (comet assay) is a popular method for measuring DNA migration as an estimate of DNA damage. No standardised comet assay protocol exists, which make comparisons between studies complicated. In a previous inter-laboratory validation study of the comet assay, we identified important parameters in the protocol that might affect DNA migration. The aim of this study was to assess how different comet assay protocols affect DNA migration. The results in this study suggest that (i) there is a significant linear dose-response relationship between the agarose gel's density and DNA migration and that damaged cells are more sensitive to the agarose gel's density; (ii) incubation with formamidopyrimidine DNA glycosylase for 10 min is inadequate, whereas 30 min is sufficient; (iii) the typically used 20 min of alkaline treatment might be to short when analysing samples that contain particular alkali-labile sites (ALS) and (iv) the duration of electrophoresis as well as the strength of the electric field applied affects the DNA migration. By using protocol-specific calibration curves, it is possible to reduce the variation in DNA migration caused by differences in comet assay protocols. This does, however, not completely remove the impact of the durations of alkaline treatment and electrophoresis when analysing cells containing ALS that are relatively resistant to high alkaline treatment.

  5. Platinum- and membrane-free swiss-roll mixed-reactant alkaline fuel cell.

    PubMed

    Aziznia, Amin; Oloman, Colin W; Gyenge, Előd L

    2013-05-01

    Eliminating the expensive and failure-prone proton exchange membrane (PEM) together with the platinum-based anode and cathode catalysts would significantly reduce the high capital and operating costs of low-temperature (<373 K) fuel cells. We recently introduced the Swiss-roll mixed-reactant fuel cell (SR-MRFC) concept for borohydride-oxygen alkaline fuel cells. We now present advances in anode electrocatalysis for borohydride electrooxidation through the development of osmium nanoparticulate catalysts supported on porous monolithic carbon fiber materials (referred to as an osmium 3D anode). The borohydride-oxygen SR-MRFC operates at 323 K and near atmospheric pressure, generating a peak power density of 1880 W m(-2) in a single-cell configuration by using an osmium-based anode (with an osmium loading of 0.32 mg cm(-2)) and a manganese dioxide gas-diffusion cathode. To the best of our knowledge, 1880 W m(-2) is the highest power density ever reported for a mixed-reactant fuel cell operating under similar conditions. Furthermore, the performance matches the highest reported power densities for conventional dual chamber PEM direct borohydride fuel cells.

  6. Sodium borohydride removes aldehyde inhibitors for enhancing biohydrogen fermentation.

    PubMed

    Lin, Richen; Cheng, Jun; Ding, Lingkan; Song, Wenlu; Zhou, Junhu; Cen, Kefa

    2015-12-01

    To enhance biohydrogen production from glucose and xylose in the presence of aldehyde inhibitors, reducing agent (i.e., sodium borohydride) was in situ added for effective detoxification. The detoxification efficiencies of furfural (96.7%) and 5-hydroxymethylfurfural (5-HMF, 91.7%) with 30mM NaBH4 were much higher than those of vanillin (77.3%) and syringaldehyde (69.3%). Biohydrogen fermentation was completely inhibited without detoxification, probably because of the consumption of nicotinamide adenine dinucleotide (NADH) by inhibitors reduction (R-CHO+2NADH→R-CH2OH+2NAD(+)). Addition of 30mM NaBH4 provided the reducing power necessary for inhibitors reduction (4R-CHO+NaBH4+2H2O→4R-CH2OH+NaBO2). The recovered reducing power in fermentation resulted in 99.3% recovery of the hydrogen yield and 64.6% recovery of peak production rate. Metabolite production and carbon conversion after detoxification significantly increased to 63.7mM and 81.9%, respectively.

  7. Optical properties of humic substances and CDOM: effects of borohydride reduction.

    PubMed

    Ma, Jiahai; Del Vecchio, Rossana; Golanoski, Kelli S; Boyle, Erin S; Blough, Neil V

    2010-07-15

    Treatment of Suwanee River humic (SRHA) and fulvic (SRFA) acids, a commercial lignin (LAC), and a series of solid phase extracts (C18) from the Middle Atlantic Bight (MAB extracts) with sodium borohydride (NaBH(4)), a selective reductant of carbonyl-containing compounds including quinones and aromatic ketones, produces a preferential loss of visible absorption (> or = 50% for SRFA) and substantially enhanced, blue-shifted fluorescence emission (2- to 3-fold increase). Comparison of the results with those obtained from a series of model quinones and hydroquinones demonstrates that these spectral changes cannot be assigned directly to the absorption and emission of visible light by quinones/hydroquinones. Instead, these results are consistent with a charge transfer model in which the visible absorption is due primarily to charge transfer transitions arising among hydroxy- (methoxy-) aromatic donors and carbonyl-containing acceptors. Unlike most of the model hydroquinones, the changes in optical properties of the natural samples following NaBH(4) reduction were largely irreversible in the presence of air and following addition of a Cu(2+) catalyst, providing tentative evidence that aromatic ketones (or other similar carbonyl-containing structures) may play a more important role than quinones in the optical properties of these materials.

  8. Unveiling the effects of post-deposition treatment with different alkaline elements on the electronic properties of CIGS thin film solar cells.

    PubMed

    Pianezzi, Fabian; Reinhard, Patrick; Chirilă, Adrian; Bissig, Benjamin; Nishiwaki, Shiro; Buecheler, Stephan; Tiwari, Ayodhya N

    2014-05-21

    Thin film solar cells with a Cu(In,Ga)Se2 (CIGS) absorber layer achieved efficiencies above 20%. In order to achieve such high performance the absorber layer of the device has to be doped with alkaline material. One possibility to incorporate alkaline material is a post deposition treatment (PDT), where a thin layer of NaF and/or KF is deposited onto the completely grown CIGS layer. In this paper we discuss the effects of PDT with different alkaline elements (Na and K) on the electronic properties of CIGS solar cells. We demonstrate that whereas Na is more effective in increasing the hole concentration in CIGS, K significantly improves the pn-junction quality. The beneficial role of K in improving the PV performance is attributed to reduced recombination at the CdS/CIGS interface, as revealed by temperature dependent J-V measurements, due to a stronger electronically inverted CIGS surface region. Computer simulations with the software SCAPS are used to verify this model. Furthermore, we show that PDT with either KF or NaF has also a distinct influence on other electronic properties of the device such as the position of the N1 signal in admittance spectroscopy and the roll-over of the J-V curve at low temperature. In view of the presented results we conclude that a model based on a secondary diode at the CIGS/Mo interface can best explain these features.

  9. Development of high-performance cathode catalyst of polypyrrole modified carbon supported CoOOH for direct borohydride fuel cell

    NASA Astrophysics Data System (ADS)

    He, Yan; Zhu, Cai; Chen, Kaijian; Wang, Juan; Qin, Haiying; Liu, Jiabin; Yan, Shuai; Yang, Ke; Li, Aiguo

    2017-01-01

    Polypyrrole modified carbon supported CoOOH electrocatalyst (CoOOH-PPy-C) is prepared by impregnation-chemical method, and the catalytic properties for the oxygen reduction reaction (ORR) in alkaline media are investigated. The X-ray diffraction and transmission electron microscopy results confirm the presence of the expected CoOOH. The electrochemical tests show that the CoOOH-PPy-C catalyst exhibits good electrocatalytic activity towards ORR. The direct borohydride fuel cell using CoOOH-PPy-C as the cathode catalyst demonstrates a good stability performance. There is only 4% decrease of the cell voltage after 80-h operation. The ORR occurs an average 4-electron transfer pathway on the CoOOH-PPy-C catalyst. The good catalytic activity towards ORR benefits from the Cosbnd N bond, which is identified by X-ray photoelectron spectroscopy test. X-ray absorption fine structure experiments further show that two nearest O atoms are substituted by two N atoms bonding to Co ion at a distance of 1.64 Å. The CoOOH-PPy-C exhibits better electrochemical properties than the Co(OH)2 counterpart even though the valence state of Co ion is +3 in CoOOH-PPy-C. Those results indicate that the bonding of Co ion with N atoms should be a key issue regardless the valence of Co ion.

  10. A new cementless total hip arthroplasty with bioactive titanium porous-coating by alkaline and heat treatment: average 4.8-year results.

    PubMed

    Kawanabe, Keiichi; Ise, Kentaro; Goto, Koji; Akiyama, Haruhiko; Nakamura, Takashi; Kaneuji, Ayumi; Sugimori, Tanzo; Matsumoto, Tadami

    2009-07-01

    A method has been developed for creating a bioactive coating on titanium by alkaline and heat treatment, and shown that it forms a thin layer of hydroxyapatite (HA) on the surface of implants when soaked in simulated body fluid. A series of 70 cementless primary total hip arthroplasties using this coating technique on a porous titanium surface was performed, and followed up the patients for a mean period of 4.8 years. There were no instances of loosening or revision, or formation of a reactive line on the porous coating. Although radiography just after operation showed a gap between the host bone and the socket in over 70% of cases, all the gaps disappeared within a year, indicating the good osteoconduction provided by the coating. Alkaline-heat treatment of titanium to provide a thin HA coating has several advantages over plasma-spraying, including no degeneration or absorption of the HA coating, simplicity of the manufacturing process, and cost effectiveness. In addition, this method allows homogeneous deposition of bone-like apatite within a porous implant. Although this was a relatively short-term study, treatment that creates a bioactive surface on titanium and titanium alloy implants has considerable promise for clinical application.

  11. Advanced alkaline water electrolysis

    NASA Astrophysics Data System (ADS)

    Wakabayashi, N.; Torikai, E.; Kawami, Y.; Takenaka, H.

    Results are presented of experimental studies of possible separators and electrodes for use in advanced, high-temperature, high-pressure alkaline water electrolyzers. Material evaluations in alkaline water electrolyzers at temperatures from 100 to 120 C have shown a new type polytetrafluoroethylene membrane impregnated with potassium titanate to be the most promising when the separator is prepared by the hydrothermal treatment of a porous PFTE membrane impregnated with hydrated titanium oxide. Measurements of cell voltages in 30% KOH at current densities from 5 to 100 A/sq dm at temperatures up to 120 C with nickel electrodes of various structures have shown the foamed nickel electrode, with an average pore size of 1-1.5 mm, to have the best performance. When the foamed nickel is coated by fine powdered nickel, carbonyl nickel or Raney nickel to increase electrode surface areas, even lower cell voltages were found, indicating better performance.

  12. Removal of toxic and alkali/alkaline earth metals during co-thermal treatment of two types of MSWI fly ashes in China.

    PubMed

    Yu, Jie; Qiao, Yu; Jin, Limei; Ma, Chuan; Paterson, Nigel; Sun, Lushi

    2015-12-01

    This study aims to vaporize heavy metals and alkali/alkaline earth metals from two different types of fly ashes by thermal treatment method. Fly ash from a fluidized bed incinerator (HK fly ash) was mixed with one from a grate incinerator (HS fly ash) in various proportions and thermally treated under different temperatures. The melting of HS fly ash was avoided when treated with HK fly ash. Alkali/alkaline earth metals in HS fly ash served as Cl-donors to promote the vaporization of heavy metals during thermal treatment. With temperature increasing from 800 to 900°C, significant amounts of Cl, Na and K were vaporized. Up to 1000°C in air, less than 3% of Cl and Na and less than 5% of K were retained in ash. Under all conditions, Cd can be vaporized effectively. The vaporization of Pb was mildly improved when treated with HS fly ash, while the effect became less pronounced above 900°C. Alkali/alkaline earth metals can promote Cu vaporization by forming copper chlorides. Comparatively, Zn vaporization was low and only slightly improved by HS fly ash. The low vaporization of Zn could be caused by the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4. Under all conditions, less than 20% of Cr was vaporized. In a reductive atmosphere, the vaporization of Cd and Pb were as high as that in oxidative atmosphere. However, the vaporization of Zn was accelerated and that of Cu was hindered because the formation of Zn2SiO4, ZnFe2O4 and ZnAl2O4 and copper chloride was depressed in reductive atmosphere.

  13. Novel approaches using alkaline or acid/guanidine treatment to eliminate therapeutic antibody interference in the measurement of total target ligand.

    PubMed

    Salimi-Moosavi, Hossein; Lee, Jean; Desilva, Binodh; Doellgast, George

    2010-04-06

    Measurement of the total target ligand can help to provide pharmacokinetic (PK) and pharmacodynamic (PD) informations. However, the presence of monocloncal antibody therapeutics (ThAs) interferes with ELISA determinations of the total target proteins. The interferences can cause over- or under-estimation of the target protein analysis. The nature of interferences was dependent upon the ThA, target protein, antibody reagents and assay conditions of the ELISA. We have developed novel alkaline and acid/guanidine treatment approaches to dissociate the protein binding and preferentially denature the ThA. The neutralized target proteins can be determined by ELISA. These methods provide reproducible measurements of total target protein without ThA interference. Serum samples, standards and QCs containing target protein and ThA were treated with alkaline buffer (pH>13) containing casein or acid/guanidine buffer (pH<1). Total target proteins for two different ThA systems were successfully measured and interferences were completely eliminated by the treatments. These methods were successfully applied to analysis in pre-clinical serum samples.

  14. Effects of co-application of biosolids and water treatment residuals on corn growth and bioavailable phosphorus and aluminum in alkaline soils in egypt.

    PubMed

    Mahdy, A M; Elkhatib, E A; Fathi, N O; Lin, Z-Q

    2009-01-01

    The co-application of biosolids and water treatment residuals (WTRs) has been previously trialed to reduce excessive bioavailable P in the soil treated with biosolids. However, uncertainty still exists regarding the environmental consequences of the co-application of biosolids and WTRs, especially in alkaline soils in Egypt or the Middle East region. A greenhouse pot study was conducted with Egyptian alkaline soils to (i) quantify the effects of co-application of biosolids and drinking WTRs on biomass production of corn (Zea mays L. cultivar single hybrid 10), (ii) determine the co-application effects on Olsen-P and KCl-extractable Al in relation to their accumulation in plant tissues, and (iii) optimize the co-application ratio of biosolids to WTRs for the best yield and effective reduction of soil bioavailable P. The results show that, among the studied soils treated with 1% biosolids along with various rates of WTRs, the corn yield increased significantly (P < 0.01) with increasing WTR application rate from 0 to 3% (w/w), but decreased at 4% application rate. The corn yield also significantly correlated with soil water holding capacity that increased with the addition of WTRs. Phosphorus uptake by plants significantly (P < 0.01) increased when the biosolid application rate was increased from 1 to 3% in the three studied soils that were treated with 1, 2, or 3% WTRs. The application of 4% WTRs in the biosolid-amended soils resulted in a significant reduction in soil Olsen-P values, but without having observable phytotoxicity of metals (such as Al) to corn during the growth period. The effective co-application ratio of biosolids to WTRs, for increasing corn yield and minimizing the potential for bioavailable P in runoff, was approximately 1:1 at the application rate of 3% biosolids and 4% WTRs in the alkaline soils.

  15. Viscosity of alkaline suspensions of ground black and white pepper samples: An indication or an identification of high dose radiation treatment?

    NASA Astrophysics Data System (ADS)

    Schreiber, G. A.; Leffke, A.; Mager, M.; Helle, N.; Bögl, K. W.

    1994-11-01

    Forty-nine pepper samples were taken from retail food stores of different cities in Germany. Most of the black and all white pepper samples showed high viscosity values after jellification in alkaline solution. After irradiation with a γ-ray dose of 6 kGy, viscosity was largely reduced in each case. Some black pepper samples showed a low viscosity level already before irradiation. However, thermoluminescence analysis did not reveal any sign for irradiation treatment prior to examination. Furthermore, the low viscosity level of these samples could not be correlated with a low starch content. It is concluded that the viscosity levels of irradiated white pepper samples clearly reveal high dose irradiation treatment. In case of black peppers it is judged that the method can be used to screen for irradiated samples since it is fast, easy and cheap. However, a positive result should be confirmed by another technique, e.g. thermoluminescence.

  16. A Microwave-Assisted Reduction of Cyclohexanone Using Solid-State-Supported Sodium Borohydride

    ERIC Educational Resources Information Center

    White, Lori L.; Kittredge, Kevin W.

    2005-01-01

    The reduction of carbonyl groups by sodium borohydride though is a well-known reaction in most organic lab texts, a difficulty for an instructor adopting this reaction in a student lab is that it is too long. Using a microwave assisted organic synthesis solves this difficulty and one such reaction, which is the microwave-assisted reduction of…

  17. Borohydride Reduction of Estrone: Demonstration of Diastereoselectivity in the Undergraduate Organic Chemistry Laboratory

    ERIC Educational Resources Information Center

    Aditya, Animesh; Nichols, David E.; Loudon, G. Marc

    2008-01-01

    This experiment presents a guided-inquiry approach to the demonstration of diastereoselectivity in an undergraduate organic chemistry laboratory. Chiral hindered ketones such as estrone, undergo facile reduction with sodium borohydride in a highly diastereoselective manner. The diastereomeric estradiols produced in the reaction can be analyzed and…

  18. A Guided-Inquiry Approach to the Sodium Borohydride Reduction and Grignard Reaction of Carbonyl Compounds

    ERIC Educational Resources Information Center

    Rosenberg, Robert E.

    2007-01-01

    The guided-inquiry approach is applied to the reactions of sodium borohydride and phenyl magnesium bromide with benzaldehyde, benzophenone, benzoic anhydride, and ethyl benzoate. Each team of four students receives four unknowns. Students identify the unknowns and their reaction products by using the physical state of the unknown, an…

  19. Exploiting hydrophobic borohydride-rich ionic liquids as faster-igniting rocket fuels.

    PubMed

    Liu, Tianlin; Qi, Xiujuan; Huang, Shi; Jiang, Linhai; Li, Jianling; Tang, Chenglong; Zhang, Qinghua

    2016-02-04

    A family of hydrophobic borohydride-rich ionic liquids was developed, which exhibited the shortest ignition delay times of 1.7 milliseconds and the lowest viscosity (10 mPa s) of hypergolic ionic fluids, demonstrating their great potential as faster-igniting rocket fuels to replace toxic hydrazine derivatives in liquid bipropellant formulations.

  20. By-Product Carrying Humidified Hydrogen: An Underestimated Issue in the Hydrolysis of Sodium Borohydride.

    PubMed

    Petit, Eddy; Miele, Philippe; Demirci, Umit B

    2016-07-21

    Catalyzed hydrolysis of sodium borohydride generates up to four molecules of hydrogen, but contrary to what has been reported so far, the humidified evolved gas is not pure hydrogen. Elemental and spectroscopic analyses show, for the first time, that borate by-products pollute the stream as well as the vessel.

  1. Self-Printing on Graphitic Nanosheets with Metal Borohydride Nanodots for Hydrogen Storage

    NASA Astrophysics Data System (ADS)

    Li, Yongtao; Ding, Xiaoli; Zhang, Qingan

    2016-08-01

    Although the synthesis of borohydride nanostructures is sufficiently established for advancement of hydrogen storage, obtaining ultrasmall (sub-10 nm) metal borohydride nanocrystals with excellent dispersibility is extremely challenging because of their high surface energy, exceedingly strong reducibility/hydrophilicity and complicated composition. Here, we demonstrate a mechanical-force-driven self-printing process that enables monodispersed (~6 nm) NaBH4 nanodots to uniformly anchor onto freshly-exfoliated graphitic nanosheets (GNs). Both mechanical-forces and borohydride interaction with GNs stimulate NaBH4 clusters intercalation/absorption into the graphite interlayers acting as a ‘pen’ for writing, which is accomplished by exfoliating GNs with the ‘printed’ borohydrides. These nano-NaBH4@GNs exhibit favorable thermodynamics (decrease in ∆H of ~45%), rapid kinetics (a greater than six-fold increase) and stable de-/re-hydrogenation that retains a high capacity (up to ~5 wt% for NaBH4) compared with those of micro-NaBH4. Our results are helpful in the scalable fabrication of zero-dimensional complex hydrides on two-dimensional supports with enhanced hydrogen storage for potential applications.

  2. Self-Printing on Graphitic Nanosheets with Metal Borohydride Nanodots for Hydrogen Storage

    PubMed Central

    Li, Yongtao; Ding, Xiaoli; Zhang, Qingan

    2016-01-01

    Although the synthesis of borohydride nanostructures is sufficiently established for advancement of hydrogen storage, obtaining ultrasmall (sub-10 nm) metal borohydride nanocrystals with excellent dispersibility is extremely challenging because of their high surface energy, exceedingly strong reducibility/hydrophilicity and complicated composition. Here, we demonstrate a mechanical-force-driven self-printing process that enables monodispersed (~6 nm) NaBH4 nanodots to uniformly anchor onto freshly-exfoliated graphitic nanosheets (GNs). Both mechanical-forces and borohydride interaction with GNs stimulate NaBH4 clusters intercalation/absorption into the graphite interlayers acting as a ‘pen’ for writing, which is accomplished by exfoliating GNs with the ‘printed’ borohydrides. These nano-NaBH4@GNs exhibit favorable thermodynamics (decrease in ∆H of ~45%), rapid kinetics (a greater than six-fold increase) and stable de-/re-hydrogenation that retains a high capacity (up to ~5 wt% for NaBH4) compared with those of micro-NaBH4. Our results are helpful in the scalable fabrication of zero-dimensional complex hydrides on two-dimensional supports with enhanced hydrogen storage for potential applications. PMID:27484735

  3. Self-Printing on Graphitic Nanosheets with Metal Borohydride Nanodots for Hydrogen Storage.

    PubMed

    Li, Yongtao; Ding, Xiaoli; Zhang, Qingan

    2016-08-03

    Although the synthesis of borohydride nanostructures is sufficiently established for advancement of hydrogen storage, obtaining ultrasmall (sub-10 nm) metal borohydride nanocrystals with excellent dispersibility is extremely challenging because of their high surface energy, exceedingly strong reducibility/hydrophilicity and complicated composition. Here, we demonstrate a mechanical-force-driven self-printing process that enables monodispersed (~6 nm) NaBH4 nanodots to uniformly anchor onto freshly-exfoliated graphitic nanosheets (GNs). Both mechanical-forces and borohydride interaction with GNs stimulate NaBH4 clusters intercalation/absorption into the graphite interlayers acting as a 'pen' for writing, which is accomplished by exfoliating GNs with the 'printed' borohydrides. These nano-NaBH4@GNs exhibit favorable thermodynamics (decrease in ∆H of ~45%), rapid kinetics (a greater than six-fold increase) and stable de-/re-hydrogenation that retains a high capacity (up to ~5 wt% for NaBH4) compared with those of micro-NaBH4. Our results are helpful in the scalable fabrication of zero-dimensional complex hydrides on two-dimensional supports with enhanced hydrogen storage for potential applications.

  4. Treatment of PCR products with exonuclease I and heat-labile alkaline phosphatase improves the visibility of combined bisulfite restriction analysis

    SciTech Connect

    Watanabe, Kousuke; Emoto, Noriko; Sunohara, Mitsuhiro; Kawakami, Masanori; Kage, Hidenori; Nagase, Takahide; Ohishi, Nobuya; Takai, Daiya

    2010-08-27

    Research highlights: {yields} Incubating PCR products at a high temperature causes smears in gel electrophoresis. {yields} Smears interfere with the interpretation of methylation analysis using COBRA. {yields} Treatment with exonuclease I and heat-labile alkaline phosphatase eliminates smears. {yields} The elimination of smears improves the visibility of COBRA. -- Abstract: DNA methylation plays a vital role in the regulation of gene expression. Abnormal promoter hypermethylation is an important mechanism of inactivating tumor suppressor genes in human cancers. Combined bisulfite restriction analysis (COBRA) is a widely used method for identifying the DNA methylation of specific CpG sites. Here, we report that exonuclease I and heat-labile alkaline phosphatase can be used for PCR purification for COBRA, improving the visibility of gel electrophoresis after restriction digestion. This improvement is observed when restriction digestion is performed at a high temperature, such as 60 {sup o}C or 65 {sup o}C, with BstUI and TaqI, respectively. This simple method can be applied instead of DNA purification using spin columns or phenol/chloroform extraction. It can also be applied to other situations when PCR products are digested by thermophile-derived restriction enzymes, such as PCR restriction fragment length polymorphism (RFLP) analysis.

  5. Evaluation of various concentrations of alkaline surface treatment on interfacial bond strengths of amalgam bonded to amalgam.

    PubMed

    Mirza, Asaad Javaid; Ahmad, Asif; Mohammad, Taqi; Khan, Zahid Akhter

    2013-09-01

    This study was done to assess the influence of alkaline surface modification on interfacial bond strength of existing fractured (old) amalgam restoration bonded to fresh amalgam. Old and Fresh amalgam interfaced samples were prepared by applying a 4-methacryloyloxyethy trimellitate anhydride (4-META) containing adhesive. The adhesive used was Amalgabond (Parkell, Farmingdale, NY 11735, USA). Four concentrations of calcium hydroxide Ca(OH)2 solutions were used as a surface modifiers for old amalgam to increase the pH of the amalgam surfaces. The concentrations used were 2.5, 5, 10 and 15%. Direct measurement of the interfacial bond strength was carried out using an electromechanical universal tensile testing machine at crosshead speed of 10mm per minute. Results show that all the calcium hydroxide modified samples produced the increased tensile bond strength (TBS) as compared to their control group. The highest values of bond strength were achieved using 15% Ca(OH)2 solution as surface modifier. Pretreatment of fractured amalgam with calcium hydroxide improves the bond strength of 4-META adhesives. Its use in repair of amalgam may therefore be considered.

  6. Acetate biostimulation as an effective treatment for cleaning up alkaline soil highly contaminated with Cr(VI).

    PubMed

    Lara, Paloma; Morett, Enrique; Juárez, Katy

    2016-08-15

    Stimulation of microbial reduction of Cr(VI) to the less toxic and less soluble Cr(III) through electron donor addition has been regarded as a promising approach for the remediation of chromium-contaminated soil and groundwater sites. However, each site presents different challenges; local physicochemical characteristics and indigenous microbial communities influence the effectiveness of the biostimulation processes. Here, we show microcosm assays stimulation of microbial reduction of Cr(VI) in highly alkaline and saline soil samples from a long-term contaminated site in Guanajuato, Mexico. Acetate was effective promoting anaerobic microbial reduction of 15 mM of Cr(VI) in 25 days accompanied by an increase in pH from 9 to 10. Our analyses showed the presence of Halomonas, Herbaspirillum, Nesterenkonia/Arthrobacter, and Bacillus species in the soil sample collected. Moreover, from biostimulated soil samples, it was possible to isolate Halomonas spp. strains able to grow at 32 mM of Cr(VI). Additionally, we found that polluted groundwater has bacterial species different to those found in soil samples with the ability to resist and reduce chromate using acetate and yeast extract as electron donors.

  7. Determination of cobalt in biological samples by line-source and high-resolution continuum source graphite furnace atomic absorption spectrometry using solid sampling or alkaline treatment

    NASA Astrophysics Data System (ADS)

    Ribeiro, Anderson Schwingel; Vieira, Mariana Antunes; da Silva, Alessandra Furtado; Borges, Daniel L. Gallindo; Welz, Bernhard; Heitmann, Uwe; Curtius, Adilson José

    2005-06-01

    Two procedures for the determination of Co in biological samples by graphite furnace atomic absorption spectrometry (GF AAS) were compared: solid sampling (SS) and alkaline treatment with tetramethylammonium hydroxide (TMAH) using two different instruments for the investigation: a conventional line-source (LS) atomic absorption spectrometer and a prototype high-resolution continuum source atomic absorption spectrometer. For the direct introduction of the solid samples, certified reference materials (CRM) were ground to a particle size ≤50 μm. Alkaline treatment was carried out by placing about 250 mg of the sample in polypropylene flasks, adding 2 mL of 25% m/v tetramethylammonium hydroxide and de-ionized water. Due to its unique capacity of providing a 3-D spectral plot, a high-resolution continuum source (HR-CS) graphite furnace atomic absorption spectrometry was used as a tool to evaluate potential spectral interferences, including background absorption for both sample introduction procedures, revealing that a continuous background preceded the atomic signal for pyrolysis temperatures lower than 700 °C. Molecular absorption bands with pronounced rotational fine structure appeared for atomization temperatures >1800 °C probably as a consequence of the formation of PO. After optimization had been carried out using high resolution continuum source atomic absorption spectrometry, the optimized conditions were adopted also for line-source atomic absorption spectrometry. Six biological certified reference materials were analyzed, with calibration against aqueous standards, resulting in agreement with the certified values (according to the t-test for a 95% confidence level) and in detection limits as low as 5 ng g -1.

  8. Probing the pH dependent optical properties of aquatic, terrestrial and microbial humic substances by sodium borohydride reduction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chemically reducing humic (HA) and fulvic acids (FA) provides insight into spectroscopically identifiable structural moieties generating the optical properties of HA/FA from aquatic, microbial and terrestrial sources. Sodium borohydride reduction provides targeted reduction of carbonyl groups. The...

  9. Preparation of Pt/Rh bimetallic colloidal particles in polymer solutions using borohydride-reduction.

    PubMed

    Harada, Masafumi; Einaga, Hisahiro

    2007-04-15

    Colloidal dispersions of Pt/Rh bimetallic particles have been synthesized by the reduction of Pt(IV)/Rh(III) ionic solutions by using borohydride-reduction in the presence of poly(N-vinyl-2-pyrrolidone). The size and the structure of the synthesized particles have been examined by transmission electron micrograph (TEM) and extended X-ray absorption fine structure (EXAFS). We have succeeded in producing the bimetallic Pt/Rh particles with an average diameter of 2.8 nm in polymer solutions by the stepwise addition of sodium borohydride aqueous solution. The distribution of different metallic species in a particle tended to be "cluster-in-cluster" structure, in contrast to the bimetallic particle with an average diameter of 1.4 nm synthesized by alcohol-reduction which have a core-shell structure.

  10. Structure and spectroscopy of CuH prepared via borohydride reduction

    PubMed Central

    Bennett, Elliot L.; Wilson, Thomas; Murphy, Patrick J.; Refson, Keith; Hannon, Alex C.; Imberti, Silvia; Callear, Samantha K.; Chass, Gregory A.; Parker, Stewart F.

    2015-01-01

    Copper(I) hydride (cuprous hydride, CuH) was the first binary metal hydride to be discovered (in 1844) and is singular in that it is synthesized in solution, at ambient temperature. There are several synthetic paths to CuH, one of which involves reduction of an aqueous solution of CuSO4·5H2O by borohydride ions. The product from this procedure has not been extensively characterized. Using a combination of diffraction methods (X-ray and neutron) and inelastic neutron scattering spectroscopy, we show that the CuH from the borohydride route has the same bulk structure as CuH produced by other routes. Our work shows that the product consists of a core of CuH with a shell of water and that this may be largely replaced by ethanol. This offers the possibility of modifying the properties of CuH produced by aqueous routes. PMID:26634717

  11. Efficient hydrogen generation from sodium borohydride hydrolysis using silica sulfuric acid catalyst

    NASA Astrophysics Data System (ADS)

    Manna, Joydev; Roy, Binayak; Sharma, Pratibha

    2015-02-01

    A heterogeneous acid catalyst, silica sulfuric acid, was prepared from silica gel (SiO2) and sulfuric acid (H2SO4). Addition of SO3H functional group to SiO2 has been confirmed through various characterization techniques. The effect of this heterogeneous acid catalyst on hydrogen generation from sodium borohydride hydrolysis reaction was studied for different ratios of catalyst to NaBH4 and at different temperatures. The catalyst exhibited high catalytic activity towards sodium borohydride hydrolysis reaction. The activation energy of the NaBH4 hydrolysis reaction in the presence of silica sulfuric acid was calculated to be the lowest (17 kJ mol-1) among reported heterogeneous catalysts till date.

  12. Reversible Dehydrogenation of Magnesium Borohydride to Magnesium Triborane in the Solid State Under Moderate Conditions

    SciTech Connect

    Chong, Marina; Karkamkar, Abhijeet J.; Autrey, Thomas; Orimo, Shin-ichi; Jalisatgi, Satish; Jensen, Craig M.

    2011-02-17

    Thermal decomposition of magnesium borohydride, Mg(BH4)2, in the solid state was studied by a combination of PCT, TGA/MS and NMR spectroscopy. Dehydrogenation of Mg(BH4)2 at 200 °C, results in the highly selective formation of magnesium triborane, Mg(B3H8)2. This process is reversible at 250 °C under 120 atm H2. Dehydrogenation at higher temperature, > 300 °C, produces a complex mixture of polyborane species. Solution phase 11B NMR spectra of the hydrolyzed decomposition products reveals the formation of the B3H8 anion, boric acid from hydrolysis of the unstable polyboranes (BnHx) (n = 3-11, x >8), and the closoborane B12H12 dianion as a minor product. A BH condensation mechanism involving metal hydride formation is proposed to explain the limited reversible hydrogen storage in magnesium borohydride.

  13. First-principles investigations of ionic conduction in Li and Na borohydrides

    NASA Astrophysics Data System (ADS)

    Varley, Joel; Heo, Tae-Wook; Ray, Keith; Bonev, Stanimir; Wood, Brandon

    Recent experimental studies have identified a family of alkali borohydride materials that exhibit superionic transition temperatures approaching room temperature and ionic conductivities exceeding 0.1 S/cm-1, making them highly promising solid electrolytes for next-generation batteries. Despite the rapid advances in improving the superionic conductivity in these materials, an understanding of the exact mechanisms driving the transport remains unknown. Here we use ab initio molecular dynamics calculations to address this issue by characterizing the diffusivity of the Li and Na species in a representative set of closoborane ionic conductors. We investigate both the Na and Li-containing borohydrides with icosahedral (B12H12) and double-capped square antiprism (B10H10) anion species and discuss the trends in ionic conductivity as a function of stoichiometry and the incorporation of various dopants. Our results support the borohydrides as a subset of a larger family of very promising solid electrolytes and identify strategies to improving the conductivity in these materials. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize (Zea mays L.) lines.

    PubMed

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D; Williams, Daniel L; Magee, Timothy D; Kaeppler, Shawn M; de Leon, Natalia; Hodge, David B

    2015-07-01

    A maize (Zea mays L. subsp. mays) diversity panel consisting of 26 maize lines exhibiting a wide range of cell-wall properties and responses to hydrolysis by cellulolytic enzymes was employed to investigate the relationship between cell-wall properties, cell-wall responses to mild NaOH pre-treatment, and enzymatic hydrolysis yields. Enzymatic hydrolysis of the cellulose in the untreated maize was found to be positively correlated with the water retention value, which is a measure of cell-wall susceptibility to swelling. It was also positively correlated with the lignin syringyl/guaiacyl ratio and negatively correlated with the initial cell-wall lignin, xylan, acetate, and p-coumaric acid (pCA) content, as well as pCA released from the cell wall by pre-treatment. The hydrolysis yield following pre-treatment exhibited statistically significant negative correlations to the lignin content after pre-treatment and positive correlations to the solubilized ferulic acid and pCA. Several unanticipated results were observed, including a positive correlation between initial lignin and acetate content, lack of correlation between acetate content and initial xylan content, and negative correlation between each of these three variables to the hydrolysis yields for untreated maize. Another surprising result was that pCA release was negatively correlated with hydrolysis yields for untreated maize and, along with ferulic acid release, was positively correlated with the pre-treated maize hydrolysis yields. This indicates that these properties that may negatively contribute to the recalcitrance in untreated cell walls may positively contribute to their deconstruction by alkaline pre-treatment.

  15. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize (Zea mays L.) lines

    PubMed Central

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; Williams, Daniel L.; Magee, Timothy D.; Kaeppler, Shawn M.; de Leon, Natalia; Hodge, David B.

    2015-01-01

    A maize (Zea mays L. subsp. mays) diversity panel consisting of 26 maize lines exhibiting a wide range of cell-wall properties and responses to hydrolysis by cellulolytic enzymes was employed to investigate the relationship between cell-wall properties, cell-wall responses to mild NaOH pre-treatment, and enzymatic hydrolysis yields. Enzymatic hydrolysis of the cellulose in the untreated maize was found to be positively correlated with the water retention value, which is a measure of cell-wall susceptibility to swelling. It was also positively correlated with the lignin syringyl/guaiacyl ratio and negatively correlated with the initial cell-wall lignin, xylan, acetate, and p-coumaric acid (pCA) content, as well as pCA released from the cell wall by pre-treatment. The hydrolysis yield following pre-treatment exhibited statistically significant negative correlations to the lignin content after pre-treatment and positive correlations to the solubilized ferulic acid and pCA. Several unanticipated results were observed, including a positive correlation between initial lignin and acetate content, lack of correlation between acetate content and initial xylan content, and negative correlation between each of these three variables to the hydrolysis yields for untreated maize. Another surprising result was that pCA release was negatively correlated with hydrolysis yields for untreated maize and, along with ferulic acid release, was positively correlated with the pre-treated maize hydrolysis yields. This indicates that these properties that may negatively contribute to the recalcitrance in untreated cell walls may positively contribute to their deconstruction by alkaline pre-treatment. PMID:25871649

  16. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize ( Zea mays L.) lines

    SciTech Connect

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; Williams, Daniel L.; Magee, Timothy D.; Kaeppler, Shawn M.; de Leon, Natalia; Hodge, David B.

    2015-02-20

    A maize (Zea mays L. subsp. mays) diversity panel consisting of 26 maize lines exhibiting a wide range of cell-wall properties and responses to hydrolysis by cellulolytic enzymes was employed to investigate the relationship between cell-wall properties, cell-wall responses to mild NaOH pre-treatment, and enzymatic hydrolysis yields. Enzymatic hydrolysis of the cellulose in the untreated maize was found to be positively correlated with the water retention value, which is a measure of cell-wall susceptibility to swelling. It was also positively correlated with the lignin syringyl/guaiacyl ratio and negatively correlated with the initial cell-wall lignin, xylan, acetate, and p-coumaric acid (pCA) content, as well as pCA released from the cell wall by pre-treatment. The hydrolysis yield following pre-treatment exhibited statistically significant negative correlations to the lignin content after pre-treatment and positive correlations to the solubilized ferulic acid and pCA. Several unanticipated results were observed, including a positive correlation between initial lignin and acetate content, lack of correlation between acetate content and initial xylan content, and negative correlation between each of these three variables to the hydrolysis yields for untreated maize. Also, another surprising result was that pCA release was negatively correlated with hydrolysis yields for untreated maize and, along with ferulic acid release, was positively correlated with the pre-treated maize hydrolysis yields. In conclusion, this indicates that these properties that may negatively contribute to the recalcitrance in untreated cell walls may positively contribute to their deconstruction by alkaline pre-treatment

  17. Cell-wall properties contributing to improved deconstruction by alkaline pre-treatment and enzymatic hydrolysis in diverse maize ( Zea mays L.) lines

    DOE PAGES

    Li, Muyang; Heckwolf, Marlies; Crowe, Jacob D.; ...

    2015-02-20

    A maize (Zea mays L. subsp. mays) diversity panel consisting of 26 maize lines exhibiting a wide range of cell-wall properties and responses to hydrolysis by cellulolytic enzymes was employed to investigate the relationship between cell-wall properties, cell-wall responses to mild NaOH pre-treatment, and enzymatic hydrolysis yields. Enzymatic hydrolysis of the cellulose in the untreated maize was found to be positively correlated with the water retention value, which is a measure of cell-wall susceptibility to swelling. It was also positively correlated with the lignin syringyl/guaiacyl ratio and negatively correlated with the initial cell-wall lignin, xylan, acetate, and p-coumaric acid (pCA)more » content, as well as pCA released from the cell wall by pre-treatment. The hydrolysis yield following pre-treatment exhibited statistically significant negative correlations to the lignin content after pre-treatment and positive correlations to the solubilized ferulic acid and pCA. Several unanticipated results were observed, including a positive correlation between initial lignin and acetate content, lack of correlation between acetate content and initial xylan content, and negative correlation between each of these three variables to the hydrolysis yields for untreated maize. Also, another surprising result was that pCA release was negatively correlated with hydrolysis yields for untreated maize and, along with ferulic acid release, was positively correlated with the pre-treated maize hydrolysis yields. In conclusion, this indicates that these properties that may negatively contribute to the recalcitrance in untreated cell walls may positively contribute to their deconstruction by alkaline pre-treatment« less

  18. Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue

    PubMed Central

    Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; Pattrick, Richard A.D.; Thomas, Russell A.P.; Kalin, Robert; Lloyd, Jonathan R.

    2015-01-01

    Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ∼25% (BnM) and ∼50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions. In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ⩾5% w/w BnM or ⩾1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4–7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable

  19. Effective treatment of alkaline Cr(VI) contaminated leachate using a novel Pd-bionanocatalyst: Impact of electron donor and aqueous geochemistry

    PubMed Central

    Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; Thomas, Russell A.P.; Kalin, Robert; Lloyd, Jonathan R.

    2015-01-01

    Palladium catalysts offer the potential for the effective treatment of a variety of priority reducible pollutants in natural waters. In this study, microbially synthesized magnetite nanoparticles were functionalized with Pd(0), creating a highly reactive, magnetically recoverable, nano-scale catalyst (Pd-BnM). This was then investigated for the treatment of model Cr(VI) contaminated solutions at a range of pH values, and also alkaline Cr(VI) contaminated leachates from chromite ore processing residue (COPR); a contaminant issue of global concern. The sample of COPR used in this study was obtained from a site in Glasgow, UK, where extensive Cr(VI) contamination has been reported. In initial experiments Pd-BnM was supplied with H2 gas or formate as electron donors, and Cr(VI) removal from model synthetic solutions was quantified at various pH values (2–12). Effective removal was noted at neutral to environmentally relevant alkaline (pH 12) pH values, while the use of formate as an electron donor resulted in loss of performance under acidic conditions (pH 2). Reaction kinetics were then assessed with increasing Pd-BnM loading in both model pH 12 Cr(VI) solutions and the COPR leachate. When formate was used as the electron donor for Pd-BnM, to treat COPR leachate, there was significant inhibition of Cr(VI) removal. In contrast, a promotion of reaction rate, was observed when H2 was employed. Upon sustained reaction with model Cr(VI) solutions, in the presence of excess electron donor (formate or H2), appreciable quantities of Cr(VI) were removed before eventual inactivation of the catalyst. Faster onset of inactivation was reported in the COPR leachates, removing 4% and 64% of Cr(VI) observed from model Cr(VI) solutions, when formate and H2 were used as electron donors, respectively. XAS, TEM-EDX and XPS analysis of the catalysts that had been inactivated in the model solution, showed that the surface had an extensive covering of reduced Cr(III), most likely as a Cr

  20. Effective treatment of alkaline Cr(VI) contaminated leachate using a novel Pd-bionanocatalyst: Impact of electron donor and aqueous geochemistry.

    PubMed

    Watts, Mathew P; Coker, Victoria S; Parry, Stephen A; Thomas, Russell A P; Kalin, Robert; Lloyd, Jonathan R

    2015-07-01

    Palladium catalysts offer the potential for the effective treatment of a variety of priority reducible pollutants in natural waters. In this study, microbially synthesized magnetite nanoparticles were functionalized with Pd(0), creating a highly reactive, magnetically recoverable, nano-scale catalyst (Pd-BnM). This was then investigated for the treatment of model Cr(VI) contaminated solutions at a range of pH values, and also alkaline Cr(VI) contaminated leachates from chromite ore processing residue (COPR); a contaminant issue of global concern. The sample of COPR used in this study was obtained from a site in Glasgow, UK, where extensive Cr(VI) contamination has been reported. In initial experiments Pd-BnM was supplied with H2 gas or formate as electron donors, and Cr(VI) removal from model synthetic solutions was quantified at various pH values (2-12). Effective removal was noted at neutral to environmentally relevant alkaline (pH 12) pH values, while the use of formate as an electron donor resulted in loss of performance under acidic conditions (pH 2). Reaction kinetics were then assessed with increasing Pd-BnM loading in both model pH 12 Cr(VI) solutions and the COPR leachate. When formate was used as the electron donor for Pd-BnM, to treat COPR leachate, there was significant inhibition of Cr(VI) removal. In contrast, a promotion of reaction rate, was observed when H2 was employed. Upon sustained reaction with model Cr(VI) solutions, in the presence of excess electron donor (formate or H2), appreciable quantities of Cr(VI) were removed before eventual inactivation of the catalyst. Faster onset of inactivation was reported in the COPR leachates, removing 4% and 64% of Cr(VI) observed from model Cr(VI) solutions, when formate and H2 were used as electron donors, respectively. XAS, TEM-EDX and XPS analysis of the catalysts that had been inactivated in the model solution, showed that the surface had an extensive covering of reduced Cr(III), most likely as a Cr

  1. Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue.

    PubMed

    Watts, Mathew P; Coker, Victoria S; Parry, Stephen A; Pattrick, Richard A D; Thomas, Russell A P; Kalin, Robert; Lloyd, Jonathan R

    2015-03-01

    Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ∼25% (BnM) and ∼50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions. In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ⩾5% w/w BnM or ⩾1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4-7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable capacity

  2. Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue

    DOE PAGES

    Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; ...

    2014-12-11

    Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ~25% (BnM) and ~50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions.more » In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ≥5% w/w BnM or ≥1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4–7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable

  3. Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue

    SciTech Connect

    Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; Pattrick, Richard A. D.; Thomas, Russell A. P.; Kalin, Robert; Lloyd, Jonathan R.

    2014-12-11

    Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ~25% (BnM) and ~50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions. In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ≥5% w/w BnM or ≥1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4–7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable

  4. Sodium carbonate treatment induces scoparone accumulation, structural changes, and alkalinization in the albedo of wounded citrus fruits.

    PubMed

    Venditti, Tullio; Molinu, Maria Giovanna; Dore, Antonio; Agabbio, Mario; D'hallewin, Guy

    2005-05-04

    Following sodium carbonate treatment, accumulation of scoparone (6,7-dimethoxycoumarin) but not scopoletin (6-methoxy-7-hydroxycoumarin) was found in the albedo of wounded fruit from different Citrus sp. and cultivars. Treating wounded mandarin fruit cv. Fairchild with 5% Na(2)CO(3) (SC) lead to a scoparone accumulation in the albedo of 310, 361, and 382 microg g(-1) fresh weight after 7, 10, and 15 days, respectively. Scoparone accumulation was associated with a decrease in decay severity. When oranges cv. Biondo comune wounded and treated with 5% SC were inoculated with Penicillium digitatum or Penicillium italicum conidia 3 days posttreatment, the decay percentage as compared to untreated wounds was reduced by 97.2 and 93.9%, respectively. Observations by scanning electron microscopy of wounded Citrus fruits treated at 20 degrees C with 2, 3, 4, or 5% (w/v) solutions of sodium carbonate showed structural modifications to the albedo as well as damage to 24-48 h old mycelia of P. digitatum, the cause of citrus green mold. Modifications were more evident in orange, lemon, and grapefruit as compared to mandarin fruit. The efficacy of the treatment was strictly related to the SC interaction with the albedo tissue that, in addition to structural changes, significantly increased tissue pH, affecting P. digitatum pathogenicity. The SC remaining as a film on unwounded flavedo had no effect in preventing contact infection by the Penicillia.

  5. Effect of heat-alkaline treatment as a pretreatment method on volatile fatty acid production and protein degradation in excess sludge, pure proteins and pure cultures.

    PubMed

    Tan, Reasmey; Miyanaga, Kazuhiko; Uy, Davin; Tanji, Yasunori

    2012-08-01

    This study investigated the effect of heat-alkaline treatment (HAT) at pH 11 and 60 °C on volatile fatty acid (VFA) production and protein degradation in excess sludge, soluble and insoluble proteins, and pure cultures. In addition, quantification of bacteria present in the sludge was also examined. Experimental results showed that following acid fermentation under pH 7 and 37 °C, HAT enhanced VFA production in excess sludge, albumin, and Gram-negative bacteria, but not in casein or Gram-positive bacteria. Protein solubility was therefore found not to be the main criteria for VFA production. In the protein analysis, it was shown that the outer membrane protein (OmpC) of Escherichia coli K12 was resistant to chemical and enzymatic hydrolysis. Gram staining revealed that Gram-negative bacteria were predominant in the activated sludge used in this study. In addition, the bacteria present in the activated sludge comprised only 10% of mixed liquor suspended solids (MLSS) by quantitative PCR.

  6. Quaternized polymeric microgels as metal free catalyst for H2 production from the methanolysis of sodium borohydride

    NASA Astrophysics Data System (ADS)

    Sahiner, Nurettin; Sengel, Sultan Butun

    2016-12-01

    Polymeric microgels derived from tris(2-amino ethyl)amine (TAEA) and glycerol diglycidyl ether as p(TAEA-co-GDE) via microemulsion polymerization techniques are protonated by 0.5 M HCl treatment as p(TAEA-co-GDE)-HCl). These microgels are then exposed to anion exchange reactions with differ ionic liquid forming salts, such as potassium thiocyanate (PTC), sodium dicyanamide (SDCA), ammonium hexafluorophosphate (AHFP), and sodium tetrafluoroborate (STFB) in aqueous medium for the preparation of p(TAEA-co-GDE) based ionic liquid colloidal microgels. These anions exchanged p(TAEA-co-GDE) ionic liquid colloids (ILCs) are directly used as catalyst for hydrogen (H2) generation from the methanol solution of sodium borohydride (NaBH4). Various parameters affecting the H2 production rate such as the catalyst types, NaBH4 amount, and the temperature are investigated. It is found that the methanolysis of NaBH4 catalyzed by p(TAEA-co-GDE)-HCl obeys the first order reaction kinetic. The activation energy, enthalpy and entropy of the protonated p(TAEA-co-GDE) microgels are calculated and found as the 30.37 kJ mol-1, 27.96 kJ mol-1, and -148.08 J mol-1 K-1, respectively. Furthermore, the hydrogen generation rate of 3018 mL min-1 g-1 catalyzed by p(TAEA-co-GDE)-HCl catalyst is attained.

  7. Structural phase transitions and adduct release in calcium borohydride

    SciTech Connect

    Paolone, A.; Palumbo, O.; Rispoli, P.; Miriametro, A.; Cantelli, R.; Luedtke, A.; Rönnebro, E.; Chandra, D.

