Pretreatment of industrial phosphoric acid by Algerian filter-aids

International Nuclear Information System (INIS)

Mellah, A.; Setti, Louisa; Chegrouche, Salah

1993-01-01

The present work involves the filtration of industrial phosphoric acid by different filter-aids such as kieselguhr, celite and bleaching clay. The retention of substances contained in wet phosphoric acid was determined using the three filter-aids. Thus, the phosphoric acid, obtained by filtration on kieselguhr has the same specifications as technical phosphoric acid produced by Rhone-Poulenc (France) as standard

Electrolyte Additives for Phosphoric Acid Fuel Cells

DEFF Research Database (Denmark)

Gang, Xiao; Hjuler, H.A.; Olsen, C.A.

1993-01-01

, as a fuel-cell performance with the modified electrolytes. Specific conductivity measurements of some of the modified phosphoric acid electrolytes are reported. At a given temperature, the conductivity of the C4F9SO3K-modified electrolyte decreases with an increasing amount of the additive; the conductivity...... of the remains at the same value as the conductivity of the pure phosphoric acid. At a given composition, the conductivity of any modified electrolyte increases with temperature. We conclude that the improved cell performance for modified electrolytes is not due to any increase in conductivity.......Electrochemical characteristics of a series of modified phosphoric acid electrolytes containing fluorinated car on compounds and silicone fluids as additives are presented. When used in phosphoric acid fuel cells, the modified electrolytes improve the performance due to the enhanced oxygen...

Method of recovering phosphoric acid type decontaminating electrolytes by electrodeposition

International Nuclear Information System (INIS)

Sasaki, Takashi; Wada, Koichi; Kobayashi, Toshio.

1985-01-01

Purpose: To recoving phosphoric acid type highly concentrated decontaminating liquid used for the electrolytic decontamination of contaminated equipments, components, etc in nuclear power plants or the like through electrodeposition by diaphragm electrolysis. Method: Before supplying phosphoric acid decontaminating liquid at high concentration used in the electrolytic decontaminating step to an electrodeposition recovering tank, phosphoric acid in the decontaminating electrolyte is extracted with solvents and decomposed liquid extracts (electrolyte reduced with the phosphoric acid component) are supplied to the cathode chamber of the electrodeposition recovering tank, where phosphoric acid is back-extracted with water from the solvents after extraction of phosphoric acid. Then, the back-extracted liquids (aqueous phosphoric acid solution scarcely containing metal ions) are sent to the anode chamber of the electrodeposition recovering tank. Metal ions in the liquid are captured by electrodeposition in the cathode chamber, as well as phosphoric acid in the liquids is concentrated to the initial concentration of the electrolyte in the anode chamber for reuse as the decontaminating electrolyte. As the phosphoric acid extracting agent used in the electrodeposition recovering step for the decontaminating electrolyte, water-insoluble and non-combustible tributyl phosphate (TBP) is most effective. (Horiuchi, T.)

Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

International Nuclear Information System (INIS)

Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M.; Sapsay, V.I.; Klymchuk, D.O.; Puziy, A.M.

2012-01-01

Highlights: ► Phosphoric acid activation results in formation of carbons with acidic surface groups. ► Maximum amount of surface groups is introduced at impregnation ratio 1.25. ► Phosphoric acid activated carbons show high capacity to copper. ► Phosphoric acid activated carbons are predominantly microporous. ► Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S BET = 2081 m 2 /g, V tot = 1.1 cm 3 /g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0–2.6), weakly acidic carboxylic (pK = 4.7–5.0), enol/lactone (pK = 6.7–7.4; 8.8–9.4) and phenol (pK = 10.1–10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

Energy Technology Data Exchange (ETDEWEB)

Sych, N.V.; Trofymenko, S.I.; Poddubnaya, O.I.; Tsyba, M.M. [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine); Sapsay, V.I.; Klymchuk, D.O. [M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2 Tereshchenkivska St., 01601 Kyiv (Ukraine); Puziy, A.M., E-mail: alexander.puziy@ispe.kiev.ua [Institute for Sorption and Endoecology Problems, National Academy of Sciences of Ukraine, 13 General Naumov St., 03164 Kyiv (Ukraine)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Phosphoric acid activation results in formation of carbons with acidic surface groups. Black-Right-Pointing-Pointer Maximum amount of surface groups is introduced at impregnation ratio 1.25. Black-Right-Pointing-Pointer Phosphoric acid activated carbons show high capacity to copper. Black-Right-Pointing-Pointer Phosphoric acid activated carbons are predominantly microporous. Black-Right-Pointing-Pointer Maximum surface area and pore volume achieved at impregnation ratio 1.0. - Abstract: Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 Degree-Sign C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (S{sub BET} = 2081 m{sup 2}/g, V{sub tot} = 1.1 cm{sup 3}/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

Process for winning uranium from wet process phosphoric acid

International Nuclear Information System (INIS)

1980-01-01

A process is described for winning uranium from wet process phosphoric acid by means of liquid-liquid extraction with organic phosphoric acid esters. The process is optimised by keeping the sulphate percentage in the phosphoric acid below 2% by weight, and preferably below 0.6% by weight, as compared to P 2 O 5 in the phosphoric acid. This is achieved by adding an excess of Ba and/or Ca carbonate or sulfide solution and filtering off the formed calcium and/or barium sulphate precipitates. Solid KClO 3 is then added to the filtrate to oxidise U 4+ to U 6+ . The normal extraction procedure using organic phosphoric esters as extraction liquid, can then be applied. (Th.P.)

Recuperation of uranium from phosphoric acid

International Nuclear Information System (INIS)

Cordero, G.; Jodra, L.G.; Otero, J.L.; Josa, J.M.

1977-01-01

The Spanish capacity for phosphoric acid production is 500.000 t P 2 O 5 /yr. This acid has an average concentration of 365 g U 3 O 8 / t P 2 O 5 . Therefore about 180 t U 3 O 8 /yr are dissolved. In 1969, the Junta de Energia Nuclear (JEN) developed, in bench scale, a solvent extraction process to recover the uranium from the phosphoric acid. The solvent used was a synergistic mixture of D2EHPA and TOPO. The results were very promising with good recovery and very high quality for the uranium concentrate. Later, the J.E.N. continued the studies in a pilot plant scale. For this purpose, was built an experimental facility in Huelva; it can treat about 7 cu. m/day of brown acid. Fosforico Espanol, S.A. (FESA) collaborated in the studies and agreed to setting up these installations in their factory. They also provided fresh phosphoric acid for the tests. In this pilot plant we studied the following stages: a) Clarification and conditioning of the phosphoric acid; b) Uranium extraction followed by stripping in a reducing medium; c) Purification by extraction and washing; d) Obtention of the concentrate by stripping with ammonia and CO 2 gas, followed by crystallization of the ammonium uranyl tricarbonate (AUT); and e) Calcination of the concentrate to decompose the AUT to uranium oxides. The results confirmed the laboratory test data. Recuperation levels were between 85 and 90%. The AUT calcined at 550 0 C. gave a product with 96-98% U 3 O 8 . In view of the pilot plant results we have prepared a black book for an industrial plant to treat about 3700 cu. m/day of phosphoric acid. At the present time the financial aspects of this installation are being studied [es

Phosphates and phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Becker, P [Compagnie Francaise de l' Azote, Paris (France)

1983-01-01

In chapter 8.5 the following aspects of uranium recovery are treated: basis of extraction process, extraction principle, solvents, strength of the acid to be treated, technology, main processes in use, impact of uranium recovery on phosphoric acid plants, and economics of uranium recovery plants.

Use of glucose as reductant to recover Co from spent lithium ions batteries.

Science.gov (United States)

Meng, Qi; Zhang, Yingjie; Dong, Peng

2017-06-01

A hydrometallurgical leaching process has been developed for recovery of Co and Li from cathode material (LiCoO 2 ) collected from spent LIBs using a mix solution of glucose and phosphoric acid. The spent LiCoO 2 before and after leaching process are analyzed by scanning electron microscopy. A leaching rate of about 98% Co and nearly 100% Li is presented with 1.5mol/L phosphoric acid and 0.02mol/L glucose at 80°C in about 2h. During leaching process, glucose was oxidized into monocarboxylic acid with reduction of Co(III) to Co(II). Co in solution was recovered as Co-oxalate after leaching process. Using glucose as reductant to dissolve LiCoO 2 with chelating agent of phosphoric acid is achieved here. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and complex forming property of phosphor acid derivatives

International Nuclear Information System (INIS)

Babaev, B.N.