    2011-09-01

    Ca(BH4)2 compounds were investigated above room temperature by anelastic spectroscopy (AS) and concomitant measurements of thermogravimetry and mass spectrometry (TGA/MS). Both AS and TGA/MS indicate that even after a thermal treatment at 125 °C for 20 h, a non-negligible residual of THF adduct is still present in the sample, which can be removed on a subsequent thermal treatment at temperatures lower than 250 °C. Above 250 °C dehydrogenation takes place. Moreover, AS sensitively detects the occurrence of the α → α’ structural phase transition around 180 °C, and the α’ → β transformation, which is completed around 330 °C. Finally, we also show that both transitions are irreversible and are not accompanied by a latent heat.

  8. Modeling the effect of membrane conductivity on the performance of alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Raya, Isaac P.; Ellis, Michael W.; Hernandez-Guerrero, Abel; Elizalde-Blancas, Francisco

    2016-03-01

    The present work proposes and demonstrates a methodology to capture the effect of operating conditions on ionic conductivity of membranes immersed in alkaline media. Based on reported experimental results for an anion exchange membrane (A-201 by Tokuyama) and a cation exchange membrane (Nafion 211), two novel expressions are developed for the ionic conductivity by incorporating the effects of solution concentration and temperature. The expression for the cationic conductivity is applied in a cell-level model to predict the performance of an alkaline direct borohydride fuel cell; it is found that the membrane ionic conductivity significantly affects the cell performance and capturing its functionality is essential to accurately predict the fuel cell performance.

  9. Deposition of Poly(diphenylamine-co-3-aminobenzonitrile)/Palladium Nanocomposite Film and Evaluation of Electrocatalytic Activity Toward Borohydride Oxidation.

    PubMed

    Philips, M Francklin; Lee, Kwang-Pill; Gopalan, Anantha Iyengar

    2015-09-01

    New nanocomposites, poly(diphenylamine-co-3-aminobenzonitrile)/palladium (P(DPA-co-3ABN)/Pd) and poly(diphenylamine)/palladium (PDPA/Pd), have been prepared by pulse potentiostatic method and used as electrocatalysts for borohydride oxidation. Linear sweep voltammogram of P(DPA-co-3ABN)/Pd-ME exhibited the oxidation wave between -0.8 V and 0.4 V that corresponds to the direct, potentially four-electron, oxidation of borohydride ions. The peak current for borohydride oxidation is much higher at P(DPA-co-3ABN)/Pd-ME electrode as compared to PDPA/Pd-ME. The incorporation of 3ABN units augments electrocatalytic behavior and thermal stability for the P(DPA-co-3ABN)/Pd catalyst.

  10. Alkali metal – yttrium borohydrides: The link between coordination of small and large rare-earth

    SciTech Connect

    Sadikin, Yolanda; Stare, Katarina; Schouwink, Pascal; Brix Ley, Morten; Jensen, Torben R.; Meden, Anton; Černý, Radovan

    2015-05-15

    The system Li–A–Y–BH{sub 4} (A=K, Rb, Cs) is found to contain five new compounds and four further ones known from previous work on the homoleptic borohydrides. Crystal structures have been solved and refined from synchrotron X-ray powder diffraction, thermal stability of new compounds have been investigated and ionic conductivity measured for selected samples. Significant coordination flexibility for Y{sup 3+} is revealed, which allows the formation of both octahedral frameworks and tetrahedral complex anions with the tetrahydroborate anion BH{sub 4} both as a linker and terminal ligand. Bi- and trimetallic cubic double-perovskites c-A{sub 3}Y(BH{sub 4}){sub 6} or c-A{sub 2}LiY(BH{sub 4}){sub 6} (A=Rb, Cs) form in all the investigated systems, with the exception of the Li–K–Y system. The compounds with the stoichiometry AY(BH{sub 4}){sub 4} crystallize in all investigated systems with a great variety of structure types which find their analog amongst metal oxides. In-situ formation of a new borohydride – closo-borane is observed during decomposition of all double perovskites. - Graphical abstract: The system Li–A–Y–BH{sub 4} (A=K, Rb, Cs) is found to contain five novel compounds and four further ones previously reported. Significant coordination flexibility of Y{sup 3+} is revealed, which can be employed to form both octahedral frameworks and tetrahedral complex anions, very different structural topologies. Versatility is also manifested in three different simultaneously occurring coordination modes of borohydrides for one metal cation, as proposed by DFT optimization of the monoclinic KY(BH{sub 4}){sub 4} structural model observed by powder diffraction. - Highlights: • The system Li-A-Y-BH{sub 4} (A=K, Rb, Cs) contains nine compounds in total. • Y{sup 3+} forms octahedral frameworks and tetrahedral complex anions. • Bi- and trimetallic double-perovskites crystallize in most systems. • Various AY(BH{sub 4}){sub 4} crystallize with

  11. Anodes for alkaline electrolysis

    DOEpatents

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  12. Borohydride Catalysis of Nitramine Thermal Decomposition and Combustion. 3. Literature Review and Wrap-Up Discussion of Possible Chemical Mechanisms

    DTIC Science & Technology

    1990-07-01

    NO2 )) forms. ie have already alluded above to the effects of added BroHIO= and BI2HI2 on formation of these products. 5 Initially, formic acid ...TIC 7;LE COPY- TECHNICAL REPORT BRL-TR-3126 co ’-0BRL N N 1 BOROHYDRIDE CATALYSIS OF NITRAMINE THERMAL DECOMPOSITION AND COMBUSTION: "III...SUITITLE O""maI BOROHYDRIDE CATALYSIS OF NITRAMINE THERMAL DECOMPOSITION AND COMBUSTION: 111. LITERATURE REVIEW AND WRAP-UP DISCUSSION OF POSSIBLE

  13. A new family of metal borohydride guanidinate complexes: Synthesis, structures and hydrogen-storage properties

    NASA Astrophysics Data System (ADS)

    Wu, Hui; Zhou, Xiuquan; Rodriguez, Efrain E.; Zhou, Wei; Udovic, Terrence J.; Yildirim, Taner; Rush, John J.

    2016-10-01

    We report on a new class of complex hydrides: borohydride guanidinate complexes (MBH4·nCN3H5, M=Li, Mg, and Ca). They can be prepared via facile solid-state synthesis routes. Their crystal structures were successfully determined using a combination of X-ray diffraction, first-principles calculations and neutron vibrational spectroscopy. Among these compounds, Mg(BH4)2·6CN3H5 is composed of large complex Mg[CN3H5]62+ cations and surrounding BH4- ions, while Ca(BH4)2·2CN3H5 possesses layers of corner-sharing Ca[BH4]4(CN3H5)2 octahedra. Our dehydrogenation results show that ≈10 wt% hydrogen can be released from MBH4·nCN3H5 (M=Li, Mg, and Ca) at moderate temperatures with minimal ammonia and diborane contamination thanks to the synergistic effect of C-N bonds from guanidine and hydridic H from borohydrides leading to a weakening of the N-H bonds, thus impeding ammonia gas liberation. Further tuning the dehydrogenation with different cation species indicates that Mg(BH4)2·nCN3H5 can exhibit the optimum properties with nearly thermally neutral dehydrogenation and very high purity hydrogen release.

  14. Alkali metal - yttrium borohydrides: The link between coordination of small and large rare-earth

    NASA Astrophysics Data System (ADS)

    Sadikin, Yolanda; Stare, Katarina; Schouwink, Pascal; Brix Ley, Morten; Jensen, Torben R.; Meden, Anton; Černý, Radovan

    2015-05-01

    The system Li-A-Y-BH4 (A=K, Rb, Cs) is found to contain five new compounds and four further ones known from previous work on the homoleptic borohydrides. Crystal structures have been solved and refined from synchrotron X-ray powder diffraction, thermal stability of new compounds have been investigated and ionic conductivity measured for selected samples. Significant coordination flexibility for Y3+ is revealed, which allows the formation of both octahedral frameworks and tetrahedral complex anions with the tetrahydroborate anion BH4 both as a linker and terminal ligand. Bi- and trimetallic cubic double-perovskites c-A3Y(BH4)6 or c-A2LiY(BH4)6 (A=Rb, Cs) form in all the investigated systems, with the exception of the Li-K-Y system. The compounds with the stoichiometry AY(BH4)4 crystallize in all investigated systems with a great variety of structure types which find their analog amongst metal oxides. In-situ formation of a new borohydride - closo-borane is observed during decomposition of all double perovskites.

  15. Spectroscopic study of surface enhanced Raman scattering of caffeine on borohydride-reduced silver colloids

    NASA Astrophysics Data System (ADS)

    Chen, Xiaomin; Gu, Huaimin; Shen, Gaoshan; Dong, Xiao; Kang, Jian

    2010-06-01

    The surface enhanced Raman scattering (SERS) of caffeine on borohydride-reduced silver colloids system under different aqueous solution environment has been studied in this paper. The relative intensity of SERS of caffeine significantly varies with different concentrations of sodium chloride and silver particles. However, at too high or too low concentration of sodium chloride and silver particle, the enhancement of SERS spectra is not evident. The SERS spectra of caffeine suggest that the contribution of the charge transfer mechanism to SERS may be dominant. The chloride ions can significantly enhance the efficiency of SERS, while the enhancement is selective, as the efficiency in charge transfer enhancement is higher than in electromagnetic enhancement. Therefore, it can be concluded that the active site of chloride ion locates on the bond between the caffeine and the silver surface. In addition, the SERS spectra of caffeine on borohydride-reduced and citrate-reduced silver colloids are different, which may be due to different states caffeine adsorbed on silver surface under different silver colloids.

  16. Alkaline battery operational methodology

    DOEpatents

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  17. Al3Li4(BH4)13: a complex double-cation borohydride with a new structure.

    PubMed

    Lindemann, Inge; Domènech Ferrer, Roger; Dunsch, Lothar; Filinchuk, Yaroslav; Cerný, Radovan; Hagemann, Hans; D'Anna, Vincenza; Lawson Daku, Latévi Max; Schultz, Ludwig; Gutfleisch, Oliver

    2010-08-02

    The new double-cation Al-Li-borohydride is an attractive candidate material for hydrogen storage due to a very low hydrogen desorption temperature (approximately 70 degrees C) combined with a high hydrogen density (17.2 wt%). It was synthesised by high-energy ball milling of AlCl(3) and LiBH(4). The structure of the compound was determined from image-plate synchrotron powder diffraction supported by DFT calculations. The material shows a unique 3D framework structure within the borohydrides (space group=P-43n, a=11.3640(3) A). The unexpected composition Al(3)Li(4)(BH(4))(13) can be rationalized on the basis of a complex cation [(BH(4))Li(4)](3+) and a complex anion [Al(BH(4))(4)](-). The refinements from synchrotron powder diffraction of different samples revealed the presence of limited amounts of chloride ions replacing the borohydride on one site. In situ Raman spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TG) and thermal desorption measurements were used to study the decomposition pathway of the compound. Al-Li-borohydride decomposes at approximately 70 degrees C, forming LiBH(4). The high mass loss of about 20 % during the decomposition indicates the release of not only hydrogen but also diborane.

  18. Suppressing diborane production during the hydrogen release in metal borohydrides: The example of doped Al(BH4)3

    NASA Astrophysics Data System (ADS)

    Harrison, David; Thonhauser, Timo

    Aluminum borohydride (Al(BH4)3) is an example of a promising hydrogen storage material with exceptional hydrogen densities by weight and volume and a low hydrogen desorption temperature. But, unfortunately its production of diborane (B2H6) gases upon heating restricts its practical use. To elucidate this issue, we investigate the properties of a number of metal borohydrides with the same problem and find that the electronegativity of the metal cation is not the best descriptor of diborane production. We show that, instead, the closely related formation enthalpy is a much better descriptor and we find that diborane production is an exponential function thereof. We conclude that diborane production is sufficiently suppressed for formation enthalpies of -80 kJ/mol BH4 or lower, providing specific design guidelines to tune existing metal borohydrides or synthesize new ones. We then use first-principles methods to study the stabilizing effects of Sc alloying in Al(BH4)3, predicting that with sufficient alloying diborane can be fully suppressed. We conclude that stabilizing Al(BH4)3 and similar borohydrides via alloying or other means is a promising route to suppress diborane production and thus develop viable hydrogen storage materials. Supported by NSF DMR-1145968.

  19. Borane and borohydride complexes of the rare-earth elements: synthesis, structures, and butadiene polymerization catalysis.

    PubMed

    Jenter, Jelena; Meyer, Nils; Roesky, Peter W; Thiele, Sven K-H; Eickerling, Georg; Scherer, Wolfgang

    2010-05-10

    The reaction of potassium 2,5-bis[N-(2,6-diisopropylphenyl)iminomethyl]pyrrolyl [(dip(2)-pyr)K] with the borohydrides of the larger rare-earth metals, [Ln(BH(4))(3)(thf)(3)] (Ln=La, Nd), afforded the expected products [Ln(BH(4))(2)(dip(2)-pyr)(thf)(2)]. As usual, the trisborohydrides reacted like pseudohalide compounds forming KBH(4) as a by-product. To compare the reactivity with the analogous halides, the dimeric neodymium complex [NdCl(2)(dip(2)-pyr)(thf)](2) was prepared by reaction of [(dip(2)-pyr)K] with anhydrous NdCl(3). Reaction of [(dip(2)-pyr)K] with the borohydrides of the smaller rare-earth metals, [Sc(BH(4))(3)(thf)(2)] and [Lu(BH(4))(3)(thf)(3)], resulted in a redox reaction of the BH(4) (-) group with one of the Schiff base functions of the ligand. In the resulting products, [Ln(BH(4)){(dip)(dip-BH(3))-pyr}(thf)(2)] (Ln=Sc, Lu), a dinegatively charged ligand with a new amido function, a Schiff base, and the pyrrolyl function is bound to the metal atom. The by-product of the reaction of the BH(4) (-) anion with the Schiff base function (a BH(3) molecule) is trapped in a unique reaction mode in the coordination sphere of the metal complex. The BH(3) molecule coordinates in an eta(2) fashion to the metal atom. The rare-earth-metal atoms are surrounded by the eta(2)-coordinated BH(3) molecule, the eta(3)-coordinated BH(4) (-) anion, two THF molecules, and the nitrogen atoms from the Schiff base and the pyrrolyl function. All new compounds were characterized by single-crystal X-ray diffraction. Low-temperature X-ray diffraction data at 6 K were collected to locate the hydrogen atoms of [Lu(BH(4)){(dip)(dip-BH(3))-pyr}(thf)(2)]. The (DIP(2)-pyr)(-) borohydride and chloride complexes of neodymium, [Nd(BH(4))(2)(dip(2)-pyr)(thf)(2)] and [NdCl(2)(dip(2)-pyr)(thf)](2), were also used as Ziegler-Natta catalysts for the polymerization of 1,3-butadiene to yield poly(cis-1,4-butadiene). Very high activities and good cis selectivities were observed by using each

  20. Depression of hydrogen evolution during operation of a direct borohydride fuel cell

    NASA Astrophysics Data System (ADS)

    Li, Z. P.; Liu, B. H.; Zhu, J. K.; Suda, S.

    Hydrogen evolution from the anode usually occurs during operation of a Direct Borohydride Fuel Cell (DBFC). This would not only decrease the fuel utilization, but also lower the cell performance because hydrogen bubbles would hinder ion movement in the anolyte. In this paper, the hydrogen evolution behavior is investigated based on relations of hydrogen evolution rates versus operation currents of the DBFC. The effects of anode modification on the hydrogen evolution rate and the cell performance were investigated. It was found that hydrogen evolution was depressed by adding Pd, Ag and Au catalysts in the anode. Coating a thin Nafion film on the catalyst surfaces was another effective way to decrease the hydrogen evolution rate. Depression of the hydrogen evolution and improvement of the DBFC performance can be achieved by adding carbon supported Pd in Ni anode with a suitable content of Nafion. However, too much Nafion in the anode would degrade the DBFC performance.

  1. THE HYDROLYSIS AND OXIDATION BEHAVIOR OF LITHIUM BOROHYDRIDE AND MAGNESIUM HYDRIDE DETERMINED BY CALORIMETRY

    SciTech Connect

    Brinkman, K; Donald Anton, D; Joshua Gray, J; Bruce Hardy, B

    2008-03-13

    Lithium borohydride, magnesium hydride and the 2:1 'destabilized' ball milled mixtures (2LiBH{sub 4}:MgH{sub 2}) underwent liquid phase hydrolysis, gas phase hydrolysis and air oxidation reactions monitored by isothermal calorimetry. The experimentally determined heats of reaction and resulting products were compared with those theoretically predicted using thermodynamic databases. Results showed a discrepancy between the predicted and observed hydrolysis and oxidation products due to both kinetic limitations and to the significant amorphous character of observed reaction products. Gas phase and liquid phase hydrolysis were the dominant reactions in 2LiBH{sub 4}:MgH{sub 2} with approximately the same total energy release and reaction products; liquid phase hydrolysis displayed the maximum heat flow for likely environmental exposure with a peak energy release of 6 (mW/mg).

  2. Performance enhancement of a direct borohydride fuel cell in practical running conditions

    NASA Astrophysics Data System (ADS)

    Kim, Cheolhwan; Kim, Kyu-Jung; Ha, Man Yeong

    To investigate the possibility of a cost-effective direct borohydride fuel cell (DBFC), the performance enhancement of a single cell is investigated under practical running conditions by adopting non-precious metal for the anode. Fluorinated Zr-based AB 2-type hydrogen storage alloy with an effective area of 100 cm 2 is selected as the anode catalyst. To minimize pressure loss from the enlarged cell size, a parallel-type anode channel is designed, then the principal reasons for performance degradation are analyzed. Single-cell performance is mainly enhanced by adopting a corrugated anode design, applying an anti-corrosion coating on the cathode channel, and controlling the fuel flow-rate and air humidity. The cell performance is estimated simply by measuring the wall temperature of the cell.

  3. Magnesium Ethylenediamine Borohydride as Solid-State Electrolyte for Magnesium Batteries

    PubMed Central

    Roedern, Elsa; Kühnel, Ruben-Simon; Remhof, Arndt; Battaglia, Corsin

    2017-01-01

    Solid-state magnesium ion conductors with exceptionally high ionic conductivity at low temperatures, 5 × 10−8 Scm−1 at 30 °C and 6 × 10−5 Scm−1 at 70 °C, are prepared by mechanochemical reaction of magnesium borohydride and ethylenediamine. The coordination complexes are crystalline, support cycling in a potential window of 1.2 V, and allow magnesium plating/stripping. While the electrochemical stability, limited by the ethylenediamine ligand, must be improved to reach competitive energy densities, our results demonstrate that partially chelated Mg2+ complexes represent a promising platform for the development of an all-solid-state magnesium battery. PMID:28387305

  4. A direct borohydride fuel cell with a polymer fiber membrane and non-noble metal catalysts.

    PubMed

    Yang, Xiaodong; Liu, Yongning; Li, Sai; Wei, Xiaozhu; Wang, Li; Chen, Yuanzhen

    2012-01-01

    Polymer electrolyte membranes (PEM) and Pt-based catalysts are two crucial components which determine the properties and price of fuel cells. Even though, PEM faces problem of fuel crossover in liquid fuel cells such as direct methanol fuel cell (DMFC) and direct borohydride fuel cell (DBFC), which lowers power output greatly. Here, we report a DBFC in which a polymer fiber membrane (PFM) was used, and metal oxides, such as LaNiO₃ and MnO₂, were used as cathode catalysts, meanwhile CoO was used as anode catalyst. Peak power density of 663 mW·cm⁻² has been achieved at 65°C, which increases by a factor of 1.7-3.7 compared with classic DBFCs. This fuel cell structure can also be extended to other liquid fuel cells, such as DMFC.

  5. A direct borohydride fuel cell with a polymer fiber membrane and non-noble metal catalysts

    PubMed Central

    Yang, Xiaodong; Liu, Yongning; Li, Sai; Wei, Xiaozhu; Wang, Li; Chen, Yuanzhen

    2012-01-01

    Polymer electrolyte membranes (PEM) and Pt-based catalysts are two crucial components which determine the properties and price of fuel cells. Even though, PEM faces problem of fuel crossover in liquid fuel cells such as direct methanol fuel cell (DMFC) and direct borohydride fuel cell (DBFC), which lowers power output greatly. Here, we report a DBFC in which a polymer fiber membrane (PFM) was used, and metal oxides, such as LaNiO3 and MnO2, were used as cathode catalysts, meanwhile CoO was used as anode catalyst. Peak power density of 663 mW·cm−2 has been achieved at 65°C, which increases by a factor of 1.7–3.7 compared with classic DBFCs. This fuel cell structure can also be extended to other liquid fuel cells, such as DMFC. PMID:22880160

  6. A cobalt polypyrrole composite catalyzed cathode for the direct borohydride fuel cell

    NASA Astrophysics Data System (ADS)

    Qin, H. Y.; Liu, Z. X.; Yin, W. X.; Zhu, J. K.; Li, Z. P.

    A cobalt polypyrrole carbon (Co-PPY-C) composite has been attempted for use as a cathode catalyst in a direct borohydride fuel cell (DBFC). A Co-PPY-C composite has been fabricated in laboratory and characterized by the field emission scanning electron microscopy, transmission electron microscopy, as well as X-ray photoemission spectroscopy. Fabricated Co-PPY-C catalyst demonstrates good short-term durability and activity which are comparable to those obtained from the Pt/C catalyst. A maximum power density of 65 mW cm -2 has been achieved at ambient conditions. This research concludes that metallo-organic coordination compounds would be potential candidates for use as cathode catalysts in the DBFC.

  7. Synthesis, Structure, and Reactivity of Co(II) and Ni(II) PCP Pincer Borohydride Complexes

    PubMed Central

    2015-01-01

    The 15e square-planar complexes [Co(PCPMe-iPr)Cl] (2a) and [Co(PCP-tBu)Cl] (2b), respectively, react readily with NaBH4 to afford complexes [Co(PCPMe-iPr)(η2-BH4)] (4a) and [Co(PCP-tBu)(η2-BH4)] (4b) in high yields, as confirmed by IR spectroscopy, X-ray crystallography, and elemental analysis. The borohydride ligand is symmetrically bound to the cobalt center in η2-fashion. These compounds are paramagnetic with effective magnetic moments of 2.0(1) and 2.1(1) μB consistent with a d7 low-spin system corresponding to one unpaired electron. None of these complexes reacted with CO2 to give formate complexes. For structural and reactivity comparisons, we prepared the analogous Ni(II) borohydride complex [Ni(PCPMe-iPr)(η2-BH4)] (5) via two different synthetic routes. One utilizes [Ni(PCPMe-iPr)Cl] (3) and NaBH4, the second one makes use of the hydride complex [Ni(PCPMe-iPr)H] (6) and BH3·THF. In both cases, 5 is obtained in high yields. In contrast to 4a and 4b, the borohydride ligand is asymmetrically bound to the nickel center but still in an η2-mode. [Ni(PCPMe-iPr)(η2-BH4)] (5) loses readily BH3 at elevated temperatures in the presence of NEt3 to form 6. Complexes 5 and 6 are both diamagnetic and were characterized by a combination of 1H, 13C{1H}, and 31P{1H} NMR, IR spectroscopy, and elemental analysis. Additionally, the structure of these compounds was established by X-ray crystallography. Complexes 5 and 6 react with CO2 to give the formate complex [Ni(PCPMe-iPr)(OC(C=O)H] (7). The extrusion of BH3 from [Co(PCPMe-iPr)(η2-BH4)] (4a) and [Ni(PCPMe-iPr)(η2-BH4)] (5) with the aid of NH3 to yield the respective hydride complexes [Co(PCPMe-iPr)H] and [Ni(PCPMe-iPr)H] (6) and BH3NH3 was investigated by DFT calculations showing that formation of the Ni hydride is thermodynamically favorable, whereas the formation of the Co(II) hydride, in agreement with the experiment, is unfavorable. The electronic structures and the bonding of the borohydride ligand in [Co

  8. The Discovery-Oriented Approach to Organic Chemistry. 6. Selective Reduction in Organic Chemistry: Reduction of Aldehydes in the Presence of Esters Using Sodium Borohydride

    ERIC Educational Resources Information Center

    Baru, Ashvin R.; Mohan, Ram S.

    2005-01-01

    A discovery-oriented lab experiment is developed that illustrates the chemoselective nature of reductions using sodium borohydride. Products are of sufficient purity to allow analysis by spectroscopy without further purification.

  9. First-principles studies of phase stability and crystal structures in Li-Zn mixed-metal borohydrides

    NASA Astrophysics Data System (ADS)

    Wang, Yongli; Zhang, Yongsheng; Wolverton, C.

    2013-07-01

    We address the problem of finding mixed-metal borohydrides with favorable thermodynamics and illustrate the approach using the example of LiZn2(BH4)5. Using density functional theory (DFT), along with the grand-canonical linear programming method (GCLP), we examine the experimentally and computationally proposed crystal structures and the finite-temperature thermodynamics of dehydrogenation for the quaternary hydride LiZn2(BH4)5. We find the following: (i) For LiZn2(BH4)5, DFT calculations of the experimental crystal structures reveal that the structure from the neutron diffraction experiments of Ravnsbæk is more stable [by 24 kJ/(mol f.u.)] than that based on a previous x-ray study. (ii) Our DFT calculations show that when using the neutron-diffraction structure of LiZn2(BH4)5, the recently theoretically predicted LiZn(BH4)3 compound is unstable with respect to the decomposition into LiZn2(BH4)5+LiBH4. (iii) GCLP calculations show that even though LiZn2(BH4)5 is a combination of weakly [Zn(BH4)2] and strongly (LiBH4) bound borohydrides, its decomposition is not intermediate between the two individual borohydrides. Rather, we find that the decomposition of LiZn2(BH4)5 is divided into a weakly exothermic step [LiZn2(BH4)5→2Zn+(1)/(5)LiBH4+(2)/(5)Li2B12H12+(36)/(5)H2] and three strong endothermic steps (12LiBH4→10LiH+Li2B12H12+13H2; Zn+LiH→LiZn+(1)/(2)H2; 2Zn+Li2B12H12→2LiZn+12B+6H2). DFT-calculated ΔHZPET=0K values for the first three LiZn2(BH4)5 decomposition steps are -19, +37, +74 kJ/(mol H2), respectively. The behavior of LiZn2(BH4)5 shows that mixed-metal borohydrides formed by mixing borohydrides of high and low thermodynamics stabilities do not necessarily have an intermediate decomposition tendency. Our results suggest the correct strategy to find intermediate decomposition in mixed-metal borohydrides is to search for stable mixed-metal products such as ternary metal borides.

  10. Alkaline flooding injection strategy

    SciTech Connect

    French, T.R.; Josephson, C.B.

    1992-03-01

    The objective of this project is to improved alkali-surfactant flooding methods, and this includes determining the proper design of injection strategy. Several different injection strategies have been used or suggested for recovering heavy oils with surfactant-enhanced alkaline flooding methods. Oil recovery was compared for four different injection strategies: (1) surfactant followed by polymer, (2) surfactant followed by alkaline polymer, (3) alkaline surfactant followed by polymer, and (4) alkali, surfactant, and polymer mixed in a single formulation. The effect of alkaline preflush was also studied under two different conditions. All of the oil recovery experiments were conducted under optimal conditions with a viscous, non-acidic oil from Hepler (KS) oil field. The coreflood experiments were conducted with Berea sandstone cores since field core was not available in sufficient quantity for coreflood tests. The Tucker sand of Hepler field is a Class I fluvial dominated deltaic reservoir, as classified by the Department of Energy, which has been selected as the site of a DOE-sponsored field pilot test.

  11. PtRu-LiCoO 2—an efficient catalyst for hydrogen generation from sodium borohydride solutions

    NASA Astrophysics Data System (ADS)

    Krishnan, Palanichamy; Yang, Tae-Hyun; Lee, Won-Yong; Kim, Chang-Soo

    Hydrogen generation by the hydrolysis of aqueous sodium borohydride (NaBH 4) solutions is studied using IRA-400 anion resin dispersed Pt, Ru catalysts and lithium cobalt oxide (LiCoO 2) supported Pt, Ru and PtRu catalysts. The performance of the LiCoO 2 supported catalysts is better than that of ion-exchange resin dispersed catalysts. There is a marked concentration dependence on the performance of the LiCoO 2 supported catalysts and the hydrogen generation rate decreases if the borohydride concentration is increased beyond 10 wt.%. The efficiency of PtRu-LiCoO 2 is almost double that of either Ru-LiCoO 2 or Pt-LiCoO 2 for NaBH 4 concentrations up to 10 wt.%.

  12. Alkaline quinone flow battery.

    PubMed

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy.

  13. Sodium borohydride as an additive to enhance the performance of direct ethanol fuel cells

    NASA Astrophysics Data System (ADS)

    Wang, Lianqin; Bambagioni, Valentina; Bevilacqua, Manuela; Bianchini, Claudio; Filippi, Jonathan; Lavacchi, Alessandro; Marchionni, Andrea; Vizza, Francesco; Fang, Xiang; Shen, Pei Kang

    The effect of adding small quantities (0.1-1 wt.%) of sodium borohydride (NaBH 4) to the anolyte solution of direct ethanol fuel cells (DEFCs) with membrane-electrode assemblies constituted by nanosized Pd/C anode, Fe-Co cathode and anion-exchange membrane (Tokuyama A006) was investigated by means of various techniques. These include cyclic voltammetry, in situ FTIR spectroelectrochemistry, a study of the performance of monoplanar fuel cells and an analysis of the ethanol oxidation products. A comparison with fuel cells fed with aqueous solutions of ethanol proved unambiguously the existence of a promoting effect of NaBH 4 on the ethanol oxidation. Indeed, the potentiodynamic curves of the ethanol-NaBH 4 mixtures showed higher power and current densities, accompanied by a remarkable increase in the fuel consumption at comparable working time of the cell. A 13C and 11B { 1H}NMR analysis of the cell exhausts and an in situ FTIR spectroelectrochemical study showed that ethanol is converted selectively to acetate while the oxidation product of NaBH 4 is sodium metaborate (NaBO 2). The enhancement of the overall cell performance has been explained in terms of the ability of NaBH 4 to reduce the PdO layer on the catalyst surface.

  14. Fundamental study of reduction graphene oxide by sodium borohydride for gas sensor application

    NASA Astrophysics Data System (ADS)

    Muda, M. R.; Ramli, Muhammad M.; Isa, Siti S. Mat; Jamlos, M. F.; Murad, S. A. Z.; Norhanisah, Z.; Isa, M. Mohamad; Kasjoo, S. R.; Ahmad, N.; Nor, N. I. M.; Khalid, N.

    2017-03-01

    The efficient reduction of graphene oxide (rGO) was performed using Sodium Borohydride (NaBH4). These reduction approaches remove the majority of the oxygen-containing functional groups at the basal plane and surface of graphene oxide sheets. Structural and physiochemical properties of the GO were investigated with help of Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), and Ultraviolet-Visible-Near infrared (UV-Vis-NIR). The effects of the chemical reduction on a GO surface were analyzed using a Semiconductor Parameter Analyzer (SPA) in order to obtain the electrical resistance measurement. It was found that the resistance of reduced graphene oxide was greatly reduced when compared to the condition of before reduction process. Then, the formation of uniform thin film of rGO sheets was produced using vacuum filtration method in order to fabricate a gas sensor. In this project, plastic was used as a substrate. The sensor was then being exposed to NO2 gas at room temperature in order to demonstrate the sensing ability of rGO.

  15. Aqueous sodium borohydride induced thermally stable porous zirconium oxide for quick removal of lead ions

    PubMed Central

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-01-01

    Aqueous sodium borohydride (NaBH4) is well known for its reducing property and well-established for the development of metal nanoparticles through reduction method. In contrary, this research paper discloses the importance of aqueous NaBH4 as a precipitating agent towards development of porous zirconium oxide. The boron species present in aqueous NaBH4 play an active role during gelation as well as phase separated out in the form of boron complex during precipitation, which helps to form boron free zirconium hydroxide [Zr(OH)4] in the as-synthesized condition. Evolved in-situ hydrogen (H2) gas-bubbles also play an important role to develop as-synthesized loose zirconium hydroxide and the presence of intra-particle voids in the loose zirconium hydroxide help to develop porous zirconium oxide during calcination process. Without any surface modification, this porous zirconium oxide quickly adsorbs almost hundred percentages of toxic lead ions from water solution within 15 minutes at normal pH condition. Adsorption kinetic models suggest that the adsorption process was surface reaction controlled chemisorption. Quick adsorption was governed by surface diffusion process and the adsorption kinetic was limited by pore diffusion. Five cycles of adsorption-desorption result suggests that the porous zirconium oxide can be reused efficiently for removal of Pb (II) ions from aqueous solution. PMID:26980545

  16. Aqueous sodium borohydride induced thermally stable porous zirconium oxide for quick removal of lead ions

    NASA Astrophysics Data System (ADS)

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-03-01

    Aqueous sodium borohydride (NaBH4) is well known for its reducing property and well-established for the development of metal nanoparticles through reduction method. In contrary, this research paper discloses the importance of aqueous NaBH4 as a precipitating agent towards development of porous zirconium oxide. The boron species present in aqueous NaBH4 play an active role during gelation as well as phase separated out in the form of boron complex during precipitation, which helps to form boron free zirconium hydroxide [Zr(OH)4] in the as-synthesized condition. Evolved in-situ hydrogen (H2) gas-bubbles also play an important role to develop as-synthesized loose zirconium hydroxide and the presence of intra-particle voids in the loose zirconium hydroxide help to develop porous zirconium oxide during calcination process. Without any surface modification, this porous zirconium oxide quickly adsorbs almost hundred percentages of toxic lead ions from water solution within 15 minutes at normal pH condition. Adsorption kinetic models suggest that the adsorption process was surface reaction controlled chemisorption. Quick adsorption was governed by surface diffusion process and the adsorption kinetic was limited by pore diffusion. Five cycles of adsorption-desorption result suggests that the porous zirconium oxide can be reused efficiently for removal of Pb (II) ions from aqueous solution.

  17. A calibrated hydrogen-peroxide direct-borohydride fuel cell model

    NASA Astrophysics Data System (ADS)

    Stroman, Richard O.; Jackson, Gregory S.; Garsany, Yannick; Swider-Lyons, Karen

    2014-12-01

    A numerical model with global reaction rates is calibrated to measurements from a simple hydrogen-peroxide direct-borohydride fuel cell (H2O2-DBFC), and then used to unravel complex electrochemical and competing parasitic reactions. In this H2O2-DBFC, fuel (1-50 mM NaBH4/2 M NaOH) is oxidized at a Au anode and oxidizer (10-40 mM H2O2/1 M H2SO4) is reduced at a Pd:Ir cathode. Polarization curves and electrode potentials, as functions of fuel and oxidizer feeds support global reaction rate parameter fitting. The measurements and calibrated model showed H2O2 decomposition at the cathode depresses open circuit voltage from 3.01 V theoretical to 1.65 V, and when H2O2 supply is limited, cathode potentials are sufficiently negative to make H+ reduction to H2 thermodynamically favorable. Calibrated model results show that thin concentration boundary layers limit reactant utilization and current density. Decreasing the inlet concentrations, flow rates, and cell voltage slow parasitic reactions and favor desirable charge transfer reactions. Peak conversion efficiency and peak power density coincide because thermodynamic efficiency and parasitic reaction rates decrease (relative to charge transfer reaction rates) with increasing current density. We conclude that the performance of a fuel cell with parasitic side reactions can be predicted through numerical modeling.

  18. Structure determination of ultra dense magnesium borohydride: A first-principles study

    NASA Astrophysics Data System (ADS)

    Fan, Jing; Duan, Defang; Jin, Xilian; Bao, Kuo; Liu, Bingbing; Cui, Tian

    2013-06-01

    Magnesium borohydride (Mg(BH4)2) is one of the potential hydrogen storage materials. Recently, two experiments [Y. Filinchuk, B. Richter, T. R. Jensen, V. Dmitriev, D. Chernyshov, and H. Hagemann, Angew. Chem., Int. Ed. 50, 11162 (2011);, 10.1002/anie.201100675 L. George, V. Drozd, and S. K. Saxena, J. Phys. Chem. C 113, 486 (2009), 10.1021/jp807842t] found that α-Mg(BH4)2 can irreversibly be transformed to an ultra dense δ-Mg(BH4)2 under high pressure. Its volumetric hydrogen content at ambient pressure (147 g/cm3) exceeds twice of DOE's (U.S. Department of Energy) target (70 g/cm3) and that of α-Mg(BH4)2 (117 g/cm3) by 20%. In this study, the experimentally proposed P42nm structure of δ-phase has been found to be dynamically unstable. A new Fddd structure has been reported as a good candidate of δ-phase instead. Its enthalpy from 0 to 12 GPa is much lower than P42nm structure and the simulated X-ray diffraction spectrum is in satisfied agreement with previous experiments. In addition, the previously proposed P-3m1 structure, which is denser than Fddd, is found to be a candidate of ɛ-phase due to the agreement of Raman shifts.

  19. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... publicly owned treatment works resulting from operations in which steel and steel products are immersed...

  20. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... publicly owned treatment works resulting from operations in which steel and steel products are immersed...

  1. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... publicly owned treatment works resulting from operations in which steel and steel products are immersed...

  2. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... publicly owned treatment works resulting from operations in which steel and steel products are immersed...

  3. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... publicly owned treatment works resulting from operations in which steel and steel products are immersed...

  4. Preparation and Growth of N-Doped Hollow Carbon Nanospheres and Their Application as Catalyst Support in Direct Borohydride Fuel Cell.

    PubMed

    Chen, Yuanzhen; Dong, Shujuan; Li, Sai; Liu, Yongning; Yan, Wei

    2015-05-01

    N-doped hollow carbon nanospheres (HCNSs) were prepared by electric arc discharge method in N2 atmosphere. X-ray Photoelectron Spectroscopy (XPS) analysis shows that their nitrogen content reaches up to 4.9 atom%. Both the low thermal conductivity of N2 and the doping of nitrogen atom make carbon unit bend to form hollow nanosphere structure. High-resolution transmission electron microscopy (HRTEM) and X-ray diffusion (XRD) analysis prove the presence of detected defects and a poor crystallinity on the HCNSs shell. Moreover, annealing treatment of HCNSs was carried out at 1100 degrees C/10 h and 1400 degrees C/2 h to research their fracture extension. It is found that HCNSs could grow into closed-tubes even with a shell at high annealing temperature. HCNSs were applied in direct borohydride fuel cell (DBFC) to evaluate their catalytic performance. The electrochemical results show that pure HCNSs doesn't have any catalysis effect, but they can greatly promote the catalytic performance of CoO, and the largest polarization current density of which achieves 1.845 A x cm(-2) at -0.7 V (vs. Hg/HgO electrode).

  5. (Iminophosphoranyl)(thiophosphoranyl)methane rare-earth borohydride complexes: synthesis, structures and polymerization catalysis.

    PubMed

    Schmid, Matthias; Oña-Burgos, Pascual; Guillaume, Sophie M; Roesky, Peter W

    2015-07-21

    The (iminophosphoranyl)(thiophosphoranyl)methanide {CH(PPh2=NSiMe3)(PPh2=S)}(-) ligand has been used for the synthesis of divalent and trivalent rare-earth borohydride complexes. The salt metathesis of the potassium reagent [K{CH(PPh2=NSiMe3)(PPh2=S)}]2 with [Yb(BH4)2(THF)2] resulted in the divalent monoborohydride ytterbium complex [{CH(PPh2=NSiMe3)(PPh2=S)}Yb(BH4)(THF)2]. The 2D (31)P/(171)Yb HMQC-NMR spectrum clearly showed the coupling between both nuclei. The trivalent bisborohydrides [{CH(PPh2=NSiMe3)(PPh2=S)}Ln(BH4)2(THF)] (Ln = Y, Sm, Tb, Dy, Er, Yb and Lu) were obtained by reaction of [K{CH(PPh2=NSiMe3)(PPh2=S)}]2 with [Ln(BH4)3(THF)3]. All new compounds were characterized by single X-ray diffraction. The divalent and trivalent compounds were next used as initiators in the ring-opening polymerization (ROP) of ε-caprolactone (CL) and trimethylene carbonate (TMC). All complexes afforded a generally well-controlled ROP of both of these cyclic esters. High molar mass poly(ε-caprolactone) diols (Mn,NMR < 101,300 g mol(-1), ĐM = 1.44), and α,ω-dihydroxy and α-hydroxy,ω-formate telechelic poly(trimethylene carbonate)s (Mn,NMR < 20,000 g mol(-1), ĐM = 1.61) were thus synthesized under mild operating conditions.

  6. Ammine-Stabilized Transition-Metal Borohydrides of Iron, Cobalt, and Chromium: Synthesis and Characterization.

    PubMed

    Roedern, Elsa; Jensen, Torben R

    2015-11-02

    Iron and cobalt borohydrides stabilized by ammonia (NH3), [Fe(NH3)6](BH4)2 and [Co(NH3)6](BH4)2, were synthesized along with a solid solution, [Co(NH3)6](BH4)(2-x)Cl(x) (x ∼ 1), and a bimetallic compound, [Fe(NH3)6](Li2(BH4)4). The compounds were prepared by new low-temperature, solvent-based synthesis methods, using dimethyl sulfide or liquid NH3, which allow for the removal of inert metal halides. The crystal structures were determined from synchrotron radiation powder X-ray diffraction (SR-PXD) data. [M(NH3)6](BH4)2 (M = Fe, Co) and [Co(NH3)6](BH4)(2-x)Cl(x) crystallize in the cubic crystal system, where the transition metals are octahedrally coordinated by NH3. Polymeric chains of lithium coordinated by four bridging BH4(-) anions are found in [Fe(NH3)6](Li2(BH4)4). The new compounds have high hydrogen densities of ∼14 wt % H2 and ∼140 g H2/L and release a mixture of hydrogen and NH3 gas at low temperatures, T < 80 °C. The decomposition mechanisms of the prepared compounds along with the composites [Fe(NH3)6](BH4)2·nNH3BH3 (n = 2, 4, 6) were studied by thermal analysis and in situ SR-PXD.

  7. Reduction of N2O and NO generation in anaerobic-aerobic (low dissolved oxygen) biological wastewater treatment process by using sludge alkaline fermentation liquid.

    PubMed

    Zhu, Xiaoyu; Chen, Yinguang

    2011-03-15

    This paper reported an efficient method to significantly reduce nitrous oxide (N(2)O) and nitric oxide (NO) generation in anaerobic-aerobic (low dissolved oxygen) processes. It was found that by the use of waste-activated sludge alkaline fermentation liquid as the synthetic wastewater-carbon source, compared with the commonly used carbon source in the literature (e.g., acetic acid), the generation of N(2)O and NO was reduced by 68.7% and 50.0%, respectively, but the removal efficiencies of total phosphorus (TP) and total nitrogen (TN) were improved. Both N(2)O and NO were produced in the low dissolved oxygen (DO) stage, and the use of sludge fermentation liquid greatly reduced their generation from the denitrification. The presences of Cu(2+) and propionic acid in fermentation liquid were observed to play an important role in the reduction of N(2)O and NO generation. The analysis of the activities of denitrifying enzymes suggested that sludge fermentation liquid caused the significant decrease of both nitrite reductase activity to NO reductase activity ratio and NO reductase activity to N(2)O reductase activity ratio, which resulted in the lower generation of NO and N(2)O. Fluorescence in situ hybridization analysis indicated that the number of glycogen accumulating bacteria, which was reported to be relevant to nitrous oxide generation, in sludge fermentation liquid reactor was much lower than that in acetic acid reactor. The quantitative detection of the nosZ gene, encoding nitrous oxide reductase, showed that the use of fermentation liquid increased the number of bacteria capable of reducing N(2)O to N(2). The feasibility of using sludge fermentation liquid to reduce NO and N(2)O generation in an anaerobic-low DO process was finally confirmed for a municipal wastewater.

  8. Kinetics of the alkaline hydrolysis of nitrocellulose.

    PubMed

    Christodoulatos, C; Su, T L; Koutsospyros, A

    2001-01-01

    Cellulose nitrate (nitrocellulose) is an explosive solid substance used in large quantities in various formulations of rocket and gun propellants. Safe destruction of nitrocellulose can be achieved by alkaline hydrolysis, which converts it to biodegradable products that can then be treated by conventional biological processes. The kinetics of the alkaline hydrolysis of munitions-grade nitrocellulose in sodium hydroxide solutions were investigated in completely mixed batch reactors. Experiments were conducted using solutions of alkaline strength ranging from 0.1 to 15% by mass and temperatures in the range of 30 to 90 degrees C. Regression analysis of the kinetic data revealed that alkaline hydrolysis of nitrocellulose is of the order 1.0 and 1.5 with respect to nitrocellulose and hydroxide concentration, respectively. The activation energy of the hydrolysis reaction was found to be 100.9 kJ/mol with a preexponential Arrhenius constant of 4.73 x 10(13). Nitrite and nitrate, in a 3:1 ratio, were the primary nitrogen species present in the posthydrolysis solution. The kinetic information is pertinent to the development and optimization of nitrocellulose chemical-biological treatment systems.

  9. Evaluation of ultrasonic, acid, thermo-alkaline and enzymatic pre-treatments on anaerobic digestion of Ulva rigida for biogas production.

    PubMed

    Karray, Raida; Hamza, Manel; Sayadi, Sami

    2015-01-01

    Pre-treatment of macroalgae has received considerable research globally due to its influence on the technical, economic and environmental sustainability of algae biogas production. Some of the most promising pre-treatment methods require the application of chemicals, enzymatic, and mechanical. This study focused on these pre-treatments of Ulva rigida for biogas production. The evaluation of different pre-treatment in terms of reducing sugar yields demonstrates that 3.62, 2.88, 2.53 and 7.3g/L of reducing sugar was obtained in acid catalysis, thermoalkaline, ultrasonication and enzymatic pre-treatment, respectively. However in crude macroalgae only 0.6g/L of reducing sugar was given. After anaerobic digestion, the enzymatic hydrolysis was demonstrated the best biogas yield than other pre-treatment which reached 626.5mL/gCODint with 62.65% of biodegradability. The best demonstrated method which uses crude broth of Aspergillus niger showed an effective and environmentally friendly strategy for enhancing the biogas production yields after the anaerobic digestion.

  10. Phosphatidylinositol anchor of HeLa cell alkaline phosphatase

    SciTech Connect

    Jemmerson, R.; Low, M.G.

    1987-09-08

    Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either /sup 3/H-fatty acids or (/sup 3/H)ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the /sup 3/H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of (/sup 3/H)ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from /sup 3/H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the /sup 3/H-fatty acid and the (/sup 3/H)ethanolamine label from purified alkaline phosphatase. Subtilisin was also able to remove the (/sup 3/H)ethanolamine label from the purified alkaline phosphatase. The /sup 3/H radioactivity in alkaline phosphatase purified from (/sup 3/H)ethanolamine-labeled cells comigrated with authentic (/sup 3/H)ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the /sup 3/H-fatty acid and (/sup 3/H)ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase.

  11. Optimized hydrogen generation in a semicontinuous sodium borohydride hydrolysis reactor for a 60 W-scale fuel cell stack

    NASA Astrophysics Data System (ADS)

    Arzac, G. M.; Fernández, A.; Justo, A.; Sarmiento, B.; Jiménez, M. A.; Jiménez, M. M.

    Catalyzed hydrolysis of sodium borohydride (SBH) is a promising method for the hydrogen supply of fuel cells. In this study a system for controlled production of hydrogen from aqueous sodium borohydride (SBH) solutions has been designed and built. This simple and low cost system operates under controlled addition of stabilized SBH solutions (fuel solutions) to a supported CoB catalyst. The system works at constant temperature delivering hydrogen at 1 L min -1 constant rate to match a 60-W polymer electrolyte membrane fuel cell (PEMFC). For optimization of the system, several experimental conditions were changed and their effect was investigated. A simple model based only on thermodynamic considerations was proposed to optimize system parameters at constant temperature and hydrogen evolution rate. It was found that, for a given SBH concentration, the use of the adequate fuel addition rate can maximize the total conversion and therefore the gravimetric storage capacity. The hydrogen storage capacity was as high as 3.5 wt% for 19 wt% SBH solution at 90% fuel conversion and an operation temperature of 60 °C. It has been demonstrated that these optimized values can also be achieved for a wide range of hydrogen generation rates. Studies on the durability of the catalyst showed that a regeneration step is needed to restore the catalytic activity before reusing.

  12. First-Principles Structure Prediction of Dual Cation Ammine Borohydrides: LiMg(BH4)3(NH3)x

    NASA Astrophysics Data System (ADS)

    Kışlak, Yusuf; Tekin, Adem

    On-board hydrogen storage for transportation applications continues to be one of the most technically challenging barriers to the widespread commercialization of hydrogen-fueled vehicles. In addition, hydrogen storage is also required for off-board purposes such as stationary power generation and hydrogen delivery and refueling infrastructure. After decades of extensive exploration, research into hydrogen storage materials based on metal borohydrides has become a highly active and exciting area owing to the high theoretical hydrogen capacities of these materials. However, they are thermodynamically too stable and therefore a very high temperature is required for their decomposition. This temperature can be lowered to the tolerable levels by the addition of ammonia and the resulting material is called as Ammine Metal Borohydrides (AMBs). In this study, we aim to search the ground state crystal structures of LiMg(BH4)3(NH3)x [1] with x = 2, 3, 4 using CrystAl Structure Prediction via Simulated Annealing (CASPESA) method. This approach was successfully located the experimentally determined structure of LiMg(BH4)3(NH3)2 [1] and other interesting local minima. For x = 3 and 4 cases, our methodology also resulted new crystal phases.

  13. Anodic behavior of carbon supported Cu@Ag core-shell nanocatalysts in direct borohydride fuel cells

    NASA Astrophysics Data System (ADS)

    Duan, Donghong; Liu, Huihong; You, Xiu; Wei, Huikai; Liu, Shibin

    2015-10-01

    Carbon-supported Cu@Ag core-shell nanoparticles are prepared by a successive reduction method in an aqueous solution and are used as an anode electrocatalyst for the direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the as-prepared electrocatalysts are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry (CV), chronopotentiometry (CP), and fuel cell tests. In situ Fourier transform infrared (FTIR) spectroscopy is employed in 2 M NaOH/0.1 M NaBH4 to understand the borohydride oxidation reaction (BOR) mechanism by studying the intermediate reactions occurring on the Cu@Ag/C electrode. The TEM images show that the average size of the Cu1@Ag1/C particles is approximately 18 nm. Among the as-prepared catalysts, the Cu2@Ag1/C catalyst presents the highest catalytic activity. As shown by in situ FTIR, the oxidation reaction mechanism of BH4- is similar to that of Ag/C: BHn(OH)4-n- + 2OH- → BHn-1(OH)5-n- +H2 O + 2e . At 25 °C, the DBHFC with Cu2@Ag1/C as the anode electrocatalyst and Pt mesh (1 cm2) as the cathode electrode exhibits a maximum anodic power density of 17.27 mW mg-1 at a discharge current density of 27.8 mA mg-1.

  14. Net alkalinity and net acidity 2: Practical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH < 6.3 after oxidation had positive Hot Acidity. Samples with similar pH values before oxidation had dissimilar Hot Acidities due to variations in their alkalinities and dissolved Fe, Mn, and Al concentrations. Hot Acidity was approximately equal to net acidity calculated based on initial pH and dissolved concentrations of Fe, Mn, and Al minus the

  15. Alkaline battery, separator therefore

    NASA Technical Reports Server (NTRS)

    Schmidt, George F. (Inventor)

    1980-01-01

    An improved battery separator for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The separator is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in separator coatings. When the separator is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.

  16. Potential of hot water extraction of birch wood to produce high-purity dissolving pulp after alkaline pulping.

    PubMed

    Borrega, Marc; Tolonen, Lasse K; Bardot, Fanny; Testova, Lidia; Sixta, Herbert

    2013-05-01

    The potential of hot water extraction of birch wood to produce highly purified dissolving pulp in a subsequent soda-anthraquinone pulping process was evaluated. After intermediate extraction intensities, pulps with low xylan content (3-5%) and high cellulose yield were successfully produced. Increasing extraction intensity further decreased the xylan content in pulp. However, below a xylan content of 3%, the cellulose yield dramatically decreased. This is believed to be due to cleavage of glycosidic bonds in cellulose during severe hot water extractions, followed by peeling reactions during alkaline pulping. Addition of sodium borohydride as well as increased anthraquinone concentration in the pulping liquor increased the cellulose yield, but had no clear effects on pulp purity and viscosity. The low intrinsic viscosity of pulps produced after severe extraction intensities and soda-anthraquinone pulping corresponded to the viscosity at the leveling-off degree of polymerization, suggesting that nearly all amorphous cellulose had been degraded.

  17. Temperature-mediated phase transformation, pore geometry and pore hysteresis transformation of borohydride derived in-born porous zirconium hydroxide nanopowders

    PubMed Central

    Nayak, Nadiya B.; Nayak, Bibhuti B.

    2016-01-01

    Development of in-born porous nature of zirconium hydroxide nanopowders through a facile hydrogen (H2) gas-bubbles assisted borohydride synthesis route using sodium borohydride (NaBH4) and novel information on the temperature-mediated phase transformation, pore geometry as well as pore hysteresis transformation of in-born porous zirconium hydroxide nanopowders with the help of X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) isotherm and Transmission Electron Microscopy (TEM) images are the main theme of this research work. Without any surfactants or pore forming agents, the borohydride derived amorphous nature of porous powders was stable up to 500 °C and then the seed crystals start to develop within the loose amorphous matrix and trapping the inter-particulate voids, which led to develop the porous nature of tetragonal zirconium oxide at 600 °C and further sustain this porous nature as well as tetragonal phase of zirconium oxide up to 800 °C. The novel hydrogen (H2) gas-bubbles assisted borohydride synthesis route led to develop thermally stable porous zirconium hydroxide/oxide nanopowders with an adequate pore size, pore volume, and surface area and thus these porous materials are further suggested for promising use in different areas of applications. PMID:27198738

  18. Design of pilot-scale solar photocatalytic reactor for the generation of hydrogen from alkaline sulfide wastewater of sewage treatment plant.

    PubMed

    Priya, R; Kanmani, S

    2013-01-01

    Experiments were conducted for photocatalytic generation of renewable fuel hydrogen from sulphide wastewater from the sewage treatment plant. In this study, pilot-scale solar photocatalytic reactor was designed for treating 1 m3 of sulphide wastewater and also for the simultaneous generation of hydrogen. Bench-scale studies were conducted both in the batch recycle and continuous modes under solar irradiation at similar experimental conditions. The maximum of 89.7% conversion was achieved in the continuous mode. The length of the pilot-scale solar photocatalytic reactor was arrived using the design parameters such as volumetric flow rate (Q) (11 x 10(-2) m3/s), inlet concentration of sulphide ion (C(in)) (28 mol/m3), conversion (89.7%) and average mass flow destruction rate (3.488 x 10(-6) mol/m2 s). The treatment cost of the process was estimated to be 6 US$/m3. This process would be suitable for India like sub-tropical country where sunlight is abundantly available throughout the year.

  19. Acid transformation of bauxite residue: Conversion of its alkaline characteristics.

    PubMed

    Kong, Xiangfeng; Li, Meng; Xue, Shengguo; Hartley, William; Chen, Chengrong; Wu, Chuan; Li, Xiaofei; Li, Yiwei

    2017-02-15

    Bauxite residue (BR) is a highly alkaline solid hazardous waste produced from bauxite processing for alumina production. Alkaline transformation appears to reduce the environmental risk of bauxite residue disposal areas (BRDAs) whilst potentially providing opportunities for the sustainable reuse and on-going management of BR. Mineral acids, a novel citric acid and a hybrid combination of acid-gypsum treatments were investigated for their potential to reduce residue pH and total alkalinity and transform the alkaline mineral phase. XRD results revealed that with the exception of andradite, the primary alkaline solid phases of cancrinite, grossular and calcite were transformed into discriminative products based on the transformation used. Supernatants separated from BR and transformed bauxite residue (TBR) displayed distinct changes in soluble Na, Ca and Al, and a reduction in pH and total alkalinity. SEM images suggest that mineral acid transformations promote macro-aggregate formation, and the positive promotion of citric acid, confirming the removal or reduction in soluble and exchangeable Na. NEXAFS analysis of Na K-edge revealed that the chemical speciation of Na in TBRs was consistent with BR. Three acid treatments and gypsum combination had no effect on Na speciation, which affects the distribution of Na revealed by sodium STXM imaging.

  20. Electronic structure of nickel(II) and zinc(II) borohydrides from spectroscopic measurements and computational modeling.

    PubMed

    Desrochers, Patrick J; Sutton, Christopher A; Abrams, Micah L; Ye, Shengfa; Neese, Frank; Telser, Joshua; Ozarowski, Andrew; Krzystek, J

    2012-03-05

    The previously reported Ni(II) complex, Tp*Ni(κ(3)-BH(4)) (Tp* = hydrotris(3,5-dimethylpyrazolyl)borate anion), which has an S = 1 spin ground state, was studied by high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy as a solid powder at low temperature, by UV-vis-NIR spectroscopy in the solid state and in solution at room temperature, and by paramagnetic (11)B NMR. HFEPR provided its spin Hamiltonian parameters: D = 1.91(1) cm(-1), E = 0.285(8) cm(-1), g = [2.170(4), 2.161(3), 2.133(3)]. Similar, but not identical parameters were obtained for its borodeuteride analogue. The previously unreported complex, Tp*Zn(κ(2)-BH(4)), was prepared, and IR and NMR spectroscopy allowed its comparison with analogous closed shell borohydride complexes. Ligand-field theory was used to model the electronic transitions in the Ni(II) complex successfully, although it was less successful at reproducing the zero-field splitting (zfs) parameters. Advanced computational methods, both density functional theory (DFT) and ab initio wave function based approaches, were applied to these Tp*MBH(4) complexes to better understand the interaction between these metals and borohydride ion. DFT successfully reproduced bonding geometries and vibrational behavior of the complexes, although it was less successful for the spin Hamiltonian parameters of the open shell Ni(II) complex. These were instead best described using ab initio methods. The origin of the zfs in Tp*Ni(κ(3)-BH(4)) is described and shows that the relatively small magnitude of D results from several spin-orbit coupling (SOC) interactions of large magnitude, but with opposite sign. Spin-spin coupling (SSC) is also shown to be significant, a point that is not always appreciated in transition metal complexes. Overall, a picture of bonding and electronic structure in open and closed shell late transition metal borohydrides is provided, which has implications for the use of these complexes in catalysis and

  1. Capacity enhancement of aqueous borohydride fuels for hydrogen storage in liquids

    SciTech Connect

    Schubert, David; Neiner, Doinita; Bowden, Mark; Whittemore, Sean; Holladay, Jamie; Huang, Zhenguo; Autrey, Tom

    2015-10-01

    In this work we demonstrate enhanced hydrogen storage capacities through increased solubility of sodium borate product species in aqueous media achieved by adjusting the sodium (NaOH) to boron (B(OH)3) ratio, i.e., M/B, to obtain a distribution of polyborate anions. For a 1:1 mole ratio of NaOH to B(OH)3, M/B = 1, the ratio of the hydrolysis product formed from NaBH4 hydrolysis, the sole borate species formed and observed by 11B NMR is sodium metaborate, NaB(OH)4. When the ratio is 1:3 NaOH to B(OH)3, M/B = 0.33, a mixture of borate anions is formed and observed as a broad peak in the 11B NMR spectrum. The complex polyborate mixture yields a metastable solution that is difficult to crystallize. Given the enhanced solubility of the polyborate mixture formed when M/B = 0.33 it should follow that the hydrolysis of sodium octahydrotriborate, NaB3H8, can provide a greater storage capacity of hydrogen for fuel cell applications compared to sodium borohydride while maintaining a single phase. Accordingly, the hydrolysis of a 23 wt% NaB3H8 solution in water yields a solution having the same complex polyborate mixture as formed by mixing a 1:3 molar ratio of NaOH and B(OH)3 and releases >8 eq of H2. By optimizing the M/B ratio a complex mixture of soluble products, including B3O3(OH)52-, B4O5(OH)42-, B3O3(OH)4-, B5O6(OH)4- and B(OH)3, can be maintained as a single liquid phase throughout the hydrogen release process. Consequently, hydrolysis of NaB3H8 can provide a 40% increase in H2 storage density compared to the hydrolysis of NaBH4 given the decreased solubility of sodium metaborate. The authors would like to thank Jim Sisco and Paul Osenar of

  2. The alkaline and alkaline-carbonatite magmatism from Southern Brazil

    NASA Astrophysics Data System (ADS)

    Ruberti, E.; Gomes, C. D. B.; Comin-Chiaramonti, P.

    2015-12-01

    Early to Late Cretaceous lasting to Paleocene alkaline magmatism from southern Brazil is found associated with major extensional structural features in and around the Paraná Basin and grouped into various provinces on the basis of several data. Magmatism is variable in size, mode of occurrence and composition. The alkaline rocks are dominantly potassic, a few occurrences showing sodic affinity. The more abundant silicate rocks are evolved undersaturated to saturated in silica syenites, displaying large variation in igneous forms. Less evolved types are restricted to subvolcanic environments and outcrops of effusive suites occur rarely. Cumulatic mafic and ultramafic rock types are very common, particularly in the alkali-carbonatitic complexes. Carbonatite bodies are represented by Ca-carbonatites and Mg-carbonatites and more scarcely by Fe-carbonatites. Available radiometric ages for the alkaline rocks fit on three main chronological groups: around 130 Ma, subcoveal with the Early Cretaceous flood tholeiites of the Paraná Basin, 100-110 Ma and 80-90 Ma (Late Cretaceous). The alkaline magmatism also extends into Paleocene times, as indicated by ages from some volcanic lavas. Geochemically, alkaline potassic and sodic rock types are distinguished by their negative and positive Nb-Ta anomalies, respectively. Negative spikes in Nb-Ta are also a feature common to the associated tholeiitic rocks. Sr-Nd-Pb systematics confirm the contribution of both HIMU and EMI mantle components in the formation of the alkaline rocks. Notably, Early and Late Cretaceous carbonatites have the same isotopic Sr-Nd initial ratios of the associated alkaline rocks. C-O isotopic Sr-Nd isotopic ratios indicate typical mantle signature for some carbonatites and the influence of post-magmatic processes in others. Immiscibility of liquids of phonolitic composition, derived from mafic alkaline parental magmas, has been responsible for the origin of the carbonatites. Close association of alkaline

  3. Formation of Rod Shape Secondary Aggregation of Copper Nanoparticles in Aqueous Solution of Sodium Borohydride with Stabilizing Polymer

    NASA Astrophysics Data System (ADS)

    Harada, Takuya; Fujiwara, Hidemichi

    2007-03-01

    Morphological variations of copper nanoparticles synthesized by the reduction of copper acetate with sodium borohydride in the presence of poly(N-vinyl-2-pyrrolidone) (PVP) have been investigated. The results indicate that the specific rod shape secondary aggregation of copper nanoparticles are formed in the case that the oxygen is dissolved in the reacting solutions. Furthermore, it is also demonstrated that the copper nanorods with the aspect ratio of 2 - 20 and the average short axis length of 5 nm are synthesized in the weak oxidizing ambiance with a medium amount of PVP. The anomalous variations of copper nanoparticles are explained by the alignments of precursor copper ions and their reducing rates, which are modified by the density of resolved oxygen and the amount of PVP.

  4. Microscale Interface Synthesis of Ni-B Amorphous Nanoparticles from NiSO4 by Sodium Borohydride Reduction in Microreactor

    NASA Astrophysics Data System (ADS)

    Xu, Lei; Peng, Jinhui; Meng, Binfang; Li, Wei; Liu, Bingguo; Luo, Huilong

    2016-09-01

    Amorphous nanoparticles have attracted a large amount of interest due to their superior catalytic activity and unique selectivity. The Ni-B amorphous nanoparticles were synthesized from aqueous reduction of NiSO4 by sodium borohydride in microscale interface at room temperature. The size, morphology, elemental compositions, and the chemical composition on the surface of Ni-B amorphous nanoparticles were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). All the results showed that the synthesized particles are Ni-B amorphous nanoparticles with uniform in size distribution and having good dispersion. The mean particle diameter of Ni-B amorphous nanoparticles was around 9 nm. The present work provides an alternative synthesis route for the Ni-B amorphous nanoparticles.

  5. Desialylated alkaline phosphatase: activation by 4-nitrophenol.

    PubMed

    Nayudu, P R

    1984-01-01

    Mouse ileal alkaline phosphatase is a sialyl enzyme (12-14 moles per mole of enzyme). When partially desialylated by treatment with neuraminidase, the enzyme loses most of its activity, associated with reduced apparent Vmax and Km. Part of that loss, however, is recovered as the product 4-nitrophenol's concentration builds up in the cuvette. Experimental results are presented to demonstrate that the activation is due to the binding of 4-nitrophenol as a ligand by the partially desialylated enzyme and that both the loss of activity by sialic acid removal and activation by ligand-binding are correlated with changes in protein conformation.

  6. Electroless Plated Co-Ni-P-B/Ni Foam Catalyst for Hydrogen Generation from Sodium Borohydride.

    PubMed

    Park, Daeil; Kim, Taegyu

    2016-02-01

    Co-Ni-P-B catalyst supported on Ni foam was prepared using electroless plating for hydrogen generation from an alkaline NaBH4 solution. Co-B, Co-P-B, and Co-Ni-B were prepared for comparison. Surface morphology of catalyst/Ni foams were observed using SEM analysis. The Co- Ni-P-B/Ni foam catalyst showed the superior performance on hydrogen generation rate due to the uniform formation of catalyst particles on the surface of Ni foam. Characteristics of hydrogen generation rate on the Co-N-P-B/Ni foam catalyst were investigated at the variety of NaBH4 and NaOH concentrations. The hydrogen generation rate increased with decreasing NaBH4 concentration, while increasing NaOH concentration. Durability test was performed, resulting in the stable hydrogen generation for 6 hours.

  7. Alkaline post-treatment of Cd(II)-glutathione coordination polymers: toward green synthesis of water-soluble and cytocompatible CdS quantum dots with tunable optical properties.

    PubMed

    Huang, Pengcheng; Jiang, Qin; Yu, Ping; Yang, Lifen; Mao, Lanqun

    2013-06-12

    In this study, we demonstrate a facile and environmentally friendly method for the synthesis of glutathione (GSH)-capped water-soluble CdS quantum dots (QDs) with a high cytocompatibility and a tunable optical property based on alkaline post-treatment of Cd-GSH coordination polymers (CPs). Cd-GSH CPs are synthesized with the coordination reaction of Cd(2+) with GSH at different pH values, and the CdS QDs are then formed by adding NaOH to the aqueous dispersion of the Cd-GSH CPs to break the coordination interaction between Cd(2+) and GSH with the release of sulfur. The particle size and optical property of the as-formed CdS QDs are found to be easily tailored by simply adjusting the starting pH values of GSH solutions used for the formation of Cd-GSH CPs, in which the wavelengths of trap-state emission of the QDs red-shift with an increase in the sizes of the QDs that is caused by an increase in the starting pH values of GSH solutions. In addition, the use of GSH as the capping reagent eventually endows the as-formed CdS QDs with enhanced water solubility and good cytocompatibility, as demonstrated with HeLa cells. The method demonstrated here is advantageous in that the cadmium precursor and the sulfur source are nontoxic and easily available, and the size, optical properties, water solubility, and cytocompatibilty of the as-formed CdS QDs are simply achieved and experimentally regulated. This study offers a new and green synthetic route to water-soluble and cytocompatible CdS QDs with tunable optical properties.

  8. Zinc electrode in alkaline electrolyte

    SciTech Connect

    McBreen, J.

    1995-12-31

    The zinc electrode in alkaline electrolyte is unusual in that supersaturated zincate solutions can form during discharge and spongy or mossy zinc deposits can form on charge at low overvoltages. The effect of additives on regular pasted ZnO electrodes and calcium zincate electrodes is discussed. The paper also reports on in situ x-ray absorption (XAS) results on mossy zinc deposits.

  9. [Alkaline phosphatase in Amoeba proteus].

    PubMed

    Sopina, V A

    2005-01-01

    In free-living Amoeba proteus (strain B), 3 phosphatase were found after disc-electrophoresis of 10 microg of protein in PAGE and using 1-naphthyl phosphate as a substrate a pH 9.0. These phosphatases differed in their electrophoretic mobilities - "slow" (1-3 bands), "middle" (one band) and "fast" (one band). In addition to 1-naphthyl phosphate, "slow" phosphatases were able to hydrolyse 2-naphthyl phosphate and p-nitrophenyl phosphate. They were slightly activated by Mg2+, completely inhibited by 3 chelators (EDTA, EGTA and 1,10-phenanthroline), L-cysteine, sodium dodecyl sulfate and Fe2+, Zn2+ and Mn2+ (50 mM), considerably inactivated by orthovanadate, molybdate, phosphatase inhibitor cocktail 1, p-nitrophenyl phosphate, Na2HPO4, DL-dithiothreitol and urea and partly inhibited by H2O2, DL-phenylalanine, 2-mercaptoethanol, phosphatase inhibitor cocktail 2 and Ca2+. Imidazole, L-(+)-tartrate, okadaic acid, NaF and sulfhydryl reagents -p-(hydroxy-mercuri)benzoate and N-ethylmaleimide - had no influence on the activity of "slow" phosphatases. "Middle" and "fast" phosphatases, in contrast to "slow" ones, were not inactivated by 3 chelators. The "middle" phosphatase differed from the "fast" one by smaller resistance to urea, Ca2+, Mn2+, phosphates and H2O2 and greater resistance to dithiothreitol and L-(+)-tartrate. In addition, the "fast" phosphatase was inhibited by L-cysteine but the "middle" one was activated by it. Of 5 tested ions (Mg2+, Cu2+, Mn2+, Ca2+ and Zn2+), only Zn2+ reactivated "slow" phosphatases after their inactivation by EDTA treatment. The reactivation of apoenzyme was only partial (about 35 %). Thus, among phosphatases found in amoebae at pH 9.0, only "slow" ones are Zn-metalloenzymes and may be considered as alkaline phosphatases (EC 3.1.3.1). It still remains uncertain, to which particular phosphatase class "middle" and "fast" phosphatases (pH 9.0) may belong.

  10. Trends in Syntheses, Structures, and Properties for Three Series of Ammine Rare-Earth Metal Borohydrides, M(BH4)3·nNH3 (M = Y, Gd, and Dy).

    PubMed

    Jepsen, Lars H; Ley, Morten B; Černý, Radovan; Lee, Young-Su; Cho, Young Whan; Ravnsbæk, Dorthe; Besenbacher, Flemming; Skibsted, Jørgen; Jensen, Torben R

    2015-08-03

    Fourteen solvent- and halide-free ammine rare-earth metal borohydrides M(BH4)3·nNH3, M = Y, Gd, Dy, n = 7, 6, 5, 4, 2, and 1, have been synthesized by a new approach, and their structures as well as chemical and physical properties are characterized. Extensive series of coordination complexes with systematic variation in the number of ligands are presented, as prepared by combined mechanochemistry, solvent-based methods, solid-gas reactions, and thermal treatment. This new synthesis approach may have a significant impact within inorganic coordination chemistry. Halide-free metal borohydrides have been synthesized by solvent-based metathesis reactions of LiBH4 and MCl3 (3:1), followed by reactions of M(BH4)3 with an excess of NH3 gas, yielding M(BH4)3·7NH3 (M = Y, Gd, and Dy). Crystal structure models for M(BH4)3·nNH3 are derived from a combination of powder X-ray diffraction (PXD), (11)B magic-angle spinning NMR, and density functional theory (DFT) calculations. The structures vary from two-dimensional layers (n = 1), one-dimensional chains (n = 2), molecular compounds (n = 4 and 5), to contain complex ions (n = 6 and 7). NH3 coordinates to the metal in all compounds, while BH4(-) has a flexible coordination, i.e., either as a terminal or bridging ligand or as a counterion. M(BH4)3·7NH3 releases ammonia stepwise by thermal treatment producing M(BH4)3·nNH3 (6, 5, and 4), whereas hydrogen is released for n ≤ 4. Detailed analysis of the dihydrogen bonds reveals new insight about the hydrogen elimination mechanism, which contradicts current hypotheses. Overall, the present work provides new general knowledge toward rational materials design and preparation along with limitations of PXD and DFT for analysis of structures with a significant degree of dynamics in the structures.

  11. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, David B.; Lao, Guifang

    1998-01-01

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium.

  12. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, D.B.; Lao, G.

    1998-01-06

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium. 3 figs.

  13. Electrocatalytic activities of alkyne-functionalized copper nanoparticles in oxygen reduction in alkaline media

    NASA Astrophysics Data System (ADS)

    Liu, Ke; Song, Yang; Chen, Shaowei

    2014-12-01

    Stable alkyne-capped copper nanoparticles were prepared by chemical reduction of copper acetate with sodium borohydride in the presence of alkyne ligands. Transmission electron microscopic measurements showed that nanoparticles were well dispersed with a diameter in the range of 4-6 nm. FTIR and photoluminescence spectroscopic measurements confirmed the successful attachment of the alkyne ligands onto the nanoparticle surface most likely forming Cu-Ctbnd interfacial bonds. XPS measurements indicated the formation of a small amount of CuO in the nanoparticles with a satellite peak where the binding energy red-shifted with increasing Cu(II) concentration. Cu2O was also detected in the nanoparticles. Similar results were observed with commercial CuO nanoparticles. Electrochemical studies showed that the as-prepared alkyne-capped copper nanoparticles exhibited apparent electrocatalytic activity in oxygen reduction in alkaline media, a performance that was markedly better than those reported earlier with poly- or single-crystalline copper electrodes; and the fraction of peroxides in the final products decreased with decreasing concentration of oxide components in the nanoparticles.

  14. The secondary alkaline zinc electrode

    NASA Astrophysics Data System (ADS)

    McLarnon, Frank R.; Cairns, Elton J.

    1991-02-01

    The worldwide studies conducted between 1975 and 1990 with the aim of improving cell lifetimes of secondary alkaline zinc electrodes are overviewed. Attention is given the design features and characteristics of various secondary alkaline zinc cells, including four types of zinc/nickel oxide cell designs (vented static-electrolyte, sealed static-electrolyte, vibrating-electrode, and flowing-electrolyte); two types of zinc/air cells (mechanically rechargeable consolidated-electrode and mechanically rechargeable particulate-electrode); zinc/silver oxide battery; zinc/manganese dioxide cell; and zinc/ferric cyanide battery. Particular consideration is given to recent research in the fields of cell thermodynamics, zinc electrodeposition, zinc electrodissolution, zinc corrosion, electrolyte properties, mathematical and phenomenological models, osmotic pumping, nonuniform current distribution, and cell cycle-life perforamnce.

  15. Development of alkaline fuel cells.

    SciTech Connect

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassovs research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herrings group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  16. Silver nanoparticles-containing dual-function hydrogels based on a guar gum-sodium borohydride system

    PubMed Central

    Dai, Lei; Nadeau, Ben; An, Xingye; Cheng, Dong; Long, Zhu; Ni, Yonghao

    2016-01-01

    Dual-function hydrogels, possessing both stimuli-responsive and self-healing properties, have recently attracted attention of both chemists and materials scientists. Here we report a new paradigm using natural polymer (guar gum, GG) and sodium borohydride (NaBH4), for the preparation of silver nanoparticles (AgNPs)-containing smart hydrogels in a simple, fast and economical way. NaBH4 performs as a reducing agent for AgNPs synthesis using silver nitrate (AgNO3) as the precursor. Meanwhile, sodium metaborate (NaBO2) (from NaBH4) behaves as a cross-linking agent between GG molecular chains. The AgNPs/GG hydrogels with excellent viscoelastic properties can be obtained within 3 min at room temperature without the addition of other cross-linkers. The resultant AgNPs/GG hydrogels are flowable and injectable, and they possess excellent pH/thermal responsive properties. Additionally, they exhibit rapid self-healing capacity. This work introduces a facile and scale-up way to prepare a class of hydrogels that can have great potential to biomedical and other industrial applications. PMID:27819289

  17. Enhanced activity of Au-Fe/C anodic electrocatalyst for direct borohydride-hydrogen peroxide fuel cell

    NASA Astrophysics Data System (ADS)

    Yi, Lanhua; Wei, Wei; Zhao, Caixian; Tian, Li; Liu, Jing; Wang, Xianyou

    2015-07-01

    Carbon supported Au-Fe bimetallic nanocatalysts (Au-Fe/C) are facilely prepared via a modified NaBH4 reduction method in aqueous solution at room temperature, and used as the anode electrocatalyst of direct borohydride-hydrogen peroxide fuel cell (DBHFC). The physical and electrochemical properties of the Au-Fe/C electrocatalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), cyclic voltammetry (CV), rotating disc electrode (RDE) voltammetry, chronoamperometry (CA), chronopotentiometry (CP), and fuel cell test. The results show that Au-Fe/C catalysts display higher catalytic activity for the direct electrooxidation of BH4- than carbon supported pure Au nanocatalyst (Au/C), especially Au50Fe50/C catalyst presents the highest catalytic activity among all as-prepared catalysts. Besides, the single DBHFC with Au50Fe50/C anode and Au/C cathode obtains the maximum power density as high as 34.9 mW cm-2 at 25 °C.

  18. Low-cost method for sodium borohydride regeneration and the energy efficiency of its hydrolysis and regeneration process

    NASA Astrophysics Data System (ADS)

    Ouyang, L. Z.; Zhong, H.; Li, Z. M.; Cao, Z. J.; Wang, H.; Liu, J. W.; Zhu, X. K.; Zhu, M.

    2014-12-01

    Hydrolysis of sodium borohydride (NaBH4) is one of the most attractive methods for energy generation of mobile systems used as hydrogen source because of the high gravimetric density and controllable hydrogen generation of NaBH4. However, regeneration of NaBH4 is a key issue that remains to be solved, and the energy efficiency of NaBH4 is unknown. In the present study, the energy efficiency of NaBH4 hydrolysis and the entire process of sodium metaborate (NaBO2) regeneration via reaction with magnesium hydride (MgH2) is determined through thermodynamics calculations. The maximum energy efficiency is 49.91%, indicating that NaBH4 generation by reaction between MgH2 and NaBO2 during ball milling is feasible. An inexpensive high-energy ball milling method is employed to regenerate NaBH4 by reaction of NaBO2 with magnesium-lanthanum hydrides (H-Mg3La). Products after ball milling are characterized through Fourier transform infrared spectroscopy and X-ray diffraction measurements. In the reaction of NaBO2 with H-Mg3La, MgH2 reacts with NaBO2 and then lanthanum hydride (LaH3) reacts with NaBO2 to produce NaBH4.

  19. Priming effect of abscisic acid on alkaline stress tolerance in rice (Oryza sativa L.) seedlings.

    PubMed

    Wei, Li-Xing; Lv, Bing-Sheng; Wang, Ming-Ming; Ma, Hong-Yuan; Yang, Hao-Yu; Liu, Xiao-Long; Jiang, Chang-Jie; Liang, Zheng-Wei

    2015-05-01

    Saline-alkaline stress is characterized by high salinity and high alkalinity (high pH); alkaline stress has been shown to be the primary factor inhibiting rice seedling growth. In this study, we investigated the potential priming effect of abscisic acid (ABA) on tolerance of rice seedlings to alkaline stress simulated by Na2CO3. Seedlings were pretreated with ABA at concentrations of 0 (control), 10, and 50 μM by root-drench for 24 h and then transferred to a Na2CO3 solution that did not contain ABA. Compared to control treatment, pretreatment with ABA substantially improved the survival rate of rice seedlings and increased biomass accumulation after 7 days under the alkaline condition. ABA application at 10 μM also alleviated the inhibitory effects of alkaline stress on the total root length and root surface area. Physiologically, ABA increased relative water content (RWC) and decreased cell membrane injury degree (MI) and Na(+)/K(+) ratios. In contrast, fluridone (an ABA biosynthesis inhibitor) decreased the RWC and increased MI in shoots under the alkaline conditions. These data suggest that ABA has a potent priming effect on the adaptive response to alkaline stress in rice and may be useful for improving rice growth in saline-alkaline paddy fields.

  20. Inhibition of renal alkaline phosphatase by cimetidine.

    PubMed

    Minai-Tehrani, Dariush; Khodai, Somayeh; Aminnaseri, Somayeh; Minoui, Saeed; Sobhani-Damavadifar, Zahra; Alavi, Sana; Osmani, Raheleh; Ahmadi, Shiva

    2011-08-01

    Alkaline phosphatase (ALP) belongs to hydrolase group of enzymes. It is responsible for removing phosphate groups from many types of molecules, including nucleotides and proteins. Cimetidine (trade name Tagamet) is an antagonist of histamine H2-receptor that inhibits the production of gastric acid. Cimetidine is used for the treatment of gastrointestinal diseases. In this study the inhibitory effect of cimetidine on mouse renal ALP activity was investigated. Our results showed that cimetidine can inhibit ALP by uncompetitive inhibition. In the absence of inhibitor the V(max) and K(m) of the enzyme were found to be 13.7 mmol/mg prot.min and 0.25 mM, respectively. Both the Vmax and Km of the enzyme decreased with increasing cimetidine concentrations (0- 1.2 mM). The Ki and IC(50) of cimetidine were determined to be about 0.5 mM and 0.52 mM, respectively.

  1. Release of bound procyanidins from cranberry pomace by alkaline hydrolysis.

    PubMed

    White, Brittany L; Howard, Luke R; Prior, Ronald L

    2010-07-14

    Procyanidins in plant products are present as extractable or unextractable/bound forms. We optimized alkaline hydrolysis conditions to liberate procyanidins and depolymerize polymers from dried cranberry pomace. Alkaline extracts were neutralized (pH 6-7) and then procyanidins were extracted with ethyl acetate and analyzed by normal phase high performance liquid chromatography. Alkaline hydrolysis resulted in an increase in low molecular weight procyanidins, and the increase was greater at higher temperature, short time combinations. The most procyanidins (DP1-DP3) were extracted at 60 degrees C for 15 min with each concentration of NaOH. When compared to conventional extraction using homogenization with acetone/water/acetic acid (70:29.5:0.5 v/v/v), treatment with NaOH increased procyanidin oligomer extraction by 3.8-14.9-fold, with the greatest increase being DP1 (14.9x) and A-type DP2 (8.4x) procyanidins. Alkaline treatment of the residue remaining after conventional extraction resulted in further procyanidin extraction, indicating that procyanidins are not fully extracted by conventional extraction methods.

  2. Diclofenac salts. III. Alkaline and earth alkaline salts.

    PubMed

    Fini, Adamo; Fazio, Giuseppe; Rosetti, Francesca; Angeles Holgado, M; Iruín, Ana; Alvarez-Fuentes, Josefa

    2005-11-01

    Diclofenac salts containing the alkaline and two earth alkaline cations have been prepared and characterized by scanning electron microscopy (SEM) and EDAX spectroscopy; and by thermal and thermogravimetric analysis (TGA): all of them crystallize as hydrate when precipitated from water. The salts dehydrate at room temperature and more easily on heating, but recovery the hydration, when placed in a humid environment. X-ray diffraction spectra suggest that on dehydration new peaks appear on diffractograms and the lattice of the salts partially looses crystallinity. This phenomenon is readily visible in the case of the calcium and magnesium salts, whose thermograms display a crystallization exotherm, before melting or decomposing at temperatures near or above 200 degrees C; these last salts appear to form solvates, when prepared from methanol. The thermogram of each salt shows a complex endotherm of dehydration about 100 degrees C; the calcium salt displays two endotherms, well separated at about 120 and 160 degrees C, which disappear after prolonged heating. Decomposition exotherms, before or soon after the melting, appear below 300 degrees C. The ammonium salt is thermally unstable and, when heated to start dehydration, dissociates and leaves acidic diclofenac.

  3. Alkaline fuel cell performance investigation

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more that two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  4. Transformation and composition evolution of nanoscale zero valent iron (nZVI) synthesized by borohydride reduction in static water.

    PubMed

    Liu, Airong; Liu, Jing; Zhang, Wei-Xian

    2015-01-01

    The reactivity of nanoscale zero valent iron (nZVI) toward targeted contaminants is affected by the initial nZVI composition and the iron oxides formed during the aging process in aquatic systems. In this paper, the aging effects of nZVI, prepared using a borohydride reduction method in static water over a period of 90 days (d), are investigated. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy are used to characterize the corrosion products of nZVI. Results show that both the structures and the compositions of the corrosion products change with the process of aging. The products of nZVI aged for 5 d in static water media are mainly magnetite (Fe3O4) and maghemite (γ-Fe2O3), accompanied by lepidocrocite (γ-FeOOH). For products aged 10 d, XRD data show the formation of ferrihydrite and lepidocrocite. When aged up to 90 d, the products are mainly γ-FeOOH mixed with small amounts of Fe3O4 and γ-Fe2O3. Transmission electronic microscopy (TEM) images show that the core-shell structure forms into a hollow spherical shape after 30 d of aging in aquatic media. The results indicate first that iron ions in the Fe(0) core diffuse outwardly toward the shell, and hollowed-out iron oxide shells emerge. Then, the iron oxide shell collapses and becomes a flaky, acicular-shaped structure. The type and the crystal phase of second iron oxide minerals are vastly different at various aging times. This study helps to explain the patterns of occurrence of specific iron oxides in different natural conditions.

  5. Alkaline detergent recycling via ultrafiltration

    SciTech Connect

    Steffani, C.; Meltzer, M.

    1995-06-01

    The metal finishing industry uses alkaline cleaners and detergents to remove oils and dirt from manufactured parts, often before they are painted or plated. The use of these cleaners has grown because environmental regulations are phasing out ozone depleting substances and placing restrictions on the use and disposal of many hazardous solvents. Lawrence Livermore National Laboratory is examining ultrafiltration as a cleaning approach that reclaims the cleaning solutions and minimizes wastes. The ultrafiltration membrane is made from sheets of polymerized organic film. The sheets are rolled onto a supporting frame and installed in a tube. Spent cleaning solution is pumped into a filter chamber and filtered through the membrane that captures oils and dirt and allows water and detergent to pass. The membrane is monitored and when pressure builds from oil and dirt, an automatic system cleans the surface to maintain solution flow and filtration quality. The results show that the ultrafiltration does not disturb the detergent concentration or alkalinity but removed almost all the oils and dirt leaving the solution in condition to be reused.

  6. Clonal Integration Enhances the Performance of a Clonal Plant Species under Soil Alkalinity Stress

    PubMed Central

    Sun, Juanjuan; Chen, Jishan; Zhang, Yingjun

    2015-01-01

    Clonal plants have been shown to successfully survive in stressful environments, including salinity stress, drought and depleted nutrients through clonal integration between original and subsequent ramets. However, relatively little is known about whether clonal integration can enhance the performance of clonal plants under alkalinity stress. We investigated the effect of clonal integration on the performance of a typical rhizomatous clonal plant, Leymus chinensis, using a factorial experimental design with four levels of alkalinity and two levels of rhizome connection treatments, connected (allowing integration) and severed (preventing integration). Clonal integration was estimated by comparing physiological and biomass features between the rhizome-connected and rhizome-severed treatments. We found that rhizome-connected treatment increased the biomass, height and leaf water potential of subsequent ramets at highly alkalinity treatments but did not affect them at low alkalinity treatments. However, rhizome-connected treatment decreased the root biomass of subsequent ramets and did not influence the photosynthetic rates of subsequent ramets. The biomass of original ramets was reduced by rhizome-connected treatment at the highest alkalinity level. These results suggest that clonal integration can increase the performance of clonal plants under alkalinity stress. Rhizome-connected plants showed dramatically increased survival of buds with negative effects on root weight, indicating that clonal integration influenced the resource allocation pattern of clonal plants. A cost-benefit analysis based on biomass measures showed that original and subsequent ramets significantly benefited from clonal integration in highly alkalinity stress, indicating that clonal integration is an important adaptive strategy by which clonal plants could survive in local alkalinity soil. PMID:25790352

  7. Clonal integration enhances the performance of a clonal plant species under soil alkalinity stress.

    PubMed

    Zhang, Wenjun; Yang, Gaowen; Sun, Juanjuan; Chen, Jishan; Zhang, Yingjun

    2015-01-01

    Clonal plants have been shown to successfully survive in stressful environments, including salinity stress, drought and depleted nutrients through clonal integration between original and subsequent ramets. However, relatively little is known about whether clonal integration can enhance the performance of clonal plants under alkalinity stress. We investigated the effect of clonal integration on the performance of a typical rhizomatous clonal plant, Leymus chinensis, using a factorial experimental design with four levels of alkalinity and two levels of rhizome connection treatments, connected (allowing integration) and severed (preventing integration). Clonal integration was estimated by comparing physiological and biomass features between the rhizome-connected and rhizome-severed treatments. We found that rhizome-connected treatment increased the biomass, height and leaf water potential of subsequent ramets at highly alkalinity treatments but did not affect them at low alkalinity treatments. However, rhizome-connected treatment decreased the root biomass of subsequent ramets and did not influence the photosynthetic rates of subsequent ramets. The biomass of original ramets was reduced by rhizome-connected treatment at the highest alkalinity level. These results suggest that clonal integration can increase the performance of clonal plants under alkalinity stress. Rhizome-connected plants showed dramatically increased survival of buds with negative effects on root weight, indicating that clonal integration influenced the resource allocation pattern of clonal plants. A cost-benefit analysis based on biomass measures showed that original and subsequent ramets significantly benefited from clonal integration in highly alkalinity stress, indicating that clonal integration is an important adaptive strategy by which clonal plants could survive in local alkalinity soil.

  8. Alkaline and alkaline earth metal phosphate halides and phosphors

    DOEpatents

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  9. Cultivation of marine shrimp in biofloc technology (BFT) system under different water alkalinities.

    PubMed

    Piérri, V; Valter-Severino, D; Goulart-de-Oliveira, K; Manoel-do-Espírito-Santo, C; Nascimento-Vieira, F; Quadros-Seiffert, W

    2015-08-01

    The aim of this study was to evaluate the influence of different levels of alkalinity for the superintensive cultivation of marine shrimp Litopenaeus vannamei in biofloc system. A total of 12 experimental circular units of 1000L were used supplied with 850L water from a nursery, populated at a density of 165 shrimps.m-3 and average weight of 5.6 g. The treatments, in triplicate, consisted in four levels of alkalinity in the water: 40, 80, 120 and 160 mg.L-1 of calcium carbonate. To correct the alkalinity was used calcium hydroxide (CaOH). It was observed a decrease in pH of the water in the treatments with lower alkalinity (p<0.05). The total suspended settleable solids were also lower in the treatment of low alkalinity. No significant difference was observed in other physico-chemical and biological parameters in the water quality assessed, as well as the zootechnical parameters of cultivation between treatments (p≥0.05). The results of survival and growth rate of shrimps were considered suitable for the cultivation system used in the different treatments. The cultivation of marine shrimp Litopenaeus vannamei in biofloc at density of 165 shrimps.m-3 can be performed in waters with alkalinity between 40 and 160 mg.L-1 of CaCO3, without compromising the zootechnical indexes of cultivation.

  10. Synthesis, structure and gas-phase reactivity of the mixed silver hydride borohydride nanocluster [Ag3(μ3-H)(μ3-BH4)LPh3]BF4 (LPh = bis(diphenylphosphino)methane)

    NASA Astrophysics Data System (ADS)

    Zavras, Athanasios; Ariafard, Alireza; Khairallah, George N.; White, Jonathan M.; Mulder, Roger J.; Canty, Allan J.; O'Hair, Richard A. J.

    2015-10-01

    Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3]+ are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(i) tetrafluoroborate and bis(dimethylphosphino)methane (LMe) or bis(diphenylphosphino)methane (LPh). By adding NaBH4 to an acetonitrile solution of AgBF4 and LPh, cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)LPh3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (LMe and LPh) and DFT calculations (LMe) reveal how loss of a ligand from the cationic complexes [Ag3(H)(BH4)L3]+ provides a change in geometry that facilitates subsequent loss of BH3 to produce the dihydride clusters, [Ag3(H)2Ln]+ (n = 1 and 2). Together with the results of previous studies (Girod et al., Chem. - Eur. J., 2014, 20, 16626), this provides a direct link between mixed silver hydride/borohydride nanoclusters, silver hydride nanoclusters, and silver nanoclusters.Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3]+ are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(i) tetrafluoroborate and bis(dimethylphosphino)methane (LMe) or bis(diphenylphosphino)methane (LPh). By adding NaBH4 to an acetonitrile solution of AgBF4 and LPh, cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)LPh3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (LMe and LPh) and DFT calculations (LMe) reveal how loss of a ligand from the cationic complexes [Ag

  11. Closed type alkaline storage battery

    SciTech Connect

    Hayama, H.

    1980-06-10

    The alkaline storage battery employs a metallic hat shaped terminal closure which has a piercing needle as well as a puncturable metallic diaphragm positioned below the piercing needle. The needle is fixed by caulking at its peripheral edge portion to a edge of the closure. A comparatively thick and hard metal plate is placed on the inner surface of the diaphragm and is applied to an open portion of a tubular metallic container which has a battery element. A peripheral edge portion of the closure, the diaphragm and the metallic plate are clamped in airtight relationship through a packing between the caulked end portion and an inner annular step portion of the metallic container of the battery. A lead wire extends from one polarity electrode of the battery element and is connected to a central portion of the metallic plate.

  12. Evolution of alkaline phosphatases in primates.

    PubMed Central

    Goldstein, D J; Rogers, C; Harris, H

    1982-01-01

    Alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum), EC 3.1.3.1] in placenta, intestine, liver, kidney, bone, and lung from a variety of primate species has been characterized by quantitative inhibition, thermostability, and immunological studies. Characteristic human placental-type alkaline phosphatase occurs in placentas of great apes (chimpanzee and orangutan) but not in placentas of other primates, including gibbon. It is also present in trace amounts in human lung but not in lung or other tissues of various Old and New World monkeys. However, a distinctive alkaline phosphatase resembling it occurs in substantial amounts in lungs from Old World monkeys but not New World monkeys. It appears that duplication of alkaline phosphatase genes and mutations of genetic elements controlling their tissue expression have occurred relatively recently in mammalian evolution. Images PMID:6950431

  13. Alkaline pH sensor molecules.

    PubMed

    Murayama, Takashi; Maruyama, Ichiro N

    2015-11-01

    Animals can survive only within a narrow pH range. This requires continual monitoring of environmental and body-fluid pH. Although a variety of acidic pH sensor molecules have been reported, alkaline pH sensor function is not well understood. This Review describes neuronal alkaline pH sensors, grouped according to whether they monitor extracellular or intracellular alkaline pH. Extracellular sensors include the receptor-type guanylyl cyclase, the insulin receptor-related receptor, ligand-gated Cl- channels, connexin hemichannels, two-pore-domain K+ channels, and transient receptor potential (TRP) channels. Intracellular sensors include TRP channels and gap junction channels. Identification of molecular mechanisms underlying alkaline pH sensing is crucial for understanding how animals respond to environmental alkaline pH and how body-fluid pH is maintained within a narrow range.

  14. Process for extracting technetium from alkaline solutions

    DOEpatents

    Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.

    1995-01-01

    A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

  15. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  16. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2003-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  17. Process for treating alkaline wastes for vitrification

    SciTech Connect

    Hsu, Chia-lin W.

    1994-01-01

    According to its major aspects and broadly stated, the present invention is a process for treating alkaline waste materials, including high level radioactive wastes, for vitrification. The process involves adjusting the pH of the wastes with nitric acid, adding formic acid (or a process stream containing formic acid) to reduce mercury compounds to elemental mercury and MnO{sub 2} to the Mn(II) ion, and mixing with class formers to produce a melter feed. The process minimizes production of hydrogen due to noble metal-catalyzed formic acid decomposition during, treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product. An important feature of the present invention is the use of different acidifying and reducing, agents to treat the wastes. The nitric acid acidifies the wastes to improve yield stress and supplies acid for various reactions; then the formic acid reduces mercury compounds to elemental mercury and MnO{sub 2}) to the Mn(II) ion. When the pH of the waste is lower, reduction of mercury compounds and MnO{sub 2}) is faster and less formic acid is needed, and the production of hydrogen caused by catalytically-active noble metals is decreased.

  18. Process for treating alkaline wastes for vitrification

    DOEpatents

    Hsu, Chia-lin W.

    1995-01-01

    A process for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO.sub.2 to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO.sub.2, noble metal compounds, nitrates, formates and so forth. The process minimizes the amount of hydrogen generated during treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product.

  19. Process for treating alkaline wastes for vitrification

    DOEpatents

    Hsu, C.L.W.

    1995-07-25

    A process is described for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO{sub 2} to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO{sub 2}, noble metal compounds, nitrates, formates and so forth. The process minimizes the amount of hydrogen generated during treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product. 4 figs.

  20. Alkaline tolerant dextranase from streptomyces anulatus

    DOEpatents

    Decker, Stephen R.; Adney, William S.; Vinzant, Todd B.; Himmel, Michael E.

    2003-01-01

    A process for production of an alkaline tolerant dextranase enzyme comprises culturing a dextran-producing microorganism Streptomyces anulatus having accession no. ATCC PTA-3866 to produce an alkaline tolerant dextranase, Dex 1 wherein the protein in said enzyme is characterized by a MW of 63.3 kDa and Dex 2 wherein its protein is characterized by a MW of 81.8 kDa.

  1. Technetium recovery from high alkaline solution

    DOEpatents

    Nash, Charles A.

    2016-07-12

    Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

  2. Toxicity of alkalinity to Hyalella azteca

    USGS Publications Warehouse

    Lasier, P.J.; Winger, P.V.; Reinert, R.E.

    1997-01-01

    Toxicity testing and chemical analyses of sediment pore water have been suggested for use in sediment quality assessments and sediment toxicity identification evaluations. However, caution should be exercised in interpreting pore-water chemistry and toxicity due to inherent chemical characteristics and confounding relationships. High concentrations of alkalinity, which are typical of sediment pore waters from many regions, have been shown to be toxic to test animals. A series of tests were conducted to assess the significance of elevated alkalinity concentrations to Hyalella azteca, an amphipod commonly used for sediment and pore-water toxicity testing. Toxicity tests with 14-d old and 7-d old animals were conducted in serial dilutions of sodium bicarbonate (NaHCO3) solutions producing alkalinities ranging between 250 to 2000 mg/L as CaCO3. A sodium chloride (NaCl) toxicity test was also conducted to verify that toxicity was due to bicarbonate and not sodium. Alkalinity was toxic at concentrations frequently encountered in sediment pore water. There was also a significant difference in the toxicity of alkalinity between 14-d old and 7-d old animals. The average 96-h LC50 for alkalinity was 1212 mg/L (as CaCO3) for 14-d old animals and 662 mg/L for the younger animals. Sodium was not toxic at levels present in the NaHCO3 toxicity tests. Alkalinity should be routinely measured in pore-water toxicity tests, and interpretation of toxicity should consider alkalinity concentration and test-organism tolerance.