2004-01-01

Full text:With the aim to get new effective and selective extra gents of noble and non-ferrous metals from acid solution and industrial sewage, research of the dependence of 'structure effectiveness' the various phosphor acid derivatives with logical changeable structure (thio phosphor acids, derivatives of dialkoxythiophosphor, O-alkyl-methylphosphon, alkylphenylphosphon, diphenylphosphine acids also 4 methyl-1,3,2 dioxaphosphorinane) which contain different functional groups, the remains of heterocyclic amines and alkaloids, new derivatives of some analytical reagents were synthesized. The structure of synthesized compounds is approved by the results of IR-, PMR-, mass-spectrum analyze. Researching mass-spectrum decay of synthesized phosphor acid derivatives we defined that differing from O-dihexyl-S-propargyl-benzylthio phosphat, mass spectrum decay of O-dialkyl-S-(piperdynobutin-2-il)thio phosphat is characterized by the appearing [M-H] + ions and during the decay ions with high intensiveness are formed. Fragmentation of M + O-alkyl-O-(aminoalkyl)phenylphosphonate proceeds in various directions and characterized with the great number of phosphor containing ions, the possession of the second phenyl radical in the molecule of diphenylphosphon acid derivatives changes the fragmentation of molecular ion of diphenylphosphon acid derivatives. The process of extraction of noble (Au, Ag, Pt, Pd, Os) metals from hydrochloric-sulphur-nitrogen acid medium was analyzed by radioactive indicator's method. It was noticed that structure, strength, conformation of compounds, the temperature, of acid medium (0,1-10 M) and the nature of acids (HCL, H 2 SO 4 , HNO 3 ) could have strong influence to the effectiveness of metal extraction. During the research of metals extraction from pure solutions we can see the followings: 1) There are such substances, which can be used as effective group reagent towards the Au, Ag and Pd. 2) Derivatives with acetylene extract ions of gold from

Separation of rare earths from solutions of phosphoric acid

International Nuclear Information System (INIS)

Jones, E.A.

1977-01-01

Rare earths are separated from 6M phosphoric acid by adsorption onto cation resin BIORAD AG50W-X8. The phosphoric acid is then washed from the column, and the rare earths are eluted with 4M hydrochloric acid

Proton conductance at elevated temperature:Formulation and investigation of poly(4-styrenesulfonic acid / 4-aminobenzylamine / phosphoric acid membranes

Directory of Open Access Journals (Sweden)

Jalal eJalili

2014-07-01

Full Text Available 4-aminobenzylamine and phosphoric acid were blended in various proportions with poly (4-styrenesulfonic acid to form a new group of membranes exhibiting proton conductance under water-free conditions. The 4-aminobenzylamine molecule, possessing an aniline-like and benzylamine-like functional group, can interact both with the phosphoric acid and the poly(4-styrenesulfonic acid via nucleophilic interaction, thereby allowing proton jumping in the structure. Physico-chemical and thermal characteristics of the prepared solid membranes were investigated by IR spectroscopy and thermo-gravimetric analysis, respectively. Electrochemical impedance spectroscopy was employed to investigate their proton-conductance properties. Transparent composite membranes were prepared. However, the membranes are opaque for relatively high content of phosphoric acid. These membranes are thermally stable up to 300°C. The proton conductivity increases with temperature and also with content of phosphoric acid. Values as high as 1.8×10–3 S cm–1 were measured at 190°C in fully anhydrous condition.

Process for recovering yttrium and lanthanides from wet-process phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Janssen, J.A.; Weterings, C.A.

1983-06-28

Process for recovering yttrium and lanthanides from wet-process phosphoric acid by adding a flocculant to the phosphoric acid, separating out the resultant precipitate and then recovering yttrium and lanthanides from the precipitate. Uranium is recovered from the remaining phosphoric acid.

Uranium extraction in phosphoric acid

International Nuclear Information System (INIS)

Araujo Figueiredo, C. de

1984-01-01

Uranium is recovered from the phosphoric liquor produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). The proposed process consists of two extraction cycles. In the first one, uranium is reduced to its tetravalent state and then extracted by dioctylpyrophosphoric acid, diluted in Kerosene. Re-extraction is carried out with concentrated phosphoric acid containing an oxidising agent to convert uranium to its hexavalent state. This extract (from the first cycle) is submitted to the second cycle where uranium is extracted with DEPA-TOPO (di-2-hexylphosphoric acid/tri-n-octyl phosphine oxide) in Kerosene. The extract is then washed and uranium is backextracted and precipitated as commercial concentrate. The organic phase is recovered. Results from discontinuous tests were satisfactory, enabling to establish operational conditions for the performance of a continuous test in a micro-pilot plant. (Author) [pt

Recovering of uranium from phosphoric acid produced by the wet process

International Nuclear Information System (INIS)

Barreiro, A.J.; Lyon, W.L.; Holleman, R.A.; Randell, C.C.

1977-01-01

Process for recovering uranium as from an aqueous solution of phosphoric acid arising from a wet process, with a scrubbing agent essentially composed of a hydrocarbon whose boiling point is situated between 150 0 C and 300 0 C, which reacts with the contaminents formed in the sludge in the phosphoric acid, in an efficient enough quantity to wash the contamination products forming the phosphoric acid sludge, give a sludge phase and a purified phosphoric acid phase, after which the sludge phase is extracted [fr

Uranium recovery from wet-process phosphoric acid with octylphenyl acid phosphate. Progress report

International Nuclear Information System (INIS)

Arnold, W.D.; McKamey, D.R.; Baes, C.F.

1980-01-01

Studies were continued of a process for recovering uranium from wet-process phosphoric acid with octylphenyl acid phosphate (OPAP), a mixture of mono- and dioctylphenyl phosphoric acids. The mixture contained at least nine impurities, the principal one being octyl phenol, and also material that readily hydrolyzed to octyl phenol and orthophosphoric acid. The combination of mono- and dioctylphenyl phosphoric acids was the principal uranium extractant, but some of the impurities also extracted uranium. Hydrolysis of the extractant had little effect on uranium extraction, as did the presence of moderate concentrations of octyl phenol and trioctylphenyl phosphate. Diluent choice among refined kerosenes, naphthenic mixtures, and paraffinic hydrocarbons also had little effect on uranium extraction, but extraction was much lower when an aromatic diluent was used. Purified OPAP fractions were sparingly soluble in aliphatic hydrocarbon diluents. The solubility was increased by the presence of impurities such as octyl phenol, and by the addition of water or an acidic solution to the extractant-diluent mixture. In continuous stability tests, extractant loss by distribution to the aqueous phase was much less to wet-process phosphoric acid than to reagent grade acid. Uranium recovery from wet-process acid decreased steadily because of the combined effects of extractant poisoning and precipitation of the extractant as a complex with ferric iron. Unaccountable losses of organic phase volume occurred in the continuous tests. While attempts to recover the lost organic phase were unsuccessful, the test results indicate it was not lost by entrainment or dissolution in the phosphoric acid solutions. 21 figures, 8 tables

Radionuclide concentrations in raw and purified phosphoric acids from Brazil and their processing wastes: implications for radiation exposures.