  3. De Novo Transcriptional Analysis of Alfalfa in Response to Saline-Alkaline Stress

    PubMed Central

    An, Yi-Min; Song, Li-Li; Liu, Ying-Rui; Shu, Yong-Jun; Guo, Chang-Hong

    2016-01-01

    Saline-alkaline stress, caused by high levels of harmful carbonate salts and high soil pH, is a major abiotic stress that affects crop productivity. Alfalfa is a widely cultivated perennial forage legume with some tolerance to biotic and abiotic stresses, especially to saline-alkaline stress. To elucidate the mechanism underlying plant saline-alkaline tolerance, we conducted transcriptome analysis of whole alfalfa seedlings treated with saline-alkaline solutions for 0 day (control), 1 day (short-term treatment), and 7 days (long-term treatment) using ion torrent sequencing technology. A transcriptome database dataset of 53,853 unigenes was generated, and 2,286 and 2,233 genes were differentially expressed in the short-term and long-term treatment, respectively. Gene ontology analysis revealed 14 highly enriched pathways and demonstrated the differential response of metabolic pathways between the short-term and long-term treatment. The expression levels of 109 and 96 transcription factors were significantly altered significantly after 1 day and 7 days of treatment, respectively. Specific responses of peroxidase, flavonoids, and the light pathway component indicated that the antioxidant capacity was one of the central mechanisms of saline-alkaline stress tolerance response in alfalfa. Among the 18 differentially expressed genes examined by real time PCR, the expression levels of eight genes, including inositol transporter, DNA binding protein, raffinose synthase, ferritin, aldo/keto reductase, glutathione S-transferase, xyloglucan endotrans glucosylase, and a NAC transcription factor, exhibited different patterns in response to saline and alkaline stress. The expression levels of the NAC transcription factor and glutathione S-transferase were altered significantly under saline stress and saline-alkaline stress; they were upregulated under saline-alkaline stress and downregulated under salt stress. Physiology assays showed an increased concentration of reactive oxygen

  4. Alkaline Water and Longevity: A Murine Study

    PubMed Central

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models. PMID:27340414

  5. Performed surfactant-optimized aqueous alkaline flood

    SciTech Connect

    Thigpen, D.R.; Lawson, J.B.; Nelson, R.C.

    1991-11-26

    This paper describes improvement in a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system. The improvement comprises: selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is grater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system having a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.

  6. Application of microgels as polymer supports for organic synthesis: preparation of a small phthalide library, a scavenger, and a borohydride reagent.

    PubMed

    Shimomura, Osamu; Clapham, Bruce; Spanka, Carsten; Mahajan, Suresh; Janda, Kim D

    2002-01-01

    Microgel polymers containing a series of functional groups have been prepared. These microgels were composed of cross-linked poly(styrene) and were prepared by radical polymerization in solution. The microgel polymers exhibit good solubility in an array of different organic solvents, and in addition, they can be efficiently precipitated by the addition of methanol and isolated by filtration. A nine-member phthalide library was synthesized using an aminomethyl-functionalized microgel 5. To further demonstrate the versatility of these microgel polymers, tris(2-aminoethyl)amino microgel 11 was examined as a scavenger reagent to remove unreacted isocyanate after a urea synthesis. Finally, a microgel-supported ammonium borohydride reagent 14 was successfully prepared and used as a reducing agent. Notable features of these microgels are that in all applications the progress of the reaction could be monitored by standard NMR techniques and their preparation is performed using common glassware and techniques found in all organic laboratories.

  7. Physiological aspects of alkaline phosphatase in selected cyanobacteria.

    PubMed

    Doonan, B B; Jensen, T E

    1980-01-01

    The alkaline phosphatase of Plectonema boryanum shows a considerable increase in activity following placement of the cells in a phosphate free medium. Five days of phosphate starvation result in a 14-fold increase of alkaline phosphatase activity. Growth in the presence of inhibitors of transcription and translation indicate that the synthesis of the enzyme is de novo. Orthophosphate causes an immediate inhibition of enzyme activity. Enzyme was extracted from P. boryanum with lysozyme or polymyxin B treatment in order to make comparative studies of cell bound and cell free enzyme. Of several enzyme specific inhibitors tested, mercuric chloride was the most effective. Temperature studies showed that the cell bound enzyme was most active at 40 degrees C while the cell free enzyme was most active at 70 degrees C. The pH optimum was 9 for the cell free enzyme, and 8.8 for the cell bound. The enzyme was tested to determine if it could hydrolyse a number of different organic compounds. It hydrolysed p-nitrophenol phosphate 100%, fructose-6-phosphate 45%, beta-glycerol phosphate 25% and other compounds to a lesser degree. Of seventeen other Cyanobacteria tested for alkaline phosphatase, all were positive, and of these eleven were inducible for the enzyme. Ten of the isolates released some of the enzyme into the culture medium. Michaelis constants for the enzyme were also determined.

  8. β₂ adrenergic receptor activation suppresses bone morphogenetic protein (BMP)-induced alkaline phosphatase expression in osteoblast-like MC3T3E1 cells.

    PubMed

    Yamada, Takayuki; Ezura, Yoichi; Hayata, Tadayoshi; Moriya, Shuichi; Shirakawa, Jumpei; Notomi, Takuya; Arayal, Smriti; Kawasaki, Makiri; Izu, Yayoi; Harada, Kiyoshi; Noda, Masaki

    2015-06-01

    β adrenergic stimulation suppresses bone formation in vivo while its actions in osteoblastic differentiation are still incompletely understood. We therefore examined the effects of β2 adrenergic stimulation on osteoblast-like MC3T3-E1 cells focusing on BMP-induced alkaline phosphatase expression. Morphologically, isoproterenol treatment suppresses BMP-induced increase in the numbers of alkaline phosphatase-positive small foci in the cultures of MC3T3-E1 cells. Biochemically, isoproterenol treatment suppresses BMP-induced enzymatic activity of alkaline phosphatase in a dose-dependent manner. Isoproterenol suppression of alkaline phosphatase activity is observed even when the cells are treated with high concentrations of BMP. With respect to cell density, isoproterenol treatment tends to suppress BMP-induced increase in alkaline phosphatase expression more in osteoblasts cultured at higher cell density. In terms of treatment protocol, continuous isoproterenol treatment is compared to cyclic treatment. Continuous isoproterenol treatment is more suppressive against BMP-induced increase in alkaline phosphatase expression than cyclic regimen. At molecular level, isoproterenol treatment suppresses BMP-induced enhancement of alkaline phosphatase mRNA expression. Regarding the mode of isoproterenol action, isoproterenol suppresses BMP-induced BRE-luciferase activity. These data indicate that isoproterenol regulates BMP-induced alkaline phosphatase expression in osteoblast-like MC3T3E1 cells.

  9. The Martian ocean: First acid, then alkaline

    NASA Technical Reports Server (NTRS)

    Schaefer, M. W.

    1992-01-01

    In Mars' distant past, carbon dioxide and water may have been plentiful. Values of total outgassed CO2 from several to about 10 bar are consistent with present knowledge, and this amount of CO2 implies an amount of water outgassed equal to an equivalent depth of 500 to 1000 m. It is quite reasonable, therefore, to envision an early Mars in which there was a body or bodies of liquid water, perhaps in the northern plains, and a dense carbon dioxide atmosphere. Under such conditions, the pH of the water will be low, due to the dissolution of carbon dioxide in the water to form carbonic acid. This acidic water is capable of weathering the available rock quite intensely, particularly because this rock is likely to be heavily fractured (from meteorite bombardment) or even consist of fine particles (such as pyroclastic deposits). As time goes on, however, the carbon dioxide atmosphere will rapidly pass through the ocean to form carbonate deposits. As the density of the atmosphere decreases, so will the flux of carbonic acid into the ocean. Without this input of carbonic acid, the effect of the dissolved weathering products will be to increase the pH of the water. The ocean will then become alkaline. To study this process, I have developed a geochemical cycle model for the atmosphere-hydrosphere-regolith system of Mars. The treatment of geochemical cycles as complex kinetic chemical reactions has been undertaken for terrestrial systems in recent years with much success. This method is capable of elegantly handling the interactions between the simultaneous chemical reactions needed to understand such a system.

  10. Biochemical Localization of Alkaline Phosphatase in the Cell Wall of a Marine Pseudomonad

    PubMed Central

    Thompson, Linda M. M.; MacLeod, Robert A

    1974-01-01

    The various layers of the cell envelope of marine pseudomonad B-16 (ATCC 19855) have been separated from the cells and assayed directly for alkaline phosphatase activity under conditions established previously to be optimum for maintenance of the activity of the enzyme. Under conditions known to lead to the release of the contents of the periplasmic space from the cells, over 90% of the alkaline phosphatase was released into the medium. Neither the loosely bound outer layer nor the outer double-track layer (cell wall membrane) showed significant activity. A small amount of the alkaline phosphatase activity of the cells remained associated with the mureinoplasts when the outer layers of the cell wall were removed. Upon treatment of the mureinoplasts with lysozyme, some alkaline phosphatase was released into the medium and some remained with the protoplasts formed. Cells washed and suspended in 0.5 M NaCl were lysed by treatment with 2% toluene, and 95% of the alkaline phosphatase in the cells was released into the medium. Cells washed and suspended in complete salts solution (0.3 M NaCl, 0.05 M MgSO4, and 0.01 M KCl) or 0.05 M MgSO4 appeared intact after treatment with toluene but lost 50 and 10%, respectively, of their alkaline phosphatase. The results suggest that the presence of Mg2+ in the cell wall is necessary to prevent disruption of the cells by toluene and may also be required to prevent the release of alkaline phosphatase by toluene when disruption of the cells by toluene does not take place. PMID:4811547

  11. Leaching properties of electric arc furnace dust prior/following alkaline extraction.

    PubMed

    Orescanin, Visnja; Mikelić, Luka; Sofilić, Tahir; Rastovcan-Mioc, Alenka; Uzarević, Krunoslav; Medunić, Gordana; Elez, Loris; Lulić, Stipe

    2007-02-15

    This study was carried out to determine the appropriate treatment of electric arc furnace (EAF) dust prior to permanent disposal. The total heavy metal content as well as heavy metal leaching from EAF dust was investigated in five composite samples obtained from three Croatian and Slovenian steelworks. In order to recover zinc and reduce its leaching from the dust, all five samples were submitted to alkaline extraction with 10 M NaOH. Reduction of Cr (VI) to Cr(III) was conducted using FeSO4 x 7H2O solution. The elements Mn, Fe, Cu, Ni, and notably Zn and Pb, exhibited highest mobility during toxicity characteristic leaching procedure (TCLP). Comparing to TCLP extracts of initial EAF dust, zinc was found to be over 15 times lower and lead over 200 times lower in TCLP extracts of EAF dust processed by the alkaline leaching method. Since Cr (VI) exceeded its permissible level in the DIN 38414-S4 extracts of both initial and alkaline digested dust, its reduction to Cr (III) prior to permanent disposal is necessary. The recovery of zinc from EAF dust treated with alkaline agent ranged from 50.3% to 73.2%. According to phase analysis, recovery yield showed dependence on zincite/franklinite ratio. The results of the study indicate that permanent disposal of EAF dust require the following procedure: alkaline digestion (followed by leachate purification and alkaline zinc electrolyses), chromate reduction (if necessary), solidification of leaching residue and its testing using the leaching analyses.

  12. [Effects of exogenous spermidine on mitochondrial function of tomato seedling roots under salinity-alkalinity stress].

    PubMed

    Pan, Xiong-bo; Xiang, Li-xia; Hu, Xiao-hui; Ren, Wen-qi; Zhang, Li; Ni, Xin-xin

    2016-02-01

    Two cultivars of tomato (Solanum lycopersicum, cvs. 'Jinpengchaoguan' and 'Zhongza No. 9', with the former being more tolerant to saline-alkaline stress) seedlings grown hydroponically were subjected to salinity-alkalinity stress condition (NaCl: Na2SO4:NaHCO3:Na2CO3 = 1:9:9:1) without or with foliar application of 0.25 mmol . L-1 spermidine (Spd), and the root morphology and physiological characteristics of mitochondrial membrane were analyzed 8 days after treatment, to explore the protective effects of exogenous Spd on mitochondrial function in tomato roots under salinity-alkalinity stress. The results showed that the salinity-alkalinity stress increased the concentrations of both mitochondrial H2O2 and MDA as well as the mitochondrial membrane permeability in the roots of the two cultivars, while it decreased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity, which impaired the mitochondria and therefore inhibited the root growth; and these effects were more obvious in 'Zhongza No. 9' than in 'Jinpengechaoguan'. Under the salinity-alkalinity stress, foliar application Spd could effectively decrease the concentrations of mitochondrial H2O2 and MDA and mitochondrial membrane permeability, while increased the mitochondrial membrane fluidity, membrane potential, Cyt c/a and H+-ATPase activity. These results suggested that exogenous Spd could effectively mitigate the damage on mitochondria induced by salinity-alkalinity stress, and the alleviation effect was more obvious in 'Zhongza No. 9' than in 'Jinpengchaoguan'.

  13. The effect of alkaline additives on the performance of surfactant systems designed to recover light oils

    SciTech Connect

    French, T.R.; Josephson, C.B.; Evans, D.B.

    1991-02-01

    Surfactant flooding is flexible because of the ability to optimize formulations for a wide range of reservoir conditions and crude oil types. The objective for this work was to determine if the addition of alkaline additives will allow the design of surfactant formulations that are effective for the recovery of crude oil, while, at the same time, maintaining the surfactant concentration at a much lower level than has previously been used for micellar flooding. Specifically, the focus of the work was on light, midcontinent crudes that typically have very low acid contents. These oils are typical of much of the midcontinent resource. The positive effect of alkaline additives on the phase behavior of the surfactant formulations and acidic crude oils is well known. The extension to nonacidic and slightly acidic oils is not obvious. Three crude oils, a variety of commercial surfactants, and several alkaline additives were tested. The oils had acid numbers that ranged from 0.13, which is quite low, to less than 0.01 mg KOH/g of oil. Alkaline additives were found to be very effective in recovering Delaware-Childers (OK) oil at elevated temperatures, but much less effective at reservoir temperatures. Alkaline additives were very effective with Teapot Dome (WY) oil. With Teapot Dome oil, surfactant/alkali systems produced ultralow IFT values and recovered 60% of the residual oil that remained after waterflooding. The effect of alkaline additives on recovering Hepler (KS) oil was minimal. The results of this work indicate that alkaline additives do have merit for use in surfactant flooding of low acid crude oils; however, no universal statement about applicability can be made. Each oil behaves differently, with this treatment, and the effect of alkaline additives must be determined (at reservoir conditions) for each oil. 23 refs., 13 figs., 3 tabs.

  14. Intermediate range order in alkaline borate glasses

    NASA Astrophysics Data System (ADS)

    Crupi, C.; Carini, G.; Ruello, G.; D'Angelo, G.

    2016-03-01

    We describe the neutron diffraction patterns of a series of alkaline borate glasses at different metal oxide content. Strong differences are observed in the intermediate range order as a function of the specific alkaline ion and of its concentration. On these results, we propose that the first sharp diffraction peak arises from correlations of atoms of voids and show that the compositional variation of this peak intensity in alkaline borate glasses is due to changes in the distribution of void sizes within the three-dimensional network. We argue that our interpretation in terms of interstitial (empty and/or filled) voids, having different sizes, provides a general explanation for all anomalous behaviours revealed for the first sharp diffraction peak.

  15. A Constructed Alkaline Consortium and Its Dynamics in Treating Alkaline Black Liquor with Very High Pollution Load

    PubMed Central

    Yang, Chunyu; Cao, Guangchun; Li, Yang; Zhang, Xiaojun; Ren, Hongyan; Wang, Xia; Feng, Jinhui; Zhao, Liping; Xu, Ping

    2008-01-01

    Background Paper pulp wastewater resulting from alkaline extraction of wheat straw, known as black liquor, is very difficult to be treated and causes serious environmental problems due to its high pH value and chemical oxygen demand (COD) pollution load. Lignin, semicellulose and cellulose are the main contributors to the high COD values in black liquor. Very few microorganisms can survive in such harsh environments of the alkaline wheat straw black liquor. A naturally developed microbial community was found accidentally in a black liquor storing pool in a paper pulp mill of China. The community was effective in pH decreasing, color and COD removing from the high alkaline and high COD black liquor. Findings Thirty-eight strains of bacteria were isolated from the black liquor storing pool, and were grouped as eleven operational taxonomy units (OTUs) using random amplified polymorphic DNA-PCR profiles (RAPD). Eleven representative strains of each OTU, which were identified as genera of Halomonas and Bacillus, were used to construct a consortium to treat black liquor with a high pH value of 11.0 and very high COD pollution load of 142,600 mg l−1. After treatment by the constructed consortium, about 35.4% of color and 39,000 mg l−1 (27.3%) CODcr were removed and the pH decreased to 7.8. 16S rRNA gene polymerase chain reaction denaturant gradient gel electrophoresis (PCR-DGGE) and gas chromatography/mass spectrometry (GC/MS) analysis suggested a two-stage treatment mechanism to elucidate the interspecies collaboration: Halomonas isolates were important in the first stage to produce organic acids that contributed to the pH decline, while Bacillus isolates were involved in the degradation of lignin derivatives in the second stage under lower pH conditions. Conclusions/Significance Tolerance to the high alkaline environment and good controllability of the simple consortium suggested that the constructed consortium has good potential for black liquor treatment

  16. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

    SciTech Connect

    Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; Fountain, Mackenzie; Ralph, John; Hodge, David B.; Hegg, Eric L.

    2016-02-09

    Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10 h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin

  17. Effective alkaline metal-catalyzed oxidative delignification of hybrid poplar

    DOE PAGES

    Bhalla, Aditya; Bansal, Namita; Stoklosa, Ryan J.; ...

    2016-02-09

    Background: Strategies to improve copper-catalyzed alkaline hydrogen peroxide (Cu-AHP) pretreatment of hybrid poplar were investigated. These improvements included a combination of increasing hydrolysis yields, while simultaneously decreasing process inputs through (i) more efficient utilization of H2O2 and (ii) the addition of an alkaline extraction step prior to the metal-catalyzed AHP pretreatment. We hypothesized that utilizing this improved process could substantially lower the chemical inputs needed during pretreatment. Results: Hybrid poplar was pretreated utilizing a modified process in which an alkaline extraction step was incorporated prior to the Cu-AHP treatment step and H2O2 was added batch-wise over the course of 10more » h. Our results revealed that the alkaline pre-extraction step improved both lignin and xylan solubilization, which ultimately led to improved glucose (86 %) and xylose (95 %) yields following enzymatic hydrolysis. An increase in the lignin solubilization was also observed with fed-batch H2O2 addition relative to batch-only addition, which again resulted in increased glucose and xylose yields (77 and 93 % versus 63 and 74 %, respectively). Importantly, combining these strategies led to significantly improved sugar yields (96 % glucose and 94 % xylose) following enzymatic hydrolysis. In addition, we found that we could substantially lower the chemical inputs (enzyme, H2O2, and catalyst), while still maintaining high product yields utilizing the improved Cu-AHP process. This pretreatment also provided a relatively pure lignin stream consisting of ≥90 % Klason lignin and only 3 % xylan and 2 % ash following precipitation. Two-dimensional heteronuclear single-quantum coherence (2D HSQC) NMR and size-exclusion chromatography demonstrated that the solubilized lignin was high molecular weight (Mw ≈ 22,000 Da) and only slightly oxidized relative to lignin from untreated poplar. In conclusion: This study demonstrated that the fed

  18. An Investigation of Technologies for Hazardous Sludge Reduction at AFLC (Air Force Logistics Command) Industrial Waste Treatment Plants. Volume 1. Sodium Borohydride Treatment and Sludge Handling Technologies.

    DTIC Science & Technology

    1983-12-01

    to individual states provided they meet a set of standards and request the authority. Thirty-four states now have interim authorization. When a...A summary describing the technologies identified in the literature search is presented in Table 6. ~~9 4.,.0 *114 A~ 0. P %*.44, 4-.24 E-4 . . 41 .4...i Lu< ( 0 ce le C- LL.Lu ul U) zS t0 z #A z 0 -J 0 0 < p LS.’ 4,z P ac -2Lu < 5.4 Ia11 .j i-L LU Y. 230 4.4 Lfl U1 E- 90 Ln 0 4~ 04 I~ d~o %,0 0~ Ř

  19. Systemic and local effects of long-term exposure to alkaline drinking water in rats.

    PubMed

    Merne, M E; Syrjänen, K J; Syrjänen, S M

    2001-08-01

    Alkaline conditions in the oral cavity may be caused by a variety of stimuli, including tobacco products, antacids, alkaline drinking water or bicarbonate toothpaste. The effects of alkaline pH on oral mucosa have not been systematically studied. To assess the systemic (organ) and local (oral mucosal) effects of alkalinity, drinking water supplemented with Ca(OH)2 or NaOH, with pH 11.2 or 12 was administered to rats (n = 36) for 52 weeks. Tissues were subjected to histopathological examination; oral mucosal biopsy samples were also subjected to immunohistochemical (IHC) analyses for pankeratin, CK19, CK5, CK4, PCNA, ICAM-1, CD44, CD68, S-100, HSP 60, HSP70, and HSP90. At completion of the study, animals in the study groups had lower body weights (up to 29% less) than controls despite equal food and water intake, suggesting a systemic response to the alkaline treatment. The lowest body weight was found in rats exposed to water with the highest pH value and starting the experiment when young (6 weeks). No histological changes attributable to alkaline exposure occurred in the oral mucosa or other tissues studied. Alkaline exposure did not affect cell proliferation in the oral epithelium, as shown by the equal expression of PCNA in groups. The up-regulation of HSP70 protein expression in the oral mucosa of rats exposed to alkaline water, especially Ca(OH)2 treated rats, may indicate a protective response. Intercellular adhesion molecule-1 (ICAM-1) positivity was lost in 6/12 rats treated with Ca(OH)2 with pH 11.2, and loss of CD44 expression was seen in 3/6 rats in both study groups exposed to alkaline water with pH 12. The results suggest that the oral mucosa in rats is resistant to the effects of highly alkaline drinking water. However, high alkalinity may have some unknown systemic effects leading to growth retardation, the cause of which remains to be determined.

  20. Dairy products and the French paradox: Could alkaline phosphatases play a role?

    PubMed

    Lallès, Jean-Paul

    2016-07-01

    The French paradox - high saturated fat consumption but low incidence of cardiovascular disease (CVD) and mortality - is still unresolved and continues to be a matter of debate and controversy. Recently, it was hypothesised that the high consumption of dairy products, and especially cheese by the French population might contribute to the explanation of the French paradox, in addition to the "(red) wine" hypothesis. Most notably this would involve milk bioactive peptides and biomolecules from cheese moulds. Here, we support the "dairy products" hypothesis further by proposing the "alkaline phosphatase" hypothesis. First, intestinal alkaline phosphatase (IAP), a potent endogenous anti-inflammatory enzyme, is directly stimulated by various components of milk (e.g. casein, calcium, lactose and even fat). This enzyme dephosphorylates and thus detoxifies pro-inflammatory microbial components like lipopolysaccharide, making them unable to trigger inflammatory responses and generate chronic low-grade inflammation leading to insulin resistance, glucose intolerance, type-2 diabetes, metabolic syndrome and obesity, known risk factors for CVD. Various vitamins present in high amounts in dairy products (e.g. vitamins A and D; methyl-donors: folate and vitamin B12), and also fermentation products such as butyrate and propionate found e.g. in cheese, all stimulate intestinal alkaline phosphatase. Second, moulded cheeses like Roquefort contain fungi producing an alkaline phosphatase. Third, milk itself contains a tissue nonspecific isoform of alkaline phosphatase that may function as IAP. Milk alkaline phosphatase is present in raw milk and dairy products increasingly consumed in France. It is deactivated by pasteurization but it can partially reactivate after thermal treatment. Experimental consolidation of the "alkaline phosphatase" hypothesis will require further work including: systematic alkaline phosphatase activity measurements in dairy products, live dairy ferments and

  1. Systemic and local effects of long-term exposure to alkaline drinking water in rats

    PubMed Central

    Merne, Marina ET; Syrjänen, Kari J; Syrjänen, Stina M

    2001-01-01

    Alkaline conditions in the oral cavity may be caused by a variety of stimuli, including tobacco products, antacids, alkaline drinking water or bicarbonate toothpaste. The effects of alkaline pH on oral mucosa have not been systematically studied. To assess the systemic (organ) and local (oral mucosal) effects of alkalinity, drinking water supplemented with Ca(OH)2 or NaOH, with pH 11.2 or 12 was administered to rats (n = 36) for 52 weeks. Tissues were subjected to histopathological examination; oral mucosal biopsy samples were also subjected to immunohistochemical (IHC) analyses for pankeratin, CK19, CK5, CK4, PCNA, ICAM-1, CD44, CD68, S-100, HSP 60, HSP70, and HSP90. At completion of the study, animals in the study groups had lower body weights (up to 29% less) than controls despite equal food and water intake, suggesting a systemic response to the alkaline treatment. The lowest body weight was found in rats exposed to water with the highest pH value and starting the experiment when young (6 weeks). No histological changes attributable to alkaline exposure occurred in the oral mucosa or other tissues studied. Alkaline exposure did not affect cell proliferation in the oral epithelium, as shown by the equal expression of PCNA in groups. The up-regulation of HSP70 protein expression in the oral mucosa of rats exposed to alkaline water, especially Ca(OH)2 treated rats, may indicate a protective response. Intercellular adhesion molecule-1 (ICAM-1) positivity was lost in 6/12 rats treated with Ca(OH)2 with pH 11.2, and loss of CD44 expression was seen in 3/6 rats in both study groups exposed to alkaline water with pH 12. The results suggest that the oral mucosa in rats is resistant to the effects of highly alkaline drinking water. However, high alkalinity may have some unknown systemic effects leading to growth retardation, the cause of which remains to be determined. PMID:11493345

  2. Laser direct write of planar alkaline microbatteries

    NASA Astrophysics Data System (ADS)

    Arnold, C. B.; Kim, H.; Piqué, A.

    We are developing a laser engineering approach to fabricate and optimize alkaline microbatteries in planar geometries. The laser direct-write technique enables multicapability for adding, removing and processing material and provides the ability to pattern complicated structures needed for fabricating complete microbattery assemblies. In this paper, we demonstrate the production of planar zinc-silver oxide alkaline cells under ambient conditions. The microbattery cells exhibit 1.55-V open-circuit potentials, as expected for the battery chemistry, and show a flat discharge behavior under constant-current loads. High capacities of over 450 μAhcm-2 are obtained for 5-mm2 microbatteries.

  3. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    DOEpatents

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  4. Alkaline Capacitors Based on Nitride Nanoparticles

    NASA Technical Reports Server (NTRS)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  5. Evaluation of high solids alkaline pretreatment of rice straw.

    PubMed

    Cheng, Yu-Shen; Zheng, Yi; Yu, Chao Wei; Dooley, Todd M; Jenkins, Bryan M; VanderGheynst, Jean S

    2010-11-01

    Fresh-harvested, air-dried rice straw was pretreated at a water content of 5 g H(2)O/g straw using sodium hydroxide (NaOH) and compared to pretreatment at 10 g H(2)O/g straw by hydrated lime (Ca(OH)(2)). Full factorial experiments including parallel wash-only treatments were completed with both sources of alkali. The experiments were designed to measure the effects of alkaline loading and pretreatment time on delignification and sugar yield upon enzymatic hydrolysis. Reaction temperature was held constant at 95 degrees C for lime pretreatment and 55 degrees C for NaOH pretreatment. The range of delignification was 13.1% to 27.0% for lime pretreatments and was 8.6% to 23.1% for NaOH pretreatments. Both alkaline loading and reaction time had significant positive effects (p < 0.001) on delignification under the design conditions, but only alkaline loading had a significant positive effect on enzymatic hydrolysis. Treatment at higher temperature also improved delignification; delignification with water alone ranged from 9.9% to 14.5% for pretreatment at 95 degrees C, but there was little effect observed at 55 degrees C. Post-pretreatment washing of biomass was not necessary for subsequent enzymatic hydrolysis. Maximum glucose yields were 176.3 mg/g dried biomass (48.5% conversion efficiency of total glucose) in lime-pretreated and unwashed biomass and were 142.3 mg/g dried biomass (39.2% conversion efficiency of total glucose) in NaOH-pretreated and unwashed biomass.

  6. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    PubMed Central

    Schwalfenberg, Gerry K.

    2012-01-01

    This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine. PMID:22013455

  7. The alkaline diet: is there evidence that an alkaline pH diet benefits health?

    PubMed

    Schwalfenberg, Gerry K

    2012-01-01

    This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine.

  8. Redistribution of wastewater alkalinity with a microbial fuel cell to support nitrification of reject water.

    PubMed

    Modin, Oskar; Fukushi, Kensuke; Rabaey, Korneel; Rozendal, René A; Yamamoto, Kazuo

    2011-04-01

    In wastewater treatment plants, the reject water from the sludge treatment processes typically contains high ammonium concentrations, which constitute a significant internal nitrogen load in the plant. Often, a separate nitrification reactor is used to treat the reject water before it is fed back into the plant. The nitrification reaction consumes alkalinity, which has to be replenished by dosing e.g. NaOH or Ca(OH)(2). In this study, we investigated the use of a two-compartment microbial fuel cell (MFC) to redistribute alkalinity from influent wastewater to support nitrification of reject water. In an MFC, alkalinity is consumed in the anode compartment and produced in the cathode compartment. We use this phenomenon and the fact that the influent wastewater flow is many times larger than the reject water flow to transfer alkalinity from the influent wastewater to the reject water. In a laboratory-scale system, ammonium oxidation of synthetic reject water passed through the cathode chamber of an MFC, increased from 73.8 ± 8.9 mgN/L under open-circuit conditions to 160.1 ± 4.8 mgN/L when a current of 1.96 ± 0.37 mA (15.1 mA/L total MFC liquid volume) was flowing through the MFC. These results demonstrated the positive effect of an MFC on ammonium oxidation of alkalinity-limited reject water.

  9. Coupling the Alkaline-Surfactant-Polymer Technology and The Gelation Technology to Maximize Oil Production

    SciTech Connect

    Malcolm Pitts; Jie Qi; Dan Wilson; Phil Dowling; David Stewart; Bill Jones

    2005-12-01

    gel producing the greatest amount. Higher oil recovery could have been due to higher differential pressures across cores. Aluminum citrate-polyacrylamide gels, chromium acetate-polyacrylamide gels, silicate-polymer, and chromium-xanthan gum gels did not alter an alkaline-surfactant-polymer solution's ability to produce incremental oil. Incremental oil was reduced with the resorcinol-formaldehyde gel system. Total waterflood plus chemical flood oil recovery sequence recoveries were generally similar. Performance and produced polymer evaluation of four alkaline-surfactant-polymer projects concluded that only one of the projects could have benefited from combining the alkaline-surfactant-polymer and gelation technologies. Cambridge, the 1993 Daqing, Mellott Ranch, and the Wardlaw alkaline-surfacant-polymer floods were studied. An initial gel treatment followed by an alkaline-surfactant-polymer flood in the Wardlaw field would have been a benefit due to reduction of fracture flow.

  10. Negative Electrode For An Alkaline Cell

    DOEpatents

    Coco, Isabelle; Cocciantelli, Jean-Michel; Villenave, Jean-Jacques

    1998-07-14

    The present invention concerns a negative electrode for an alkaline cell, comprising a current collector supporting a paste containing an electrochemically active material and a binder, characterized in that said binder is a polymer containing hydrophilic and hydrophobic groups, said polymer being selected from an acrylic homopolymer, copolymer and terpolymer, an unsaturated organic acid copolymer and an unsaturated acid anhydride copolymer.

  11. Alkaline electrochemical cells and method of making

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    Equilibrated cellulose ether membranes of increased electrolytic conductivity for use as separators in concentrated alkaline electrochemical cells are investigated. The method of making such membranes by equilibration to the degree desired in an aqueous alkali solution mantained at a temperature below about 10 C is described.

  12. MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS

    EPA Science Inventory

    The paper gives results of bench-scale mechanistic studies of mercury/sorbent reactions that showed that mercuric chloride (HgC12) is readily adsorbed by alkaline sorbents, which may offers a less expensive alternative to the use of activated carbons. A laboratory-scale, fixed-b...

  13. Alkaline earth metal catalysts for asymmetric reactions.

    PubMed

    Kobayashi, Shū; Yamashita, Yasuhiro

    2011-01-18

    The group 2 alkaline earth metals calcium (Ca), strontium (Sr), and barium (Ba) are among the most common elements on Earth, abundant in both the sea and the Earth's crust. Although they are familiar in our daily lives, their application to organic synthesis has, so far, been limited. Some particularly useful properties of these elements include (i) low electronegativity, (ii) a stable oxidation state of +2, meaning that they can potentially form two covalent bonds with anions, and (iii) the ability to occupy a variety of coordination sites due to their large ionic radius. Furthermore, the alkaline earth metals, found between the group 1 and group 3 elements, show mild but significant Lewis acidity, which can be harnessed to control coordinative molecules via a Lewis acid-base interaction. Taken together, these characteristics make the metals Ca, Sr, and Ba very promising components of highly functionalized acid-base catalysts. In this Account, we describe the development of chiral alkaline earth metal catalysts for asymmetric carbon-carbon bond-forming reactions. Recently prepared chiral alkaline earth metal complexes have shown high diastereo- and enantioselectivities in fundamental and important chemical transformations. We chose chiral bisoxazoline (Box) derivatives bearing a methylene tether as a ligand for chiral modification. These molecules are very useful because they can covalently coordinate to alkaline earth metals in a bidentate fashion through deprotonation of the tether portion. It was found that chiral calcium-Box complexes could successfully promote catalytic asymmetric 1,4-addition and [3 + 2] cycloaddition reactions with high diastereo- and enantioselectivities. Both the calcium-Box complexes and chiral strontium-bis-sulfonamide and chiral barium-BINOLate complexes could catalyze asymmetric 1,4-addition reactions with high enantioselectivities. Furthermore, we designed a calcium-neutral coordinative ligand complex as a new type of chiral alkaline

  14. Use of natural mordenite to remove chromium (III) and to neutralize pH of alkaline waste waters.

    PubMed

    Córdova-Rodríguez, Valduvina; Rodríguez-Iznaga, Inocente; Acosta-Chávez, Raquel María; Chávez-Rivas, Fernando; Petranovskii, Vitalii; Pestryakov, Alexey

    2016-01-01

    The natural mordenite from Palmarito de Cauto deposit (PZ), Cuba, was studied in this work as an ion exchanger to remove Cr(3+) cations from alkaline aqueous solutions at different pH and chromium concentrations. The mordenite stability under cyclic treatment processes with alkaline solutions and its capacity to decrease the pH of the solutions was also analyzed. It was shown that PZ removes Cr(3+) ions from alkaline solutions, and it happens independently of the starting chromium concentration and the pH of the exchange solution used. This material has an important neutralizing effect on alkaline solutions, expressed in a significant pH decrease from the early stages of the treatments. For solutions with initial pH equal to 11, it decreases to a value of around seven. The stability of this material is not affected significantly after continuous cyclic treatment with NaOH solution, which shows that mordenite, in particular from Palmarito de Cauto deposit, has high stability in alkaline solutions. The results are important as they suggest that natural zeolites may be of interest in treatments of alkaline industrial waste effluents.

  15. Crystal structure of alkaline cellulase K: insight into the alkaline adaptation of an industrial enzyme.

    PubMed

    Shirai, T; Ishida, H; Noda, J; Yamane, T; Ozaki, K; Hakamada, Y; Ito, S

    2001-07-27

    The crystal structure of the catalytic domain of alkaline cellulase K was determined at 1.9 A resolution. Because of the most alkaliphilic nature and it's highest activity at pH 9.5, it is used commercially in laundry detergents. An analysis of the structural bases of the alkaliphilic character of the enzyme suggested a mechanism similar to that previously proposed for alkaline proteases, that is, an increase in the number of Arg, His, and Gln residues, and a decrease in Asp and Lys residues. Some ion pairs were formed by the gained Arg residues, which is similar to what has been found in the alkaline proteases. Lys-Asp ion pairs are disfavored and partly replaced with Arg-Asp ion pairs. The alkaline adaptation appeared to be a remodeling of ion pairs so that the charge balance is kept in the high pH range.

  16. Osseous plate alkaline phosphatase is anchored by GPI.

    PubMed

    Pizauro, J M; Ciancaglini, P; Leone, F A

    1994-02-01

    Alkaline phosphatase activity was released up to 100% from the membrane by using 0.1 U of phosphatidylinositol-specific phospholipase C from B. thuringiensis. The M(r) of solubilized enzyme was 145,000 by Sephacryl S-300 gel filtration and 66,000 by SDS-PAGE, suggesting a dimeric structure. Solubilization of the membrane-bound enzyme with phospholipase C did not destroy its ability to hydrolyze p-nitrophenyl phosphate (PNPP) (264.3 mumol min-1 mg-1),ATP (42.0 mumol min-1 mg-1) and pyrophosphate (28.4 mumol min-1 mg-1). The hydrolysis of ATP and PNPP by solubilized enzyme exhibited "Michaelian" kinetics with K0.5 = 70 and 979 microM, respectively. For pyrophosphate, K0.5 was 128 microM and site-site interactions were observed (n = 1.4). Magnesium ions were stimulatory (Kd = 1.5 mM) but zinc ions were powerful non-competitive inhibitors (Kd = 6.2 microM) of solubilized enzyme. Treatment of solubilized alkaline phosphatase with Chellex 100 reduced the original PNPPase activity to 5%. Cobalt (K0.5 = 10.1 microM), magnesium (K0.5 = 29.5 microM) and manganese ions (K0.5 = 5 microM) restored the activity of the apoenzyme with positive cooperativity, suggesting that phosphatidylinositol-specific phospholipase C-solubilized alkaline phosphatase is a metalloenzyme. The stimulation of the apoenzyme by calcium ions (K0.5 = 653 microM) was lower than that observed for the other ions (26%) and exhibited site-site interactions (n = 0.7). Zinc ions had no effect on the apoenzyme of the solubilized enzyme.

  17. Ionized alkaline water: new strategy for management of metabolic acidosis in experimental animals.

    PubMed

    Abol-Enein, Hassan; Gheith, Osama A; Barakat, Nashwa; Nour, Eman; Sharaf, Abd-Elhameed

    2009-06-01

    Metabolic acidosis can occur as a result of either the accumulation of endogenous acids or loss of bicarbonate from the gastrointestinal tract or the kidney, which represent common causes of metabolic acidosis. The appropriate treatment of acute metabolic acidosis has been very controversial. Ionized alkaline water was not evaluated in such groups of patients in spite of its safety and reported benefits. So, we aimed to assess its efficacy in the management of metabolic acidosis in animal models. Two models of metabolic acidosis were created in dogs and rats. The first model of renal failure was induced by ligation of both ureters; and the second model was induced by urinary diversion to gut (gastrointestinal bicarbonate loss model). Both models were subjected to ionized alkaline water (orally and by hemodialysis). Dogs with renal failure were assigned to two groups according to the type of dialysate utilized during hemodialysis sessions, the first was utilizing alkaline water and the second was utilizing conventional water. Another two groups of animals with urinary diversion were arranged to receive oral alkaline water and tap water. In renal failure animal models, acid-base parameters improved significantly after hemodialysis with ionized alkaline water compared with the conventional water treated with reverse osmosis (RO). Similar results were observed in urinary diversion models as there was significant improvement of both the partial pressure of carbon dioxide and serum bicarbonate (P = 0.007 and 0.001 respectively) after utilizing alkaline water orally. Alkaline ionized water can be considered as a major safe strategy in the management of metabolic acidosis secondary to renal failure or dialysis or urinary diversion. Human studies are indicated in the near future to confirm this issue in humans.

  18. Hydrogen generation from the hydrolysis of sodium borohydride using chemically modified multiwalled carbon nanotubes with pyridinium based ionic liquid and decorated with highly dispersed Mn nanoparticles

    NASA Astrophysics Data System (ADS)

    Chinnappan, Amutha; Puguan, John Marc C.; Chung, Wook-Jin; Kim, Hern

    2015-10-01

    Multiwalled carbon nanotubes (MWCNTs)/Ionic liquid (IL)/Mn nanohybrids are synthesized and their catalytic activity is examined for hydrogen generation from the hydrolysis of sodium borohydride (NaBH4). Transmission electron microscopy reveals that Mn nanoparticles well-distributed on the MWCNTs surface. Energy dispersive x-ray spectrometer and x-ray photoelectron spectroscopy confirms the presence of Mn and Ni atom in the nanohybrids. The nanohybrids exhibit excellent catalytic lifetime and gives the total turnover number of 18496 mol H2/mol catalyst in the hydrolysis of NaBH4, which can be attributed to the presence of Mn atom and IL containing nickel halide anion. It is worthy of note that a very small amount of catalyst is used for this hydrolysis reaction. The activation energy is found to be 40.8 kJ/mol by MWCNTs/IL/Mn nanohybrids from the kinetic study of the hydrogen generation from the hydrolysis of NaBH4. The improved hydrogen generation rate, lower activation energy, and less expensive make the nanohybrids promising candidate as catalyst for the hydrogen generation from NaBH4 solution. The nanohybrids are easy to prepare, store and yet catalytically active. The recycling process is very simple and further purification is not tedious.

  19. Ag/g-C3N4 catalyst with superior catalytic performance for the degradation of dyes: a borohydride-generated superoxide radical approach.

    PubMed

    Fu, Yongsheng; Huang, Ting; Zhang, Lili; Zhu, Junwu; Wang, Xin

    2015-08-28

    A straightforward approach is developed for fabrication of a visible-light-driven Ag/g-C3N4 catalyst. Morphological observation shows that the g-C3N4 sheets are decorated with highly dispersed Ag nanoparticles having an average size of 5.6 nm. The photocatalytic activity measurements demonstrate that the photocatalytic degradation rates of methyl orange (MO), methylene blue (MB), and neutral dark yellow GL (NDY-GL) over Ag/g-C3N4-4 can reach up to 98.2, 99.3 and 99.6% in the presence of borohydride ions (BH4(-)) only with 8, 45, and 16 min visible light irradiation, respectively. The significant enhancement in photoactivity of the catalyst is mainly attributed to the high dispersity and smaller size of Ag nanoparticles, the strong surface plasmon resonance (SPR) effect of metallic Ag nanoparticles, the efficient separation of photogenerated charge carriers, the additional superoxide radicals (O) generated from the reduction of dissolved oxygen in the presence of BH4(-) and the synergistic effect of Ag nanoparticles and g-C3N4.

  20. The sulphate-reduction alkalinity pump tested

    NASA Astrophysics Data System (ADS)

    Meister, Patrick; Petrishcheva, Elena

    2016-04-01

    Carbonate precipitation has been suggested to be induced by alkalinity increase during sulphate reduction under anoxic conditions. This mechanism may explain the formation of carbonate deposits in shallow marine environments, either within a redox stratified sediment inhabited by phototrophic microbial mats or in shallow water within the photic zone where sulphidic water is upwelling onto the shelf. The alkalinity pump may work as long as the sulphide is not reoxidized to sulphate, a process that would acidify the surrounding. The alkalinity effect of sulphate reduction was recently tested by Aloisi (2008) for microbial mats using a model approach. He found that sulphate reduction does not significantly increase or even decrease carbonate saturation and is unlikely to have played a significant role through Earth history. The model considers many environmental factors, including the effect of carbonate precipitation itself on the carbonate equilbrium and on the alkalinity. We used a modified version of Aloisi's (2008) model to simulate the saturation states of aragonite, calcite and dolomite without the effects of carbonate precipitation. This is necessary to evaluate the effect of microbial metabolisms exclusively on carbonate saturation, since carbonate precipitation is only the consequence, but not the cause of oversaturation. First results show that the saturation state is increased in the zone of phototrophic CO2 uptake. In contrast, the saturation state is strongly decreased in the zone where dissolved oxygen overlaps with dissolved sulphide. Aerobic sulphide oxidation consumes most of the HS- and dissipates most of the alkalinity produced in the sulphate reduction zone below. Hence, our results are consistent with the findings of Aloisi (2008), and they even more clearly show that sulphate reduction does not induce carbonate precipitation nor contributes to carbonate precipitation in combination with phototrophic CO2 uptake. The alkalinity effect of sulphate

  1. [Leucocyte alkaline phosphatase in normal and pathological pregnancy (author's transl)].

    PubMed

    Stark, K H; Zaki, I; Sobolewski, K

    1981-01-01

    The activities of leucocyte alkaline phosphatase were determined in 511 patients with normal and pathological pregnancy. Mean values were compared and the enzyme followed up, and the conclusion was drawn that leucocyte alkaline phosphatase was no safe indicator of foetal condition. No direct relationship were found to exist between leucocyte alkaline phosphatase, total oestrogens, HSAP, HLAP, HPL, and oxytocinase.

  2. Activity of an alkaline 'cleaner' in the inactivation of the scrapie agent.

    PubMed

    Baier, M; Schwarz, A; Mielke, M

    2004-05-01

    The capacity of a routinely available alkaline cleaner for medical devices to inactivate the causative agent of a transmissible spongiform encephalopathy (TSE) was tested. The co-incubation of brain homogenates, prepared from terminally ill scrapie-infected hamsters, with the cleaner led to the denaturation of misfolded protein as the proteinase K-resistant prion protein was no longer detectable after such treatment. In addition, intra-cerebral inoculation of hamsters with the alkaline cleaner-treated and subsequently neutralized samples reduced the level of infectivity of the material below the limit of detection. This report shows the possibility that a routinely available alkaline cleaner could reduce the infectivity of TSE agents and so minimize the risk of iatrogenic transmission of TSEs by asymptomatic carriers. This study is intended to encourage further investigations in this field.

  3. Bovine Intestinal Alkaline Phosphatase Reduces Inflammation After Induction of Acute Myocardial Infarction in Mice

    PubMed Central

    Fiechter, Danielle; Kats, Suzanne; Brands, Ruud; van Middelaar, Ben; Pasterkamp, Gerard; de Kleijn, Dominique; Seinen, Willem

    2011-01-01

    Background There has been increasing evidence suggesting that lipopolysaccharide or endotoxin may be an important activator of the innate immune system after acute myocardial infarction. Bovine intestinal alkaline phosphatase reduces inflammation in several endotoxin mediated diseases by dephosphorylation of the lipid A moiety of lipopolysaccharide. The aim of this study was to investigate the effect of bovine intestinal alkaline phosphatase on reducing inflammation after acute myocardial infarction. Methods Just before permanent ligation of the left anterior descending coronary (LAD) artery to induce acute myocardial infarction in Balb/c mice, bovine intestinal alkaline phosphatase (bIAP) was administrated intravenously. After 4 hours, mice were sacrificed and the inflammatory response was assessed. Acute myocardial infarction induced the production of different cytokines, which were measured in blood. Results Treatment with bovine intestinal alkaline phosphatase resulted in a significant reduction of the pro-inflammatory cytokines IL-6, IL-1β and the chymase mouse mast cell protease-1. No difference in the production of the anti-inflammatory cytokine IL-10 was observed between the control group and the bovine intestinal alkaline phosphatase treated group. Conclusion In a mouse model of permanent LAD coronary artery ligation, bIAP diminishes the pro-inflammatory responses but does not have an effect on the anti-inflammatory response in the acute phase after acute myocardial infarction.

  4. Characterization of Schistosome Tegumental Alkaline Phosphatase (SmAP)

    PubMed Central

    Bhardwaj, Rita; Skelly, Patrick J.

    2011-01-01

    Schistosomes are parasitic platyhelminths that currently infect over 200 million people globally. The parasites can live for years in a putatively hostile environment - the blood of vertebrates. We have hypothesized that the unusual schistosome tegument (outer-covering) plays a role in protecting parasites in the blood; by impeding host immunological signaling pathways we suggest that tegumental molecules help create an immunologically privileged environment for schistosomes. In this work, we clone and characterize a schistosome alkaline phosphatase (SmAP), a predicted ∼60 kDa glycoprotein that has high sequence conservation with members of the alkaline phosphatase protein family. The SmAP gene is most highly expressed in intravascular parasite life stages. Using immunofluorescence and immuno-electron microscopy, we confirm that SmAP is expressed at the host/parasite interface and in internal tissues. The ability of living parasites to cleave exogenous adenosine monophosphate (AMP) and generate adenosine is very largely abolished when SmAP gene expression is suppressed following RNAi treatment targeting the gene. These results lend support to the hypothesis that schistosome surface enzymes such as SmAP could dampen host immune responses against the parasites by generating immunosuppressants such as adenosine to promote their survival. This notion does not rule out other potential functions for the adenosine generated e.g. in parasite nutrition. PMID:21483710

  5. Efficiency of alkaline hydrolysis method in environment protection.

    PubMed

    Kricka, Tajana; Toth, Ivan; Kalambura, Sanja; Jovicić, Nives

    2014-06-01

    Development of new technologies for the efficient use of proteins of animal origin, apart from heat treatment in rendering facilities that was used to date, has become the primary goal of the integral waste management system. The emergence of bovine spongiform encephalopathy in Europe and in the World in the 1990s opened up new questions regarding medical safety and use of meat bone meal in the animal feed, which is produced by processing animal waste. Animal waste is divided into three categories, out of which the first category is high-risk waste. Alkaline hydrolysis is alternative method for management of animal by-products not intended for human diet and imposes itself as one of the solutions for disposal of high-risk proteins. The paper will present the analyses of animal by-products not intended for human diet treated in laboratory reactor for alkaline hydrolysis, as one of the two recognized methods in EU for the disposal of this type of material and use in fertilization.

  6. High-risk biodegradable waste processing by alkaline hydrolysis.

    PubMed

    Kalambura, Sanja; Voća, Neven; Krička, Tajana; Sindrak, Zoran; Spehar, Ana; Kalambura, Dejan

    2011-09-01

    Biodegradable waste is by definition degraded by other living organisms. Every day, meat industry produces large amounts of a specific type of biodegradable waste called slaughterhouse waste. Traditionally in Europe, this waste is recycled in rendering plants which produce meat and bone meal and fat. However, feeding animals with meat and bone meal has been banned since the outbreaks of bovine spongiform encephalopathy (BSE). In consequence, new slaughterhouse waste processing technologies have been developed, and animal wastes have now been used for energy production. Certain parts of this waste, such as brains and spinal cord, are deemed high-risk substances, because they may be infected with prions. Their treatment is therefore possible only in strictly controlled conditions. One of the methods which seems to bear acceptable health risk is alkaline hydrolysis. This paper presents the results of an alkaline hydrolysis efficiency study. It also proposes reuse of the obtained material as organic fertiliser, as is suggested by the analytical comparison between meat and bone meal and hydrolysate.