Science.gov (United States)

da Conceição, Fabiano Tomazini; Antunes, Maria Lúcia Pereira; Durrant, Steven F

2012-02-01

Radionuclides from the U and Th natural series are present in alkaline rocks, which are used as feedstock in Brazil for the production of raw phosphoric acid, which can be considered as a NORM (naturally occurring radioactive material). As a result of the purification of raw phosphoric acid to food-grade phosphoric acid, two by-products are generated, i.e., solid and liquid wastes. Taking this into account, the main aim of this study was to evaluate the fluxes of natural radionuclide in the production of food-grade phosphoric acids in Brazil, to determine the radiological impact caused by ingestion of food-grade phosphoric acid, and to evaluate the solid waste environmental hazards caused by its application in crop soils. Radiological characterization of raw phosphoric acid, food-grade phosphoric acid, solid waste, and liquid waste was performed by alpha and gamma spectrometry. The (238)U, (234)U, (226)Ra, and (232)Th activity concentrations varied depending on the source of raw phosphoric acid. Decreasing radionuclides activity concentrations in raw phosphoric acids used by the producer of the purified phosphoric acid were observed as follows: Tapira (raw phosphoric acid D) > Catalão (raw phosphoric acids B and C) > Cajati (raw phosphoric acid A). The industrial purification process produces a reduction in radionuclide activity concentrations in food-grade phosphoric acid in relation to raw phosphoric acid produced in plant D and single raw phosphoric acid used in recent years. The most common use of food-grade phosphoric acid is in cola soft drinks, with an average consumption in Brazil of 72 l per person per year. Each liter of cola soft drink contains 0.5 ml of food-grade phosphoric acid, which gives an annual average intake of 36 ml of food-grade phosphoric acid per person. Under these conditions, radionuclide intake through consumption of food-grade phosphoric acid per year per person via cola soft drinks is not hazardous to human health in Brazil

World wide IFC phosphoric acid fuel cell implementation

Energy Technology Data Exchange (ETDEWEB)

King, J.M. Jr

1996-04-01

International Fuel Cells, a subsidary of United technologies Corporation, is engaged in research and development of all types of fuel cell technologies and currently manufactures alkaline fuel cell power plants for the U.S. manned space flight program and natural gas fueled stationary power plants using phosphoric acid fuel cells. This paper describes the phosphoric acid fuel cell power plants.

Determination of vanadium in Syrian commercial and raffinate phosphoric acid

International Nuclear Information System (INIS)

Al-Merey, R.

2002-04-01

This study presents two methods for vanadium determination in Syrian commercial phosphoric acid. The vanadium (V) in the oxidized commercial phosphoric acid by ammonium persulfate solution is extracted from 5-M hydrochloride acid medium using N-benzoyl-N-phenyl hydroxyl amine (BPHA) in chloroform as an extracting solution. The first method, the extract vanadium as VOL 2 Cl is changed to V 2 O 3 L 4 complex by the addition of benzimidazole in 1-butanol to the violet organic layer. The absorbance is then measured at 440 nm (the molar absorptivity was found to be 3865 M -1 cm -1 ), where Beer law is applicable up to 36-μg ml -1 . the accuracy, precision and detection limit were found to be 3.7%, 77 ppb and 37 ppb, respectively. the second method, the organic layer is heated to evaporate chloroform, the residue is digested using 20% ammonium persulfate and 2-M sulfuric acid solutions. The vanadium concentration is measured spectrophotometrically by oxidizing gallic acid with persulfate (S 2 O 8 2- ) anion in phosphoric acid medium, where the vanadium (V) acts as a catalyst in the oxidation reaction. This method has a high sensitivity (∼10 -12 ) with accuracy and precision 5% and 0.621 ppb, respectively. Also Beer law at λ m ax=415 nm (ε=∼2 x 10 6 M -1 ) is applicable in the range 2.58-33.3 ppb. (author)

Doping phosphoric acid in polybenzimidazole membranes for high temperature proton exchange membrane fuel cells

DEFF Research Database (Denmark)

He, Ronghuan; Li, Qingfeng; Jensen, Jens Oluf

2007-01-01

Polybenzimidazole (PBI) membranes were doped in phosphoric acid solutions of different concentrations at room temperature. The doping chemistry was studied using the Scatchard method. The energy distribution of the acid complexation in polymer membranes is heterogeneous, that is, there are two...... different types of sites in PBI for the acid doping. The protonation constants of PBI by phosphoric acid are found to be 12.7 L mol(-1) (K-1) for acid complexing sites with higher affinity, and 0.19 L mol(-1) (K-2) for the sites with lower affinity. The dissociation constants for the complexing acid onto...... these two types of PBI sites are found to be 5.4 X 10(-4) and 3.6 X 10(-2), respectively, that is, about 10 times smaller than that of aqueous phosphoric acid in the first case but 5 times higher in the second. The proton conducting mechanism is also discussed....

Developing a rapid method for the determination of uranium in pure phosphoric acid and D2 EHPA

International Nuclear Information System (INIS)

Koudsi, Y.; Stas, J.; Al-Merey, R.; shaddoud, G.

1996-02-01

Arsenazo (III) used in titrate uranium spectrophotometrically in phosphoric acid after its extraction into organic phase. In this work we used arsenazo(III) to complex uranyl ion in pure phosphoric acid and in the aqueous phase. The spectrum of the complex shows that λ max is at 650 nm. The linearity of the method is corelated with acid molarity, it is (1 -4, 10 - 30, 10 - 40) ppm uranium for (0.2, 1, 2) M of phosphoric acid respectively. Uranium in D 2 EHPA stripped by phosphoric acid and then determined by this method. Also it has been applied to determine uranium in pure perchloric acid. The method is direct, rapid, very cheap and relatively accurate. (author)

Method for the recovery of uranium from a concentrate using pure phosphoric acid

International Nuclear Information System (INIS)

1980-01-01

Procedure for the recovery of an uranium bearing concentrate and pure phosphoric acid from a wet process phosphoric acid from the treatment fluid with a precipitation means in conjunction with an organic diluent, the thus formed precipitate to separate and from the remaining mixture of phosphoric acid and diluent the phosphoric acid to extract, characterised in that one applies an inorganic fluorine compound. (G.C.)

Why do proton conducting polybenzimidazole phosphoric acid membranes perform well in high-temperature PEM fuel cells?

Science.gov (United States)

Melchior, Jan-Patrick; Majer, Günter; Kreuer, Klaus-Dieter

2016-12-21

Transport properties and hydration behavior of phosphoric acid/(benz)imidazole mixtures are investigated by diverse NMR techniques, thermogravimetric analysis (TGA) and conductivity measurements. The monomeric systems can serve as models for phosphoric acid/poly-benzimidazole membranes which are known for their exceptional performance in high temperature PEM fuel cells. 1 H- and 31 P-NMR data show benzimidazole acting as a strong Brønsted base with respect to neat phosphoric acid. Since benzimidazole's nitrogens are fully protonated with a low rate for proton exchange with phosphate species, proton diffusion and conduction processes must take place within the hydrogen bond network of phosphoric acid only. The proton exchange dynamics between phosphate and benzimidazole species pass through the intermediate exchange regime (with respect to NMR line separations) with exchange times being close to typical diffusion times chosen in PFG-NMR diffusion measurements (ms regime). The resulting effects, as described by the Kärger equation, are included into the evaluation of PFG-NMR data for obtaining precise proton diffusion coefficients. The highly reduced proton diffusion coefficient within the phosphoric acid part of the model systems compared to neat phosphoric acid is suggested to be the immediate consequence of proton subtraction from phosphoric acid. This reduces hydrogen bond network frustration (imbalance of the number of proton donors and acceptors) and therefore also the rate of structural proton diffusion, phosphoric acid's acidity and hygroscopicity. Reduced water uptake, shown by TGA, goes along with reduced electroosmotic water drag which is suggested to be the reason for PBI-phosphoric acid membranes performing better in fuel cells than other phosphoric-acid-containing electrolytes with higher protonic conductivity.

Extraction of uranium from phosphoric-hydrobromic acid mixture by N-lauryl tri alkyl methylamine

Energy Technology Data Exchange (ETDEWEB)

Guirguis, L A [Nuclear materials authority, Cairo, (Egypt); Tadros, N A [Hot laboratories center, atomic energy authority, Cairo, (Egypt)

1995-10-01

A uranium recovery process from phosphoric acid produced by the dihydrate method was elaborated. Decomposition of phosphate rock containing 0.02% U is carried out with sulphuric acid. Crude phosphoric acid is filtered off, steam concentrated to 45% P{sub 2} O{sub 5} (6.27 M) and then clarified with activated clay and carbon. The clear phosphoric acid is introduced to uranium extraction after the addition of 0.88 M hydrobromic acid by 0.134 M amberlite LA.2 and 5% decanol, as a modifier, in kerosene. While 10% ammonium sulphate solution is used for stripping. Over 90% uranium recovery is obtained. 6 figs., 1 tab.

Uranium recovery from wet process phosphoric acid

International Nuclear Information System (INIS)

Carrington, O.F.; Pyrih, R.Z.; Rickard, R.S.

1981-01-01

Improvement in the process for recovering uranium from wetprocess phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange liquidliquid solvent extraction circuits in which in the first circuit (A) the uranium is reduced to the uranous form; (B) the uranous uranium is recovered by liquid-liquid solvent extraction using a mixture of mono- and di-(Alkyl-phenyl) esters of orthophosphoric acid as the ion exchange agent; and (C) the uranium oxidatively stripped from the agent with phosphoric acid containing an oxidizing agent to convert uranous to uranyl ions, and in the second circuit (D) recovering the uranyl uranium from the strip solution by liquid-liquid solvent extraction using di(2ethylhexyl)phosphoric acid in the presence of trioctylphosphine oxide as a synergist; (E) scrubbing the uranium loaded agent with water; (F) stripping the loaded agent with ammonium carbonate, and (G) calcining the formed ammonium uranyl carbonate to uranium oxide, the improvement comprising: (1) removing the organics from the raffinate of step (B) before recycling the raffinate to the wet-process plant, and returning the recovered organics to the circuit to substantially maintain the required balance between the mono and disubstituted esters; (2) using hydogren peroxide as the oxidizing agent in step (C); (3) using an alkali metal carbonate as the stripping agent in step (F) following by acidification of the strip solution with sulfuric acid; (4) using some of the acidified strip solution as the scrubbing agent in step (E) to remove phosphorus and other impurities; and (5) regenerating the alkali metal loaded agent from step (F) before recycling it to the second circuit

Ion conduction mechanisms and thermal properties of hydrated and anhydrous phosphoric acids studied with 1H, 2H, and 31P NMR.

Science.gov (United States)

Aihara, Yuichi; Sonai, Atsuo; Hattori, Mineyuki; Hayamizu, Kikuko

2006-12-14

To understand the behaviors of phosphoric acids in fuel cells, the ion conduction mechanisms of phosphoric acids in condensed states without free water and in a monomer state with water were studied by measuring the ionic conductivity (sigma) using AC impedance, thermal properties, and self-diffusion coefficients (D) and spin-lattice relaxation times (T1) with multinuclear NMR. The self-diffusion coefficient of the protons (H+ or H3O+), H2O, and H located around the phosphate were always larger than the diffusion coefficients of the phosphates and the disparity increased with increasing phosphate concentration. The diffusion coefficients of the samples containing D2O paralleled those in the protonated samples. Since the 1H NMR T1 values exhibited a minimum with temperature, it was possible to determine the correlation times and they were found to be of nanosecond order for a distance of nanometer order for a flip. The agreement of the ionic conductivities measured directly and those calculated from the diffusion coefficients indicates that the ion conduction obeys the Nernst-Einstein equation in the condensed phosphoric acids. The proton diffusion plays a dominant role in the ion conduction, especially in the condensed phosphoric acids.

Synthesis of the mono- and di(4-(1,1,3,3-tetramethylbutyl)) phosphoric acids

International Nuclear Information System (INIS)

Elias, H.; Zaoui, A.; Attou, M.; Hadj Bachir, D.; Bouzidi, N.; Didi, M.

1995-09-01

This work is related to the synthesis of organophosphorus extracting agents used in purification of heavy metals such as uranium. The mono- and di (4-(1,1,3,3- tetramethylbutyl)) phenyl phosphoric acids, respectively MOPPA and DOPPA, are synthesizd by reaction of phosphorus pentoxid with 4(1,1,3,3-tetramethylbuthyl)) phenol. the separation of MOPPA from DOPPA is realised by liquid-liquid extraction. The Characterization, carried out by infrared uv-visible spectrophotometries, ph-metry and mass spectrometry, has confirmed the identity of the synthesized products. This study also showed that the products proportions are comporable to those of the homologous products obtained with 2-ethylbexanol in the same synthesis conditions

Initiation in the study of uranium recovery from the phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Anchondo Adalid, J M

1974-01-01

The loss of considerable amounts of uranium in the Mexican phosphoric acid industry makes it important to study economic methods of recovery; the studies can serve as a basis for the construction and operation of a pilot plant as a normal preliminary to larger-scale projects. Routine experimental techniques for solvent extraction were employed. Extraction efficiencies of the order of 90-95% were obtained using 0.09-0.18M solutions of a mixture of phosphoric octyl esters applied to 4 and 6M solutions of phosphoric acid (reagent grade) containing uranium in concentrations of 0.05-0.50g of U/sub 3/O/sub 8/ per litre of acid. The conclusion was reached that phosphoric octyl esters can be used for recovering uranium in satisfactory quantities from phosphoric acid solutions by means of solvent extraction, and that the uranium can be separated from the solvent by the established procedures.

Initiation in the study of uranium recovery from the phosphoric acid

International Nuclear Information System (INIS)

Anchondo Adalid, J.M.

1974-01-01

The loss of considerable amounts of uranium in the Mexican phosphoric acid industry makes it important to study economic methods of recovery; the studies can serve as a basis for the construction and operation of a pilot plant as a normal preliminary to larger-scale projects. Routine experimental techniques for solvent extraction were employed. Extraction efficiencies of the order of 90-95% were obtained using 0.09-0.18M solutions of a mixture of phosphoric octyl esters applied to 4 and 6M solutions of phosphoric acid (reagent grade) containing uranium in concentrations of 0.05-0.50g of U 3 O 8 per litre of acid. The conclusion was reached that phosphoric octyl esters can be used for recovering uranium in satisfactory quantities from phosphoric acid solutions by means of solvent extraction, and that the uranium can be separated from the solvent by the established procedures. (author)

Technology of uranium recovery from wet-process phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Inoue, Katsutoshi [Saga Univ. (Japan). Faculty of Science and Engineering; Nakashio, Fumiyuki

1982-12-01

Rock phosphate contains from 0.005 to 0.02 wt.% of uranium. Though the content is a mere 5 to 10 % of that in uranium ore, the total recovery of uranium is significant since it is used for fertilizer manufacture in a large quantity. Wet-process phosphoric acid is produced by the reaction of rock phosphate with sulfuric acid. The recovery of uranium from this phosphoric acid is mostly by solvent extraction at present. According to U/sup 4 +/ or UO/sub 2//sup 2 +/ as the form of its existence, the technique of solvent extraction differs. The following matters are described: processing of rock phosphate; recovery techniques including the extraction by OPPA-octyl pyrophosphoric acid for U/sup 4 +/, and by mixed DEHPA-Di-(2)-ethylhexyl phosphoric acid and TOPO-tryoctyl phosphine oxide for UO/sub 2//sup 2 +/, and by OPAP-octylphenyl acid phosphate for U/sup 4 +/; the recent progress of the technology as seen in patents.

Natural Radiation in byproducts of the production of phosphoric acid

International Nuclear Information System (INIS)

Silveira, Marcilei A. Guazzelli da; Cardoso, L.L.; Medina, N.H.