  7. Electrocatalysis of carbon black- or poly(diallyldimethylammonium chloride)-functionalized activated carbon nanotubes-supported Pd-Tb towards methanol oxidation in alkaline media

    NASA Astrophysics Data System (ADS)

    Wang, Li; Wang, Yi; Li, An; Yang, Yunshang; Tang, Qinghu; Cao, Hongbin; Qi, Tao; Li, Changming

    2014-07-01

    The Pd-Tb/C catalysts with different Pd/Tb ratios were synthesized by a simple simultaneous reduction reaction with sodium borohydride in aqueous solution. The structure and morphology of those catalysts had been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrocatalytic performance of those catalysts for methanol oxidation in alkaline media was investigated using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and CO stripping experiments. It is found that the 20%Pd-1%Tb/C catalyst has a higher catalytic activity than the 20%Pd/C catalyst, but the effect of Tb cannot be explained by a bi-functional mechanism. According to the X-Ray photoelectron spectroscopy (XPS) analyses, it is suggested that the higher content of metallic Pd caused by the addition of Tb contributes to the better catalytic activity of 20%Pd-1%Tb/C. Based on the good electrocatalytic performance of 20%Pd-1%Tb/C, the 20%Pd-1%Tb catalyst supported on poly(diallyldimethylammonium chloride) (PDDA)-functionalized activated carbon nanotubes was prepared, and it exhibits a better catalytic activity. The improvement mainly results from the further increase of metallic Pd due to the presence of PDDA.

  8. Surfactant-enhanced alkaline flooding field project

    SciTech Connect

    French, T.R.

    1991-10-01

    The Tucker sand of Helper (KS) field is a candidate for surfactant-enhanced alkaline flooding. The geology of the Helper site is typical of many DOE Class I reservoirs. The Tucker sand of Helper field was deposited in a fluvial dominated deltaic environment. Helper oil can be mobilized with either chemical system 2 or chemical system 3, as described in this report. Oil fields in the Gulf Coast region are also good candidates for surfactant-enhanced alkaline flooding. The results from laboratory tests conducted in Berea sandstone cores with oil brine from Helper (KS) field are encouraging. The crude oil is viscous and non-acidic and, yet, was mobilized by the chemical formulations described in this report. Significant amounts of the oil were mobilized under simulated reservoir conditions. The results in Berea sandstone cores were encouraging and should be verified by tests with field core. Consumption of alkali, measured with field core, was very low. Surfactant loss appeared to be acceptable. Despite the good potential for mobilization of Helper oil, certain reservoir characteristics such as low permeability, compartmentalization, and shallow depth place constraints on applications of any chemical system in the Tucker sand. These constraints are typical of many DOE Class I reservoirs. Although Hepler field is not a perfect reservoir in which to apply surfactant- enhanced alkaline flooding, Hepler oil is particularly amenable to mobilization by surfactant-enhanced alkaline systems. A field test is recommended, dependent upon final evaluation of well logs and cores from the proposed pilot area. 14 refs., 21 figs., 10 tabs.

  9. The alkaline earth intercalates of molybdenum disulfide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.; Samson, S.; Woollam, J. A.

    1975-01-01

    Molybdenum disulfide has been intercalated with calcium and strontium by means of the liquid ammonia technique. Chemical, X-ray, and superconductivity data are presented. The X-ray data reveal a lowering of crystal symmetry and increase of complexity of the structure upon intercalation with the alkaline earth metals. The Ca and Sr intercalates start to superconduct at 4 and 5.6 K, respectively, and show considerable anisotropy regarding the critical magnetic field.

  10. Alkaline earth cation extraction from acid solution

    DOEpatents

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  11. Oxidation catalysts on alkaline earth supports

    DOEpatents

    Mohajeri, Nahid

    2017-03-21

    An oxidation catalyst includes a support including particles of an alkaline earth salt, and first particles including a palladium compound on the support. The oxidation catalyst can also include precious metal group (PMG) metal particles in addition to the first particles intermixed together on the support. A gas permeable polymer that provides a continuous phase can completely encapsulate the particles and the support. The oxidation catalyst may be used as a gas sensor, where the first particles are chemochromic particles.

  12. Inhibition of Alkaline Phosphatase by Several Diuretics

    DTIC Science & Technology

    1980-01-01

    August 20th, 1979) . . Summary , . Acetazolamide, furosemide, ethacrynic acid and chlorothiazide, diuretics of considerable structural diversity, inhibit...Ki is calculated to be 8.4, 7.0, 2.8 and 0.1 mmol/l for acetazolamide, furosemide, ethacrynic acid and chlorothiazide, respectively. Chlorothiazide...is a much more potent inhibitor of alkaline phos- phatase than the other three diuretics. The combination of ethacrynic acid and cysteine, itself an

  13. Alkaline flooding for enhanced oil recovery

    SciTech Connect

    Gittler, W.E.

    1983-09-01

    There are over 12 active projects of varying size using one of 3 major types of alkaline agents. These include sodium silicate, caustic soda, and soda ash. Among the largest pilots currently is the THUMS project in the Wilmington field, California. Plans called for the injection of a 4% weight concentration of sodium orthosilicate over a 60% PV. Through the first 3 yr, over 27 million bbl of chemicals have been injected. Gulf Oil is operating several alkaline floods, one of which is located off shore in the Quarantine Bay field, Louisiana. In this pilot, sodium hydroxide in a weight concentration of 5 to 12% is being injected. Belco Petroleum Corp. has reported that their pilot operating in the Isenhour Unit in Wyoming is using a .5% weight concentration of soda ash in conjunction with a polymer. Other uses for alkaline agents in chemical flooding include the use of silicate as a preflush or sacrificial agent in micellar/polymer and surfactant recovery systems. In addition, caustic has been tested in the surface-mixed caustic emulsion process while orthosilicate has been tested in a recovery method known as mobility-controlled caustic floods.

  14. Alkaline phosphatase of Physarum polycephalum is insoluble.

    PubMed

    Furuhashi, Kiyoshi

    2008-02-01

    The plasmodia of Physarum polycephalum grow as multinucleated cells in the presence of sufficient humidity and nutriment. Under non-illuminating conditions, stresses such as low temperature or high concentrations of salts transform the plasmodia into spherules whereas dehydration induces sclerotization. Some phosphatases including protein phosphatase and acid phosphatase have been purified from the plasmodia, but alkaline phosphatase remains to be elucidated. Phosphatase of the plasmodia, spherules and sclerotia was visualized by electrophoresis gel-staining assay using 5-bromo-4-chloro-3-indolyl phosphate. Insoluble fractions of the sclerotia were abundant in phosphatase activity. The phosphatase which was extracted by nonionic detergent was subjected to column chromatography and preparative electrophoresis. Purified phosphatase showed the highest activity at pH 8.8, indicating that this enzyme belongs to alkaline phosphatase. The apparent molecular mass from sodium dodecyl sulfate-polyacrylamide gel electrophoresis under non-reducing condition was estimated to be 100 kDa whereas that under reducing was 105 kDa. An amount of 1% sodium dodecyl sulfate or 0.5 M NaCl had no effects on the activity although the phosphatase showed heat instability, Mg(2+)-dependency and sensitivity to 2-glycerophosphate or NaF. The extracting conditions and enzymatic properties suggest that this alkaline phosphatase which is in a membrane-bound form plays important roles in phosphate metabolism.

  15. Limits for alkaline detoxification of dilute-acid lignocellulose hydrolysates.

    PubMed

    Nilvebrant, Nils-Olof; Persson, Per; Reimann, Anders; De Sousa, Filipe; Gorton, Lo; Jönsson, Leif J

    2003-01-01

    In addition to fermentable sugars, dilute-acid hydrolysates of lignocellulose contain compounds that inhibit fermenting microorganisms, such as Saccharomyces cerevisiae. Previous results show that phenolic compounds and furan aldehydes, and to some extent aliphatic acids, act as inhibitors during fermentation of dilute-acid hydrolysates of spruce. Treatment of lignocellulose hydrolysates with alkali, usually in the form of overliming to pH 10.0, has been frequently employed as a detoxification method to improve fermentability. A spruce dilute-acid hydrolysate was treated with NaOH in a factorial design experiment, in which the pH was varied between 9.0 and 12.0, the temperature between 5 and 80 degrees C, and the time between 1 and 7 h. Already at pH 9.0, >25% of the glucose was lost when the hydrolysate was treated at 80 degrees C for 1 h. Among the monosaccharides, xylose was degraded faster under alkaline conditions than the hexoses (glucose, mannose, and galactose), which, in turn, were degraded faster than arabinose. The results suggest that alkali treatment of hydrolysates can be performed at temperatures below 30 degrees C at any pH between 9.0 and 12.0 without problems with sugar degradation or formation of inhibiting aliphatic acids. Treatment with Ca(OH)2 instead of NaOH resulted in more substantial degradation of sugars. Under the harsher conditions of the factorial design experiment, the concentrations of furfural and 5-hydroxymethylfurfural decreased while the total phenolic content increased. The latter phenomenon was tentatively attributed to fragmentation of soluble aromatic oligomers in the hydrolysate. Separate phenolic compounds were affected in different ways by the alkaline conditions with some compounds showing an increase in concentration while others decreased. In conclusion, the conditions used for detoxification with alkali should be carefully controlled to optimize the positive effects and minimize the degradation of fermentable sugars.

  16. Control of placental alkaline phosphatase gene expression in HeLa cells: induction of synthesis by prednisolone and sodium butyrate

    SciTech Connect

    Chou, J.Y.; Takahashi, S.

    1987-06-16

    HeLa S/sub 3/ cells produce an alkaline phosphatase indistinguishable from the enzyme from human term placenta. The phosphatase activity in these cells was induced by both prednisolone and sodium butyrate. Both agents stimulated de novo synthesis of the enzyme. The increase in phosphatase activity paralleled the increase in immunoactivity and biosynthesis of placental alkaline phosphatase. The fully processed phosphatase monomer in control, prednisolone-treated or butyrate-treated cells was a 64.5 K polypeptide, measured by both incorporation of L-(/sup 35/S)methionine into enzyme protein and active-site labeling. The 64.5K polypeptide was formed by the incorporation of additional N-acetylneuraminic acid moieties to a precursor polypeptide of 61.5K. However, this biosynthetic pathway was identified only in butyrate-treated cells. In prednisolone-treated cells, the processing of 61.5K to 64.5K monomer was accelerated, and the presence of the 61.5 precursor could only be detected by either neuraminidase or monensin treatment. Phosphatase mRNA which comigrated with the term placental alkaline phosphatase mRNA of 2.7 kilobases was induced in the presence of either prednisolone or butyrate. Alkaline phosphatase mRNA is untreated HeLa S/sub 3/ cells migrated slightly faster than the term placental alkaline phosphatase mRNA. Butyrate also induced a second still faster migrating alkaline phosphatase mRNA. Both prednisolone and butyrate increased the steady-state levels of placental alkaline phosphatase mRNA. The data indicate that the increase in phosphatase mRNA by prednisolone and butyrate resulted in the induction of alkaline phosphatase activity and biosynthesis in HeLa S/sub 3/ cells. Furthermore, both agents induced the expression of different alkaline phosphatase gene transcripts without altering its protein product.

  17. Mesozoic mafic alkaline magmatism of southern Scandinavia

    NASA Astrophysics Data System (ADS)

    Tappe, Sebastian

    2004-11-01

    More than 100 volcanic necks in central Scania (southern Sweden) are the product of Jurassic continental rift-related mafic alkaline magmatism at the southwest margin of the Baltic Shield. They are mainly basanites, with rarer melanephelinites. Both rock groups display overlapping primitive Mg-numbers, Cr and Ni contents, steep chondrite-normalized rare earth element patterns (LaN /YbN = 17 27) and an overall enrichment in incompatible elements. However, the melanephelinites are more alkaline and have stronger high field strength element enrichment than the basanites. The existence of distinct primary magmas is also indicated by heterogeneity in highly incompatible element ratios (e.g. Zr/Nb, La/Nb). Trace element modelling indicates that the magmas were generated by comparably low degrees of melting of a heterogeneous mantle source. Such a source can best be explained by a metasomatic overprint of the mantle lithosphere by percolating evolved melts. The former existence of such alkaline trace element-enriched melts can be demonstrated by inversion of the trace element content of green-core clinopyroxenes and anorthoclase which occur as xenocrysts in the melanephelinites and are interpreted as being derived from crystallization of evolved mantle melts. Jurassic magmatic activity in Scania was coeval with the generation of nephelinites in the nearby Egersund Basin (Norwegian North Sea). Both Scanian and North Sea alkaline magmas share similar trace element characteristics. Mantle enrichment processes at the southwest margin of the Baltic Shield and the North Sea Basin generated trace element signatures similar to those of ocean island basalts (e.g. low Zr/Nb and La/Nb) but there are no indications of plume activity during the Mesozoic in this area. On the contrary, the short duration of rifting, absence of extensive lithospheric thinning, and low magma volumes argue against a Mesozoic mantle plume. It seems likely that the metasomatic imprint resulted from the

  18. Clinical utility of a wheat-germ precipitation assay for determination of bone alkaline phosphatase concentrations in patients with different metabolic bone diseases.

    PubMed

    Braga, V; Dorizzi, R; Brocco, G; Rossini, M; Zamberlan, N; Gatti, D; Adami, S

    1995-07-01

    Bone alkaline phosphatase was evaluated by wheat-germ lectin precipitation in several clinical conditions. The study included 33 premenopausal healthy women, 46 postmenopausal apparently healthy women, 19 growing children, 24 patients with Paget's disease, 31 patients with primary hyperparathyroidism and 66 patients with hepatobiliary diseases. In postmenopausal women the mean T score (i.e.: the number of SD below or above the mean for premenopausal women) was 2.6 +/- 1.3 (SD) for bone alkaline phosphatase and 1.61 +/- 1.21 for total alkaline phosphatase (p < 0.001). The T score for bone alkaline phosphatase provided a better discrimination from normals for both Paget's disease (22.1 +/- 27.8 versus 12.8 +/- 16 p < 0.001) and primary hyperparathyroidism (8.2 +/- 4.3 versus 4.6 +/- 3.7 p < 0.005 for bone alkaline phosphatase and total alkaline phosphatase respectively). After treatment with intravenous bisphosphonate the percent decrease of bone alkaline phosphatase was larger than that of total alkaline phosphatase both in patients with Paget's disease (-46% versus -72% p < 0.01) and in patients with primary hyperparathyroidism (-21% versus -47% p < 0.02) and an estimate of the precision (delta mean/SD of the delta mean) for bone alkaline phosphatase was 1.9-3.7 times higher than that of total alkaline phosphatase. In twelve osteoporotic patients treated for six months with oral alendronate the decrease in bone turnover was detected with significantly higher precision with bone alkaline phosphatase than with total alkaline phosphatase (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Alkaline and ultrasound assisted alkaline pretreatment for intensification of delignification process from sustainable raw-material.

    PubMed

    Subhedar, Preeti B; Gogate, Parag R

    2014-01-01

    Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique.

  20. Alkaline solution/binder ratio as a determining factor in the alkaline activation of aluminosilicates

    SciTech Connect

    Ruiz-Santaquiteria, C.; Fernandez-Jimenez, A.; Palomo, A.

    2012-09-15

    This study investigates the effect of the alkaline solution/binder (S/B) ratio on the composition and nanostructure of the reaction products generated in the alkaline activation of aluminosilicates. The experiments used two mixtures of fly ash and dehydroxylated white clay and for each of these, varying proportions of the solution components. The alkali activator was an 8 M NaOH solution (with and without sodium silicate) used at three S/B ratios: 0.50, 0.75 and 1.25. The {sup 29}Si, {sup 27}Al MAS NMR and XRD characterisation of the reaction products reveal that for ratios nearest the value delivering suitable paste workability, the reaction-product composition and structure depend primarily on the nature and composition of the starting materials and the alkaline activator used. However, when an excess alkaline activator is present in the system, the reaction products tend to exhibit SiO{sub 2}/Al{sub 2}O{sub 3} ratios of approximately 1, irrespective of the composition of the starting binder or the alkaline activator.

  1. [Risks associated with unrestricted consumption of alkaline-reduced water].

    PubMed

    Henry, Marc; Chambron, Jacques

    2014-01-01

    Consumption of alkaline reduced water produced by domestic electrolysis devices was approved in Japan in 1965 by the Minister of Health, Work and Wellbeing, for the treatment of gastrointestinal disorders. Today, these devices are also freely available in France. The commercial information provided with the devices recommends the consumption of 1 to 1.5 liters per day, not only for gastrointestinal disorders but also for numerous other illnesses such as diabetes, cancer and inflammation. Academic research on this subject has been undergoing in Japan since 1990, and has established that the active ingredient is dissolved dihydrogen, which eliminates the free radical HO· in vivo. It has also been shown that electrode degradation during use of the devices releases highly reactive platinum nanoparticles, the toxicity of which is unknown. The authors of this report recommend alerting the French health authorities to the uncontrolled availability of these devices that generate drug substances and should therefore be subject to regulatory requirements.

  2. Effect of exogenous spermidine on polyamine content and metabolism in tomato exposed to salinity-alkalinity mixed stress.

    PubMed

    Hu, Xiaohui; Zhang, Yi; Shi, Yu; Zhang, Zhi; Zou, Zhirong; Zhang, Hao; Zhao, Jiuzhou

    2012-08-01

    We investigated the effects of seeds pretreatment with exogenous spermidine (Spd) on the polyamine content and metabolism in the roots of two cultivars of tomato (Solanum lycopersicum), Jinpengchaoguan and Zhongza No. 9 grown under conditions of mixed salinity-alkalinity stress. These cultivars differ in their tolerance to salinity stress, with the former more tolerant than the latter. PA content, whether in its free forms, soluble conjugated forms, or insoluble bound forms, increased significantly during salinity-alkalinity stress. The activities of S-adenosylmethionine decarboxylase (SAMDC) and diamine oxidase (DAO), concentrations of free Spd, soluble conjugated forms of Spd and spermine (Spm), and insoluble bound form of Spd in the roots were enhanced to a greater extent in cv. Jinpengchaoguan roots than in cv. Zhongza No.9 in response to salinity-alkalinity stress. Interestingly, Spd application to seeds markedly suppressed the accumulation of free Put, but promoted an increase in free Spd and Spm concentrations, as well as soluble conjugated forms of Spd and insoluble bound forms of Put in both cultivars. From these data, we deduced that exogenous Spd promotes the conversion of free Put into free Spd and Spm, and soluble conjugated forms and insoluble bound forms of PAs under salinity-alkalinity stress. Furthermore, under salinity-alkalinity stress conditions, exogenous Spd enhanced the activities of ODC, SAMDC and DAO, and reduced the activities of ADC and polyamine oxidase (PAO) in cv. Zhongza No.9 roots. In addition, exogenous Spd reduced the activities of ADC and ODC, and increased the activities of DAO and SAMDC in cv. Jinpengchaoguan roots under salinity-alkalinity stress conditions. These results suggest that exogenous Spd treatment can regulate the metabolic status of polyamines caused by salinity-alkalinity stress, and eventually enhance tolerance of tomato plants to salinity-alkalinity stress. Additionally, Spd treatments have varying effects on

  3. Ag/g-C3N4 catalyst with superior catalytic performance for the degradation of dyes: a borohydride-generated superoxide radical approach

    NASA Astrophysics Data System (ADS)

    Fu, Yongsheng; Huang, Ting; Zhang, Lili; Zhu, Junwu; Wang, Xin

    2015-08-01

    A straightforward approach is developed for fabrication of a visible-light-driven Ag/g-C3N4 catalyst. Morphological observation shows that the g-C3N4 sheets are decorated with highly dispersed Ag nanoparticles having an average size of 5.6 nm. The photocatalytic activity measurements demonstrate that the photocatalytic degradation rates of methyl orange (MO), methylene blue (MB), and neutral dark yellow GL (NDY-GL) over Ag/g-C3N4-4 can reach up to 98.2, 99.3 and 99.6% in the presence of borohydride ions (BH4-) only with 8, 45, and 16 min visible light irradiation, respectively. The significant enhancement in photoactivity of the catalyst is mainly attributed to the high dispersity and smaller size of Ag nanoparticles, the strong surface plasmon resonance (SPR) effect of metallic Ag nanoparticles, the efficient separation of photogenerated charge carriers, the additional superoxide radicals (O&z.rad;-2) generated from the reduction of dissolved oxygen in the presence of BH4- and the synergistic effect of Ag nanoparticles and g-C3N4.A straightforward approach is developed for fabrication of a visible-light-driven Ag/g-C3N4 catalyst. Morphological observation shows that the g-C3N4 sheets are decorated with highly dispersed Ag nanoparticles having an average size of 5.6 nm. The photocatalytic activity measurements demonstrate that the photocatalytic degradation rates of methyl orange (MO), methylene blue (MB), and neutral dark yellow GL (NDY-GL) over Ag/g-C3N4-4 can reach up to 98.2, 99.3 and 99.6% in the presence of borohydride ions (BH4-) only with 8, 45, and 16 min visible light irradiation, respectively. The significant enhancement in photoactivity of the catalyst is mainly attributed to the high dispersity and smaller size of Ag nanoparticles, the strong surface plasmon resonance (SPR) effect of metallic Ag nanoparticles, the efficient separation of photogenerated charge carriers, the additional superoxide radicals (O&z.rad;-2) generated from the reduction of

  4. Alkaline phosphatase relieves desensitization of adenylate cyclase-coupled beta-adrenergic receptors in avian erythrocyte membranes

    SciTech Connect

    Stadel, J.M.; Rebar, R.; Crooke, S.T.

    1987-05-01

    Desensitization of adenylate cyclase-coupled ..beta..-adrenergic receptors in avian erythrocytes results in 40-65% decrease in agonist-stimulated adenylate cyclase activity and correlates with increased phosphorylation of ..beta..-adrenergic receptors. To assess the role of phosphorylation in desensitization, membranes from isoproterenol- and cAMP-desensitized turkey erythrocytes were incubated with alkaline phosphatase for 30 min at 37/sup 0/C, pH = 8.0. In both cases alkaline phosphatase treatment significantly reduced desensitization of agonist-stimulated adenylate cyclase activity by 40-60%. Similar results were obtained following alkaline phosphatase treatment of membranes from isoproterenol- and cAMP-desensitized duck erythrocytes. In addition, alkaline phosphatase treatment of membranes from duck erythrocytes desensitized with phorbol 12-mystrate 13-acetate returned adenylate cyclase activity to near control values. In all experiments inclusion of 20 mM NaPO/sub 4/ to inhibit alkaline phosphatase during treatment of membranes blocked the enzyme's effect on agonist-stimulated adenylate cyclase activity. These results demonstrate a role for phosphorylation in desensitization of adenylate cyclase-coupled ..beta..-adrenergic receptors in avian erythrocytes.

  5. Rapid changes in water hardness and alkalinity: Calcite formation is lethal to Daphnia magna.

    PubMed

    Bogart, Sarah J; Woodman, Samuel; Steinkey, Dylan; Meays, Cindy; Pyle, Greg G

    2016-07-15

    There is growing concern that freshwater ecosystems may be negatively affected by ever-increasing anthropogenic inputs of extremely hard, highly alkaline effluent containing large quantities of Ca(2+), Mg(2+), CO3(2-), and HCO3(-) ions. In this study, the toxicity of rapid and extreme shifts in water hardness (38-600mg/L as CaCO3) and alkalinity (30-420mg/L as CaCO3) to Daphnia magna was tested, both independently and in combination. Within these ranges, where no precipitation event occurred, shifts in water hardness and/or alkalinity were not toxic to D. magna. In contrast, 98-100% of D. magna died within 96h after exposure to 600mg/L as CaCO3 water hardness and 420mg/L as CaCO3 alkalinity (LT50 of 60h with a 95% CI of 54.2-66.0h). In this treatment, a CaCO3 (calcite) precipitate formed in the water column which was ingested by and thoroughly coated the D. magna. Calcite collected from a mining impacted stream contained embedded organisms, suggesting field streams may also experience similar conditions and possibly increased mortality as observed in the lab tests. Although further investigation is required to determine the exact fate of aquatic organisms exposed to rapid calcite precipitation in the field, we caution that negative effects may occur more quickly or at lower concentrations of water hardness and alkalinity in which we observed effects in D. magna, because some species, such as aquatic insects, are more sensitive than cladocerans to changes in ionic strength. Our results provide evidence that both calcite precipitation and the major ion balance of waters should be managed in industrially affected ecosystems and we support the development of a hardness+alkalinity guideline for the protection of aquatic life.

  6. Simulation of hydrogen sulphide absorption in alkaline solution using a packed column.

    PubMed

    Azizi, Mohamed; Biard, Pierre-François; Couvert, Annabelle; Ben Amor, Mohamed

    2014-01-01

    In this work, a simulation tool was developed for hydrogen sulphide (H₂S) removal in an alkaline solution in packed columns working at countercurrent. Modelling takes into account the mass-transfer enhancement due to the reversible reactions between H₂S and the alkaline species (CO(²⁻)(3), HCO⁻(3), and HO⁻) in the liquid film. Many parameters can be controlled by the user such as the gas and liquid inlet H₂S concentrations, the gas and liquid flow rates, the scrubbing liquid pH, the desired H₂S removal efficiency, the temperature, the alkalinity, etc. Since the influence of the hydrodynamic and mass-transfer performances in a packed column is well known, the numerical resolutions performed were dedicated to the study of the influence of the chemical conditions (through the pH and the alkalinity), the temperature and the liquid-to-gas mass flow rate ratio (L/G). A packed column of 3 m equipped with a given random packing material working at countercurrent and steady state has been modelled. The results show that the H₂S removal efficiency increases with the L/G, the pH, the alkalinity and more surprisingly with the temperature. Alkalinity has a very significant effect on the removal efficiency through the mass-transfer enhancement and buffering effect, which limits pH decreasing due to H₂S absorption. This numerical resolution provides a tool for designers and researchers involved in H₂S treatment to understand deeper the process and optimize their processes.

  7. Response of Desulfovibrio vulgaris to alkaline stress.

    PubMed

    Stolyar, Sergey; He, Qiang; Joachimiak, Marcin P; He, Zhili; Yang, Zamin Koo; Borglin, Sharon E; Joyner, Dominique C; Huang, Katherine; Alm, Eric; Hazen, Terry C; Zhou, Jizhong; Wall, Judy D; Arkin, Adam P; Stahl, David A

    2007-12-01

    The response of exponentially growing Desulfovibrio vulgaris Hildenborough to pH 10 stress was studied using oligonucleotide microarrays and a study set of mutants with genes suggested by microarray data to be involved in the alkaline stress response deleted. The data showed that the response of D. vulgaris to increased pH is generally similar to that of Escherichia coli but is apparently controlled by unique regulatory circuits since the alternative sigma factors (sigma S and sigma E) contributing to this stress response in E. coli appear to be absent in D. vulgaris. Genes previously reported to be up-regulated in E. coli were up-regulated in D. vulgaris; these genes included three ATPase genes and a tryptophan synthase gene. Transcription of chaperone and protease genes (encoding ATP-dependent Clp and La proteases and DnaK) was also elevated in D. vulgaris. As in E. coli, genes involved in flagellum synthesis were down-regulated. The transcriptional data also identified regulators, distinct from sigma S and sigma E, that are likely part of a D. vulgaris Hildenborough-specific stress response system. Characterization of a study set of mutants with genes implicated in alkaline stress response deleted confirmed that there was protective involvement of the sodium/proton antiporter NhaC-2, tryptophanase A, and two putative regulators/histidine kinases (DVU0331 and DVU2580).

  8. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions.

  9. Advanced inorganic separators for alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W. (Inventor)

    1982-01-01

    A flexible, porous battery separator comprising a coating applied to a porous, flexible substrate is described. The coating comprises: (1) a thermoplastic rubber-based resin which is insoluble and unreactive in the alkaline electrolyte; (2) a polar organic plasticizer which is reactive with the alkaline electrolyte to produce a reaction product which contains a hydroxyl group and/or a carboxylic acid group; and (3) a mixture of polar particulate filler materials which are unreactive with the electrolyte, the mixture comprising at least one first filler material having a surface area of greater than 25 meters sq/gram, at least one second filler material having a surface area of 10 to 25 sq meters/gram, wherein the volume of the mixture of filler materials is less than 45% of the total volume of the fillers and the binder, the filler surface area per gram of binder is about 20 to 60 sq meters/gram, and the amount of plasticizer is sufficient to coat each filler particle. A method of forming the battery separator is also described.

  10. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    SciTech Connect

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  11. Thermodynamic model for an alkaline fuel cell

    NASA Astrophysics Data System (ADS)

    Verhaert, Ivan; De Paepe, Michel; Mulder, Grietus

    Alkaline fuel cells are low temperature fuel cells for which stationary applications, e.g. cogeneration in buildings, are a promising market. In order to guarantee a long life, water and thermal management has to be done in a careful way. In order to better understand the water, alkali and thermal flows, a two-dimensional model for an Alkaline Fuel Cell is developed using a control volume approach. In each volume the electrochemical reactions together with the mass and energy balance are solved. The model is created in Aspen Custom Modeller, the development environment of Aspen Plus, where special attention is given to the physical flow of hydrogen, water and air in the system. In this way the developed component, the AFC-cell, can be built into stack configurations to understand its effect on the overall performance. The model is validated by experimental data from measured performance by VITO with their Cell Voltage Monitor at a test case, where the AFC-unit is used as a cogeneration unit.

  12. Evaluation of alkaline electrolyzed water to replace traditional phosphate enhancement solutions: Effects on water holding capacity, tenderness, and sensory characteristics.

    PubMed

    Rigdon, Macc; Hung, Yen-Con; Stelzleni, Alexander M

    2017-01-01

    Sixty-four pork loins were randomly assigned to one of four treatments to evaluate the use of alkaline electrolyzed reduced water as a replacement for traditional enhancement solutions. Treatments included: alkaline electrolyzed reduced water (EOH; pH≈11.5), EOH plus 2.5% potassium-lactate (EOK), industry standard (IS; 0.35% sodium tri-polyphosphate, 0.14% sodium chloride, 2.5% potassium-lactate), and no enhancement (CON). After enhancement (targeting 110%) and rest period, chops were cut (2.54-cm) to test treatment effects on water holding capacity, Warner-Bratzler shear force (WBSF), and sensory attributes. Despite its alkaline nature EOH chops exuded more water (P<0.05) than EOK, IS, or CON chops. Control chops were similar (P>0.05) to EOK, however CON and EOK both lost more moisture (P<0.05) than IS. The use of alkaline electrolyzed reduced water did not improve WBSF or sensory characteristics compared to IS treated chops. As a stand-alone enhancement solution alkaline electrolyzed reduced water was not a suitable replacement for industry standard solutions.

  13. The effect of alkaline agents on retention of EOR chemicals

    SciTech Connect

    Lorenz, P.B.

    1991-07-01

    This report summarizes a literature survey on how alkaline agents reduce losses of surfactants and polymers in oil recovery by chemical injection. Data are reviewed for crude sulfonates, clean anionic surfactants, nonionic surfactants, and anionic and nonionic polymers. The role of mineral chemistry is briefly described. Specific effects of various alkaline anions are discussed. Investigations needed to improve the design of alkaline-surfactant-polymer floods are suggested. 62 refs., 28 figs., 6 tabs.

  14. Electrophoretic separation of alkaline and acid phosphatase isoenzymes from the pulp of monkey teeth.

    PubMed

    Franzén, A; Hasselgren, G

    1978-01-01

    Monkey pulps were homogenized in a Triton tris solution. After three centrifugation steps (800, 20000, and 105000 g) the supernatant was applied on acryl amide columns at pH 7.5 in a tris-diethyl barbituric acid buffer. Electrophoresis was performed at a constant current of 2.5 mA per gel column at 18--20 degrees C. Incubations for alkaline phosphatase (E.C. 3.1.3.1) were carried out at pH 8.3 using naphthol-AS-MX-phosphate as substrate and Fast Red Violet LB salt as coupler. Incubations for acid phosphatase (E.C. 3.1.3.2) were undertaken at pH 5.0 using alpha-naphtyl phosphate as substrate and hexazotized pararosanilin as coupling agent. After the incubations for alkaline phosphatase as well as acid phosphatase two bands showing enzyme activity were demonstrated. By means of treatment with heat (56 degrees C) prior to incubation or addition of vanadate or pyrophosphate to the incubation medium it was shown that the main part of the fast moving alkaline phosphatase band was sensitive to these procedures. The alkaline phosphatase of the slow moving band appeared to be resistant to heat or the addition of inhibitors.

  15. Dolomite Dissolution in Alkaline Cementious Media

    NASA Astrophysics Data System (ADS)

    Mittermayr, Florian; Klammer, Dietmar; Köhler, Stephan; Dietzel, Martin

    2010-05-01

    Chemical alteration of concrete has gained much attention over the past years as many cases of deterioration due to sulphate attack, thaumasite formation (TSA) or alkali silica reactions (ASR) have been reported in various constructions (Schmidt et al, 2009). Much less is known about the so called alkali carbonate reaction (ACR). It is believed that dolomite aggregates can react with the alkalis from the cement, dissolve and form calcite and brucite (Katayama, 2004). Due to very low solubility of dolomite in alkaline solutions this reaction seems doubtful. In this study we are trying to gain new insides about the conditions that can lead to the dissolution of dolomite in concrete. Therefore we investigated concrete samples from Austrian tunnels that show partially dissolved dolomite aggregates. Petrological analysis such as microprobe, SEM and Raman spectroscopy as well as a hydrochemical analysis of interstitial solutions and ground water and modelling with PhreeqC (Parkhurst and Appelo, 1999) are carried out. In addition a series of batch experiments is set up. Modelling approaches by PhreeqC show a thermodynamically possibility in the alkaline range when additional Ca2+ in solution causes dolomite to become more and more undersaturated as calcite gets supersaturated. Interacting ground water is enriched in Ca2+and saturated with respect to gypsum as marine evaporites are found in situ rocks. Furthermore it is more likely that Portlandite (Ca(OH)2) plays a more important role than Na and K in the cement. Portlandite acts as an additional Ca2+ source and is much more abundant than the alkalies. Some interstitial solutions are dominated mainly by Na+ and SO42- and reach concentrations up to 30 g/l TDS. It is believed that solutions can even reach thenardite saturation as efflorescences are found on the tunnel walls. In consequence dolomite solubility increases with increasing ionic strength. pH > 11 further accelerate the process of dedolomitization by the removal

  16. Stainless steel anodes for alkaline water electrolysis and methods of making

    SciTech Connect

    Soloveichik, Grigorii Lev

    2014-01-21

    The corrosion resistance of stainless steel anodes for use in alkaline water electrolysis was increased by immersion of the stainless steel anode into a caustic solution prior to electrolysis. Also disclosed herein are electrolyzers employing the so-treated stainless steel anodes. The pre-treatment process provides a stainless steel anode that has a higher corrosion resistance than an untreated stainless steel anode of the same composition.

  17. Development of an alkaline fuel cell subsystem

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A two task program was initiated to develop advanced fuel cell components which could be assembled into an alkaline power section for the Space Station Prototype (SSP) fuel cell subsystem. The first task was to establish a preliminary SSP power section design to be representative of the 200 cell Space Station power section. The second task was to conduct tooling and fabrication trials and fabrication of selected cell stack components. A lightweight, reliable cell stack design suitable for the SSP regenerative fuel cell power plant was completed. The design meets NASA's preliminary requirements for future multikilowatt Space Station missions. Cell stack component fabrication and tooling trials demonstrated cell components of the SSP stack design of the 1.0 sq ft area can be manufactured using techniques and methods previously evaluated and developed.

  18. Properties of cathode materials in alkaline cells

    NASA Astrophysics Data System (ADS)

    Salkind, A. J.; McBreen, J.; Freeman, R.; Parkhurst, W. A.

    1984-04-01

    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve type silver zinc batteries, a new material - AgNiO2 and several nickel electrodes for nickel cadmium and nickel hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities. After the first discharge AgNiO2 can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)2 largely eliminate this.

  19. Advanced-capability alkaline fuel cell powerplant

    NASA Astrophysics Data System (ADS)

    Deronck, Henry J.

    The alkaline fuel cell powerplant utilized in the Space Shuttle Orbiter has established an excellent performance and reliability record over the past decade. Recent AFC technology programs have demonstrated significant advances in cell durability and power density. These capabilities provide the basis for substantial improvement of the Orbiter powerplant, enabling new mission applications as well as enhancing performance in the Orbiter. Improved durability would extend the powerplant's time between overhaul fivefold, and permit longer-duration missions. The powerplant would also be a strong candidate for lunar/planetary surface power systems. Higher power capability would enable replacement of the Orbiter's auxiliary power units with electric motors, and benefits mass-critical applications such as the National AeroSpace Plane.

  20. Polyvinyl alcohol membranes as alkaline battery separators

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Gonzalez-Sanabria, O.; Manzo, M. A.

    1982-01-01

    Polyvinly alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the separator and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of separator screening tests and cell tests for several variations of PBA films are discussed.

  1. Rechargeable alkaline manganese dioxide/zinc batteries

    NASA Astrophysics Data System (ADS)

    Kordesh, K.; Weissenbacher, M.

    The rechargeable alkaline manganese dioxide/zinc MnO 2/Zn) system, long established commercial as a primay battery, has reached a high level of performance as a secondary battery system. The operating principles are presented and the technological achievements are surveyed by referencing the recent publications and patent literature. A review is also given of the improvements obtained with newly formulated cathodes and anodes and specially designed batteries. Supported by modelling of the cathode and anode processes and by statistical evidence during cycling of parallel/series-connected modules, the envisioned performance of the next generation of these batteries is described. The possibility of extending the practical use of the improved rechargeable MnO 2/Zn system beyond the field of small electronics into the area of power tools, and even to kW-sized power sources, is demonstrated. Finally, the commercial development in comparison with other rechargeable battery systems is examined.

  2. Oxygen electrodes for rechargeable alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Swette, Larry; Giner, Jose

    1987-09-01

    Electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells were investigated and developed. The electrocatalysts are defined as the material with a higher activity for the oxygen electrode reaction than the support. Advanced development will require that the materials be prepared in high surface area forms, and may also entail integration of various candidate materials. Eight candidate support materials and seven electrocatalysts were investigated. Of the 8 support, 3 materials meet the preliminary requirements in terms of electrical conductivity and stability. Emphasis is now on preparing in high surface area form and testing under more severe corrosion stress conditions. Of the 7 electrocatalysts prepared and evaluated, at least 5 materials remain as potential candidates. The major emphasis remains on preparation, physical characterization and electrochemical performance testing.

  3. Development of an alkaline fuel cell subsystem

    NASA Astrophysics Data System (ADS)

    1987-03-01

    A two task program was initiated to develop advanced fuel cell components which could be assembled into an alkaline power section for the Space Station Prototype (SSP) fuel cell subsystem. The first task was to establish a preliminary SSP power section design to be representative of the 200 cell Space Station power section. The second task was to conduct tooling and fabrication trials and fabrication of selected cell stack components. A lightweight, reliable cell stack design suitable for the SSP regenerative fuel cell power plant was completed. The design meets NASA's preliminary requirements for future multikilowatt Space Station missions. Cell stack component fabrication and tooling trials demonstrated cell components of the SSP stack design of the 1.0 sq ft area can be manufactured using techniques and methods previously evaluated and developed.

  4. Acylglucuronide in alkaline conditions: migration vs. hydrolysis.

    PubMed

    Di Meo, Florent; Steel, Michele; Nicolas, Picard; Marquet, Pierre; Duroux, Jean-Luc; Trouillas, Patrick

    2013-06-01

    This work rationalizes the glucuronidation process (one of the reactions of the phase II metabolism) for drugs having a carboxylic acid moiety. At this stage, acylglucuronides (AG) metabolites are produced, that have largely been reported in the literature for various drugs (e.g., mycophenolic acid (MPA), diclofenac, ibuprofen, phenylacetic acids). The competition between migration and hydrolysis is rationalized by adequate quantum calculations, combing MP2 and density functional theory (DFT) methods. At the molecular scale, the former process is a real rotation of the drug around the glucuconic acid. This chemical-engine provides four different metabolites with various toxicities. Migration definitely appears feasible under alkaline conditions, making proton release from the OH groups. The latter reaction (hydrolysis) releases the free drug, so the competition is of crucial importance to tackle drug action and elimination. From the theoretical data, both migration and hydrolysis appear kinetically and thermodynamically favored, respectively.

  5. The Alkaline Dissolution Rate of Calcite.

    PubMed

    Colombani, Jean

    2016-07-07

    Due to the widespread presence of calcium carbonate on Earth, several geochemical systems, among which is the global CO2 cycle, are controlled to a large extent by the dissolution and precipitation of this mineral. For this reason, the dissolution of calcite has been thoroughly investigated for decades. Despite this intense activity, a consensual value of the dissolution rate of calcite has not been found yet. We show here that the inconsistency between the reported values stems mainly from the variability of the chemical and hydrodynamic conditions of measurement. The spreading of the values, when compared in identical conditions, is much less than expected and is interpreted in terms of sample surface topography. This analysis leads us to propose benchmark values of the alkaline dissolution rate of calcite compatible with all the published values, and a method to use them in various chemical and hydrodynamic contexts.

  6. Alkaline oxide conversion coatings for aluminum alloys

    SciTech Connect

    Buchheit, R.G.

    1996-02-01

    Three related conversion coating methods are described that are based on film formation which occurs when aluminum alloys are exposed to alkaline Li salt solutions. Representative examples of the processing methods, resulting coating structure, composition and morphology are presented. The corrosion resistance of these coatings to aerated 0.5 M NaCl solution has been evaluated as a function of total processing time using electrochemical impedance spectroscopy (EIS). This evaluation shows that excellent corrosion resistance can be uniformly achieved using no more than 20 minutes of process time for 6061-T6. Using current methods a minimum of 80 minutes of process time is required to get marginally acceptable corrosion resistance for 2024-T3. Longer processing times are required to achieve uniformly good corrosion resistance.

  7. Oxygen electrodes for rechargeable alkaline fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, Larry; Giner, Jose

    1987-01-01

    Electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells were investigated and developed. The electrocatalysts are defined as the material with a higher activity for the oxygen electrode reaction than the support. Advanced development will require that the materials be prepared in high surface area forms, and may also entail integration of various candidate materials. Eight candidate support materials and seven electrocatalysts were investigated. Of the 8 support, 3 materials meet the preliminary requirements in terms of electrical conductivity and stability. Emphasis is now on preparing in high surface area form and testing under more severe corrosion stress conditions. Of the 7 electrocatalysts prepared and evaluated, at least 5 materials remain as potential candidates. The major emphasis remains on preparation, physical characterization and electrochemical performance testing.

  8. Alkaline pulping of some eucalypts from Sudan.

    PubMed

    Khristova, P; Kordsachia, O; Patt, R; Dafaalla, S

    2006-03-01

    Four eucalypts (Eucalyptus camaldulensis, Eucalyptus microtheca, Eucalyptus tereticornis and Eucalyptus citriodora) grown in Sudan were examined for their suitability for pulping and papermaking with different alkaline methods. Their physical, morphological and chemical characteristics are reported. The pulping trials with E. citriodora and E. tereticornis were carried out using the kraft-AQ, soda-AQ, modified AS/AQ (ASA), ASAM and kraft methods. For the other two species, only the ASAM and the kraft process were applied. ASAM pulping gave the best results in terms of yield, degree of delignification, mechanical and optical pulp properties. The best pulps, obtained in kraft and ASAM cooking of E. citriodora, were bleached to 88% ISO brightness in a totally chlorine free bleaching sequence (OQ1O/PQ2P). The bleached pulps, especially the ASAM pulp, showed good papermaking properties and would be suitable for manufacture of writing and printing grades of paper.

  9. Treatment

    MedlinePlus

    ... Ban For Clinicians Clinical Recognition Specimen Collection Treatment Smallpox Vaccine Guidance Infection Control: Hospital Infection Control: Home ... Mouth Infection) Poxvirus and Rabies Branch Travelers’ Health: Smallpox & Other Orthopoxvirus-Associated Infections Poxvirus Treatment Recommend on ...

  10. The Nickel(111)/Alkaline Electrolyte Interface

    NASA Technical Reports Server (NTRS)

    Wang, Kuilong; Chottiner, G. S.; Scherson, D. A.; Reid, Margaret A.

    1991-01-01

    The electrochemical properties of Ni (111) prepared and characterized in ultra high vacuum, UHV, by surface analytical techniques have been examined in alkaline media by cyclic voltammetry using an UHV-electrochemical cell transfer system designed and built in this laboratory. Prior to the transfer, the Ni(111) surfaces were exposed to saturation coverages of CO in UHV in an attempt to protect the surface from possible contamination with other gases during the transfer. Temperature Programmed Desorption, TPD, of CO-dosed Ni (111) surfaces displaying sharp c(4x2), LEED patterns, subsequently exposed to water-saturated Ar at atmospheric pressure in an auxiliary UHV compatible chamber and finally transferred back to the main UHV chamber, yielded CO2 and water as the only detectable products. This indicates that the CO-dosed surfaces react with water and/or bicarbonate and hydroxide as the most likely products. Based on the integration of the TPD peaks, the combined amounts of H2O and CO2 were found to be on the order of a single monolayer. The reacted c(4x2)CO/Ni(111) layer seems to protect the surface from undergoing spontaneous oxidation in strongly alkaline solutions. This was evidenced by the fact that the open circuit potential observed immediately after contact with deaerated 0.1 M KOH was about 0.38 V vs. DHE, drifting slightly towards more negative values prior to initiating the voltametric scans. The average ratio of the integrated charge obtained in the first positive linear scan in the range of 0.35 to 1.5 V vs. DHE (initiated at the open circuit potential) and the first (and subsequent) linear negative scans in the same solution yielded for various independent runs a value of 3.5 +/- 0.3. Coulometric analysis of the cyclic voltammetry curves indicate that the electrochemically formed oxyhydroxide layer involves a charge equivalent to 3.2 +/- 0.4 layers of Ni metal.

  11. Alkaline cleaner replacement for printed wiring board fabrication

    SciTech Connect

    Goldammer, S.E.; Pemberton, S.E.; Tucker, D.R.

    1997-04-01

    A replacement alkaline cleaning chemistry was qualified for the copper cleaning process used to support printed wiring board fabrication. The copper cleaning process was used to prepare copper surfaces for enhancing the adhesion of dry film photopolymers (photoresists and solder masks) and acrylic adhesives. The alkaline chemistry was used to remove organic contaminates such as fingerprints.

  12. Exploring Alkaline Stable Organic Cations for Polymer Hydroxide Exchange Membranes

    DTIC Science & Technology

    2015-04-29

    Organic Cations for Polymer Hydroxide Exchange Membranes Hydroxide exchange membranes (HEMs) are important polymer electrolytes for electrochemical...Exploring Alkaline Stable Organic Cations for Polymer Hydroxide Exchange Membranes Report Title Hydroxide exchange membranes (HEMs) are important polymer ...constructing HEMs. EXPLORING ALKALINE STABLE ORGANIC CATIONS FOR POLYMER HYDROXIDE EXCHANGE MEMBRANES by Bingzi Zhang

  13. The Chemistry of Paper Preservation Part 4. Alkaline Paper.

    ERIC Educational Resources Information Center

    Carter, Henry A.

    1997-01-01

    Discusses the problem of the inherent instability of paper due to the presence of acids that catalyze the hydrolytic degradation of cellulose. Focuses on the chemistry involved in the sizing of both acid and alkaline papers and the types of fillers used. Discusses advantages and problems of alkaline papermaking. Contains 48 references. (JRH)

  14. Removal of plutonium and americium from alkaline waste solutions

    DOEpatents

    Schulz, Wallace W.

    1979-01-01

    High salt content, alkaline waste solutions containing plutonium and americium are contacted with a sodium titanate compound to effect removal of the plutonium and americium from the alkaline waste solution onto the sodium titanate and provide an effluent having a radiation level of less than 10 nCi per gram alpha emitters.

  15. Changes of serum alkaline phosphatase isoenzymes in fasted rats.

    PubMed

    Wada, H; Niwa, N; Hayakawa, T; Tsuge, H

    1996-10-01

    Changes of serum alkaline phosphatase (sALP) isoenzymes under fasting conditions were examined using polyacrylamide gel electrophoresis (PAGE), amino-acids (L-phenylalanine (L-Phe), L-homoarginine (L-HArg)) inhibition and wheat germ agglutinin (WGA) treatment. The sALP of non-fasted rats was separated into three bands (S1, S2, S3) by PAGE. The molecular weight (M.W.) of S1 corresponded to that of an isoenzyme found in the ileum. By the addition of L-Phe, the staining intensity of S1 was weakened, S2 and S3 remained unchanged and the total activity of the isoenzymes extracted from intestine decreased. On the other hand, the activity of isoenzymes extracted from kidney and bone decreased by the addition of L-HArg. Therefore, S1 was judged to be derived from intestine. The activities of total sALP and S1 decreased from 16 h of fasting. Total sALP activity and sALP activity of the supernatant prepared by WGA treatment decreased, whereas the ALP activity of the precipitate (difference between total sALP activity and supernatant sALP activity) did not change. The activity band of the precipitate corresponded to that of S3 by PAGE. Therefore, S3 was judged to be derived from bone. In conclusion, under fasting conditions, the activity of S1 decreased while the activities of S2 and S3 remained unchanged.

  16. Role of sialic acid and alkaline DNase in breast cancer.

    PubMed

    Raval, G N; Parekh, L J; Patel, M M; Patel, P S; Rawal, R M; Balar, D B; Patel, D D

    1997-01-01

    Serum levels of sialic acid and alkaline DNase (ADA) were analysed in 495 blood samples collected from 170 breast cancer patients before and during/after anticancer treatment. Fifty-six healthy females were included in the study to define the cutoff values. The markers were analysed by highly sensitive spectrophotometric methods. Statistical evaluation of the data was done using Student's 't' test, paired 't' test and ROC curve analysis. The total sialic acid (TSA), lipid bound sialic acid (LSA) and ADA in sera of untreated breast cancer patients were significantly higher than in controls. ROC curve analysis revealed TSA and LSA to be useful markers for diagnosis of breast cancer. Serum levels of TSA and LSA were significantly decreased in complete responders as compared to their pretreatment values. The pretreatment ADA values showed much individual variation. However, responders showed higher levels of ADA than untreated patients. In nonresponders the values of the biomarkers were comparable with pretreatment levels. The study suggested that TSA and LSA can be helpful in the diagnosis of breast cancer. All three markers can be used for assessment of response to anticancer treatment in breast cancer patients.