2014-01-01

Natural radiation is the largest source of radiation exposure to which man is subject. It is formed basically by cosmic radiation and the radionuclides present in the Earth crust, as 40 K and the elements of the decay series of 232 Th and 238 U. Phosphate ores, which constitutes the raw material for the production of phosphoric acid, have a high rate of natural radiation from the decay series of 232 Th and 238 U. Phosphogypsum, which is naturally radioactivity, is a by-product of the production of phosphoric acid by the wet method. For each ton of phosphoric acid it is produced about 4.5 tons of phosphogypsum. This work presents the analysis of samples collected in all stages of the manufacturing process of phosphoric acid, which generates the phosphogypsum. Gamma-ray spectrometry was used to measure the concentration of the elements of the decay series of 232 Th and 238 U. All analyzed samples showed a high concentration of radionuclides, promoting the need for further steps in the process in order to reduce the presence of such radionuclides in the phosphogypsum. The results indicate the radionuclide 238 U has higher contribution in some samples of the intermediate stages of the process. All samples exceeded the international average range of human exposure to terrestrial gamma radiation, which is 0.3 to 1.0 mSv/year. (author)

Performance of phosphoric acid activated montmorillonite as buffer materials for radioactive waste repository

International Nuclear Information System (INIS)

Wang, Tsing-Hai; Liu, Tsung-Ying; Wu, Ding-Chiang; Li, Ming-Hsu; Chen, Jiann-Ruey; Teng, Shi-Ping

2010-01-01

In this study, the performance of phosphoric acid activated montmorillonite (PAmmt) was evaluated by cesium ions adsorption experiments. The PAmmt samples were obtained by activating with 1, 3 and 5 mol L -1 of phosphoric acid, respectively under reflux for 3, 12, and 24 h. Experimental results demonstrated that the treatment of raw K-10 montmorillonite with phosphoric acid increased the materials' affinity for Cs uptake and no significant amount of suspension solids were produced. A relatively insignificant variation in the CEC value was observed. Furthermore, PAmmt also showed high adsorption selectivity toward Cs ions. The improved sorptive properties were mainly related to the increased surface area and the relatively higher surface charge density. Increased specific surface area was the resulted from partial decomposition of lamellar structure of mmt; while the higher surface charge density was caused by the protonation of octahedral Al-OH sites during the acid activation. Generally speaking, stronger acid concentration and longer activation times would produce relatively more decomposed PAmmt particles. However, as the activation exceeds 3 h, the precipitation of Si 4+ would passivate PAmmt against further acid attacks. Based upon our results, acid activation by phosphoric acid could produce PAmmt samples with high sorption capacity and selectivity, and good structural integrity, which are beneficial to be used at radioactive waste repository.

Method for separating mono- and di-octylphenyl phosphoric acid esters

International Nuclear Information System (INIS)

Arnold, W.D. Jr.

1977-01-01

A method for separating mono-octylphenyl phosphoric acid ester and di-octylphenyl phosphoric acid ester from a mixture thereof comprises reacting the ester mixture with a source of lithium or sodium ions to form a mixture of the phosphate salts; contacting the salt mixture with an organic solvent which causes the dioctylphenyl phosphate salt to be dissolved in the organic solvent phase and the mono-octylphenyl phosphate salt to exist in a solid phase; separating the phases; recovering the phosphate salts from their respective phases; and acidifying the recovered salts to form the original phosphoric acid esters

Phosphoric acid fuel cell R and D activities at KACST

International Nuclear Information System (INIS)

Ghouse, M.; Aba-Oud, H.; Ba-Junaid, M.; Al-Garni, M.; Quadri, M.I.

1993-01-01

The PAFC (Phosphoric Acid Fuel Cell) activities are directed towards the development of components of single cell and experimental stacks at KACST. The main aim of the present task is to design and construct a 1 kW PAFC Stack and demonstrate it by integrating with an electrolyser using a DC current generated by a photovoltaic power source. This paper describes the preparation of porous teflon bonded gas diffusion carbon electrodes and their evaluation as single phosphoric acid fuel cells using hydrogen as a fuel and oxygen/air as an oxidant. 6 figs., 2 tabs., 15 refs

Properties of precipitates formed during ammonization of extractional phosphoric acid

International Nuclear Information System (INIS)

Zakharova, B.S.; Komissarova, L.N.; Naumov, S.V.; Traskin, V.Yu.

1992-01-01

Dimensions of precipitated rare-earth phosphate particles -(0.1 μm)- are near the boundary of colloidal system sedimentation stability range at neutralization of extraction phosphoric acid. Thus, formation of multiple aggregates of colloidal particles results in immediate sedimentation of the precipitate. Processes occurring within the system may be described using second order reaction equation. Average efficient size of precipitates grows at reduction of reaction mixture pH. About 30% of rare-earth elements and yttrium in the extraction phosphoric acid is extracted from it; concentration of rare-earth elements, yttrium and scandium in precipitate is maximum 2 mass. %

Uranium recovery from the concentrated phosphoric acid prepared by the hemi-hydrate process

Energy Technology Data Exchange (ETDEWEB)

Fouad, E A; Mahdy, M A; Bakr, M Y [Nuclear materials authority, Cairo, (Egypt); Zatout, A A [Faculty of engineering, Alex. university, Alex, (Egypt)

1995-10-01

It has been proved that the uranium dissolution from El-sebaiya phosphate ore was possible by using 10 Kg of K Cl O{sub 4}/ ton rock during the preparation of high strength phosphoric acid using the hemi hydrate process. In the present work, effective extraction of uranium (about 90%) from the high strength phosphoric acid using a new synergistic solvent mixture of 0.75 M D 2 EHPA/0.1 M TOHPO had been a success. Stripping of uranium from the organic phase was possible by 10 M phosphoric acid while the direct precipitation of uranium concentrate from the later was feasible by using N H{sub 4} F in presence of acetone. 8 figs.

Uranium recovery from the concentrated phosphoric acid prepared by the hemi-hydrate process

International Nuclear Information System (INIS)

Fouad, E.A.; Mahdy, M.A.; Bakr, M.Y.; Zatout, A.A.

1995-01-01

It has been proved that the uranium dissolution from El-sebaiya phosphate ore was possible by using 10 Kg of K Cl O 4 / ton rock during the preparation of high strength phosphoric acid using the hemi hydrate process. In the present work, effective extraction of uranium (about 90%) from the high strength phosphoric acid using a new synergistic solvent mixture of 0.75 M D 2 EHPA/0.1 M TOHPO had been a success. Stripping of uranium from the organic phase was possible by 10 M phosphoric acid while the direct precipitation of uranium concentrate from the later was feasible by using N H 4 F in presence of acetone. 8 figs

Porous structure and surface chemistry of phosphoric acid activated carbon from corncob

Science.gov (United States)

Sych, N. V.; Trofymenko, S. I.; Poddubnaya, O. I.; Tsyba, M. M.; Sapsay, V. I.; Klymchuk, D. O.; Puziy, A. M.

2012-11-01

Active carbons have been prepared from corncob using chemical activation with phosphoric acid at 400 °C using varied ratio of impregnation (RI). Porous structure of carbons was characterized by nitrogen adsorption and scanning electron microscopy. Surface chemistry was studied by IR and potentiometric titration method. It has been shown that porosity development was peaked at RI = 1.0 (SBET = 2081 m2/g, Vtot = 1.1 cm3/g), while maximum amount of acid surface groups was observed at RI = 1.25. Acid surface groups of phosphoric acid activated carbons from corncob includes phosphate and strongly acidic carboxylic (pK = 2.0-2.6), weakly acidic carboxylic (pK = 4.7-5.0), enol/lactone (pK = 6.7-7.4; 8.8-9.4) and phenol (pK = 10.1-10.7). Corncob derived carbons showed high adsorption capacity to copper, especially at low pH. Maximum adsorption of methylene blue and iodine was observed for carbon with most developed porosity (RI = 1.0).