  17. Alkaline stability of quaternary ammonium cations for alkaline fuel cell membranes and ionic liquids.

    PubMed

    Marino, M G; Kreuer, K D

    2015-02-01

    The alkaline stability of 26 different quaternary ammonium groups (QA) is investigated for temperatures up to 160 °C and NaOH concentrations up to 10 mol L(-1) with the aim to provide a basis for the selection of functional groups for hydroxide exchange membranes in alkaline fuel cells and of ionic-liquid cations stable in basic conditions. Most QAs exhibit unexpectedly high alkaline stability with the exception of aromatic cations. β-Protons are found to be far less susceptible to nucleophilic attack than previously suggested, whereas the presence of benzyl groups, nearby hetero-atoms, or other electron-withdrawing species promote degradation reactions significantly. Cyclic QAs proved to be exceptionally stable, with the piperidine-based 6-azonia-spiro[5.5]undecane featuring the highest half-life at the chosen conditions. Absolute and relative stabilities presented herein stand in contrast to literature data, the differences being ascribed to solvent effects on degradation.

  18. Salt- and alkaline-tolerance are linked in Acacia.

    PubMed

    Bui, Elisabeth N; Thornhill, Andrew; Miller, Joseph T

    2014-07-01

    Saline or alkaline soils present a strong stress on plants that together may be even more deleterious than alone. Australia's soils are old and contain large, sometimes overlapping, areas of high salt and alkalinity. Acacia and other Australian plant lineages have evolved in this stressful soil environment and present an opportunity to understand the evolution of salt and alkalinity tolerance. We investigate this evolution by predicting the average soil salinity and pH for 503 Acacia species and mapping the response onto a maximum-likelihood phylogeny. We find that salinity and alkalinity tolerance have evolved repeatedly and often together over 25 Ma of the Acacia radiation in Australia. Geographically restricted species are often tolerant of extreme conditions. Distantly related species are sympatric in the most extreme soil environments, suggesting lack of niche saturation. There is strong evidence that many Acacia have distributions affected by salinity and alkalinity and that preference is lineage specific.

  19. Salt- and alkaline-tolerance are linked in Acacia

    PubMed Central

    Bui, Elisabeth N.; Thornhill, Andrew; Miller, Joseph T.

    2014-01-01

    Saline or alkaline soils present a strong stress on plants that together may be even more deleterious than alone. Australia's soils are old and contain large, sometimes overlapping, areas of high salt and alkalinity. Acacia and other Australian plant lineages have evolved in this stressful soil environment and present an opportunity to understand the evolution of salt and alkalinity tolerance. We investigate this evolution by predicting the average soil salinity and pH for 503 Acacia species and mapping the response onto a maximum-likelihood phylogeny. We find that salinity and alkalinity tolerance have evolved repeatedly and often together over 25 Ma of the Acacia radiation in Australia. Geographically restricted species are often tolerant of extreme conditions. Distantly related species are sympatric in the most extreme soil environments, suggesting lack of niche saturation. There is strong evidence that many Acacia have distributions affected by salinity and alkalinity and that preference is lineage specific. PMID:25079493

  20. Membrane-bound alkaline phosphatase from ectopic mineralization and rat bone marrow cell culture.

    PubMed

    Simão, Ana Maria S; Beloti, Márcio M; Cezarino, Rodrigo M; Rosa, Adalberto Luiz; Pizauro, João M; Ciancaglini, Pietro

    2007-04-01

    Cells from rat bone marrow exhibit the proliferation-differentiation sequence of osteoblasts, form mineralized extracellular matrix in vitro and release alkaline phosphatase into the medium. Membrane-bound alkaline phosphatase was obtained by method that is easy to reproduce, simpler and fast when compared with the method used to obtain the enzyme from rat osseous plate. The membrane-bound alkaline phosphatase from cultures of rat bone marrow cells has a MW(r) of about 120 kDa and specific PNPP activity of 1200 U/mg. The ecto-enzyme is anchored to the plasma membrane by the GPI anchor and can be released by PIPLC (selective treatment) or polidocanol (0.2 mg/mL protein and 1% (w/v) detergent). The apparent optimum pH for PNPP hydrolysis by the enzyme was pH 10. This fraction hydrolyzes ATP (240 U/mg), ADP (350 U/mg), glucose 1-phosphate (1100 U/mg), glucose 6-phosphate (340 U/mg), fructose 6-phosphate (460 U/mg), pyrophosphate (330 U/mg) and beta-glycerophosphate (600 U/mg). Cooperative effects were observed for the hydrolysis of PPi and beta-glycerophosphate. PNPPase activity was inhibited by 0.1 mM vanadate (46%), 0.1 mM ZnCl2 (68%), 1 mM levamisole (66%), 1 mM arsenate (44%), 10 mM phosphate (21%) and 1 mM theophylline (72%). We report the biochemical characterization of membrane-bound alkaline phosphatase obtained from rat bone marrow cells cultures, using a method that is simple, rapid and easy to reproduce. Its properties are compared with those of rat osseous plate enzyme and revealed that the alkaline phosphatase obtained has some kinetics and structural behaviors with higher levels of enzymatic activity, facilitating the comprehension of the mineralization process and its function.

  1. Mechanical properties of untreated and alkaline treated fibers from zalacca midrib wastes

    NASA Astrophysics Data System (ADS)

    Raharjo, Wahyu Purwo; Soenoko, Rudy; Purnowidodo, Anindito; Choiron, Mochammad Agus; Triyono

    2016-03-01

    The environmental concern has been raised due to the abundance of waste from synthetic materials which cannot be biodegraded after their life-time. It provides opportunity to exploit natural resources which are neglected. For example, midrib wastes from zalacca plants after cutting are able to utilize as composite reinforcement. The aim of this research was to characterize the mechanical properties of zalacca midrib fibers. As other ones, zalacca midrib fibers consisted of cellulose, hemicellulose and lignin, which their compositions were 42.54, 34.35 and 28.01 % respectively. To raise their cellulose content, the zalacca fibers were alkaline treated by immersion in the sodium hydroxide for 2 hours and rinsing in the distilled water. The concentration of sodium hydroxide was varied 1 and 5%. To investigate the influence of alkaline treatment, the mechanical testing and morphological analysis was performed. The tensile testing was done to obtain ultimate strength, elastic modulus and strain to fracture. The surface morphology of fibers was observed by SEM. The average ultimate tensile strength of zalacca fibers ranged from 182.12 MPa (untreated) to 417.94 MPa (5%NaOH treated). The diameter measurement showed that the alkaline treatment reduce the average fiber diameters due to the decline of the hemicellulose and lignin content as fiber matrix. This caused the increase of the tensile strength and elastic modulus due to the reduction of diameters as divider meanwhile the cellulose content as structural supporter of the fibers was relatively constant. From the SEM analysis, it was shown that the alkaline treatment reduced the fiber matrix so that its surface morphology became rougher due to the microfibrils appearance.

  2. Removal of K+, Na+, Ca2+, and Mg2+ from saline-alkaline water using the microalga Scenedesmus obliquus

    NASA Astrophysics Data System (ADS)

    Yao, Zongli; Ying, Chengqi; Lu, Jianxue; Lai, Qifang; Zhou, Kai; Wang, Hui; Chen, Ling

    2013-11-01

    The capability of Scenedesmus obliquus to remove cations (K+, Na+, Ca2+, Mg2+) from saline-alkaline water was investigated at different salinities (0, 5, 10, 15, 20, 25) and carbonate alkalinities (0, 5, 10, 15, 20, 25, 30, 35 mmol/L). K+, Na+, Ca2+, and Mg2+ in saline-alkaline water were efficiently removed by S. obliquus. The maximum removal of the cations (29.37 mg for K+, 185.85 mg for Na+, 23.07 mg for Ca2+, 66.14 mg for Mg2+) occurred at salinity 25. The maximum removal of K+ (2.28 mg), Na+ (6.62 mg), Ca2+ (1.01 mg), and Mg2+ (0.62 mg) occurred at carbonate alkalinities of 25 mmol/L for K+, 35 mmol/L for Na+, 20 mmol/L for Ca2+, and 25 mmol/L for Mg2+, respectively. Under a salinity stress, the concentration of Na+ in S. obliquus increased significantly, while that of K+ decreased significantly. The concentrations of Ca2+ and Mg2+ decreased as well. The ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly lower in all salinity treatments than those of the control. Under alkaline stress, the concentrations of Na+ and K+ in S. obliquus decreased significantly and the ratios of K+/Na+, Ca2+/Na+, and Mg2+/Na+ were significantly higher in all treatments than in the control. Moreover, the concentrations of Ca2+ and Mg2+ in S. obliquus at alkalinities of 5-10 mmol/L were significantly higher than those of the other treatments. The removal of Na+ by S. obliquus mainly occurs through biosorption, and Mg2+ and Ca2+ were removed through both biosorption and bioaccumulation.

  3. Batteries: from alkaline to zinc-air.

    PubMed

    Dondelinger, Robert M

    2004-01-01

    There is no perfect disposable battery--one that will sit on the shelf for 20 years, then continually provide unlimited current, at a completely constant voltage until exhausted, without producing heat. There is no perfect rechargeable battery--one with all of the above characteristics and will also withstand an infinite overcharge while providing an equally infinite cycle life. There are only compromises. Every battery selection is a compromise between the ideally required characteristics, the advantages, and the limitations of each battery type. General selection of a battery type to power a medical device is largely outside the purview of the biomed. Initially, these are engineering decisions made at the time of medical equipment design and are intended to be followed in perpetuity. However, since newer cell types evolve and the manufacturer's literature is fixed at the time of printing, some intelligent substitutions may be made as long as the biomed understands the characteristics of both the recommended cell and the replacement cell. For example, when the manufacturer recommends alkaline, it is usually because of the almost constant voltage it produces under the devices' design load. Over time, other battery types may be developed that will meet the intent of the manufacturer, at a lower cost, providing longer operational life, at a lower environmental cost, or with a combination of these advantages. In the Obstetrical Doppler cited at the beginning of this article, the user had put in carbon-zinc cells, and the biomed had unknowingly replaced them with carbonzinc cells. If the alkaline cells recommended by the manufacturer had been used, there would have been the proper output voltage at the battery terminals when the [table: see text] cells were at their half-life. Instead, the device refused to operate since the battery voltage was below presumed design voltage. While battery-type substitutions may be easily and relatively successfully made in disposable

  4. Microbial Thiocyanate Utilization under Highly Alkaline Conditions

    PubMed Central

    Sorokin, Dimitry Y.; Tourova, Tatyana P.; Lysenko, Anatoly M.; Kuenen, J. Gijs

    2001-01-01

    Three kinds of alkaliphilic bacteria able to utilize thiocyanate (CNS−) at pH 10 were found in highly alkaline soda lake sediments and soda soils. The first group included obligate heterotrophs that utilized thiocyanate as a nitrogen source while growing at pH 10 with acetate as carbon and energy sources. Most of the heterotrophic strains were able to oxidize sulfide and thiosulfate to tetrathionate. The second group included obligately autotrophic sulfur-oxidizing alkaliphiles which utilized thiocyanate nitrogen during growth with thiosulfate as the energy source. Genetic analysis demonstrated that both the heterotrophic and autotrophic alkaliphiles that utilized thiocyanate as a nitrogen source were related to the previously described sulfur-oxidizing alkaliphiles belonging to the gamma subdivision of the division Proteobacteria (the Halomonas group for the heterotrophs and the genus Thioalkalivibrio for autotrophs). The third group included obligately autotrophic sulfur-oxidizing alkaliphilic bacteria able to utilize thiocyanate as a sole source of energy. These bacteria could be enriched on mineral medium with thiocyanate at pH 10. Growth with thiocyanate was usually much slower than growth with thiosulfate, although the biomass yield on thiocyanate was higher. Of the four strains isolated, the three vibrio-shaped strains were genetically closely related to the previously described sulfur-oxidizing alkaliphiles belonging to the genus Thioalkalivibrio. The rod-shaped isolate differed from the other isolates by its ability to accumulate large amounts of elemental sulfur inside its cells and by its ability to oxidize carbon disulfide. Despite its low DNA homology with and substantial phenotypic differences from the vibrio-shaped strains, this isolate also belonged to the genus Thioalkalivibrio according to a phylogenetic analysis. The heterotrophic and autotrophic alkaliphiles that grew with thiocyanate as an N source possessed a relatively high level of cyanase

  5. Identification of a major QTL allele from wild soybean (Glycine soja Sieb. & Zucc.) for increasing alkaline salt tolerance in soybean.

    PubMed

    Tuyen, D D; Lal, S K; Xu, D H

    2010-07-01

    Salt-affected soils are generally classified into two main categories, sodic (alkaline) and saline. Our previous studies showed that the wild soybean accession JWS156-1 (Glycine soja) from the Kinki area of Japan was tolerant to NaCl salt, and the quantitative trait locus (QTL) for NaCl salt tolerance was located on soybean linkage group N (chromosome 3). Further investigation revealed that the wild soybean accession JWS156-1 also had a higher tolerance to alkaline salt stress. In the present study, an F(6) recombinant inbred line mapping population (n = 112) and an F(2) population (n = 149) derived from crosses between a cultivated soybean cultivar Jackson and JWS156-1 were used to identify QTL for alkaline salt tolerance in soybean. Evaluation of soybean alkaline salt tolerance was carried out based on salt tolerance rating (STR) and leaf chlorophyll content (SPAD value) after treatment with 180 mM NaHCO(3) for about 3 weeks under greenhouse conditions. In both populations, a significant QTL for alkaline salt tolerance was detected on the molecular linkage group D2 (chromosome 17), which accounted for 50.2 and 13.0% of the total variation for STR in the F(6) and the F(2) populations, respectively. The wild soybean contributed to the tolerance allele in the progenies. Our results suggest that QTL for alkaline salt tolerance is different from the QTL for NaCl salt tolerance found previously in this wild soybean genotype. The DNA markers closely associated with the QTLs might be useful for marker-assisted selection to pyramid tolerance genes in soybean for both alkaline and saline stresses.

  6. Calixarene crown ether solvent composition and use thereof for extraction of cesium from alkaline waste solutions

    DOEpatents

    Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.; Presley, Derek J.

    2001-01-01

    A solvent composition and corresponding method for extracting cesium (Cs) from aqueous neutral and alkaline solutions containing Cs and perhaps other competing metal ions is described. The method entails contacting an aqueous Cs-containing solution with a solvent consisting of a specific class of lipophilic calix[4]arene-crown ether extractants dissolved in a hydrocarbon-based diluent containing a specific class of alkyl-aromatic ether alcohols as modifiers. The cesium values are subsequently recovered from the extractant, and the solvent subsequently recycled, by contacting the Cs-containing organic solution with an aqueous stripping solution. This combined extraction and stripping method is especially useful as a process for removal of the radionuclide cesium-137 from highly alkaline waste solutions which are also very concentrated in sodium and potassium. No pre-treatment of the waste solution is necessary, and the cesium can be recovered using a safe and inexpensive stripping process using water, dilute (millimolar) acid solutions, or dilute (millimolar) salt solutions. An important application for this invention would be treatment of alkaline nuclear tank wastes. Alternatively, the invention could be applied to decontamination of acidic reprocessing wastes containing cesium-137.

  7. Low pH alkaline chemical formulations

    SciTech Connect

    French, T.R.; Peru, D.A.; Thornton, S.D.

    1989-01-01

    This report describes the development of a surfactant-enhanced alkaline flooding system that is applicable to specific reservoir conditions in Wilmington (California) field. The cost of the chemicals for an ASP (alkali/surfactant/polymer) flood is calculated to be $3.90/bbl of oil produced, with 78% of that cost attributable to polymer. This research included phase behavior tests, oil displacement tests, mineral dissolution tests, and adsorption measurements. It was discovered that consumption of low pH alkalis is low enough in the Wilmington field to be acceptable. In addition, alkali dramatically reduced surfactant adsorption and precipitation. A mixture of NaHCO3 and Na2CO3 was recommended for use as a preflush and in the ASP formulation. Research was also conducted on the synergistic effect that occurs when a mixture of alkali and synthetic surfactant contacts crude oil. It appears that very low IFT is predominantly a result of the activation of the natural surfactants present in the Wilmington oil, and the sustained low IFT is primarily the result of the synthetic surfactant. It also appears that removal of acids from the crude oil by the alkali renders the oil more interfacially reactive to synthetic surfactant. These phenomena help to explain the synergism that results from combining alkali and synthetic surfactant into a single oil recovery formulation. 19 refs., 24 figs., 10 tabs.

  8. Identification of human pulmonary alkaline phosphatase isoenzymes.

    PubMed

    Capelli, A; Cerutti, C G; Lusuardi, M; Donner, C F

    1997-04-01

    An increase of alkaline phosphatase (ALP) activity has been observed in the bronchoalveolar lavage fluid (BALF) of patients affected by pulmonary fibrosis in chronic interstitial lung disorders. To characterize the ALP isoenzymes in such cases, we used gel filtration, agarose gel electrophoresis, heat and amino acid inhibition assays, wheat-germ agglutinin (WGA) precipitation, and an immunoassay specific for the bone-isoform of ALP. Only one anodic band representing a high-molecular-weight isoform of ALP (Mr approximately 2,000 kDa) was observed on electrophoresis of BALF. The inhibition assay results were consistent for a tissue-nonspecific isoenzyme sensitive to a temperature of 56 degrees C (71.9 +/- 2.5% inhibition) and to homoarginine (65.7 +/- 1.9%), and resistant to L-phenylalanine and L-leucine. Less than 13% of ALP activity was heat-stable. After incubation of BALF specimens with glycosyl-phosphatidylinositol-phospholipase D plus Nonidet P-40, or with phosphatidylinositol-phospholipase C alone, an electrophoretic cathodic band (Mr approximately 220 kDa) appeared near the bone band of a standard serum. With the WGA assay, 84.4 +/- 3.3% of ALP precipitated and the band disappeared. After immunoassay for the bone isoform, a mean of less than 5% enzyme activity was measured. We conclude that the ALP found in BALF is a pulmonary isoform of a tissue nonspecific isoenzyme.

  9. Extracellular alkaline proteinase of Colletotrichum gloeosporioides.

    PubMed

    Dunaevsky, Ya E; Matveeva, A R; Beliakova, G A; Domash, V I; Belozersky, M A

    2007-03-01

    The main proteinase of the filamentous fungus Colletotrichum gloeosporioides causing anthracnoses and serious problems for production and storage of agricultural products has molecular mass of 57 kD and was purified more than 200-fold to homogeneity with the yield of 5%. Maximal activity of the proteinase is at pH 9.0-10.0, and the enzyme is stable at pH 6.0-11.5 (residual activity not less than 70%). The studied enzyme completely kept its activity to 55 degrees C, with a temperature optimum of 45 degrees C. The purified C. gloeosporioides proteinase is stable at alkaline pH values, but rapidly loses its activity at pH values lower than 5.0. Addition of bovine serum albumin stabilizes the enzyme under acidic conditions. Data on inhibitor analysis and substrate specificity of the enzyme allow its classification as a serine proteinase of subtilisin family. It is demonstrated that the extracellular proteinase of C. gloeosporioides specifically effects plant cell wall proteins. It is proposed that the studied proteinase--via hydrolysis of cell wall--provides for penetration of the fungus into the tissues of the host plant.

  10. Production of alkaline protease from Cellulosimicrobium cellulans

    PubMed Central

    Ferracini-Santos, Luciana; Sato, Hélia H

    2009-01-01

    Cellulosimicrobium cellulans is one of the microorganisms that produces a wide variety of yeast cell wall-degrading enzymes, β-1,3-glucanase, protease and chitinase. Dried cells of Saccharomyces cerevisiae were used as carbon and nitrogen source for cell growth and protease production. The medium components KH2PO4, KOH and dried yeast cells showed a significant effect (p<0.05) on the factorial fractional design. A second design was prepared using two factors: pH and percentage of dried yeast cells. The results showed that the culture medium for the maximum production of protease was 0.2 g/l of MgSO4.7H2O, 2.0 g/l of (NH4)2SO4 and 8% of dried yeast cells in 0.15M phosphate buffer at pH 8.0. The maximum alkaline protease production was 7.0 ± 0.27 U/ml over the center point. Crude protease showed best activity at 50ºC and pH 7.0-8.0, and was stable at 50ºC. PMID:24031317

  11. Solubility of pllutonium in alkaline salt solutions

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1993-02-26

    Plutonium solubility data from several studies have been evaluated. For each data set, a predictive model has been developed where appropriate. In addition, a statistical model and corresponding prediction intervals for plutonium solubility as a quadratic function of the hydroxide concentration have been developed. Because of the wide range of solution compositions, the solubility of plutonium can vary by as much as three orders of magnitude for any given hydroxide concentration and still remain within the prediction interval. Any nuclear safety assessments that depend on the maximum amount of plutonium dissolved in alkaline salt solutions should use concentrations at least as great as the upper prediction limits developed in this study. To increase the confidence in the prediction model, it is recommended that additional solubility tests be conducted at low hydroxide concentrations and with all of the other solution components involved. To validate the model for application to actual waste solutions, it is recommended that the plutonium solubilities in actual waste solutions be determined and compared to the values predicted by the quadratic model.

  12. Engineering challenges of ocean alkalinity enhancement

    NASA Astrophysics Data System (ADS)

    Kruger, T.; Renforth, P.

    2012-04-01

    The addition of calcium oxide (CaO) to the ocean as a means of enhancing the capacity of the ocean as a carbon sink was first proposed by Haroon Kheshgi in 1995. Calcium oxide is created by heating high purity limestone in a kiln to temperatures of approximately 1000°C. Addition of this material to the ocean draws carbon dioxide out of the atmosphere (approximately 1 tonne of CaO could sequester 1.3 tonnes of CO2). Abiotic carbonate precipitation is inhibited in the surface ocean. This is a carbon and energy expensive process, where approximately 0.8 tonnes of CO2 are produced at a point source for every tonne sequestered. The feasibility of ocean alkalinity enhancement requires capture and storage of the point source of CO2. We present details of a feasibility study of the engineering challenges of Kheshgi's method focusing on the potential scalability and costs of the proposed process. To draw down a PgC per year would require the extraction and processing of ~6Pg of limestone per year, which is similar in scale to the current coal industry. Costs are estimated at ~USD30-40 per tonne of CO2 sequestered through the process, which is favourable to comparative processes. Kheshgi, H. (1995) Energy 20 (9) 915-922

  13. Response of Desulfovibrio vulgaris to Alkaline Stress

    SciTech Connect

    Stolyar, S.; He, Q.; He, Z.; Yang, Z.; Borglin, S.E.; Joyner, D.; Huang, K.; Alm, E.; Hazen, T.C.; Zhou, J.; Wall, J.D.; Arkin, A.P.; Stahl, D.A.

    2007-11-30

    The response of exponentially growing Desulfovibrio vulgarisHildenborough to pH 10 stress was studied using oligonucleotidemicroarrays and a study set of mutants with genes suggested by microarraydata to be involved in the alkaline stress response deleted. The datashowed that the response of D. vulgaris to increased pH is generallysimilar to that of Escherichia coli but is apparently controlled byunique regulatory circuits since the alternative sigma factors (sigma Sand sigma E) contributing to this stress response in E. coli appear to beabsent in D. vulgaris. Genes previously reported to be up-regulated in E.coli were up-regulated in D. vulgaris; these genes included three ATPasegenes and a tryptophan synthase gene. Transcription of chaperone andprotease genes (encoding ATP-dependent Clp and La proteases and DnaK) wasalso elevated in D. vulgaris. As in E. coli, genes involved in flagellumsynthesis were down-regulated. The transcriptional data also identifiedregulators, distinct from sigma S and sigma E, that are likely part of aD. vulgaris Hildenborough-specific stress response system.Characterization of a study set of mutants with genes implicated inalkaline stress response deleted confirmed that there was protectiveinvolvement of the sodium/proton antiporter NhaC-2, tryptophanase A, andtwo putative regulators/histidine kinases (DVU0331 andDVU2580).

  14. Ultrafine polybenzimidazole (PBI) fibers. [separators for alkaline batteries and dfuel cells

    NASA Technical Reports Server (NTRS)

    Chenevey, E. C.

    1979-01-01

    Mats were made from ultrafine polybenzimidazole (PBI) fibers to provide an alternate to the use of asbestos as separators in fuel cells and alkaline batteries. To minimize distortion during mat drying, a process to provide a dry fibrid was developed. Two fibrid types were developed: one coarse, making mats for battery separators; the other fine, making low permeability matrices for fuel cells. Eventually, it was demonstrated that suitable mat fabrication techniques yielded fuel cell separators from the coarser alkaline battery fibrids. The stability of PBI mats to 45% KOH at 123 C can be increased by heat treatment at high temperatures. Weight loss data to 1000 hours exposure show the alkali resistance of the mats to be superior to that of asbestos.

  15. Immobilized E. coli alkaline phosphatase. Its properties, stability, and utility in studying the dephosphorylation of proteins.

    PubMed

    Basheeruddin, K; Rothman, V; Margolis, S

    1985-04-01

    We have immobilized E. coli alkaline phosphatase (EC 3.1.3.1) by linking it covalently to sepharose 4B. This preparation has several advantages over the soluble enzyme. The immobilized enzyme is easily separable from other constituents in incubation mixtures. The immobilized enzyme can be reused repeatedly and is more stable than the soluble enzyme to heat treatment in the presence of 10 mM Mg2+. The insoluble and soluble phosphatases removed 75 and 77%, respectively, of the inorganic phosphorus from casein. The immobilized enzyme inactivated two enzymes believed to be active in the phosphorylated state, acyl-CoA:cholesterol acyltransferase (ACAT) by 39% and NADPH-cytochrome P-450 reductase by 89%. The utility of immobilized alkaline phosphatase for studying the phosphorylation and dephosphorylation of soluble or membrane-bound enzymes and proteins is discussed.

  16. Automatic online buffer capacity (alkalinity) measurement of wastewater using an electrochemical cell.

    PubMed

    Cheng, Liang; Charles, Wipa; Cord-Ruwisch, Ralf

    2016-10-01

    The use of an automatic online electrochemical cell (EC) for measuring the buffer capacity of wastewater is presented. pH titration curves of different solutions (NaHCO3, Na2HPO4, real municipal wastewater, and anaerobic digester liquid) were obtained by conventional chemical titration and compared to the online EC measurements. The results show that the pH titration curves from the EC were comparable to that of the conventional chemical titration. The results show a linear relationship between the response of the online EC detection system and the titrimetric partial alkalinity and total alkalinity of all tested samples. This suggests that an EC can be used as a simple online titration device for monitoring the buffer capacity of different industrial processes including wastewater treatment and anaerobic digestion processes.

  17. Enhanced coproduction of hydrogen and methane from cornstalks by a three-stage anaerobic fermentation process integrated with alkaline hydrolysis.

    PubMed

    Cheng, Xi-Yu; Liu, Chun-Zhao

    2012-01-01

    A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%.

  18. DECREASE IN DYNAMIC VISCOSITY AND AVERAGE MOLECULAR WEIGHT OF ALGINATE FROM LAMINARIA DIGITATA DURING ALKALINE EXTRACTION(1).

    PubMed

    Vauchel, Peggy; Arhaliass, Abdellah; Legrand, Jack; Kaas, Raymond; Baron, Régis

    2008-04-01

    Alginates are natural polysaccharides that are extracted from brown seaweeds and widely used for their rheological properties. The central step in the extraction protocol used in the alginate industry is the alkaline extraction, which requires several hours. In this study, a significant decrease in alginate dynamic viscosity was observed after 2 h of alkaline treatment. Intrinsic viscosity and average molecular weight of alginates from alkaline extractions 1-4 h in duration were determined, indicating depolymerization of alginates: average molecular weight decreased significantly during the extraction, falling by a factor of 5 between 1 and 4 h of extraction. These results suggested that reducing extraction time could enable preserving the rheological properties of the extracted alginates.

  19. Anditalea andensis ANESC-ST--An Alkaliphilic Halotolerant Bacterium Capable of Electricity Generation under Alkaline-Saline Conditions.

    PubMed

    Shi, Wei; Wang, Victor Bochuan; Zhao, Cui-E; Zhang, Qichun; Loo, Say Chye Joachim; Yang, Liang; Xu, Chenjie

    2015-01-01

    A great challenge in wastewater bioremediation is the sustained activity of viable microorganisms, which can contribute to the breakdown of waste contaminants, especially in alkaline pH conditions. Identification of extremophiles with bioremediation capability can improve the efficiency of wastewater treatment. Here, we report the discovery of an electrochemically active alkaliphilic halotolerant bacterium, Anditalea andensis ANESC-ST (=CICC10485T=NCCB 100412T), which is capable of generating bioelectricity in alkaline-saline conditions. A. andensis ANESC-ST was shown to grow in alkaline conditions between pH 7.0-11.0 and also under high salt condition (up to 4 wt% NaCl). Electrical output was further demonstrated in microbial fuel cells (MFCs) with an average current density of ~0.5 µA/cm2, even under the harsh condition of 4 wt% NaCl and pH 9.0. Subsequent introduction of secreted extracellular metabolites into MFCs inoculated with Escherichia coli or Pseudomonas aeruginosa yielded enhanced electrical output. The ability of A. andensis ANESC-ST to generate energy under alkaline-saline conditions points towards a solution for bioelectricity recovery from alkaline-saline wastewater. This is the first report of A.andensis ANESC-ST producing bioelectricity at high salt concentration and pH.

  20. Identification of differentially expressed genes potentially involved in the tolerance of Lotus tenuis to long-term alkaline stress.

    PubMed

    Paz, Rosalía Cristina; Rocco, Rubén Anibal; Jiménez-Bremont, Juan Francisco; Rodríguez-Kessler, Margarita; Becerra-Flora, Alicia; Menéndez, Ana Bernardina; Ruíz, Oscar Adolfo

    2014-09-01

    Soil alkalinity is one of the most serious agricultural problems limiting crop yields. The legume Lotus tenuis is an important forage acknowledged by its ability to naturally grow in alkaline soils. To gain insight into the molecular responses that are activated by alkalinity in L. tenuis plants, subtractive cDNA libraries were generated from leaves and roots of these plants. Total RNAs of non-stressed plants (pH 5.8; E.C. 1.2), and plants stressed by the addition of 10 mM of NaHCO3 (pH 9.0; E.C. 1.9), were used as source of the driver and the tester samples, respectively. RNA samples were collected after 14 and 28 days of treatment. A total of 158 unigenes from leaves and 92 unigenes from roots were obtained and classified into 11 functional categories. Unigenes from these categories (4 for leaves and 8 for roots), that were related with nutrient metabolism and oxidative stress relief were selected, and their differential expression analyzed by qRT-PCR. These genes were found to be differentially expressed in a time dependent manner in L. tenuis during the alkaline stress application. Data generated from this study will contribute to the understanding of the general molecular mechanisms associated to plant tolerance under long-term alkaline stress in plants.

  1. Copper release in low and high alkaline water.

    PubMed

    D'Antonio, L; Fabbricino, M; Nasso, M; Trifuoggi, M

    2008-04-01

    Copper release in drinking water, caused by electrochemical corrosion of household distribution systems, was investigated. Experiments were developed testing both low and high alkaline water in stagnant conditions. The effect of varying stagnation time was investigated also. Both soluble and insoluble copper compounds, produced by corrosion processes are quantified, using appropriate experimental procedures. On the basis of obtained results, copper concentration in stagnant water is defined as a function of water alkalinity, while total metal release is defined as a function of stagnation length, and is not dependent on water alkalinity.

  2. Method of increasing the sulfation capacity of alkaline earth sorbents

    DOEpatents

    Shearer, J.A.; Turner, C.B.; Johnson, I.

    1980-03-13

    A system and method for increasing the sulfation capacity of alkaline earth carbonates to scrub sulfur dioxide produced during the fluidized bed combustion of coal in which partially sulfated alkaline earth carbonates are hydrated in a fluidized bed to crack the sulfate coating and convert the alkaline earth oxide to the hydroxide. Subsequent dehydration of the sulfate-hydroxide to a sulfate-oxide particle produces particles having larger pore size, increased porosity, decreased grain size and additional sulfation capacity. A continuous process is disclosed.

  3. Method of increasing the sulfation capacity of alkaline earth sorbents

    DOEpatents

    Shearer, John A.; Turner, Clarence B.; Johnson, Irving

    1982-01-01

    A system and method for increasing the sulfation capacity of alkaline earth carbonates to scrub sulfur dioxide produced during the fluidized bed combustion of coal in which partially sulfated alkaline earth carbonates are hydrated in a fluidized bed to crack the sulfate coating and convert the alkaline earth oxide to the hydroxide. Subsequent dehydration of the sulfate-hydroxide to a sulfate-oxide particle produces particles having larger pore size, increased porosity, decreased grain size and additional sulfation capacity. A continuous process is disclosed.

  4. Polyvinyl alcohol battery separator containing inert filler. [alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Hsu, L. C.; Manzo, M. A. (Inventor)

    1981-01-01

    A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

  5. Postgraduate Symposium: Positive influence of nutritional alkalinity on bone health.

    PubMed

    Wynn, E; Krieg, M A; Lanham-New, S A; Burckhardt, P

    2010-02-01

    patients with an already-high fracture risk. The latter study adds to knowledge by confirming a positive link between dietary alkalinity and bone health indices in the very elderly. In a further study to complement these findings it has also been shown in a group of thirty young women that in Ca sufficiency an acid Ca-rich water has no effect on bone resorption, while an alkaline bicarbonate-rich water leads to a decrease in both serum parathyroid hormone and serum C-telopeptide. Further investigations need to be undertaken to study whether these positive effects on bone loss are maintained over long-term treatment. Mineral-water consumption could be an easy and inexpensive way of helping to prevent osteoporosis and could be of major interest for long-term prevention of bone loss.

  6. Spectroscopic studies of alkaline activated slag geopolymers

    NASA Astrophysics Data System (ADS)

    Mozgawa, W.; Deja, J.

    2009-04-01

    In the work, results of structural studies of different geopolymers, obtained using a granulated blast furnace slag, are presented. The slag was subjected to an alkaline activation process. As activators, NaOH, Na 2CO 3 and liquid glass were applied. IR and NMR spectroscopy were the main experimental methods used, the results obtained were compared with XRD phase analysis and SEM observations. In the IR spectra of raw slag as well as in the spectra of products of paste hydration, the bands due to the characteristic vibrations of bonds observed in both types of oxygen bridges: Si-O-Si and Si-O-Al, were assigned. These bridges constitute basic structural units, forming tetrahedral geopolymer chains. It was found that the slag composition, mainly SiO 2/Al 2O 3 ratio and modification in oxides concentration, influences the presence of the bands connected with the phases (mainly C-S-H) formed during the hydration in the IR spectra. Additionally, significant effect of amorphous phases share on the spectra shape was established. 29Si and 27Al MAS-NMR spectra of initial slag geopolymers and pastes provided information concerning coordination of both atoms in the structures. It was revealed that the kind of slag geopolymers and the conditions of paste hydration influence connectedness of silicooxygen tetrahedra and coordination number of aluminium atoms. Based on IR spectra, it was also possible to determine the influence of the activator type, activation time and hydration conditions on the products formed. Significant changes were observed for the bands assigned to vibrations of carbonate and hydroxide groups. The changes were also noticed in the case of bands due to vibrations of silicate and aluminosilicate bonds.

  7. Alkaline decomposition of synthetic jarosite with arsenic

    PubMed Central

    2013-01-01

    The widespread use of jarosite-type compounds to eliminate impurities in the hydrometallurgical industry is due to their capability to incorporate several elements into their structures. Some of these elements are of environmental importance (Pb2+, Cr6+, As5+, Cd2+, Hg2+). For the present paper, AsO43- was incorporated into the lattice of synthetic jarosite in order to carry out a reactivity study. Alkaline decomposition is characterized by removal of sulfate and potassium ions from the lattice and formation of a gel consisting of iron hydroxides with absorbed arsenate. Decomposition curves show an induction period followed by a conversion period. The induction period is independent of particle size and exponentially decreases with temperature. The conversion period is characterized by formation of a hydroxide halo that surrounds an unreacted jarosite core. During the conversion period in NaOH media for [OH-] > 8 × 10-3 mol L-1, the process showed a reaction order of 1.86, and an apparent activation energy of 60.3 kJ mol-1 was obtained. On the other hand, during the conversion period in Ca(OH)2 media for [OH-] > 1.90 × 10-2 mol L-1, the reaction order was 1.15, and an apparent activation energy of 74.4 kJ mol-1 was obtained. The results are consistent with the spherical particle model with decreasing core and chemical control. PMID:23566061

  8. Alkaline decomposition of synthetic jarosite with arsenic.

    PubMed

    Patiño, Francisco; Flores, Mizraim U; Reyes, Iván A; Reyes, Martín; Hernández, Juan; Rivera, Isauro; Juárez, Julio C

    2013-01-01

    The widespread use of jarosite-type compounds to eliminate impurities in the hydrometallurgical industry is due to their capability to incorporate several elements into their structures. Some of these elements are of environmental importance (Pb(2+), Cr(6+), As(5+), Cd(2+), Hg(2+)). For the present paper, AsO4 (3-) was incorporated into the lattice of synthetic jarosite in order to carry out a reactivity study. Alkaline decomposition is characterized by removal of sulfate and potassium ions from the lattice and formation of a gel consisting of iron hydroxides with absorbed arsenate. Decomposition curves show an induction period followed by a conversion period. The induction period is independent of particle size and exponentially decreases with temperature. The conversion period is characterized by formation of a hydroxide halo that surrounds an unreacted jarosite core. During the conversion period in NaOH media for [OH(-)] > 8 × 10(-3) mol L(-1), the process showed a reaction order of 1.86, and an apparent activation energy of 60.3 kJ mol(-1) was obtained. On the other hand, during the conversion period in Ca(OH)2 media for [OH(-)] > 1.90 × 10(-2) mol L(-1), the reaction order was 1.15, and an apparent activation energy of 74.4 kJ mol(-1) was obtained. The results are consistent with the spherical particle model with decreasing core and chemical control.

  9. Improving the alkaline stability of imidazolium cations by substitution.

    PubMed

    Dong, Huilong; Gu, Fenglou; Li, Min; Lin, Bencai; Si, Zhihong; Hou, Tingjun; Yan, Feng; Lee, Shuit-Tong; Li, Youyong

    2014-10-06

    Imidazolium cations are promising candidates for preparing anion-exchange membranes because of their good alkaline stability. Substitution of imidazolium cations is an efficient way to improve their alkaline stability. By combining density functional theory calculations with experimental results, it is found that the LUMO energy correlates with the alkaline stability of imidazolium cations. The results indicate that alkyl groups are the most suitable substituents for the N3 position of imidazolium cations, and the LUMO energies of alkyl-substituted imidazolium cations depend on the electron-donating effect and the hyperconjugation effect. Comparing 1,2-dimethylimidazolium cations (1,2-DMIm+) and 1,3-dimethylimidazolium cations (1,3-DMIm+) with the same substituents reveals that the hyperconjugation effect is more significant in influencing the LUMO energy of 1,3-DMIms. This investigation reveals that LUMO energy is a helpful aid in predicting the alkaline stability of imidazolium cations.

  10. Processes affecting the oceanic distributions of dissolved calcium and alkalinity

    SciTech Connect

    Shiller, A.M.; Gieskes, J.M.

    1980-05-20

    Recent studies of the CO/sub 2/ system have suggested that chemical processes in addition to the dissolution and precipitation of calcium carbonate affect the oceanic calcium and alkalinity distributions. Calcium and alkalinity data from the North Pacific have been examined both by using the simple physical-chemical model of previous workers and by a study involving the broader oceanographic context of these data. The simple model is shown to be an inadequate basis for these studies. Although a proton flux associated with organic decomposition may affect the alkalinity, previously reported deviations of calcium-alkalinity correlations from expected trends appear to be related to boundary processes that have been neglected rather than to this proton flux. The distribution of calcium in the surface waters of the Pacific Ocean is examined.

  11. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS - ALKALINE HYDROLYSIS

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to allow the calculation of alkaline hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition state...

  12. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS. I. ALKALINE HYDROLYSIS

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to allow the calculation of alkaline hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition state...

  13. Regulation of alkaline phosphatase expression in human choriocarcinoma cell lines.

    PubMed Central

    Hamilton, T A; Tin, A W; Sussman, H H

    1979-01-01

    The coincident expression of two structurally distinct isoenzymes of human alkaline phosphatase was demonstrated in two independently derived gestational choriocarcinoma cell lines. These proteins were shown to have enzymatic, antigenic, and physical-chemical properties resembling those of isoenzymes from term placenta and adult liver. The regulation of these isoenzymes has been studied during the exposure of both cell lines to 5-bromodeoxyuridine and dibutyryl cyclic AMP. The responses of the alkaline phosphatase isoenzymes to these agents have also been compared with the response of another protein phenotypic to placenta, the alpha subunit of chorionic gonadotropin. The results show that (i) the separate structural genes coding for placental and liver alkaline phosphatases are regulated in a noncoordinate fashion; (ii) both alkaline phosphatase genes respond independently of the alpha subunit; and (iii) the induction of the placental type isoenzyme occurs via at least two independent pathways. Images PMID:218197

  14. Net alkalinity and net acidity 1: Theoretical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A.

    2005-01-01

    Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a

  15. Cinacalcet Lowers Serum Alkaline Phosphatase in Maintenance Hemodialysis Patients

    PubMed Central

    Belozeroff, Vasily; Goodman, William G.; Ren, Lulu; Kalantar-Zadeh, Kamyar

    2009-01-01

    Background and objectives: Studies suggest an association between elevated serum alkaline phosphatase (AP) and increased mortality in hemodialysis patients, but the effect of existing therapies on AP is not fully understood. We assessed the effects of cinacalcet on AP in a secondary analysis of controlled trial data. Design, setting, participants, & measurements: This was a post hoc analysis of data from three 26-wk randomized, double-blind, placebo-controlled, phase 3 trials and a 26-wk double-blind, placebo-controlled extension trial that investigated cinacalcet in secondary hyperparathyroidism treatment in dialysis patients. Hemodialysis patients (n = 890) with intact parathyroid hormone ≥300 pg/ml and serum calcium ≥8.4 mg/dl received cinacalcet plus standard therapy or standard therapy alone for up to 52 wk. Total, not bone-specific, AP was assessed (proportion of cinacalcet/control subjects achieving a ≥20% or any AP reduction from baseline; the proportion of subjects with AP ≥120 U/L) at baseline; the end of titration; and study weeks 26, 42, and 52. Results: At 52 wk, a greater proportion of cinacalcet-treated patients had either a ≥20% (39 versus 18%) or any (58 versus 36%) AP reduction compared with control subjects, respectively. The likelihood of achieving either a ≥20% or any AP reduction (determined by relative proportion) was 2.33 (95% confidence interval 1.50 to 3.61) and 1.74 (95% confidence interval 1.31 to 2.31), respectively, at week 52. Cinacalcet treatment tended toward a decreased percentage of patients with AP ≥120 U/L (baseline, 42.6%; week 52, 30.6%) compared with control (35.0 to 48.6%, respectively). Conclusions: In this combined analysis of controlled trials of patients who were receiving hemodialysis, cinacalcet lowered total serum AP. PMID:19261825

  16. Cation exchange properties of zeolites in hyper alkaline aqueous media.

    PubMed

    Van Tendeloo, Leen; de Blochouse, Benny; Dom, Dirk; Vancluysen, Jacqueline; Snellings, Ruben; Martens, Johan A; Kirschhock, Christine E A; Maes, André; Breynaert, Eric

    2015-02-03

    Construction of multibarrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchange resins have been developed for most pollutants, they can serve as a growth medium for bacterial proliferation, impairing their long-term stability and introducing unpredictable parameters into the evolution of the system. Zeolites represent a family of inorganic cation exchangers, which naturally occur in hyper alkaline conditions and cannot serve as an electron donor or carbon source for microbial proliferation. Despite their successful application as industrial cation exchangers under near neutral conditions, their performance in hyper alkaline, saline water remains highly undocumented. Using Cs(+) as a benchmark element, this study aims to assess the long-term cation exchange performance of zeolites in concrete derived aqueous solutions. Comparison of their exchange properties in alkaline media with data obtained in near neutral solutions demonstrated that the cation exchange selectivity remains unaffected by the increased hydroxyl concentration; the cation exchange capacity did however show an unexpected increase in hyper alkaline media.

  17. The alkalinizing effects of metabolizable bases in the healthy calf.

    PubMed Central

    Naylor, J M; Forsyth, G W

    1986-01-01

    The alkalinizing effect of citrate, acetate, propionate, gluconate, L and DL-lactate were compared in healthy neonatal calves. The calves were infused for a 3.5 hour period with 150 mmol/L solutions of the sodium salts of the various bases. Blood pH, base excess, and metabolite concentrations were measured and the responses compared with sodium bicarbonate and sodium chloride infusion. D-gluconate and D-lactate had poor alkalinizing abilities and accumulated in blood during infusion suggesting that they are poorly metabolized by the calf. Acetate, L-lactate and propionate had alkalinizing effects similar to bicarbonate, although those of acetate had a slightly better alkalinizing effect than L-lactate. Acetate was more effectively metabolized because blood acetate concentrations were lower than L-lactate concentrations. There was a tendency for a small improvement in metabolism of acetate and lactate with age. Sodium citrate infusion produced signs of hypocalcemia, presumably because it removed ionized calcium from the circulation. D-gluconate, D-lactate and citrate are unsuitable for use as alkalinizing agents in intravenous fluids. Propionate, acetate and L-lactate are all good alkalinizing agents in healthy calves but will not be as effective in situations where tissue metabolism is impaired. PMID:3024796

  18. Nitrogen isotope evidence for alkaline lakes on late Archean continents

    NASA Astrophysics Data System (ADS)

    Stüeken, E. E.; Buick, R.; Schauer, A. J.

    2015-02-01

    Nitrogen isotope ratios in ancient sedimentary rocks are generally interpreted as a proxy for metabolic nitrogen pathways and the redox state of the water column. Fractionation processes occurring under anoxic, alkaline conditions during the dissociation of NH4+ to H+ and volatile NH3 are frequently overlooked, although this mechanism imparts large isotopic fractionations. Here we propose that NH3 volatilization is largely responsible for δ15N values of up to + 50 ‰ at high C/N ratios in the late Archean Tumbiana Formation. This sequence of sedimentary rocks represents a system of lakes that formed on subaerial flood basalts and were partly filled by basaltic volcanic ash. Aqueous alteration of volcanic glass followed by evaporative concentration of ions should have led to the development of high alkalinity with a pH of 9 or higher, as in modern analogues. In this sedimentologically unusual setting, nitrogen isotope ratios thus provide indirect evidence for the oldest alkaline lake system in the rock record. These very heavy lacustrine δ15N values contrast markedly with those of Archean marine sedimentary rocks, making a Precambrian "soda ocean" unlikely. Today, alkaline lakes are among the most productive ecosystems on Earth. Some nutrients, in particular molybdenum, are more soluble at high pH, and certain prebiotic reactions would likely have been favored under alkaline conditions in similar settings earlier in Earth's history. Hence alkaline lakes in the Archean could have been significant for the origin and early evolution of life.

  19. Characteristics of plasmalemma alkaline phosphatase of rat mesenteric artery.

    PubMed

    Kwan, C Y

    1983-01-01

    General characteristics of alkaline phosphatase activity of the plasma membrane-enriched fraction isolated from rat mesenteric arteries were investigated. The vascular smooth muscle plasmalemma alkaline phosphatase is a metalloenzyme which is strongly inhibited by chelating agents and this inhibition can be completely overcome by addition of Mg2+ or Ca2+. Zn2+ only partially reactivates the enzyme in the presence of low concentrations of EDTA. The enzymatic hydrolysis of p-nitrophenyl phosphate, beta-glycerophosphate, alpha-glycerophosphate, or 3'-adenosine monophosphate showed an optimal activity in the alkaline region between pH 9 and 11. The alkaline phosphatase activity is distinctly different from the plasmalemma ATPase and 5'-nucleotidase activities with respect to their pH dependence, influence by added divalent metal ions and stability against heat inactivation. Vanadate ion, being structurally similar to the transition state analog of the phosphoryl group, potently inhibits alkaline phosphatase with an apparent Ki of 1.5 microM. The altered alkaline phosphatase activity of vascular smooth muscle in relation to its possible physiological function and pathophysiological manifestation associated with hypertensive disease are discussed.

  20. Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

    NASA Technical Reports Server (NTRS)

    Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  1. Susceptibility of a polycaprolactone-based root canal filling material to degradation. I. Alkaline hydrolysis.

    PubMed

    Tay, Franklin R; Pashley, David H; Williams, M Chad; Raina, Rakesh; Loushine, Robert J; Weller, R Norman; Kimbrough, W Frank; King, Nigel M

    2005-08-01

    Polycaprolactone, a thermoplastic aliphatic polyester, is reportedly susceptible to both alkaline and enzymatic hydrolyzes. This screening study examined the susceptibility of Resilon, a polycaprolactone-based root filling composite, to alkaline hydrolysis. There were 15-mm diameter disks of Resilon and Obtura gutta-percha prepared by compressive molding and immersed in 20% sodium ethoxide for 20 or 60 min. Control disks were immersed in ethanol for 60 min. These disks were examined using field-emission scanning electron microscopy and energy dispersive X-ray analysis. For Resilon, the surface resinous component was hydrolyzed after 20 min of sodium ethoxide immersion, exposing the spherulitic polymer structure and subsurface glass and bismuth oxychloride fillers. More severe erosion occurred after 60 min of sodium ethoxide treatment. Gutta-percha was unaffected after immersion in sodium ethoxide. As Resilon is susceptible to alkaline hydrolysis, it is possible that enzymatic hydrolysis may occur. Biodegradation of Resilon by bacterial/salivary enzymes and endodontically relevant bacteria warrants further investigation.

  2. Optimization of alkaline pretreatment of coffee pulp for production of bioethanol.

    PubMed

    Menezes, Evandro G T; do Carmo, Juliana R; Alves, José Guilherme L F; Menezes, Aline G T; Guimarães, Isabela C; Queiroz, Fabiana; Pimenta, Carlos J

    2014-01-01

    The use of lignocellulosic raw materials in bioethanol production has been intensively investigated in recent years. However, for efficient conversion to ethanol, many pretreatment steps are required prior to hydrolysis and fermentation. Coffee stands out as the most important agricultural product in Brazil and wastes such as pulp and coffee husk are generated during the wet and dry processing to obtain green grains, respectively. This work focused on the optimization of alkaline pretreatment of coffee pulp with the aim of making its use in the alcoholic fermentation. A central composite rotatable design was used with three independent variables: sodium hydroxide and calcium hydroxide concentrations and alkaline pretreatment time, totaling 17 experiments. After alkaline pretreatment the concentration of cellulose, hemicellulose, and lignin remaining in the material, the subsequent hydrolysis of the cellulose component and its fermentation of substrate were evaluated. The results indicated that pretreatment using 4% (w/v) sodium hydroxide solution, with no calcium hydroxide, and 25 min treatment time gave the best results (69.18% cellulose remaining, 44.15% hemicelluloses remaining, 25.19% lignin remaining, 38.13 g/L of reducing sugars, and 27.02 g/L of glucose) and produced 13.66 g/L of ethanol with a yield of 0.4 g ethanol/g glucose.

  3. CHARACTERIZATION OF ACTINIDES IN SIMULATED ALKALINE TANK WASTE SLUDGES AND LEACHATES

    SciTech Connect

    Nash, Kenneth L.

    2008-11-20

    In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.

  4. Enhanced coagulation with polyaluminum chlorides: role of pH/alkalinity and speciation.

    PubMed

    Yan, Mingquan; Wang, Dongsheng; Yu, Jianfeng; Ni, Jinren; Edwards, Marc; Qu, Jiuhui

    2008-04-01

    Enhanced coagulation is considered to be among the best available techniques (BAT) for disinfection by-product (DBP) precursor removal in water treatment. Improving existing understanding requires further consideration of nuances of chemical speciation relative to source water chemistry. In this paper, the effect of alkalinity/pH and speciation on inorganic polymer flocculants, polyaluminum chlorides (PACls) for enhanced particle and natural organic matter (NOM) removal was investigated. Three kinds of well-characterized typical source waters in China with low, moderate, and high alkalinity were selected. Performance of coagulants is controlled not only by preformed species but also by those formed in situ. At neutral and basic pH values, PACls with higher basicity (ratio of OH(-)/Al), which have more stable preformed Alb (the rapid reacted species as in ferron assay), are more efficient for turbidity and NOM removal. At slightly acidic pH, PACls with lower basicity are more efficient since more Alb can be formed in situ. Optimal NOM removal was achieved at pH 5.5-6.5 for all PACls. Basicity, speciation, and dosage of coagulant should be optimized based on raw water alkalinity to enhance the removal efficiency of NOM.

  5. Utilization of phosphorus loaded alkaline residue to immobilize lead in a shooting range soil.

    PubMed

    Yan, Yubo; Qi, Fangjie; Seshadri, Balaji; Xu, Yilu; Hou, Jiexi; Ok, Yong Sik; Dong, Xiaoli; Li, Qiao; Sun, Xiuyun; Wang, Lianjun; Bolan, Nanthi

    2016-11-01

    The alkaline residue generated from the production of soda ash using the ammonia-soda method has been successfully used in removing phosphorus (P) from aqueous solution. But the accumulation of P-containing solid after P removal is an undesirable menace to the environment. To achieve the goal of recycling, this study explored the feasibility of reusing the P loaded alkaline residue as an amendment for immobilization of lead (Pb) in a shooting range soil. The main crystalline phase and micromorphology of amendments were determined using X-ray diffraction (XRD) and scanning electron microscopy-electron dispersion spectroscopy (SEM-EDS) methods. The toxicity characteristic leaching procedure (TCLP), sequential extraction procedure, and physiologically based extraction test (PBET) were employed to evaluate the effectiveness of Pb immobilization in soil after 45 d incubation. Treatment with P loaded alkaline residue was significantly effective in reducing the TCLP and PBET extractable Pb concentrations in contrast to the untreated soil. Moreover, a positive change in the distribution of Pb fractions was observed in the treated soil, i.e., more than 60% of soil-Pb was transformed to the residual fraction compared to the original soil. On the other hand, P loaded amendments also resulted in a drastic reduction in phytoavailable Pb to the winter wheat and a mild release of P as a nutrient in treated soil, which also confirmed the improvement of soil quality.

  6. Alkaline phosphatase revisited: hydrolysis of alkyl phosphates.

    PubMed

    O'Brien, Patrick J; Herschlag, Daniel

    2002-03-05

    Escherichia coli alkaline phosphatase (AP) is the prototypical two metal ion catalyst with two divalent zinc ions bound approximately 4 A apart in the active site. Studies spanning half a century have elucidated many structural and mechanistic features of this enzyme, rendering it an attractive model for investigating the potent catalytic power of bimetallic centers. Unfortunately, fundamental mechanistic features have been obscured by limitations with the standard assays. These assays generate concentrations of inorganic phosphate (P(i)) in excess of its inhibition constant (K(i) approximately 1 muM). This tight binding by P(i) has affected the majority of published kinetic constants. Furthermore, binding limits k(cat)/K(m) for reaction of p-nitrophenyl phosphate, the most commonly employed substrate. We describe a sensitive (32)P-based assay for hydrolysis of alkyl phosphates that avoids the complication of product inhibition. We have revisited basic mechanistic features of AP with these alkyl phosphate substrates. The results suggest that the chemical step for phosphorylation of the enzyme limits k(cat)/K(m). The pH-rate profile and additional results suggest that the serine nucleophile is active in its anionic form and has a pK(a) of < or = 5.5 in the free enzyme. An inactivating pK(a) of 8.0 is observed for binding of both substrates and inhibitors, and we suggest that this corresponds to ionization of a zinc-coordinated water molecule. Counter to previous suggestions, inorganic phosphate dianion appears to bind to the highly charged AP active site at least as strongly as the trianion. The dependence of k(cat)/K(m) on the pK(a) of the leaving group follows a Brønsted correlation with a slope of beta(lg) = -0.85 +/- 0.1, differing substantially from the previously reported value of -0.2 obtained from data with a less sensitive assay. This steep leaving group dependence is consistent with a largely dissociative transition state for AP-catalyzed hydrolysis of

  7. Alkaline-assisted screw press pretreatment affecting enzymatic hydrolysis of wheat straw.

    PubMed

    Yan, Qingqi; Wang, Yumei; Rodiahwati, Wawat; Spiess, Antje; Modigell, Michael

    2017-02-01

    Screw press processing of biomass can be considered as a suitable mechanically based pretreatment for biofuel production since it disrupts the structure of lignocellulosic biomass with high shear and pressure forces. The combination with chemical treatment has been suggested to increase the conversion of lignocellulosic biomass to fermentable sugars. Within the study, the synergetic effect of alkaline (sodium hydroxide, NaOH) soaking and screw press pretreatment on wheat straw was evaluated based on, e.g., sugar recovery and energy efficiency. After alkaline soaking (at 0.1 M for 30 min) and sequential screw press pretreatment with various screw press configurations and modified screw barrel, the lignin content of pretreated wheat straw was quantified. In addition, the structure of pretreated wheat straw was investigated by scanning electron microscopy and measurement of specific surface area. It could be shown that removal of lignin is more important than increase of surface area of the biomass to reach a high sugar recovery. The rate constant of the enzymatic hydrolysis increased from 1.1 × 10(-3) 1/h for the non-treated material over 2.3 × 10(-3) 1/h for the alkaline-soaked material to 26.9 × 10(-3) 1/h for alkaline-assisted screw press pretreated material, indicating a nearly 25-fold improvement of the digestibility by the combined chemo-mechanical pretreatment. Finally, the screw configuration was found to be an important factor for improving the sugar recovery and for reducing the specific energy consumption of the screw press pretreatment.

  8. In vitro assessment of genotoxic effects of electric arc furnace dust on human lymphocytes using the alkaline comet assay.

    PubMed

    Garaj-Vrhovac, Vera; Orescanin, Visnja; Ruk, Damir; Gajski, Goran

    2009-02-15

    In vitro genotoxic effects of leachates of electric arc furnace dust (EAFD) on human peripheral lymphocytes, assessed prior and following the treatment with a strong alkaline solution were investigated using the alkaline comet assay. Prior and following the treatment, lymphocytes were incubated with leachate of EAFD for 6 and 24 hours at 37 degrees C. Negative controls were also included. Mean values of the tail lengths established in the samples treated with the leachate stemming from the original dust for 6 and 24 hours, were 15.70 microm and 16.78 microm, respectively, as compared to 12.33 microm found in the control sample. Slight, but significant increase in the tail length was also found with the dust treated with a strong alkaline solution (13.37 microm and 13.60 microm). In case of high heavy metal concentrations (the extract of the original furnace dust), the incubation period was revealed to be of significance as well. The obtained results lead to the conclusion that alkaline comet assay could be used as a rapid, sensitive and low-cost tool when assessing genotoxicity of various waste materials, such as leachates of the electric arc furnace dust.

  9. Supplementation of alkaline phytase (Ds11) in whole-wheat bread reduces phytate content and improves mineral solubility.

    PubMed

    Park, Yun-Jong; Park, Jiwon; Park, Ki-Hwan; Oh, Byung-Chul; Auh, Joong-Hyuck

    2011-08-01

    In this study, alkaline phytase was added to whole-wheat bread and the phytate content and mineral profiles were compared to commercially available acidic phytase. At neutral pH, some phytate (approximately 20%) was degraded by endogenous phytase in wheat flour, while 40% of phytate was hydrolyzed by alkaline phytase DS11 and a 35% reduction was observed with acidic phytase. Most of the enzymatic activity occurred during the proofing stage, and the rate of reaction depended on pH. DS11 phytase effectively degraded the phytate level within a 30 min treatment at pH 7; however, at least 60 min was needed with acidic phytase to achieve the same hydrolysis level. Mineral profiles were also dramatically affected by the phytate reduction. The biggest increase was observed in Fe²⁺ by the phytase treatment. The Fe²⁺ content increased 10-fold at pH 7 and 8-fold at pH 5 with alkaline phytase DS11. Alkaline phytase DS11 was shown to be effective at phytate reduction in whole-wheat bread preparation. Additionally, phytate degradation enhanced the mineral availability of bread.

  10. Quantitation of Alkaline Phosphatase Isoenzymes Using Agarose Containing Wheat Germ Lectin

    DTIC Science & Technology

    1989-07-01

    SIl Quantitation of Alkaline Phosphatase Isoenzymes Using Agarose Containing Wheat Germ Lectin A thesis submitted in partial fulfillment of the...16 Wheat Germ Lectin Electrophoresis to Quantitate Alkaline Phosphatase Isoenzymes ................ 16 Alkaline Phosphatase Isoenzyme...vs Polyacrylamide Gel Electrophoresis ......................... 40 Clinical Correlation Using Wheat Germ Lectin 45 Placental Alkaline Phosphatase

  11. A Comparison of Oligogalacturonide- and Auxin-Induced Extracellular Alkalinization and Growth Responses in Roots of Intact Cucumber Seedlings1

    PubMed Central

    Spiro, Mark D.; Bowers, Jonathan F.; Cosgrove, Daniel J.

    2002-01-01

    Oligogalacturonic acid (OGA) affects plant growth and development in an antagonistic manner to that of the auxin indole-3-acetic acid (IAA), the mechanism by which remains to be determined. This study describes the relationship between IAA and OGA activity in intact cucumber (Cucumis sativus) seedlings. Both OGA and IAA induced rapid and transient extracellular alkalinization; however, the characteristics of the OGA and IAA responses differed in their kinetics, magnitude, calcium dependence, and region of the root in which they induced their maximal response. IAA (1 μm) induced a saturating alkalinization response of approximately 0.2 pH unit and a rapid reduction (approximately 80%) in root growth that only partially recovered over 20 h. OGAs, specifically those with a degree of polymerization of 10 to 13, induced a maximal alkalinization response of 0.48 pH unit, but OGA treatment did not alter root growth. Saturating concentrations of OGA did not block IAA-induced alkalinization or the initial IAA-induced inhibition of root growth but allowed IAA-treated roots to recover their initial growth rate within 270 min. IAA-induced alkalinization occurs primarily in the growing apical region of the root, whereas OGA induced its maximal response in the basal region of the root. This study demonstrates that OGA and IAA act by distinct mechanisms and that OGA does not simply act by inhibition of IAA action. These results also suggest that IAA-induced extracellular alkalinization is not sufficient to account for the mechanism by which IAA inhibits root growth. PMID:12376654

  12. Advanced alkaline water electrolysis. Task 2 summary report. Model for alkaline water electrolysis systems

    SciTech Connect

    Yaffe, M.R.; Murray, J.N.

    1980-04-01

    Task 2 involved the establishment of an engineering and economic model for the evaluation of various options in water electrolysis. The mode, verification of the specific coding and four case studies are described. The model was tested by evaluation of a nearly commercial technology, i.e., an 80-kW alkaline electrolyte system, operating at 60/sup 0/C, which delivers approximately 255 SLM, hydrogen for applications such as electrical generation cooling or semiconductor manufacturing. The calculated cost of hydrogen from this installed non-optimized case system with an initial cost to the customer of $87,000 was $6.99/Kg H/sub 2/ ($1.67/100 SCF) on a 20-yr levelized basis using 2.5 cents/kWh power costs. This compares favorably to a levelized average merchant hydrogen cost value of $9.11/Kg H/sub 2/ ($2.17/100 SCF) calculated using the same program.

  13. Alkalinity Enrichment Enhances Net Calcification of a Coral Reef Flat

    NASA Astrophysics Data System (ADS)

    Albright, R.; Caldeira, K.

    2015-12-01

    Ocean acidification is projected to shift reefs from a state of net accretion to one of net dissolution sometime this century. While retrospective studies show large-scale changes in coral calcification over the last several decades, it is not possible to unequivocally link these results to ocean acidification due to confounding factors of temperature and other environmental parameters. Here, we quantified the calcification response of a coral reef flat to alkalinity enrichment to test whether reef calcification increases when ocean chemistry is restored to near pre-industrial conditions. We used sodium hydroxide (NaOH) to increase the total alkalinity of seawater flowing over a reef flat, with the aim of increasing carbonate ion concentrations [CO32-] and the aragonite saturation state (Ωarag) to values that would have been attained under pre-industrial atmospheric pCO2 levels. We developed a dual tracer regression method to estimate alkalinity uptake (i.e., calcification) in response to alkalinity enrichment. This approach uses the change in ratios between a non-conservative tracer (alkalinity) and a conservative tracer (a non-reactive dye, Rhodamine WT) to assess the fraction of added alkalinity that is taken up by the reef as a result of an induced increase in calcification rate. Using this method, we estimate that an average of 17.3% ± 2.3% of the added alkalinity was taken up by the reef community. In providing results from the first seawater chemistry manipulation experiment performed on a natural coral reef community (without artificial confinement), we demonstrate that, upon increase of [CO32-] and Ωarag to near pre-industrial values, reef calcification increases. Thus, we conclude that, the impacts of ocean acidification are already being felt by coral reefs. This work is the culmination of years of work in the Caldeira lab at the Carnegie Institution for Science, involving many people including Jack Silverman, Kenny Schneider, and Jana Maclaren.

  14. Functional interrelationships in the alkaline phosphatase superfamily: phosphodiesterase activity of Escherichia coli alkaline phosphatase.

    PubMed

    O'Brien, P J; Herschlag, D

    2001-05-15

    Escherichia coli alkaline phosphatase (AP) is a proficient phosphomonoesterase with two Zn(2+) ions in its active site. Sequence homology suggests a distant evolutionary relationship between AP and alkaline phosphodiesterase/nucleotide pyrophosphatase, with conservation of the catalytic metal ions. Furthermore, many other phosphodiesterases, although not evolutionarily related, have a similar active site configuration of divalent metal ions in their active sites. These observations led us to test whether AP could also catalyze the hydrolysis of phosphate diesters. The results described herein demonstrate that AP does have phosphodiesterase activity: the phosphatase and phosphodiesterase activities copurify over several steps; inorganic phosphate, a strong competitive inhibitor of AP, inhibits the phosphodiesterase and phosphatase activities with the same inhibition constant; a point mutation that weakens phosphate binding to AP correspondingly weakens phosphate inhibition of the phosphodiesterase activity; and mutation of active site residues substantially reduces both the mono- and diesterase activities. AP accelerates the rate of phosphate diester hydrolysis by 10(11)-fold relative to the rate of the uncatalyzed reaction [(k(cat)/K(m))/k(w)]. Although this rate enhancement is substantial, it is at least 10(6)-fold less than the rate enhancement for AP-catalyzed phosphate monoester hydrolysis. Mutational analysis suggests that common active site features contribute to hydrolysis of both phosphate monoesters and phosphate diesters. However, mutation of the active site arginine to serine, R166S, decreases the monoesterase activity but not the diesterase activity, suggesting that the interaction of this arginine with the nonbridging oxygen(s) of the phosphate monoester substrate provides a substantial amount of the preferential hydrolysis of phosphate monoesters. The observation of phosphodiesterase activity extends the previous observation that AP has a low level of

  15. Crystal structure of rat intestinal alkaline phosphatase--role of crown domain in mammalian alkaline phosphatases.

    PubMed

    Ghosh, Kaushik; Mazumder Tagore, Debarati; Anumula, Rushith; Lakshmaiah, Basanth; Kumar, P P B S; Singaram, Senthuran; Matan, Thangavelu; Kallipatti, Sanjith; Selvam, Sabariya; Krishnamurthy, Prasad; Ramarao, Manjunath

    2013-11-01

    Intestinal alkaline phosphatases (IAPs) are involved in the cleavage of phosphate prodrugs to liberate the drug for absorption in the intestine. To facilitate in vitro characterization of phosphate prodrugs, we have cloned, expressed, purified and characterized IAPs from rat and cynomolgus monkey (rIAP and cIAP respectively) which are important pre-clinical species for drug metabolism studies. The recombinant rat and monkey enzymes expressed in Sf9 insect cells (IAP-Ic) were found to be glycosylated and active. Expression of rat IAP in Escherichia coli (rIAP-Ec) led to ~200-fold loss of activity that was partially recovered by the addition of external Zn(2+) and Mg(2+) ions. Crystal structures of rIAP-Ec and rIAP-Ic were determined and they provide rationale for the discrepancy in enzyme activities. Rat IAP-Ic retains its activity in presence of both Zn(2+) and Mg(2+) whereas activity of most other alkaline phosphatases (APs) including the cIAP was strongly inhibited by excess Zn(2+). Based on our crystal structure, we hypothesized the residue Q317 in rIAP, present within 7 Å of the Mg(2+) at M3, to be important for this difference in activity. The Q317H rIAP and H317Q cIAP mutants showed reversal in effect of Zn(2+), corroborating the hypothesis. Further analysis of the two structures indicated a close linkage between glycosylation and crown domain stability. A triple mutant of rIAP, where all the three putative N-linked glycosylation sites were mutated showed thermal instability and reduced activity.

  16. Martian alkaline basites chemically resemble basic rocks of the Lovozero alkaline massif, Kola peninsula

    NASA Astrophysics Data System (ADS)

    Kochemasov, G.

    The comparative wave planetology [1, 5] successfully overcomes the most principal martian test having now analyses of alkaline rocks from Columbia Hills [2, 3, 4]. This kind of rocks was predicted earlier on basis of the wave paradigm having stated that "the higher planetary relief range - the higher density difference between lithologies composing hypsometrically (tectonically) contrasting blocks [5]. This paradigm declares that "celestial bodies are dichotomic"(Theorem 1), "celestial bodies are sectoral" (Theorem 2), "celestial bodies are granular"(Theorem 3), "angular momenta of different level blocks tend to be equal" (Theorem 4)[1, 5]. Mars is a typical terrestrial planet but the farthest from Sun and thus with the smallest tide effects. Nevertheless it has the highest relief range and seems to be most distorted (ellipsoid in shape) and broken by deep fissures. The wave approach explains this by a warping action of standing waves of 4 ortho- and diagonal directions - they are the longest and highest in the martian case. These interfering warping waves caused by the elliptic keplerian orbits implying periodically changing accelerations and inertia-gravity forces produce inevitable tectonic dichotomy (the fundamental wave 1 long 2πR), sectoring (wave 2, πR, and other overtones), granulation. A granule size depends on an orbital frequency: the higher frequency the smaller granule. The Earth's granule, as a scale, is πR/4 (see it in NASA's PIA04159), Venus ` πR/6, Mercury's πR/16, Mars' πR/2 (the sizes are strictly tied to orb. fr.). Along with the granule sizes increase relief ranges ( Mercury ˜5 km, Venus 14, Earth 20, Mars ˜30) and compositional (density) difference between lowland and highland lithologies [5]. The lowland compositions become Fericher and denser: enstatite (Mercury), Mg-basalt (Venus), tholeiite (Earth), Fe-basalt (Mars). The highland compositions get less dense, lighter: anorthosite, alkaline basalt, andesite and conditional "albitite

  17. A modified alkaline Comet assay for in vivo detection of oxidative DNA damage in Drosophila melanogaster.

    PubMed

    Shukla, A K; Pragya, P; Chowdhuri, D Kar

    2011-12-24

    Modifications to the alkaline Comet assay by using lesion-specific endonucleases, such as formamidopyrimidine-DNA glycosylase (FPG) and endonuclease III (ENDOIII, also known as Nth), can detect DNA bases with oxidative damage. This modified assay can be used to assess the genotoxic/carcinogenic potential of environmental chemicals. The goal of this study was to validate the ability of this modified assay to detect oxidative stress-induced genotoxicity in Drosophila melanogaster (Oregon R(+)). In this study, we used three well known chemical oxidative stress inducers: hydrogen peroxide (H(2)O(2)), cadmium chloride (CdCl(2)) and copper sulfate (CuSO(4)). Third instar larvae of D. melanogaster were fed various concentrations of the test chemicals (50-200μM) mixed with a standard Drosophila food for 24h. Alkaline Comet assays with and without the FPG and ENDOIII enzymes were performed with midgut cells that were isolated from the control and treated larvae. Our results show a concentration-dependent increase (p<0.05-0.001) in the migration of DNA from the treated larvae. ENDOIII treatment detected more oxidative DNA damage (specifically pyrimidine damage) in the H(2)O(2) exposed larvae compared to FPG or no enzyme treatment (buffer only). In contrast, FPG treatment detected more oxidative DNA damage (specifically purine damage) in CuSO(4) exposed larvae compared to ENDOIII. Although previously reported to be a potent genotoxic agent, CdCl(2) did not induce more oxidative DNA damage than the other test chemicals. Our results show that the modified alkaline Comet assay can be used to detect oxidative stress-induced DNA damage in D. melanogaster and thus may be applicable for in vivo genotoxic assessments of environmental chemicals.

  18. Alkaline Phosphatase: A Biomarker of Cardiac Function in Pediatric Patients.

    PubMed

    Makil, Elizabeth S; Tang, Xinyu; Frazier, Elizabeth A; Collins, R Thomas

    2017-02-09

    Myocardial dysfunction and heart failure are common in pediatric patients with congenital and acquired heart disease. Alkaline phosphatase (AP) has been suggested as a biomarker for myocardial dysfunction after Fontan operation. We hypothesized that pediatric patients with myocardial dysfunction requiring orthotopic heart transplant (OHT) have diminished AP compared to normal. A retrospective review was performed in all patients who underwent OHT at Arkansas Children's Hospital between January 2007 and October 2012. Anatomic diagnoses, therapeutic interventions, and ventricular ejection fraction (EF) were recorded. Z scores for AP levels in the study group were determined by comparing the observed AP levels to age- and gender-matched normative values. T tests were performed to compare the mean AP Z score prior to and after OHT. p values <0.05 were considered statistically significant. During the study period, 124 OHTs were performed. Complete study data were available and analyzed from 71/124 patients (mean age at OHT 3.9 years; 51% female). The mean AP Z score was significantly lower in the study group prior to OHT compared to normal (p < 0.0001). The initiation of ACE inhibitor therapy prior to OHT was associated with a significant increase in AP and the ventricular EF (p < 0.001 for both). Treatment with milrinone was associated with an increase in EF. AP is significantly lower in pediatric patients with myocardial dysfunction prior to OHT compared to normal. AP increases significantly after the initiation of therapies to improve myocardial function. Diminished AP is an indicator of myocardial dysfunction in pediatric patients.

  19. In situ arsenic removal in an alkaline clastic aquifer

    USGS Publications Warehouse

    Welch, A.H.; Stollenwerk, K.G.; Paul, A.P.; Maurer, D.K.; Halford, K.J.

    2008-01-01

    In situ removal of As from ground water used for water supply has been accomplished elsewhere in circum-neutral ground water containing high dissolved Fe(II) concentrations. The objective of this study was to evaluate in situ As ground-water treatment approaches in alkaline ground-water (pH > 8) that contains low dissolved Fe (

  20. Escherichia coli alkaline phosphatase. Kinetic studies with the tetrameric enzyme.

    PubMed

    Halford, S E; Schlesinger, M J; Gutfreund, H

    1972-03-01

    1. The stability of the tetrameric form of Escherichia coli alkaline phosphatase was examined by analytical ultracentrifugation. 2. The stopped-flow technique was used to study the hydrolysis of nitrophenyl phosphates by the alkaline phosphatase tetramer at pH7.5 and 8.3. In both cases transient product formation was observed before the steady state was attained. Both transients consisted of the liberation of 1mol of nitrophenol/2mol of enzyme subunits within the dead-time of the apparatus. The steady-state rates were identical with those observed with the dimer under the same conditions. 3. The binding of 2-hydroxy-5-nitrobenzyl phosphonate to the alkaline phosphatase tetramer was studied by the temperature-jump technique. The self-association of two dimers to form the tetramer is linked to a conformation change within the dimer. This accounts for the differences between the transient phases in the reactions of the dimer and the tetramer with substrate. 4. Addition of P(i) to the alkaline phosphatase tetramer caused it to dissociate into dimers. The tetramer is unable to bind this ligand. It is suggested that the tetramer undergoes a compulsory dissociation before the completion of its first turnover with substrate. 5. On the basis of these findings a mechanism is proposed for the involvement of the alkaline phosphatase tetramer in the physiology of E. coli.

  1. Characterization of Human Bone Alkaline Phosphatase in Pichia Pastoris

    NASA Technical Reports Server (NTRS)

    Malone, Christine C.; Ciszak, Eva; Karr, Laurel J.

    1999-01-01

    A soluble form of human bone alkaline phosphatase has been expressed in a recombinant strain of the methylotrophic yeast Pichia pastoris. We constructed a plasmid containing cDNA encoding for human bone alkaline phosphatase, with the hydrophobic carboxyl terminal portion deleted. Alkaline phosphatase was secreted into the medium to a level of 32mg/L when cultured in shake flasks, and enzyme activity was 12U/mg, as measured by a spectrophotometric assay. By conversion to a fermentation system, a yield of 880mg/L has been achieved with an enzyme activity of 968U/mg. By gel electrophoresis analysis, it appears that greater than 50% of the total protein in the fermentation media is alkaline phosphatase. Although purification procedures are not yet completely optimized, they are expected to include filtration, ion exchange and affinity chromatography. Our presentation will focus on the purification and crystallization results up to the time of the conference. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  2. Field measurement of alkalinity and pH

    USGS Publications Warehouse

    Barnes, Ivan

    1964-01-01

    The behavior of electrometric pH equipment under field conditions departs from the behavior predicted from Nernst's law. The response is a linear function of pH, and hence measured pH values may be corrected to true pH if the instrument is calibrated with two reference solutions for each measurement. Alkalinity titrations may also be made in terms of true pH. Standard methods, such as colorimetric titrations, were rejected as unreliable or too cumbersome for rapid field use. The true pH of the end point of the alkalinity titration as a function of temperature, ionic strength, and total alkalinity has been calculated. Total alkalinity in potable waters is the most important factor influencing the end point pH, which varies from 5.38 (0 ? C, 5 ppm (parts per million) HC0a-) to 4.32 (300 ppm HC0a-,35 ? C), for the ranges of variables considered. With proper precautions, the pH may be determined to =i:0.02 pH and the alkalinity to =i:0.6 ppm HCO3- for many naturally occurring bodies of fresh water.

  3. Effect of gingival application of melatonin on alkaline and acid phosphatase, osteopontin and osteocalcin in patients with diabetes and periodontal disease

    PubMed Central

    López-Valverde, Antonio; Gómez-de-Diego, Rafel; Arias-Santiago, Salvador; de Vicente-Jiménez, Joaquín

    2013-01-01

    Objectives: To assess the effect of topical application of melatonin to the gingiva on salivary fluid concentrations of acid phosphatase, alkaline phosphatase, osteopontin, and osteocalcin. Study Design: Cross-sectional study of 30 patients with diabetes and periodontal disease and 30 healthy subjects. Diabetic patients were treated with topical application of melatonin (1% orabase cream formula) once daily for 20 days and controls with a placebo formulation. Results: Before treatment with melatonin, diabetic patients showed significantly higher mean salivary levels of alkaline and acid phosphatase, osteopontin and osteocalcin than healthy subjects (P < 0.01). After treatment with melatonin, there was a statistically significant decrease of the gingival index (15.84± 10.3 vs 5.6 ± 5.1) and pocket depth (28.3 ± 19.5 vs 11.9 ± 9.0) (P < 0.001). Also, use of melatonin was associated with a significant reduction of the four biomarkers. Changes of salivary acid phosphatase and osteopontin correlated significantly with changes in the gingival index, whereas changes of alkaline phosphatase and osteopontin correlated significantly with changes in the pocket depth. Conclusions: Treatment with topical melatonin was associated with an improvement in the gingival index and pocket depth, a reduction in salivary concentrations of acid phosphatase, alkaline phosphatase, osteopontin and osteocalcin. Key words:Melatonin, diabetes mellitus, alkaline phosphatase, acid phosphatase, osteopontin, osteocalcin. PMID:23524437

  4. Inhibition of microbiological sulfide oxidation by methanethiol and dimethyl polysulfides at natron-alkaline conditions.

    PubMed

    van den Bosch, Pim L F; de Graaff, Marco; Fortuny-Picornell, Marc; van Leerdam, Robin C; Janssen, Albert J H

    2009-06-01

    To avoid problems related to the discharge of sulfidic spent caustics, a biotechnological process is developed for the treatment of gases containing both hydrogen sulfide and methanethiol. The process operates at natron-alkaline conditions (>1 mol L(-1) of sodium- and potassium carbonates and a pH of 8.5-10) to enable the treatment of gases with a high partial CO(2) pressure. In the process, methanethiol reacts with biologically produced sulfur particles to form a complex mixture predominantly consisting of inorganic polysulfides, dimethyl disulfide (DMDS), and dimethyl trisulfide (DMTS). The effect of these organic sulfur compounds on the biological oxidation of sulfide to elemental sulfur was studied with natron-alkaliphilic bacteria belonging to the genus Thioalkalivibrio. Biological oxidation rates were reduced by 50% at 0.05 mM methanethiol, while for DMDS and DMTS, this was estimated to occur at 1.5 and 1.0 mM, respectively. The inhibiting effect of methanethiol on biological sulfide oxidation diminished due to its reaction with biologically produced sulfur particles. This reaction increases the feasibility of biotechnological treatment of gases containing both hydrogen sulfide and methanethiol at natron-alkaline conditions.

  5. Alkaline direct alcohol fuel cells using an anion exchange membrane

    NASA Astrophysics Data System (ADS)

    Matsuoka, Koji; Iriyama, Yasutoshi; Abe, Takeshi; Matsuoka, Masao; Ogumi, Zempachi

    Alkaline direct alcohol fuel cells using an OH-form anion exchange membrane and polyhydric alcohols were studied. A high open circuit voltage of ca. 800 mV was obtained for a cell using Pt-Ru/C (anode) and Pt/C (cathode) at 323 K, which was about 100-200 mV higher than that for a DMFC using Nafion ®. The maximum power densities were in the order of ethylene glycol > glycerol > methanol > erythritol > xylitol. Silver catalysts were used as a cathode catalyst to fabricate alkaline fuel cells, since silver catalyst is almost inactive in the oxidation of polyhydric alcohols. Alkaline direct ethylene glycol fuel cells using silver as a cathode catalyst gave excellent performance because higher concentrations of fuel could be supplied to the anode.

  6. Alkaline Comet Assay for Assessing DNA Damage in Individual Cells.

    PubMed

    Pu, Xinzhu; Wang, Zemin; Klaunig, James E

    2015-08-06

    Single-cell gel electrophoresis, commonly called a comet assay, is a simple and sensitive method for assessing DNA damage at the single-cell level. It is an important technique in genetic toxicological studies. The comet assay performed under alkaline conditions (pH >13) is considered the optimal version for identifying agents with genotoxic activity. The alkaline comet assay is capable of detecting DNA double-strand breaks, single-strand breaks, alkali-labile sites, DNA-DNA/DNA-protein cross-linking, and incomplete excision repair sites. The inclusion of digestion of lesion-specific DNA repair enzymes in the procedure allows the detection of various DNA base alterations, such as oxidative base damage. This unit describes alkaline comet assay procedures for assessing DNA strand breaks and oxidative base alterations. These methods can be applied in a variety of cells from in vitro and in vivo experiments, as well as human studies.

  7. Metasomatized lithosphere and the origin of alkaline lavas.

    PubMed

    Pilet, Sébastien; Baker, Michael B; Stolper, Edward M

    2008-05-16

    Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that partial melts of metasomatic veins can reproduce key major- and trace-element features of oceanic and continental alkaline magmas. Moreover, experiments with hornblendite plus lherzolite showed that reaction of melts of amphibole-rich veins with surrounding lherzolite can explain observed compositional trends from nephelinites to alkali olivine basalts. We conclude that melting of metasomatized lithosphere is a viable alternative to models of alkaline basalt formation by melting of recycled oceanic crust with or without sediment.

  8. Kinetic Release of Alkalinity from Particle-Containing Oil-in-Water Emulsions

    NASA Astrophysics Data System (ADS)

    Muller, K.; Chapra, S. C.; Ramsburg, A.

    2014-12-01

    Oil-in-water emulsions are typically employed during remediation to promote biotic reduction of contaminants. Emulsions, however, hold promise for encapsulated delivery of many types of active ingredients required for successful site remediation or long-term site stewardship. Our research is currently focused on using alkalinity-containing particles held within oil-in-water emulsions to sustain control of subsurface pH. Here we describe results from laboratory experiments and mathematical modeling conducted to quantify the kinetics associated with the emulsion delivery and alkalinity release process. Kinetically stable oil-in-water emulsions containing (~60 nmCaCO3 or ~100 nm MgO particles) were previously developed using soybean oil and Gum Arabic as a stabilizing agent. Batch and column experiments were employed to assess the accessibility and release of the alkalinity from the emulsion. Successive additions of HCl were used in batch systems to produce several pH responses (pH rebounds) that were subsequently modeled to elucidate release mechanisms and rates for varying emulsion compositions and particle types. Initial results suggest that a linear-driving-force model is generally able to capture the release behavior in the batch system when the temporally-constant, lumped mass-transfer coefficient is scaled by the fraction of particle mass remaining within the droplets. This result suggests that the rate limiting step in the release process may be the interphase transfer of reactive species at the oil-water interface. 1-d column experiments were also completed in order to quantify the extent and rate of alkalinity release from emulsion droplets retained in a sandy medium. Alkalinity release from the retained droplets treated a pH 4 influent water for 25-60 pore volumes (the duration depended on particle type and mass loading), and the cessation in treatment corresponded to exhaustion of the particle mass held within the oil. Column experiments were simulated

  9. Alkalinity production in intertidal sands intensified by lugworm bioirrigation

    PubMed Central

    Rao, Alexandra M.F.; Malkin, Sairah Y.; Montserrat, Francesc; Meysman, Filip J.R.

    2014-01-01

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer. PMID:25431515

  10. Alkaline earth metal cation exchange: effect of mobile counterion and dissolved organic matter.

    PubMed

    Indarawis, Katrina; Boyer, Treavor H

    2012-04-17

    The goal of this research was to provide an improved understanding of the interactions between alkaline earth metals and DOM under conditions that are encountered during drinking water treatment with particular focus on cation exchange. Both magnetically enhanced and nonmagnetic cation exchange resins were converted to Na, Mg, Ca, Sr, and Ba mobile counterion forms as a novel approach to investigate the exchange behavior between the cations and the interactions between the cations and DOM. The results show that cation exchange is a robust process for removal of Ca(2+) and Mg(2+) considering competition with cations on the resin surface and presence of DOM. DOM was actively involved during the cation exchange process through complexation, adsorption, and coprecipitation reactions. In addition to advancing the understanding of ion exchange processes for water treatment, the results of this work are applicable to membrane pretreatment to minimize fouling, treatment of membrane concentrate, and precipitative softening.

  11. Surfactant-enhanced low-pH alkaline flooding

    SciTech Connect

    Peru, D.A. and Co., Columbia, MD . Research Div.); Lorenz, P.B. )

    1990-08-01

    This paper reports sodium bicarbonate investigated as a potential alkaline agent in surfactant-enhanced alkaline flooding because it has very little tendency to dissolve silicate minerals. In experiments performed with Wilmington, CA, crude oil and three types of surfactants, the bicarbonate/surfactant combination caused a marked lowering of interfacial tension (IFT). Bicarbonate protected the surfactant against divalent cations and reduced adsorption of surfactant and polymer on various minerals. Coreflood test confirm that sodium bicarbonate plus surfactant can be an effective alternative to the high-pH flooding process.

  12. Immobilization of cesium in alkaline activated fly ash matrix

    NASA Astrophysics Data System (ADS)

    Fernandez-Jimenez, A.; Macphee, D. E.; Lachowski, E. E.; Palomo, A.

    2005-11-01

    The immobilization potential of alkaline activated fly ash (AAFA) matrices for cesium has been investigated. The presence of Cs in the AAFA pastes, prepared using 8M NaOH solution as activator, showed no significant adverse effects on mechanical strength or microstructure, nor were significant quantities of Cs leached following application of the Toxic Characteristic Leaching Procedure (TCLP) and American Nuclear Society (ANS) 16.1 leaching protocols. Microstructural analysis shows Cs associated with the main reaction product in the AAFA suggesting that cesium is chemically bound rather than physically encapsulated. It is proposed that cesium is incorporated into the alkaline aluminosilicate gel, a precursor for zeolite formation.

  13. Study of point defects in alkaline-earth sulfides

    SciTech Connect

    Pandey, R.; Kunz, A.B.; Vail, J.M.

    1988-11-01

    The results of a computer simulation study of point defects including vacancy, interstitial, and F/sup +/ center in alkaline-earth sulfides are presented. The study is based on ICECAP/HADES simulation procedures and uses empirical interionic potentials obtained from the analysis of macroscopic data for these materials. The results predict the dominance of Schottky disorder and suggest that vacancy migration predominates in alkaline-earth sulfides. Furthermore, the calculated F/sup +/ center absorption energy is in good agreement with the experimental data deduced from the optical stimulated studies in these materials.

  14. Advanced technology for extended endurance alkaline fuel cells

    NASA Astrophysics Data System (ADS)

    Sheibley, D. W.; Martin, R. A.

    Advanced components have been developed for alkaline fuel cells with a view to the satisfaction of NASA Space Station design requirements for extended endurance. The components include a platinum-on-carbon catalyst anode, a potassium titanate-bonded electrolyte matrix, a lightweight graphite electrolyte reservoir plate, a gold-plated nickel-perforated foil electrode substrate, a polyphenylene sulfide cell edge frame material, and a nonmagnesium cooler concept. When incorporated into the alkaline fuel cell unit, these components are expected to yield regenerative operation in a low earth orbit Space Station with a design life greater than 5 years.

  15. Advanced technology for extended endurance alkaline fuel cells

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Martin, R. A.

    1987-01-01

    Advanced components have been developed for alkaline fuel cells with a view to the satisfaction of NASA Space Station design requirements for extended endurance. The components include a platinum-on-carbon catalyst anode, a potassium titanate-bonded electrolyte matrix, a lightweight graphite electrolyte reservoir plate, a gold-plated nickel-perforated foil electrode substrate, a polyphenylene sulfide cell edge frame material, and a nonmagnesium cooler concept. When incorporated into the alkaline fuel cell unit, these components are expected to yield regenerative operation in a low earth orbit Space Station with a design life greater than 5 years.

  16. Tuning NaYF4 Nanoparticles through Alkaline Earth Doping

    PubMed Central

    Chen, Xian; Peng, Dengfeng; Wang, Feng

    2013-01-01

    Phase and size of lanthanide-doped nanoparticles are the most important characteristics that dictate optical properties of these nanoparticles and affect their technological applications. Herein, we present a systematic study to examine the effect of alkaline earth doping on the formation of NaYF4 upconversion nanoparticles. We show that alkaline earth doping has a dual function of tuning particle size of hexagonal phase NaYF4 nanoparticles and stabilizing cubic phase NaYF4 nanoparticles depending on composition and concentration of the dopant ions. The study described here represents a facile and general strategy to tuning the properties of NaYF4 upconversion nanoparticles. PMID:28348353

  17. Alkaline solution absorption of carbon dioxide method and apparatus

    DOEpatents

    Hobbs, D.T.

    1991-01-01

    Disclosed is a method for measuring the concentration of hydroxides (or pH) in alkaline solutions, using the tendency of hydroxides to adsorb CO{sub 2}. The method comprises passing CO{sub 2} over the surface of an alkaline solution in a remote tank before and after measurements of the CO{sub 2} concentration. Comparison of the measurements yields the adsorption fraction from which the hydroxide concentration can be calculated using a correlation of hydroxide or pH to adsorption fraction. A schematic is given of a process system according to a preferred embodiment of the invention. 2 figs.

  18. Spin-Orbit-Coupled Correlated Metal Phase in Kondo Lattices: An Implementation with Alkaline-Earth Atoms

    NASA Astrophysics Data System (ADS)

    Isaev, L.; Schachenmayer, J.; Rey, A. M.

    2016-09-01

    We show that an interplay between quantum effects, strong on-site ferromagnetic exchange interaction, and antiferromagnetic correlations in Kondo lattices can give rise to an exotic spin-orbit coupled metallic state in regimes where classical treatments predict a trivial insulating behavior. This phenomenon can be simulated with ultracold alkaline-earth fermionic atoms subject to a laser-induced magnetic field by observing dynamics of spin-charge excitations in quench experiments.

  19. Transformation of glucocorticoid receptors bound to the antagonist RU 486: Effects of alkaline phosphatase

    SciTech Connect

    Gruol, D.J.; Wolfe, K.A. )

    1990-08-28

    RU 486 is a synthetic steroid that binds avidly to glucocorticoid receptors without promoting their transformation into activated transcription factors. A significant part of this behavior has been shown to be due to a failure of the RU 486 bound receptor to be efficiently released from a larger (sedimenting at 8-9 S) multimeric complex containing the 90-kDa heat shock protein. The studies have found that in vitro at 15{degree}C the RU 486-receptor was slowly released from the 8-9S complex and converted into a DNA binding protein by a process that could be blocked by sodium fluoride. Moreover, this transition was significantly accelerated by treatment with alkaline phosphatase. High-resolution anion-exchange chromatography showed that the profile of receptor subspecies released from the 8-9S complex was different for the RU 486 bound receptor when compared to the receptor occupied by the agonist triamcinolone acetonide. Production of the earliest eluting receptor form (peak A) was inhibited with RU 486. Treatment of the Ru 486-receptor with alkaline phosphatase increased the formation of the peak A subspecies as well as the capacity of receptor to bind DNA-cellulose. Taken together, the results indicate that phosphorylation of the receptor or a tightly bound factor contributes to defining the capacity with which individual steroids can promote dissociation of the 8-9S complex and conversion of the glucocorticoid receptor into a DNA-binding protein.

  20. Alkaline peroxide delignification of agricultural residues to enhance enzymatic saccharification. [Trichoderma reesei

    SciTech Connect

    Gould, J.M.

    1984-01-01

    Approximately one-half of the lignin and most of the hemicellulose present in agricultural residues such as wheat straw and corn stover are solubilized when the residue is treated at 25/sup 0/C in an alkaline solution of hydrogen peroxide. The delignification reaction is most efficient when the ratio of hydrogen peroxide to substrate is at least 0.25 (w/w) and the pH is 11.5. The supernatant fraction from a given pretreatment, after addition of makeup peroxide and readjustment of the pH, can be recycled to treat at least six additional batches of substrate, resulting in a substantial concentration of hemicellulose and soluble lignin degradation products. Hydrolysis of the insoluble fraction with Trichoderma reesei cellulase after alkline peroxide treatment yields glucose with almost 100% efficiency, based upon the cellulose content of the residue before treatment. These data indicate that alkaline peroxide pretreatment is a simple and efficient method for enhancing the enzymatic digestibility of lignocellulosic crop residues to levels approaching the theoretical maximum.

  1. Surfactant adsorption at fluid-fluid interfaces with applications to alkaline flooding

    SciTech Connect

    Borwankar, R.P.

    1984-01-01

    Adsorption of surfactants at fluid-fluid interfaces is studied with respect to equilibrium and dynamic behavior. An equilibrium model is developed wherein the surface concentration of ionic surfactants is distinguished from their surface excess concentration by the contribution from the electrical double layer. A consistent treatment of adsorption dynamics is formulated using a continuum approach. Surfactant transport in the bulk is assumed to consist of diffusion (and convection) with constant transport coefficients. Activation energy barriers to solute exchange between the bulk and the dividing surface are represented by means of kinetics of interphase reactions. This treatment is used to develop diffusion-kinetic models for gas-liquid systems under stagnant batch conditions and for liquid-liquid systems under gyrostatic conditions of the spinning drop tensiometer. In the liquid-liquid case, the acidic oil/caustic system of alkaline flooding for enhanced oil recovery is investigated. A continuous flow model is developed to assess the role of dynamic effects in alkaline flooding processes. Axial dispersion of caustic and its uptake by the reservoir rock are taken into account. An unsteady state solution is obtained when a linear isotherm governs the caustic uptake by the reservoir rock while a steady state solution is obtained for a Langmuir isotherm. Predictions of interfacial tension behavior are made for Wilmington Field crude oil.

  2. Extracellular Alkalinization as a Defense Response in Potato Cells

    PubMed Central

    Moroz, Natalia; Fritch, Karen R.; Marcec, Matthew J.; Tripathi, Diwaker; Smertenko, Andrei; Tanaka, Kiwamu

    2017-01-01

    A quantitative and robust bioassay to assess plant defense response is important for studies of disease resistance and also for the early identification of disease during pre- or non-symptomatic phases. An increase in extracellular pH is known to be an early defense response in plants. In this study, we demonstrate extracellular alkalinization as a defense response in potatoes. Using potato suspension cell cultures, we observed an alkalinization response against various pathogen- and plant-derived elicitors in a dose- and time-dependent manner. We also assessed the defense response against a variety of potato pathogens, such as protists (Phytophthora infestans and Spongospora subterranea) and fungi (Verticillium dahliae and Colletotrichum coccodes). Our results show that extracellular pH increases within 30 min in proportion to the number of pathogen spores added. Consistently with the alkalinization effect, the higher transcription level of several defense-related genes and production of reactive oxygen species was observed. Our results demonstrate that the alkalinization response is an effective marker to study early stages of defense response in potatoes. PMID:28174578

  3. Oxygen electrodes for rechargeable alkaline fuel cells-II

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.

    1989-01-01

    The primary objective of this program is the investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single-unit rechargeable alkaline fuel cells. Approximately six support materials and five catalyst materials have been identified to date for further development.

  4. Alkaline fuel cells for prime power and energy storage

    NASA Astrophysics Data System (ADS)

    Stedman, J. K.

    Alkaline fuel cell technology and its application to future space missions requiring high power and energy storage are discussed. Energy densities exceeding 100 watthours per pound and power densities approaching 0.5 pounds per kilowatt are calculated for advanced systems. Materials research to allow reversible operation of cells for energy storage and higher temperature operation for peaking power is warranted.

  5. Extracellular Alkalinization as a Defense Response in Potato Cells.

    PubMed

    Moroz, Natalia; Fritch, Karen R; Marcec, Matthew J; Tripathi, Diwaker; Smertenko, Andrei; Tanaka, Kiwamu

    2017-01-01

    A quantitative and robust bioassay to assess plant defense response is important for studies of disease resistance and also for the early identification of disease during pre- or non-symptomatic phases. An increase in extracellular pH is known to be an early defense response in plants. In this study, we demonstrate extracellular alkalinization as a defense response in potatoes. Using potato suspension cell cultures, we observed an alkalinization response against various pathogen- and plant-derived elicitors in a dose- and time-dependent manner. We also assessed the defense response against a variety of potato pathogens, such as protists (Phytophthora infestans and Spongospora subterranea) and fungi (Verticillium dahliae and Colletotrichum coccodes). Our results show that extracellular pH increases within 30 min in proportion to the number of pathogen spores added. Consistently with the alkalinization effect, the higher transcription level of several defense-related genes and production of reactive oxygen species was observed. Our results demonstrate that the alkalinization response is an effective marker to study early stages of defense response in potatoes.

  6. [Granulocyte alkaline phosphatase--a biomarker of chronic benzene exposure].