Porous polybenzimidazole membranes doped with phosphoric acid: Preparation and application in high-temperature proton-exchange-membrane fuel cells

International Nuclear Information System (INIS)

Li, Jin; Li, Xiaojin; Yu, Shuchun; Hao, Jinkai; Lu, Wangting; Shao, Zhigang; Yi, Baolian

2014-01-01

Highlights: • Porous polybenzimidazole membrane was prepared with glucose as porogen. • Phosphoric acid content was as high as 15.7 mol H 3 PO 4 per PBI repeat unit. • 200 h Constant current density test was carried out at 150 °C. • Degradation was due to the gap between membrane and catalyst layer. - Abstract: In this paper, the preparation and characterization of porous polybenzimidazole membranes doped with phosphoric acid were reported. For the preparation of porous polybenzimidazole membranes, glucose and saccharose were selected as porogen and added into PBI resin solution before solvent casting. The prepared porous PBI membranes had high proton conductivity and high content of acid doping at room temperature with 15.7 mol H 3 PO 4 per PBI repeat unit, much higher than pure PBI membrane at the same condition. Further, the performance and stability of the porous PBI membrane in high-temperature proton-exchange-membrane fuel cells was tested. It was found that the cell performance remained stable during 200 h stability test under a constant current discharge of 0.5 A cm −2 except for the last fifty hours. The decay in the last fifty hours was ascribed to the delamination between the catalyst layer and membrane increasing the charge-transfer resistance

Promotion of Crystal Growth on Biomass-based Carbon using Phosphoric Acid Treatments

Directory of Open Access Journals (Sweden)

Liwei Yu

2015-02-01

Full Text Available The effect of phosphoric acid treatments on graphitic microcrystal growth of biomass-based carbons was investigated using X-ray diffraction, infrared spectroscopy, and Raman spectroscopy. Although biomass-based carbons are believed to be hard to graphitize even after heat treatments well beyond 2000 °C, we found that graphitic microcrystals of biomass-based carbons were significantly promoted by phosphoric acid treatments above 800 °C. Moreover, twisted spindle-like whiskers were formed on the surface of the carbons. This suggests that phosphorus-containing groups turn graphitic microcrystalline domains into graphite during phosphoric acid treatments. In addition, the porous texture of the phosphoric acid-treated carbon has the advantage of micropore development.

Process for recovery of uranium from wet process phosphoric acid

International Nuclear Information System (INIS)

Wiewiorowski, T.K.; Thornsberry, W.L. Jr.

1978-01-01

Process is claimed for the recovery of uranium from wet process phosphoric acid solution in which an organic extractant, containing uranium values and dissolved iron impurities and comprising a dialkylphosphoric acid and a trialkylphosphine oxide dissolved in a water immiscible organic solvent, is contacted with a substantially iron-free dilute aqueous phosphoric acid to remove said iron impurities. The removed impurities are bled from the system by feeding the resulting iron-loaded phosphoric acid to a secondary countercurrent uranium extraction operation from which they leave as part of the uranium-depleted acid raffinate. Also, process for recovering uranium in which the extractant, after it has been stripped of uranium values by aqueous ammonium carbonate, is contacted with a dilute aqueous acid selected from the group consisting of H 2 SO 4 , HCl, HNO 3 and iron-free H 3 PO 4 to improve the extraction efficiency of the organic extractant

Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution

International Nuclear Information System (INIS)

Liu, Hu; Zhang, Shengen; Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin; Volinsky, Alex A.

2014-01-01

Highlights: • The article provides a new method for recycling rare earth (RE) from waste phosphor. • When compared with the traditional methods, leach rate was much higher. • Y–Eu concentrate and Tb–Ce concentrate were obtained successively. • It would reduce the burden of later extraction, separation and purification. - Abstract: This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y 0.95 Eu 0.05 ) 2 O 3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce 0.67 Tb 0.33 MgAl 11 O 19 ) and the Blue phosphor (Ba 0.9 Eu 0.1 MgAl 10 O 17 ) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO 2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications

Flocculation of suspended matter in a crude wet phosphoric acid (Algeria)

International Nuclear Information System (INIS)

Brikci Nigassa, M.; Bensebaa, A.

1994-11-01

Prior to the recovery of uranium, a pre-treatment of the phosphoric acid is necessary to remove soluble impurities of different origins. In this work, synthetic flocculants have been used. the influence of operating conditions on flocculation and filtration, such as, type of flocculants, polymer concentration, temperature, mixing and time of agitation, has been studied for both aged and fresh phosphoric acid. It has been shown that synthetic flocculants can be used for flocculation ins a phosphoric acid medium and that flocculation and filtration processes are strongly linked

Cadmium elemination from phosphoric acid by ionic flotation

International Nuclear Information System (INIS)

Brikci-Nigassa, Mounir; Hamouche, Hafida

1995-11-01

The ion flotation process for the recovery of cadmium from wet phosphoric acid (30%P2O5) has been studied. This technique combines a chemical recation between the collector and the cadmium to form a precipitate (sublate) which is carried to the surface of the solution by air bubbles. the resulting foam containing the cadmium may then separated from solution. The influence of parameters such as collector and cadmium concentration as well as iron content have been investigated for the case a synthetic acid (30% P2O5). The result have been applied to the industrial phosphoric acid produced from Djebel Onk's phosphates (Algeria)

Solid phase extraction of uranium from phosphoric acid. Kinetic and thermodynamic study

Energy Technology Data Exchange (ETDEWEB)

Abdel-Magied, Ahmed Fawzy [Nuclear Materials Authority, Cairo (Egypt); Stockholm Univ. (Sweden). Dept. of Organic Chemistry

2017-07-01

There is a high interest to develop suitable solid phase extractants for uranium separation from aqueous solutions in order to reduce cost and enhance the efficiency. This paper describes solid phase extraction of uranium(VI) from aqueous phosphoric acid solution using MCM-41 based D2HEPA-TOPO organophosphorous extractants. The mixture of D2HEPA (di-2-ethyl-hexylphosphoric acid) and TOPO (tri-n-octylphosphine oxide) was impregnated into the pores of MCM-41 and the synthesized sorbent was fully characterized. The influences of different factors such as synergistic mixture ratio, phosphoric acid concentration, mixing time and temperature were investigated. The results showed that 90% of uranium(VI) extraction can be achieved within 5 min, using D2HEPA-TOPO rate at MCM-41 (mass ratio 2:1 w/w) from 1 M phosphoric acid containing 64 ppm of uranium at room temperature. High adsorption capacity of uranium(VI) have been achieved at the mentioned conditions. The rate constant for the chemical adsorption of uranium(VI) was 0.988 g mg{sup -1} min{sup -1} calculated by the pseudo-second order rate equation. The obtained thermodynamics parameters showed that uranium(VI) adsorption from H{sub 3}PO{sub 4} is an exothermic and spontaneous process.

Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution

Energy Technology Data Exchange (ETDEWEB)

Liu, Hu [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Shengen, E-mail: zhangshengen@mater.ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A. [Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States)

2014-05-01

Highlights: • The article provides a new method for recycling rare earth (RE) from waste phosphor. • When compared with the traditional methods, leach rate was much higher. • Y–Eu concentrate and Tb–Ce concentrate were obtained successively. • It would reduce the burden of later extraction, separation and purification. - Abstract: This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y{sub 0.95}Eu{sub 0.05}){sub 2}O{sub 3} in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce{sub 0.67}Tb{sub 0.33}MgAl{sub 11}O{sub 19}) and the Blue phosphor (Ba{sub 0.9}Eu{sub 0.1}MgAl{sub 10}O{sub 17}) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO{sub 2} are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications.

Oxidation-extraction of uranium from wet-process phosphoric acid

International Nuclear Information System (INIS)

Lawes, B.C.

1985-01-01

The invention involves an improvement to the reductive stripping process for recovering uranium values from wet-process phosphoric acid solution, where uranium in the solution is oxidized to uranium (VI) oxidation state and then extracted from the solution by contact with a water immiscible organic solvent, by adding sufficient oxidant, hydrogen peroxide, to obtain greater than 90 percent conversion of the uranium to the uranium (VI) oxidation state to the phosphoric acid solution and simultaneously extracting the uranium (VI)

40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid polyamine condensate... New Uses for Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric acid... substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and P-90-1985...

Recovering uranium from phosphoric acid

International Nuclear Information System (INIS)

Abodishish, H.A.; Ritchey, R.W.

1982-01-01

Precipitation of Fe 3 HN 4 H 8 (PO 4 ) 6 is prevented in the second cycle extractor, in a two cycle uranium recovery process, by washing ammonia laden organic solvent stream, from the second cycle stripper, with first cycle raffinate iron stream containing phosphoric acid, prior to passing the solvent stream into the second cycle extractor. (author)

Recovery of uranium in the production of concentrated phosphoric acid by a hemihydrate process

International Nuclear Information System (INIS)

Nakajima, S.; Miyamoto, M.