    PubMed

    Khristeva, V; Meshkov, T

    1994-01-01

    In tracing the cellular population status in the peripheral blood of workers, exposed to benzene, was included and cytochemical determination of the alkaline phosphatase activity in leucocytes. This enzyme is accepted as marker of the neutrophilic granulocytes, as maturation of the cells and their antibacterial activity are parallel to the cytochemical activity of the enzyme. 78 workers from the coke-chemical production from state firm "Kremikovtsi" and 41 workers from the production "Benzene" and "Isopropylbenzene"--Oil Chemical Plant, Burgas are included. The benzene concentrations in the air of the working places in all productions are in the range of 5 to 50 mg/m3. For cytochemical determination of the alkaline phosphatase activity is used the method of L. Kaplow and phosphatase index was calculated. It was established that in 98.4% of all examined the alkaline phosphatase activity is inhibited to different rate, as from 46.5% [61 workers] it is zero. In considerably lower percentage of workers were established and other deviations: leucocytosis or leucopenia, neutropenia, increased percent of band neutrophils and toxic granules. The results of the investigation of the granulocyte population show that from all indices, the activity of granulocyte alkaline phosphatase demonstrates most convincing the early myelotoxic effect of benzene.

  7. The catalytic properties of alkaline phosphatases under various conditions

    NASA Astrophysics Data System (ADS)

    Atyaksheva, L. F.; Chukhrai, E. S.; Poltorak, O. M.

    2008-11-01

    A comparative study was performed to examine the catalytic properties of alkaline phosphatases from bacteria Escherichia coli and bovine and chicken intestines. The activity of enzyme dimers and tetramers was determined. The activity of the dimer was three or four times higher than that of the tetramer. The maximum activity and affinity for 4-nitrophenylphosphate was observed for the bacterial alkaline phosphatase ( K M = 1.7 × 10-5 M, V max = 1800 μmol/(min mg of protein) for dimers and V max = 420 μmol/(min mg of protein) for tetramers). The Michaelis constants were equal for two animal phosphatases in various buffer media (pH 8.5) ((3.5 ± 0.2) × 10-4 M). Five buffer systems were investigated: tris, carbonate, hepes, borate, and glycine buffers, and the lowest catalytic activity of alkaline phosphatases at equal pH was observed in the borate buffer (for enzyme from bovine intestine, V max = 80 μmol/(min mg of protein)). Cu2+ cations formed a complex with tris-(oxymethyl)-aminomethane ( tris-HCl buffer) and inhibited the intestine alkaline phosphatases by a noncompetitive mechanism.

  8. Alkalinity and hardness: Critical but elusive concepts in aquaculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Total alkalinity and total hardness are familiar variables to those involved in aquatic animal production. Aquaculturists – both scientists and practitioners alike – tend to have some understanding of the two variables and of methods for adjusting their concentrations. The chemistry and the biolog...

  9. Alkaline extraction of phenolic compounds from intact sorghum kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aqueous sodium hydroxide solution was employed to extract phenolic compounds from whole grain sorghum without decortication or grinding as determined by Oxygen Radical Absorbance Capacity (ORAC). The alkaline extract ORAC values were more stable over 32 days compared to neutralized and freeze dri...

  10. Alkalinity Analysis. Training Module 5.220.2.77.

    ERIC Educational Resources Information Center

    Bonte, John L.; Davidson, Arnold C.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the acid-base titrimetric procedure for determining the hydroxide, carbonate and bicarbonate alkalinity of a water sample. Included are objectives, an instructor guide, student handouts and transparency masters. A video tape is also…

  11. Mammalian intestinal alkaline phosphatase acts as highly active exopolyphosphatase.

    PubMed

    Lorenz, B; Schröder, H C

    2001-06-11

    Recent results revealed that inorganic polyphosphates (polyP), being energy-rich linear polymers of orthophosphate residues known from bacteria and yeast, also exist in higher eukaryotes. However, the enzymatic basis of their metabolism especially in mammalian cells is still uncertain. Here we demonstrate for the first time that alkaline phosphatase from calf intestine (CIAP) is able to cleave polyP molecules up to a chain length of about 800. The enzyme acts as an exopolyphosphatase degrading polyP in a processive manner. The pH optimum is in the alkaline range. Divalent cations are not required for catalytic activity but inhibit the degradation of polyP. The rate of hydrolysis of short-chain polyP by CIAP is comparable to that of the standard alkaline phosphatase (AP) substrate p-nitrophenyl phosphate. The specific activity of the enzyme decreases with increasing chain length of the polymer both in the alkaline and in the neutral pH range. The K(m) of the enzyme also decreases with increasing chain length. The mammalian tissue non-specific isoform of AP was not able to hydrolyze polyP under the conditions applied while the placental-type AP and the bacterial (Escherichia coli) AP displayed polyP-degrading activity.

  12. Oxygen electrodes for rechargeable alkaline fuel cells, 3

    NASA Astrophysics Data System (ADS)

    Swette, L.; Kackley, N.; McCatty, S. A.

    1991-09-01

    The investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells is described. Focus is on chemical and electrochemical stability and O2 reduction/evolution activity of the electrode in question.

  13. Alkaline regenerative fuel cell systems for energy storage

    SciTech Connect

    Schubert, F.H.; Reid, M.A.; Martin, R.E.

    1981-01-01

    This paper presents the results of a preliminary design study of a Regenerative Fuel Cell Energy Storage system for application to future low-earth orbit space missions. This high energy density storage system is based on state-of-the-art alkaline electrolyte cell technology and incorporates dedicated fuel cell and electrolysis cell modules. 11 refs.

  14. Oxygen electrodes for rechargeable alkaline fuel cells, 3

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells is described. Focus is on chemical and electrochemical stability and O2 reduction/evolution activity of the electrode in question.

  15. Ocean alkalinity and the Cretaceous/Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Caldeira, K. G.; Rampino, Michael R.

    1988-01-01

    A biogeochemical cycle model resolving ocean carbon and alkalinity content is applied to the Maestrichtian and Danian. The model computes oceanic concentrations and distributions of Ca(2+), Mg(2+), and Sigma-CO2. From these values an atmospheric pCO2 value is calculated, which is used to estimate rates of terrestrial weathering of calcite, dolomite, and calcium and magnesium silicates. Metamorphism of carbonate rocks and the subsequent outgassing of CO2 to the atmosphere are parameterized in terms of carbonate rock reservoir sizes, total land area, and a measure of overall tectonic activity, the sea-floor generation rate. The ocean carbon reservoir computed by the model is used with Deep Sea Drilling Project (DSDP) C-13 data to estimate organic detrital fluxes under a variety of ocean mixing rate assumptions. Using Redfield ratios, the biogenic detrital flux estimate is used to partition the ocean carbon and alkalinity reservoirs between the mixed layer and deep ocean. The calcite flux estimate and carbonate ion concentrations are used to determine the rate of biologically mediated CaCO3 titration. Oceanic productivity was severely limited for approximately 500 kyr following the K/T boundary resulting in significant increases in total ocean alkalinity. As productivity returned to the ocean, excess carbon and alkalinity was removed from the ocean as CaCO3. Model runs indicate that this resulted in a transient imbalance in the other direction. Ocean chemistry returned to near-equilibrium by about 64 mybp.

  16. Yield performance of cowpea genotypes grown in alkaline soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  17. Field screening of cowpea cultivars for alkaline soil tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  18. Process of treating cellulosic membrane and alkaline with membrane separator

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    The improvement of water-soluble cellulose ether membranes for use as separators in concentrated alkaline battery cells is discussed. The process of contacting membranes with an aqueous alkali solution of concentration less than that of the alkali solution to be used in the battery but above that at which the membrane is soluble is described.

  19. Managing land application of coal seam water: A field study of land amendment irrigation using saline-sodic and alkaline water on a Red Vertisol.

    PubMed

    Bennett, J McL; Marchuk, A; Raine, S R; Dalzell, S A; Macfarlane, D C

    2016-12-15

    Coal seam (CS) gas operations coproduce water with gas from confined CS aquifers. This CS water represents a potential agricultural resource if the water is able to be chemically amended to comply with management guidelines. Stoichiometric quantities of sulphur and gypsum amendments can be used to neutralise the alkalinity and reduce the sodicity of CS water respectively. These amendments can either be mixed in-line at a water treatment plant or applied directly to land prior to the application of CS water (a practice termed land amendment irrigation - LAI). This study compared the efficacy of LAI with in-line chemical amendment of CS water and irrigation with non-saline, non-sodic and non-alkaline (good quality) water under field conditions in southern Queensland. Soil chemical properties, soluble Ca, Mg, K, Na, electrical conductivity (EC), pH, chloride and alkalinity, as well as saturated hydraulic conductivity were measured to determine the impact of the irrigation treatments on soil chemical and physical conditions. Irrigation of lucerne pasture using solid-set sprinklers applied a total of 6.7 ML/ha of each treatment irrigation water to the experimental plots over a 10-month period. Alkalinity was neutralised using LAI, with no increase in soil alkalinity observed. Soil sodicity did not exceed threshold electrolyte concentration values under either CS water irrigation treatment. Soil chemical and physical properties were comparable for both LAI and in-line chemical amendment of CS water. Soil saturated hydraulic conductivity was maintained under all irrigation treatments. Results showed that the constrained capacity of the irrigation system was unable to meet crop evapotranspiration demand. This resulted in accumulation of salt within the root-zone under the CS water treatments compared to the good quality water treatment. LAI successfully chemically amended Bowen Basin CS water facilitating its beneficial use for agricultural irrigation.

  20. The effects of retinoic acid on alkaline phosphatase activity and tissue-non-specific alkaline phosphatase gene expression in human periodontal ligament cells and gingival fibroblasts.

    PubMed

    San Miguel, S M; Goseki-Sone, M; Sugiyama, E; Watanabe, H; Yanagishita, M; Ishikawa, I

    1998-10-01

    Alkaline phosphatase (ALP) in human periodontal ligament (HPDL) cells is classified as a tissue-non-specific alkaline phosphatase (TNSALP) by its enzymatic and immunological properties. Since retinoic acid (RA) has been shown as a potent inducer of TNSALP expression in various osteoblastic and fibroblastic cells, we investigated the effects of RA on the level of ALP activity and expression of TNSALP mRNAs in HPDL cells. Cultured cells were treated with desired RA concentrations (0, 10(-7), 10(-6), 10(-5) M) in medium containing 1% bovine serum albumin without serum. ALP activity was determined by the rate of hydrolysis of p-nitrophenyl phosphate and was also assayed in the presence of specific inhibitors. In order to identify the TNSALP mRNA type expressed by HPDL, a set of oligonucleotide primers corresponding to 2 types of human TNSALP mRNA (i.e. bone-type and liver-type) were designed, and mRNA isolated from HPDL was amplified by means of reverse transcription-polymerase chain reaction (RT-PCR). After treatment with RA (10(-6) M) for 4 d, there was a significant increase in the ALP activity of HPDL cells. The use of inhibitors and thermal inactivation experiments showed that the increased ALP activity had properties of the TNSALP type. RT-PCR analysis revealed that bone-type mRNA was highly stimulated in HPDL cells by RA treatment, but the expression of liver-type mRNA was not detected. These results indicated that the upregulation of ALP activity in HPDL cells by RA was due to the increased transcription of bone-type mRNA of the TNSALP gene.

  1. Remediation of Former Manufactured Gas Plant Tars Using Alkaline Flushing

    NASA Astrophysics Data System (ADS)

    Hauswirth, S.; Rylander, S.; Birak, P. S.; Miller, C. T.

    2010-12-01

    The remediation of former manufactured gas plant (FMGP) tars in the subsurface is particularly difficult due to the wetting behavior and high viscosities of these dense non-aqueous liquids (DNAPLs). Alkaline flooding is a technique which has proven effective in improving the recovery of crude oils, which share some characteristics with FMGP tars. For this study, we measured the effect of NaOH solutions on interfacial tension and conducted column experiments to investigate the feasibility of applying this technique to FMGP tars. The pendant drop technique was used to measure interfacial tensions for solutions ranging from 0-1% NaOH. Column experiments were conducted by contaminating sands with tars recovered from a FMGP then flushing the columns with NaOH solutions. A final, 70% v/v ethanol cosolvent flush was conducted to investigate the effectiveness of a two-stage remediation approach. The mass removal of tar, as well as 26 individual PAHs, was measured, along with the aqueous phase mass flux of PAHs after each flushing stage. The interfacial tension was reduced from about 20 mN/m with pure water to a minimum of 0.05 mN/m at a concentration of 0.1% NaOH. In the column experiments, alkaline flushing resulted in a 50% reduction of the residual saturation. Aqueous phase PAH concentrations, however, were similar before and after the alkaline flushing stage. The combination of alkaline and cosolvent flushing resulted in an overall reduction of 95% of the total mass of the 16 EPA PAHs. Final aqueous phase concentrations were reduced significantly for lower molecular weight PAHs, but increased slightly for the higher molecular weight compounds, likely due to their increased mole fraction within the remaining tar. Additional work is being conducted to improve the effectiveness of the alkaline flushing through the use of surfactants and polymers.

  2. Alkaline volcanisms in the Proto-Kuril forearc

    NASA Astrophysics Data System (ADS)

    Yutani, T.; Hirano, N.

    2015-12-01

    The Nemuro Group in the northeasternmost part of Japan represents forearc basin deposits of the Proto-Kuril arc that consist of Upper Cretaceous-Paleocene sedimentary rocks with andesitic volcaniclastics and alkaline lavas. Their occurrence in this setting is unusual because such alkaline lavas and intrusions are not commonly found in forearc environments. Here, we report new petrological and geological data to discuss the nature of magmatic process involved in their petrogenesis. Pillow and massive lava flows represent subaqueous volcanic activity, and the occurrence of inter-pillow sedimentary units indicates their eruption on unconsolidated sediments of the lower Nemuro Group. Sill intrusions with layered structures and thicknesses ranging from 10 to 130 m are also common widely distributed in the Nemuro Group. Major and trace element chemistry and mineralogical data distinguish the analyzed samples as K-rich alkaline rocks with low TiO2 or Nb contents, analogous to island arc-like tholeiites. These K-rich alkaline rocks can be classified into two groups of shoshonites: shoshonites containing olivine phenocrysts and intruding into the lower Nemuro Group (Group 1), and shoshonites with no olivine and making up the middle part of the Nemuro Group (Group 2). Group 1 shoshonites have higher MgO, Cr and Ni contents than those of Group 2. The bulk-rock composition of Group 2, which has lower MgO contents, shows higher SiO2 than that of Group 1. Such compositional differences possibly represent fractional crystallization of magmas between Groups 1 and 2. Based on the limited available data, we conclude that these alkaline rocks intruding into the Nemuro Group represent arc-shoshonites, and that the Group 1 magmas underwent fractional crystallization to produce the Group 2 magmas.

  3. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments.

    PubMed

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  4. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    NASA Astrophysics Data System (ADS)

    Kitadai, Norio

    2015-12-01

    Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

  5. The borohydride-reducible compounds of human aortic elastin. Demonstration of a new cyclic amino acid in alkali hydrolysate, and changes with age and in patients with annulo-aortic ectasia including one with Marfan syndrome.

    PubMed Central

    Halme, T; Jutila, M; Vihersaari, T; Oksman, P; Light, N D; Penttinen, R

    1985-01-01

    Human aortic elastin reduced with [3H]borohydride was analysed by ion-exchange chromatography after alkali or acid hydrolysis. Alkali hydrolysates of elastins contained a radioactive peak that was eluted between proline and leucine. This peak was not present in foetal elastin, but its proportion increased steadily during aging. Aortic samples from patients with annulo-aortic ectasia (aneurysm of the ascending aorta), including one with classical Marfan syndrome, contained less elastin (CNBr-insoluble material) than did the age-matched controls. The proportion of radioactivity in the new peak of all these aortas was low when compared with age-matched controls. Gas-chromatographic/mass-spectrometric analysis suggested that it contained a cyclic derivative of a hydrated aldol-condensation product. The concentration of the cross-link precursors, lysine aldehyde and aldol-condensation product (estimated from the acid-hydrolysis product 6-chloronorleucine and the acid-degradation product of reduced aldol-condensation product) was high in very young aortas but remained quite stable after childhood. No differences were observed in cross-link profiles of acid hydrolysates between pathological and control aortas. A low proportion of radioactivity in the new peak may indicate the presence of young or immature elastin in the pathological aortas. PMID:4084226

  6. Effects of 10-Year Management Regimes on the Soil Seed Bank in Saline-Alkaline Grassland

    PubMed Central

    Ma, Hongyuan; Yang, Haoyu; Liang, Zhengwei; Ooi, Mark K. J.

    2015-01-01

    Background Management regimes for vegetation restoration of degraded grasslands can significantly affect the process of ecological succession. However, few studies have focused on variation in the soil seed bank during vegetation restoration under different management regimes, especially in saline-alkaline grassland habitats. Our aim was to provide insights into the ecological effects of grassland management regimes on soil seed bank composition and vegetation establishment in mown, fenced, transplanted and natural grassland sites, all dominated by the perennial rhizomatous grass Leymus chinensis. Methodology We studied species composition and diversity in both the soil seed bank and aboveground vegetation in differently managed grasslands in Northeast China. An NMDS (nonmetric multidimensional scaling) was used to evaluate the relationship between species composition, soil seed banks, aboveground vegetation and soil properties. Principal Findings Fenced and mown grassland sites had high density and species richness in both the soil seed bank and aboveground vegetation. The Transplanted treatment exhibited the highest vegetation growth and seed production of the target species L. chinensis. Seeds of L. chinensis in the soil occurred only in transplanted and natural grassland. Based on the NMDS analysis, the number of species in both the soil seed bank and aboveground vegetation were significantly related to soil Na+, Cl-, RSC (residual sodium carbonate), alkalinity, ESP (exchangeable sodium percentage) and AP (available phosphorus). Conclusions Soil seed bank composition and diversity in the saline-alkaline grassland were significantly affected by the management regimes implemented, and were also significantly related to the aboveground vegetation and several soil properties. Based on vegetative growth, reproductive output and maintenance of soil seed bank, the transplanting was identified as the most effective method for relatively rapid restoration of the target

  7. Microbial community succession in alkaline, saline bauxite residue: a cross-refinery study

    NASA Astrophysics Data System (ADS)

    Santini, T.; Malcolm, L. I.; Tyson, G. W.; Warren, L. A.

    2015-12-01

    Bauxite residue, a byproduct of the Bayer process for alumina refining, is an alkaline, saline tailings material that is generally considered to be inhospitable to microbial life. In situ remediation strategies promote soil formation in bauxite residue by enhancing leaching of saline, alkaline pore water, and through incorporation of amendments to boost organic matter content, decrease pH, and improve physical structure. The amelioration of chemical and physical conditions in bauxite residue is assumed to support diversification of microbial communities from narrow, poorly functioning microbial communities towards diverse, well-functioning communities. This study aimed to characterise microbial communities in fresh and remediated bauxite residues from refineries worldwide, to identify (a) whether initial microbial communities differed between refineries; (b) major environmental controls on microbial community composition; and (c) whether remediation successfully shifts the composition of microbial communities in bauxite residue towards those found in reference (desired endpoint) soils. Samples were collected from 16 refineries and characterised using 16S amplicon sequencing to examine microbial community composition and structure, in conjunction with physicochemical analyses. Initial microbial community composition was similar across refineries but partitioned into two major groups. Microbial community composition changes slowly over time and indicates that alkalinity and salinity inhibit diversification. Microbially-based strategies for in situ remediation should consider the initial microbial community composition and whether the pre-treatment of chemical properties would optimise subsequent bioremediation outcomes. During in situ remediation, microbial communities become more diverse and develop wider functional capacity, indicating progression towards communities more commonly observed in natural grassland and forest soils.

  8. Continuous Proteolysis with a stabilized stabilized protease. I. Chemical stabilization of an alkaline protease.

    PubMed

    Boudrant, J; Cuq, J L; Cheftel, C

    1976-12-01

    Due to the loss of enzymatic activity as a function of time, an alkaline protease, selected for the continuous preparation of protein hydrolysates (J. Boudrant and C. Cheftel, Biotechnol. Bioeng., 18,1735, 1976), was chemically stabilized by a simple treatment with glutaraldehyde. Two fractions, soluble and insoluble, were obtained. The activities of these two fractions were measured with casein and N-benzoyl-L-arginine ethyl ester (BAEE) as a function of glutaraldehyde concentration used. It was noted that the insoluble fraction was practically inactive with the first substrate and that the heat stability of the soluble form was likewise enhanced. Molecular weights of these two forms were unchanged, but the uv-spectrum of the soluble form was modified. From amino acid analysis, it appears that this treatment mainly provokes a decrease in lysine content.

  9. Carbon segregation-induced highly metallic ni nanoparticles for electrocatalytic oxidation of hydrazine in alkaline media.

    PubMed

    Jeon, Tae-Yeol; Watanabe, Masahiro; Miyatake, Kenji

    2014-11-12

    The important roles of Ni in electrocatalytic reactions such as hydrazine oxidation are limited largely by high oxidation states because of its intrinsically high oxophilicity. Here, we report the synthesis and properties of highly metallic Ni nanoparticles (NPs) on carbon black supports. We discovered that the heat treatment of as-prepared Ni NPs with an average particle size of 5.8 nm produced highly metallic Ni NPs covered with thin carbon shells, with negligible particle coarsening. The carbon shells were formed by the segregation of carbons in the Ni lattice to the surface of the Ni NPs, leaving highly metallic Ni NPs. X-ray photoelectron spectroscopic analyses revealed that the atomic ratio of metallic Ni increased from 19.2 to 71.7% as a result of the heat treatment. The NPs exhibited higher electrocatalytic activities toward the hydrazine oxidation reaction in alkaline solution, as compared to those of the as-prepared Ni NPs and commercial Ni powders.

  10. Alkaline pH Homeostasis in Bacteria: New Insights

    PubMed Central

    Padan, Etana; Bibi, Eitan; Ito, Masahiro; Krulwich, Terry A.

    2011-01-01

    The capacity of bacteria to survive and grow at alkaline pH values is of widespread importance in the epidemiology of pathogenic bacteria, in remediation and industrial settings, as well as in marine, plant-associated and extremely alkaline ecological niches. Alkali-tolerance and alkaliphily, in turn, strongly depend upon mechanisms for alkaline pH homeostasis, as shown in pH shift experiments and growth experiments in chemostats at different external pH values. Transcriptome and proteome analyses have recently complemented physiological and genetic studies, revealing numerous adaptations that contribute to alkaline pH homeostasis. These include elevated levels of transporters and enzymes that promote proton capture and retention (e.g. the ATP synthase and monovalent cation/proton antiporters), metabolic changes that lead to increased acid production, and changes in the cell surface layers that contribute to cytoplasmic proton retention. Targeted studies over the past decade have followed up the long-recognized importance of monovalent cations in active pH homeostasis. These studies show the centrality of monovalent cation/proton antiporters in this process while microbial genomics provides information about the constellation of such antiporters in individual strains. A comprehensive phylogenetic analysis of both eukaryotic and prokaryotic genome databases has identified orthologes from bacteria to humans that allow better understanding of the specific functions and physiological roles of the antiporters. Detailed information about the properties of multiple antiporters in individual strains is starting to explain how specific monovalent cation/proton antiporters play dominant roles in alkaline pH homeostasis in cells that have several additional antiporters catalyzing ostensibly similar reactions. New insights into the pH-dependent Na+/H+ antiporter NhaA that plays an important role in Escherichia coli have recently emerged from the determination of the structure

  11. Interpretation of pH, acidity, and alkalinity in fisheries and aquaculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurements of pH, acidity, and alkalinity are commonly used to describe water quality. The three variables are interrelated and are sometimes confused. The pH of water is an intensity factor, while the acidity and alkalinity of waters are capacity factors. More precisely, acidity and alkalinity ar...

  12. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  13. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  14. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  15. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the...

  16. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the...

  17. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the...

  18. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the...

  19. 40 CFR 721.9680 - Alkaline titania silica gel (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkaline titania silica gel (generic... Specific Chemical Substances § 721.9680 Alkaline titania silica gel (generic name). (a) Chemical substance... alkaline titania silica gel (PMN P-95-529) is subject to reporting under this section for the...

  20. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  1. 40 CFR 721.4668 - Hydrated alkaline earth metal salts of metalloid oxyanions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydrated alkaline earth metal salts of... Specific Chemical Substances § 721.4668 Hydrated alkaline earth metal salts of metalloid oxyanions. (a... hydrated alkaline earth metal salts of metalloid oxyanions (PMN P-94-1557) is subject to reporting...

  2. Batch and dynamic biosorption of basic dyes from binary solutions by alkaline-treated cypress cone chips.

    PubMed

    Fernandez, M E; Nunell, G V; Bonelli, P R; Cukierman, A L

    2012-02-01

    A simple alkaline pre-treatment of Cupressus sempervirens cone chips was performed to improve their biosorption capacity towards methylene blue and rhodamine B from aqueous solutions, in batch and continuous modes. Biosorption kinetics were determined from single and binary dyes solutions, and properly described by the pseudo-second-order rate model. Experimental single-dye equilibrium isotherms fitted the Langmuir-Freundlich model, with maximum biosorption capacities of 0.68mmol/g for methylene blue and 0.50mmol/g for rhodamine B. Single-dye dynamic biosorption showed that breakthrough time for methylene blue biosorption was almost four times longer than for rhodamine B and that the alkaline modification of the chips greatly improved the biosorption performance. Competitive dynamic biosorption demonstrated the preference of the modified cone chips for biosorbing methylene blue, confirmed by the exit concentration overshoots obtained in the breakthrough curves of rhodamine B.

  3. Alkaline solubilization and microwave irradiation as a combined sludge disintegration and minimization method.

    PubMed

    Doğan, Ilgin; Sanin, F Dilek

    2009-05-01

    Commonly used pretreatment method of alkaline solubilization (using NaOH) and a relatively new technology of microwave (MW) irradiation (160 degrees C) were combined as a pretreatment method of waste activated sludge (WAS) in this study. First alkaline and MW pretreatment methods were examined separately, then their combination for different conditions was investigated in terms of their effect on COD solubilization, turbidity and capillary suction time (CST). For combined pretreatments, soluble COD to total COD ratio (SCOD/TCOD) of WAS increased from 0.005 (control) to 0.18, 0.27, 0.34 and 0.37 for combined methods of MW and pH-10, 11, 12 and 12.5, respectively. Deteriorated dewaterability due to alkaline pretreatment was also improved due to the incorporation of MW irradiation. Further, with small scale batch anaerobic reactors, pH-10, pH-12, MW (alone), MW+pH-10 and MW+pH-12 pretreated WAS samples were anaerobically digested. Highest total gas and methane productions were achieved with MW+pH-12 pretreatment with 16.3% and 18.9% improvements over control reactor, respectively. Finally the performance of MW+pH-12 pretreatment was examined with 2L anaerobic semi-continuous reactors for 92 days and compared to that of the control reactors. These reactors were operated at an SRT of 15 days. After steady state, 43.5% and 55% improvements were obtained in respective daily total gas and methane productions. TS, VS and TCOD reductions were improved by 24.9%, 35.4% and 30.3%, respectively based on a relative calculation with respect to control reactors. This way combined alkaline-microwave treatment proved to be an effective sludge minimization method. Pretreated digested sludge had 22% improved dewaterability than unpretreated digested sludge. Higher SCOD and NH(3)-N concentrations were measured in the pretreated digested sludge supernatant; however, PO(4)-P concentration did not increase much.

  4. Application of alkaline phosphatases from different sources in pharmaceutical and clinical analysis for the determination of their cofactors; zinc and magnesium ions.

    PubMed

    Muginova, Svetlana V; Zhavoronkova, Anna M; Polyakov, Alexei E; Shekhovtsova, Tatyana N

    2007-03-01

    Prospects of using different alkaline phosphatases bearing zinc and magnesium ions in their catalytic and allosteric sites, respectively, in pharmaceutical and clinical analysis were demonstrated. Also their application for the determination of zinc in insulin to control injection quality and magnesium in human urine for the diagnosis and treatment of magnesium deficiency was shown. The reaction of p-nitrophenyl phosphate hydrolysis was chosen as an indicator. The choice of appropriate alkaline phosphatase was substantiated, the influence of the nature of buffer solutions on the behavior of the enzyme-metal systems was studied, and the conditions of the indicator reaction proceeding in the presence of sample matrixes were optimized. Simple, rapid, sensitive, and selective enzymatic procedures for determining zinc and magnesium based on their inhibiting and activating effects on the catalytic activity of alkaline phosphatases from seal and chicken intestine, respectively, were developed.

  5. Beneficial role of spermidine in chlorophyll metabolism and D1 protein content in tomato seedlings under salinity-alkalinity stress.

    PubMed

    Hu, Lipan; Xiang, Lixia; Li, Shuting; Zou, Zhirong; Hu, Xiao-Hui

    2016-04-01

    Polyamines are important in protecting plants against various environmental stresses, including protection against photodamage to the photosynthetic apparatus. The molecular mechanism of this latter effect is not completely understood. Here, we have investigated the effects of salinity-alkalinity stress and spermidine (Spd) on tomato seedlings at both physiological and transcriptional levels. Salinity-alkalinity stress decreased leaf area, net photosynthetic rate, maximum net photosynthetic rate, light saturation point, apparent quantum efficiency, total chlorophyll, chlorophyll a and chlorophyll a:chlorophyll b relative to the control. The amount of D1 protein, an important component of photosystem II, was reduced compared with the control, as was the expression of psbA, which codes for D1. Expression of the chlorophyll biosynthesis gene porphobilinogen deaminase (PBGD) was reduced following salinity-alkalinity stress, whereas the expression of Chlase, which codes for chlorophyllase, was increased. These negative physiological effects of salinity-alkalinity stress were alleviated by exogenous Spd. Expression of PBGD and psbA were enhanced, whereas the expression of Chlase was reduced, when exogenous Spd was included in the stress treatment compared with when it was not. The protective effect of Spd on chlorophyll and D1 protein content during stress may maintain the photosynthetic apparatus, permitting continued photosynthesis and growth of tomato seedlings (Solanum lycopersicum cv. Jinpengchaoguan) under salinity-alkalinity stress.

  6. Sequential Washing with Electrolyzed Alkaline and Acidic Water Effectively Removes Pathogens from Metal Surfaces

    PubMed Central

    Nakano, Yuichiro; Akamatsu, Norihiko; Mori, Tsuyoshi; Sano, Kazunori; Satoh, Katsuya; Nagayasu, Takeshi; Miyoshi, Yoshiaki; Sugio, Tomomi; Sakai, Hideyuki; Sakae, Eiji; Ichimiya, Kazuko; Hamada, Masahisa; Nakayama, Takehisa; Fujita, Yuhzo; Yanagihara, Katsunori; Nishida, Noriyuki

    2016-01-01

    Removal of pathogenic organisms from reprocessed surgical instruments is essential to prevent iatrogenic infections. Some bacteria can make persistent biofilms on medical devices. Contamination of non-disposable equipment with prions also represents a serious risk to surgical patients. Efficient disinfection of prions from endoscopes and other instruments such as high-resolution cameras remains problematic because these instruments do not tolerate aggressive chemical or heat treatments. Herein, we develop a new washing system that uses both the alkaline and acidic water produced by electrolysis. Electrolyzed acidic water, containing HCl and HOCl as active substances, has been reported to be an effective disinfectant. A 0.15% NaCl solution was electrolyzed and used immediately to wash bio-contaminated stainless steel model systems with alkaline water (pH 11.9) with sonication, and then with acidic water (pH 2.7) without sonication. Two bacterial species (Staphylococcus aureus and Pseudomonas aeruginosa) and a fungus (Candida albicans) were effectively removed or inactivated by the washing process. In addition, this process effectively removed or inactivated prions from the stainless steel surfaces. This washing system will be potentially useful for the disinfection of clinical devices such as neuroendoscopes because electrolyzed water is gentle to both patients and equipment and is environmentally sound. PMID:27223116

  7. Biological Activities of a Mixture of Biosurfactant from Bacillus subtilis and Alkaline Lipase from Fusarium oxysporum

    PubMed Central

    Pereira de Quadros, Cedenir; Cristina Teixeira Duarte, Marta; Maria Pastore, Gláucia

    2011-01-01

    In this study, we investigate the antimicrobial effects of a mixture of a biosurfactant from Bacillus subtilis and an alkaline lipase from Fusarium oxysporum (AL/BS mix) on several types of microorganisms, as well as their abilities to remove Listeria innocua ATCC 33093 biofilm from stainless steel coupons. The AL/BS mix had a surface tension of around 30 mN.m-1, indicating that the presence of alkaline lipase did not interfere in the surface activity properties of the tensoactive component. The antimicrobial activity of the AL/BS mix was determined by minimum inhibitory concentration (MIC) micro-assays. Among all the tested organisms, the presence of the mixture only affected the growth of B. subtilis CCT 2576, B. cereus ATCC 10876 and L. innocua. The most sensitive microorganism was B. cereus (MIC 0.013 mg.mL-1). In addition, the effect of the sanitizer against L. innocua attached to stainless steel coupons was determined by plate count after vortexing. The results showed that the presence of the AL/BS mix improved the removal of adhered cells relative to treatment done without the sanitizer, reducing the count of viable cells by 1.72 log CFU.cm-2. However, there was no significant difference between the sanitizers tested and an SDS detergent standard (p<0.05). PMID:24031642

  8. Electrochemical Deposition and Characterization of Ni-Mo Alloys as Cathode for Alkaline Water Electrolysis

    NASA Astrophysics Data System (ADS)

    Manazoğlu, Mert; Hapçı, Gökçe; Orhan, Gökhan

    2016-01-01

    In this study, Ni-Mo alloy coatings were electrochemically deposited on a copper plate in citrate solutions. The effects of Ni/Mo mole ratio in the electrolyte and pH value on hydrogen evolution reaction (HER) as well as the electrochemical stability were investigated in the alkaline solution for electrodeposited NiMo. The electrocatalytic activity of the fabricated NiMo alloys for HER in alkaline solutions was investigated by the polarization measurements and electrochemical impedance spectroscopy techniques. The morphology and chemical composition of the electrodeposited Ni-Mo were investigated using SEM and EDS analyses. It was found that NiMo electrode with the highest molybdenum content (ca. 38 wt.%) and high surface area show high electrocatalytic activity in the HER. This was produced from a bath with a pH of 9.5, Ni/Mo ratio of 1/10 and 0.5 M sodium citrate concentration. The stability of this coating was tested by polarization measurements after different anodic and cathodic treatment in 1 M NaOH solution. The open circuit potential ( E ocp) of the electrode as a function of immersion time was also measured.

  9. Pyrophosphate Stimulates Differentiation, Matrix Gene Expression and Alkaline Phosphatase Activity in Osteoblasts

    PubMed Central

    Pujari-Palmer, Michael; Pujari-Palmer, Shiuli; Lu, Xi; Lind, Thomas; Melhus, Håkan; Engstrand, Thomas; Karlsson-Ott, Marjam; Engqvist, Hakan

    2016-01-01

    Pyrophosphate is a potent mitogen, capable of stimulating proliferation in multiple cell types, and a critical participant in bone mineralization. Pyrophosphate can also affect the resorption rate and bioactivity of orthopedic ceramics. The present study investigated whether calcium pyrophosphate affected proliferation, differentiation and gene expression in early (MC3T3 pre-osteoblast) and late stage (SAOS-2 osteosarcoma) osteoblasts. Pyrophosphate stimulated peak alkaline phosphatase activity by 50% and 150% at 100μM and 0.1μM in MC3T3, and by 40% in SAOS-2. The expression of differentiation markers collagen 1 (COL1), alkaline phosphatase (ALP), osteopontin (OPN), and osteocalcin (OCN) were increased by an average of 1.5, 2, 2 and 3 fold, by high concentrations of sodium pyrophosphate (100μM) after 7 days of exposure in MC3T3. COX-2 and ANK expression did not differ significantly from controls in either treatment group. Though both high and low concentrations of pyrophosphate stimulate ALP activity, only high concentrations (100μM) stimulated osteogenic gene expression. Pyrophosphate did not affect proliferation in either cell type. The results of this study confirm that chronic exposure to pyrophosphate exerts a physiological effect upon osteoblast differentiation and ALP activity, specifically by stimulating osteoblast differentiation markers and extracellular matrix gene expression. PMID:27701417

  10. Atomic hydrogen in. gamma. -irradiated hydroxides of alkaline-earth elements

    SciTech Connect

    Spitsyn, V.I.; Yurik, T.K.; Barsova, L.I.

    1982-04-01

    Atomic hydrogen is an important intermediate product formed in the radiolysis of compounds containing X-H bonds. H atoms have been detected in irradiated matrices of H/sub 2/ and inert gases at 4/sup 0/K, in irradiated ice and frozen solutions of acids in irradiated salts and in other systems. Here results are presented from a study of the ESR spectra of H atoms generated in polycrystalline hydroxides of alkaline-earth elements that have been ..gamma..-irradiated at 77/sup 0/K, after preliminary treatment at various temperatures. For the first time stabilization of atomic hydrogen in ..gamma..-irradiated polycrystalline alkaline-earth element hydroxides has been detected. Depending on the degree of dehydroxylation, several types of hydrogen atoms may be stabilized in the hydroxides, these hydrogen atoms having different radiospectroscopic parameters. In the magnesium-calcium-strontium-barium hydroxide series, a regular decrease has been found in the hfi constants for H atoms with the cations in the immediate surroundings. A direct proportionality has been found between the parameters ..delta..A/A/sub 0/ and the polarizability of the cation.

  11. Alkaline deoxygenated graphene oxide as adsorbent for cadmium ions removal from aqueous solutions.

    PubMed

    Liu, Jun; Du, Hongyan; Yuan, Shaowei; He, Wanxia; Yan, Pengju; Liu, Zhanhong

    2015-01-01

    Alkaline deoxygenated graphene oxide (aGO) was prepared through alkaline hydrothermal treatment and used as adsorbent to remove Cd(II) ions from aqueous solutions for the first time. The characterization results of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectra indicate that aGO was successfully synthesized. The batch adsorption experiments showed that the adsorption kinetics could be described by the pseudo-second-order kinetic model, and the isotherms equilibrium data were well fitted with the Langmuir model. The maximum adsorption capacity of Cd(II) on aGO was 156 mg/g at pH 5 and T=293 K. The adsorption thermodynamic parameters indicated that the adsorption process was a spontaneous and endothermic reaction. The mainly adsorption mechanism speculated from FT-IR results may be attributed to the electrostatic attraction between Cd2+ and negatively charged groups (-CO-) of aGO and cation-π interaction between Cd2+ and the graphene planes. The findings of this study demonstrate the potential utility of the nanomaterial aGO as an effective adsorbent for Cd(II) removal from aqueous solutions.

  12. Plutonium(IV) precipitates formed in alkaline media in the presence of various anions

    SciTech Connect

    Krot, N.N.; Shilov, V.P.; Yusov, A.B.; Tananaev, I.G.; Grigoriev, M.S.; Garnov, A.Yu.; Perminov, V.P.; Astafurova, L.N.

    1998-09-01

    The tendency of Pu(IV) to hydrolyze and form true solutions, colloid solutions, or insoluble precipitates has been known since the Manhattan Project. Since then, specific studies have been performed to examine in detail the equilibria of Pu(IV) hydrolytic reactions in various media. Great attention also has been paid to the preparation, structure, and properties of Pu(IV) polymers or colloids. These compounds found an important application in sol-gel technology for the preparation of nuclear fuel materials. A most important result of these works was the conclusion that Pu(IV) hydroxide, after some aging, consists of very small PuO{sub 2} crystallites and should therefore be considered to be Pu(IV) hydrous oxide. However, studies of the properties and behavior of solid Pu(IV) hydroxide in complex heterogeneous systems are rare. The primary goal of this investigation was to obtain data on the composition and properties of Pu(IV) hydrous oxide or other compounds formed in alkaline media under different conditions. Such information is important to understand Pu(IV) behavior and the forms of its existence in the Hanford Site alkaline tank waste sludge. This knowledge then may be applied in assessing plutonium criticality hazards in the storage, retrieval, and treatment of Hanford Site tank wastes as well as in understanding its contribution to the transuranic waste inventory (threshold at 100 nCi/g or about 5 {times} 10{sup {minus}6} M) of the separate solution and solid phases.

  13. Purification of a thermostable alkaline laccase from papaya (Carica papaya) using affinity chromatography.

    PubMed

    Jaiswal, Nivedita; Pandey, Veda P; Dwivedi, Upendra N

    2015-01-01

    A laccase from papaya leaves was purified to homogeneity by a two step procedure namely, heat treatment (at 70 °C) and Con-A affinity chromatography. The procedure resulted in 1386.7-fold purification of laccase with a specific activity of 41.3 units mg(-1) and an overall yield of 61.5%. The native purified laccase was found to be a hexameric protein of ∼ 260 kDa. The purified enzyme exhibited acidic and alkaline pH optima of 6.0 and 8.0 with the non-phenolic substrate (ABTS) and phenolic substrate (catechol), respectively. The purified laccase was found to be thermostable up to 70 °C such that it retained ∼ 80% activity upon 30 min incubation at 70 °C. The Arrhenius energy of activation for purified laccase was found to be 7.7 kJ mol(-1). The enzyme oxidized various phenolic and non-phenolic substrates having catalytic efficiency (K(cat)/K(m)) in the order of 7.25>0.67>0.27 mM(-1) min(-1) for ABTS, catechol and hydroquinone, respectively. The purified laccase was found to be activated by Mn(2+), Cd(2+), Ca(2+), Na(+), Fe(2+), Co(2+) and Cu(2+) while weakly inhibited by Hg(2+). The properties such as thermostability, alkaline pH optima and metal tolerance exhibited by the papaya laccase make it a promising candidate enzyme for industrial exploitation.

  14. Lignin recovery from alkaline hydrolysis and glycerolysis of oil palm fiber

    NASA Astrophysics Data System (ADS)

    Hassan, Nur Syakilla; Badri, Khairiah Haji

    2014-09-01

    In the present work, two types of treatment namely alkaline hydrolysis and glycerolysis have been conducted for lignin extraction from oil palm empty fruit bunch (EFB) fiber. Lignin has been retrieved from two sequential methods, which was the klason lignin from residue and lignin from precipitation of the filtrate. Alkaline hydrolysis was performed using 10% NaOH solution at room condition. This has extracted 13.0 % lignin. On the other hand, glycerolysis was carried out using 70% glycerol catalyzed with 5% of 1 M NaOH at 60-70 °C. This has successfully extracted 16.0% lignin. The SEM micrographs exhibited some physical changes on the surface where the impurities and waxes have been removed, exposing the, lumen. Besides that, FTIR analysis was conducted on untreated EFB, treated EFB and extracted lignin. Delignification of EFB fiber was confirmed based on the intensity reduction at 1245 cm-1 that showed lignin was removed from the fiber. The presence of CO, CC and CC aromatic peaks in the FTIR spectra of the dried filtrate gave an evidence on the presence of lignin.

  15. Effect of hydrothermal reaction time and alkaline conditions on the electrochemical properties of reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Vermisoglou, E. C.; Giannakopoulou, T.; Romanos, G.; Giannouri, M.; Boukos, N.; Lei, C.; Lekakou, C.; Trapalis, C.

    2015-12-01

    Reduced graphene oxide sheets (rGO) were prepared by hydrothermal treatment of aqueous dispersions of graphite oxide (GtO) applied for short (4 h) and prolonged reaction times (19-24 h). The effect of process duration as well as the alkaline conditions (pH ∼10) by addition of K2CO3 on the quality characteristics of the produced rGO materials was investigated. Both reduction and exfoliation occurred during this process as it was evidenced by FTIR and XRD data. SEM, TEM and HRTEM microscopy displayed highly exfoliated rGO materials. XPS verified that the re-establishment of the conjugated graphene network is more extensive for prolonged times of hydrothermal processing in accordance to Raman spectroscopy measurements. The sample produced under alkaline conditions bore fewer defects and almost 5 times higher BET surface area (∼181 m2/g) than the sample with no pH adjustment (∼34 m2/g) for the same hydrothermal reaction time (19 h), attributed to the developed microporosity. The specific capacitance of this material estimated by electrochemical impedance using three-electrode cell and KCl aqueous solution as an electrolyte was ∼400-500 F/g. When EDLC capacitors were fabricated from rGO materials the electrochemical testing in organic electrolyte i.e. TEABF4 in PC, revealed that the shortest hydrothermal reaction time (4 h) was more efficient resulting in capacitance around 60 F/g.

  16. Alkaline Hydrolysis/Polymerization of 2,4,6-Trinitrotoluene: Characterization of Products by 13C and 15N NMR

    USGS Publications Warehouse

    Thorn, K.A.; Thorne, P.G.; Cox, L.G.

    2004-01-01

    Alkaline hydrolysis has been investigated as a nonbiological procedure for the destruction of 2,4,6-trinitrotoluene (TNT) in explosives contaminated soils and munitions scrap. Nucleophilic substitutions of the nitro and methyl groups of TNT by hydroxide ion are the initial steps in the alkaline degradation of TNT. Potential applications of the technique include both in situ surface liming and ex situ alkaline treatment of contaminated soils. A number of laboratory studies have reported the formation of an uncharacterized polymeric material upon prolonged treatment of TNT in base. As part of an overall assessment of alkaline hydrolysis as a remediation technique, and to gain a better understanding of the chemical reactions underlying the hydrolysis/polymerization process, the soluble and precipitate fractions of polymeric material produced from the calcium hydroxide hydrolysis of unlabeled and 15N-labeled TNT were analyzed by elemental analysis and 13C and 15N nuclear magnetic resonance spectroscopy. Spectra indicated that reactions leading to polymerization included nucleophilic displacement of nitro groups by hydroxide ion, formation of ketone, carboxyl, alcohol, ether, and other aliphatic carbons, conversion of methyl groups to diphenyl methylene carbons, and recondensation of aromatic amines and reduced forms of nitrite, including ammonia and possibly hydroxylamine, into the polymer. Compared to the distribution of carbons in TNT as 14% sp 3- and 86% sp2-hybridized, the precipitate fraction from hydrolysis of unlabeled TNT contained 33% sp3- and 67% sp 2-hybridized carbons. The concentration of nitrogen in the precipitate was 64% of that in TNT. The 15N NMR spectra showed that, in addition to residual nitro groups, forms of nitrogen present in the filtrate and precipitate fractions include aminohydroquinone, primary amide, indole, imine, and azoxy, among others. Unreacted nitrite was recovered in the filtrate fraction. The toxicities and susceptibilities to

  17. Chemical degradation mechanisms of membranes for alkaline membrane fuel cells

    SciTech Connect

    Choe, Yoong-Kee; Henson, Neil J.; Kim, Yu Seung

    2015-12-31

    Chemical degradation mechanisms of membranes for alkaline membrane fuel cells have been investigated using density functional theory (DFT). We have elucidated that the aryl-ether moiety of membranes is one of the weakest site against attack of hydroxide ions. The results of DFT calculations for hydroxide initiated aryl-ether cleavage indicated that the aryl-ether cleavage occurred prior to degradation of cationic functional group. Such a weak nature of the aryl-ether group arises from the electron deficiency of the aryl group as well as the low bond dissociation energy. The DFT results suggests that removal of the aryl-ether group in the membrane should enhance the stability of membranes under alkaline conditions. In fact, an ether fee poly(phenylene) membrane exhibits excellent stability against the attack from hydroxide ions.

  18. Repeated probing of Southwestern blots using alkaline phosphatase stripping.

    PubMed

    Jia, Yinshan; Jiang, Daifeng; Jarrett, Harry W

    2010-11-05

    Southwestern blotting is when a DNA sequence is used to probe DNA-binding proteins on an electrophoretic gel blot. It would be highly desirable to be able to probe a blot repeatedly with different DNA sequences. Alkaline phosphatase can remove 5'-phosphoryl groups from DNA and radiolabeled 5'-(32)P-DNA probes are commonly used in Southwestern blotting. Here is shown that once probed, the radioisotope signal on the blot can be effectively removed by brief digestion with alkaline phosphatase, and the blot can then be repeatedly probed at least six times with different DNA probes. This exceeds the repetitions possible with another commonly used method using SDS. The technique can be used with either one-dimensional or multi-dimensional Southwestern blots and does not have a large effect on the phosphorylation state of the blotted proteins. An alternative method using T4 polynucleotide kinase stripping is also introduced but was less well characterized.

  19. Biological impacts of enhanced alkalinity in Carcinus maenas.

    PubMed

    Cripps, Gemma; Widdicombe, Stephen; Spicer, John I; Findlay, Helen S

    2013-06-15

    Further steps are needed to establish feasible alleviation strategies that are able to reduce the impacts of ocean acidification, whilst ensuring minimal biological side-effects in the process. Whilst there is a growing body of literature on the biological impacts of many other carbon dioxide reduction techniques, seemingly little is known about enhanced alkalinity. For this reason, we investigated the potential physiological impacts of using chemical sequestration as an alleviation strategy. In a controlled experiment, Carcinus maenas were acutely exposed to concentrations of Ca(OH)2 that would be required to reverse the decline in ocean surface pH and return it to pre-industrial levels. Acute exposure significantly affected all individuals' acid-base balance resulting in slight respiratory alkalosis and hyperkalemia, which was strongest in mature females. Although the trigger for both of these responses is currently unclear, this study has shown that alkalinity addition does alter acid-base balance in this comparatively robust crustacean species.

  20. Specialties of distributions of alkaline-earth metals in coal

    SciTech Connect

    Fan Jinchuan; Fan Minqiang

    1997-12-31

    Four different ranks of coal have been sampled and separated into different density fractions by Float-Sink. The contents of some trace elements in each density fraction has been analyzed by ICAP. The analyzed data show that the alkaline-earth metals (Be, Sr, and Ba) have their special distributions in coal: Be and Sr may exist in the form of organic matter. Ba often has the highest content in the middle density fraction (1.4--1.5). The relative relationship between ash (or sulfur) and the trace element in a certain type of coal was obtained by using linear regression approach. Results show that there is no significant correlation between the contents of ash or sulfur and those of Be, Sr, and Ba. On the other hand, the linear regression was done among the trace elements of 17 types of coal. The results also show that there is no significant correlation between ash or sulfur and alkaline-earth metals.