1983-01-01

Nissan Chemical Industries as manufacturers of phosphoric acid have studied the recovery of uranium, based on a concentrated phosphoric acid production process. The process consists of two stages, a hemihydrate stage with a formation of hemihydrate and a filtration section, followed by a dihydrate stage with hydration and a filtration section. In the hemihydrate stage, phosphate is treated with a mixture of phosphoric acid and sulphuric acid to produce phosphoric acid and hydrous calcium sulphate; the product is recovered in the filtration section and its concentration is 40-50% P 2 O 3 . In the dihydrate stage, the hemihydrate is transformed by re-dissolution and hydration, producing hydrous calcium sulphate, i.e. gypsum. This process therefore comprises two parts, each with different acid concentrations. As the extraction of uranium is easier in the case of a low concentration of phosphoric acid, the process consists of the recovery of uranium starting from the filtrate of the hydration section. The tests have shown that the yield of recovery of uranium was of the order of 80% disregarding the handling losses and no disadvantageous effect has been found in the combination of the process of uranium extraction with the process of concentrated phosphoric acid production. Compared with the classical process where uranium is recovered from acid with 30% P 2 O 5 , the process of producing high-concentration phosphoric acid such as the Nissan process, in which the uranium recovery is effected from acid with 15% P 2 O 5 from the hydration section, presents many advantages [fr

Determination of the activity concentration of 230Th in phosphoric acids produced in Brazil

International Nuclear Information System (INIS)

Taddei, M.H.T.; Ferreira, M.T.; Fukuma, H.T.; Xavier, T.T.; Sousa, F.V.T.S.

2017-01-01

The high uranium phosphate rock from Itataia, Brazil, was processed using the wet route in the dihydrate system to manufacture phosphoric acid. The uranium contained in phosphoric acid was recovered by the solvent extraction technique. The distribution of the long half-life radionuclides from the decay series of 238 U and 232 Th were evaluated in these processes. The 26 Ra, 228 Ra and 210 Pb radionuclides were found predominantly in phosphogypsum, while the isotopes of 228 Th, 230 Th and 232 Th predominated in phosphoric acid after extracting uranium. The main concern in the commercialization of phosphoric acid that will be produced in the Itataia plant is in relation to the content of 230 Th. This work determined the content of these radionuclides in phosphoric acid from different locations in the country in order to compare

Evidence connecting old, new and neglected glucose-lowering drugs to bile acid-induced GLP-1 secretion

DEFF Research Database (Denmark)

Kårhus, Martin L; Brønden, Andreas; Sonne, David P

2017-01-01

Bile acids are amphipathic water-soluble steroid-based molecules best known for their important lipid-solubilizing role in the assimilation of fat. Recently, bile acids have emerged as metabolic integrators with glucose-lowering potential. Among a variety of gluco-metabolic effects, bile acids have...... current evidence connecting established glucose-lowering drugs to bile acid-induced GLP-1 secretion and discusses whether bile acid-induced GLP-1 secretion may constitute a new basis for understanding how metformin, inhibitors of the apical sodium-dependent bile acids transporter, and bile acid...... sequestrants - old, new and neglected glucose-lowering drugs - improve glucose metabolism....

Extraction studies on rare earths using dinonyl phenyl phosphoric acid

International Nuclear Information System (INIS)

Anitha, M.; Singh, D.K.; Kotekar, M.K.; Vijayalakshmi, R.; Singh, H.

2011-01-01

Rare earths are widely used in phosphor materials, magnetic substances, alloys, catalyst, lasers, superconductors, solid oxide fuel cells and in nuclear applications. The high value of these elements depends on their effective separation into high purity compounds. The separation into individual rare earths is very difficult to achieve, due to the very low separation factors between two adjacent rare earths arising due to similar chemical properties. Taking the advantage of variation in basicity, the separation is generally accomplished by solvent extraction or ion exchange. There are several references on the separation of rare earth in different media employing various types of extractants such as 2-ethylhexyl 2-ethyhexylphosphonic acid (EHEHPA) and di-2-ethyl hexyl phosphoric acid (D2EHPA) which have been widely used for the separation and purification of rare earths. Dinonyl phenyl phosphoric acid (DNPPA) is an organo phosphorus extractant (pKa = 2.54) and is an aromatic analogue of D2EHPA, which extracts metal ion by cation exchange mechanism. DNPPA was explored to recover rare earths from phosphate media such as wet process phosphoric acid and merchant grade acid. However, there is no information available in literature on DNPPA for RE extraction from chloride medium. Therefore, an attempt has been made in the present study to investigate the feasibility of using DNPPA for extraction of La(III), Dy(III) and Y(III) from chloride medium

Radioactivity Content in Phosphoric Acid Used for Fertilizer Production

International Nuclear Information System (INIS)

Ibrahiem, N.M.; Hamed, A.A.

2003-01-01

Uranium content in phosphoric acid used fertilizer production was measured by alpha spectrometry, laser fluorimetry high resolution gamma spectrometry. Also, polonium-210 content was determined in phosphoric acid by alpha spectrometry. Uranium-234 and uranium-238 concentrations, measured by alpha spectroscopy, were found to be 601 and 507 Bq I -1 , respectively. Total uranium content obtained by laser fluorimetry was about 545 BqI - (45.4ppm). Gamma spectroscopy analysis gave the concentrations of 40 K, 238 U, 235 U, 214 Pb, 214 Bi and 208 TI, as 17,644,19.5, 1.2,1.3 and 9.4 Bq I -1 , respectively. Polonium-210 concentration was found to be about 3.1 Bq I -1 . Uranium-232 and polonium-208 were used as yield tracers, for alpha measurements of uranium and polonium, respectively. Samples of the tri-super phosphate (TSP) and single-super phosphate (SSP) fertilizers and the phosphogypsum produced were also analyzed by gamma spectroscopy. Uranium content in both phosphate fertilizers was 3205 and 1440 Bq Kg -1 for 238 U and 83 and 35 Bq Kg -1 for, 235 U respectively

Preliminary study on preparation of BCNO phosphor particles using citric acid as carbon source

Energy Technology Data Exchange (ETDEWEB)

Nuryadin, Bebeh W.; Pratiwi, Tripuspita; Faryuni, Irfana D.; Iskandar, Ferry, E-mail: ferry@fi.itb.ac.id; Abdullah, Mikrajuddin; Khairurrijal [Department of Physics, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Ganesha 10 Bandung, Indonesia 40132 (Indonesia); Ogi, Takashi; Okuyama, Kikuo [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima, Japan 739-8527 (Japan)

2015-04-16

A citric acid was used as a carbon source in the preparation of boron carbon oxy-nitride (BCNO) phosphor particles by a facile process. The preparation process was conducted at relatively low temperature 750 °C and at ambient pressure. The prepared BCNO phosphors showed a high photoluminescence (PL) performance at peak emission wavelength of 470 nm under excitation by a UV light 365 nm. The effects of carbon/boron and nitrogen/boron molar ratios on the PL properties were also investigated. The result showed that the emission spectra with a wavelength peak ranging from 444 nm to 496 nm can be obtained by varying carbon/boron ratios from 0.1 to 0.9. In addition, the observations showed that the BCNO phosphor material has two excitation peaks located at the 365 nm (UV) and 420 nm (blue). Based on these observations, we believe that the citric acid derived BCNO phosphor particles can be a promising inexpensive material for phosphor conversion-based white LED.

Process engineering challenges of uranium extraction from phosphoric acid on industrial scale

International Nuclear Information System (INIS)

Mouriya, Govind; Singh, Dhirendra; Nath, A.K.; Majumdar, D.

2014-01-01

Heavy Water Board (HWB) is a constituent unit of the Department of Atomic Energy. One of the diversified activities undertaken by HWB is pursuing exploitation of non-conventional resources for recovery of uranium from wet phosphoric acid being the most prominent one. Amongst the feasible processes for recovery of uranium from phosphoric acid is solvent extraction. Use of in-house solvent produced by HWB, is another key driver. To garner necessary information for developing the industrial scale facilities, the process has been studied in the laboratory scale, mini scale, bench scale at Heavy Water Plant, Talcher. The process was subsequently scaled up to an industrial prototype scale unit and was set up as a Technology Demonstration Plant coupled with a commercial phosphoric acid plant. The plant has successfully processed more than 2 lakh m 3 of wet phosphoric acid and all the parameters including the product, Yellow Cake have been qualified. No adverse effect has been observed in the fertilizer produced. The main characteristics of the process and subsequent process innovations are discussed in this paper. These innovations have been carried out to overcome hurdles faced during commissioning and subsequent operations of the Plant. The innovations include improved pretreatment of the wet phosphoric acid for feeding to the extraction cycle, improved control of the first cycle chemical environment, reducing the strength of the phosphoric acid used for stripping, reducing the number of equipment and machineries, alteration in solvent composition used in the first and second cycle in the solvent extraction units of the plant. (author)

Effect of phosphoric acid on the morphology and tensile properties of halloysite-polyurethane composites

Science.gov (United States)

Gaaz, Tayser Sumer; Luaibi, Hasan Mohammed; Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.

2018-06-01

The high aspect ratio of nanoscale reinforcements enhances the tensile properties of pure polymer matrix. The composites were first made by adding halloysite nanotubes (HNTs) at low weight percentages of 1, 2, and 3 wt% to thermoplastic polyurethane (TPU). Then, HNTs were phosphoric acid-treated before adding to TPU at same weight percentage to create phosphoric acid HNTs-TPU composites. The samples were fabricated using injection moulding. The HNTs-TPU composites were characterized according to the tensile properties including tensile strength, tensile strain and Young's modulus. The loading has shown its highest tensile values at 2 wt% HNTs loading and same findings are shown with the samples that treated with phosphoric acid. The tensile strength increased to reach 24.65 MPa compare with the 17.7 MPa of the neat TPU showing about 26% improvement. For the phosphoric acid-treated composites, the improvement has reached 35% compared to the neat sample. Regarding the tensile stain, the improvement was about 83% at 2 wt% HNTs loading. For Young's modulus, the results obtained in this study have shown that Young's modulus is linearly improved with either the loading content or the phosphoric acid treated achieving its highest values at 3 wt% HNTs of 14.53 MPa and 16.27 MPa for untreated and treated, respectively. FESEM results showed that HNTs were well dispersed in TPU matrix. Thus, HNTs-TPU has improved tensile properties compared with pure TPU due to the addition of nanofiller.

Application of a precipitation method for uranium recovery from abu-zaabal phosphoric acid plant, Egypt

International Nuclear Information System (INIS)

El-hazek, N.M.T.; Hussein, E.M.

1995-01-01

Current industrial recovery of uranium from 30% phosphoric acid-produced by the dihydrate process-is based on solvent extraction method. Uranium recovery from concentrated phosphoric acid (45-52% p o5 ) produced by evaporation of the 30% acid or directly produced by the hemihydrate process, by solvent extraction is difficult to apply in practice. In addition to possible contamination of the acid by the organic solvents and/or their deterioration. This paper investigates the possibility of applying a precipitation method (Weterings and Janssen, 1985) for uranium recovery from both low (28% P 2 O 5 ) and high (48% P 2 O 5 ) concentration phosphoric acids produced by abu-zaabal phosphoric acid plant (Abuzaabal fertilizers and chemicals Co., Egypt). The 28% acid produced by H 2 SO 4 dihydrate method and the 48% acid produced by evaporation of the 28% acid The applied precipitation method depends on using NH 4 F as a uranium precipitant from both low and high concentration phosphoric acids in presence of acetone as a dispersing agent. All the relevant factors have been studied

Carbon-13 kinetic isotope effects in the decarbonylation of lactic acid of natural isotopic composition in phosphoric acid medium

International Nuclear Information System (INIS)

Zielinski, M.; Czarnota, G.; Papiernik-Zielinska, H.; Kasprzyk, G.; Gumolka, L.; Staedter, W.

1993-01-01

The 13 C kinetic isotope effect fractionation in the decarbonylation of lactic acid (LA) of natural isotopic composition by concentrated phosphoric acids (PA) and by 85% H 3 PO 4 has been studied in the temperature interval of 60-150 deg C. The values of the 13 C (1) isotope effects in the decarbonylation of lactic acid in 100% H 3 PO 4 , in pyrophosphoric acid and in more concentrated phosphoric acids are intermediate between the values calculated assuming that the C (1)- OH bond is broken in the rate-controlling step of dehydration and those calculated for rupture of the carbon-carbon bond in the transition state. In the temperature interval of 90-130 deg C the experimental 13 C fractionation factors determined in concentrated PA approach quite closely the 13 C fractionation corresponding to C (2)- C (1) bond scission. The 13 C (1) kinetic isotope effects in the decarbonylation of LA in 85% orthophosphoric acid in the temperature range of 110-150 deg C coincide with the 13 C isotope effects calculated assuming that the frequency corresponding to the C (1) -OH vibration is lost in the transition state of decarbonylation. A change of the mechanism of decarbonylation of LA in going from concentrated PA medium to 85% H 3 PO 4 has been suggested. A possible secondary 18 O and a primary 18 O kinetic isotope effect in decarbonylation of lactic acid in phosphoric acids media have been discussed, too. (author) 21 refs.; 3 tabs

Flotation of uranium values using di (2-ethyl hexyl) phosphoric acid

International Nuclear Information System (INIS)

Singh, Ajoy Kumar; Padmanabhan, N.P.H.; Sridhar, U.; Krishna Rao, N.

1998-01-01

The use of solvent extractants for mineral flotation, especially for difficult-to-float minerals, is gaining importance as they are highly selective to specific metal ions and form strong and stable complexes mostly by chelation. Studies carried out with di(2 ethyl hexyl) phosphoric acid (D2EHPA) (an organic solvent used in the extraction of uranium from phosphoric acid) as collector for flotation of uranium minerals from ore samples of Domiasiat, Meghalaya and Jaduguda, Bihar have yielded encouraging results. Although flotation of uranium minerals using other solvent extractants like tributyl phosphoric acid (TBP) has been studied, the uraninite-D2EHPA system has not been tested so far. This technical note puts on record the findings of the preliminary studies carried out. (author)

Recent studies of uranium recovery from wet-process phosphoric acid with octylphenyl acid phosphate

International Nuclear Information System (INIS)

Arnold, W.D.

1978-01-01

Commercial OPAP is a complex mixture that contains at least 11 components. Octyl phenol is the principal impurity. Commercial OPAP contains readily-hydrolyzable material. The concentrations of octyl phenol and an unidentified impurity increase in the hydrolyzed product. Uranium extraction power is decreased slightly by hydrolysis of the reagent. Four major problems were encountered in continuous stability tests: (1) Microemulsion or micelle formation--loss of organic phase into phosphoric acid. We do not have a solution to this problem at this time. It could involve alteration of the organic, e.g., adding a modifier, changing the reagent structure, or changing the diluent. (2) Reagent poisoning--reduction of uranium extraction and interference with organic titrations by material extracted from the acid. Additional work is needed to identify the poisoning material or materials. It can then be removed if it originates in the phosphate rock, or avoided if it originates in chemicals added during processing. (3) Crystallization with iron--loss of both major components of the reagent as a complex with ferric iron. We believe this problem can be controlled by controlling the ferric iron concentration in the phosphoric acid. (4) MOPPA distribution loss--a selective loss to the aqueous phase. We believe this can be minimized by controlling the iron concentration of the phosphoric acid. The iron concentration will need to be kept low enough to avoid reagent crystallization and high enough to avoid MOPPA distribution loss. 15 figs

Nitric-phosphoric acid oxidation of solid and liquid organic materials

International Nuclear Information System (INIS)

Pierce, R.A.; Smith, J.R.; Poprik, D.C.

1995-01-01

Nitric-phosphoric acid oxidation has been developed specifically to address issues that face the Savannah River Site, other defense-related facilities, private industry, and small-volume generators such as university and medical laboratories. Initially tested to destroy and decontaminate SRS solid, Pu-contaminated job-control waste, the technology has also exhibited potential for remediating hazardous and mixed-hazardous waste forms. The process is unique to Savannah River and offers a valuable alternative to other oxidation processes that require extreme temperatures and/or elevated pressures. To address the broad categories of waste, many different organic compounds which represent a cross-section of the waste that must be treated have been successfully oxidized. Materials that have been quantitatively oxidized at atmospheric pressure below 180 degrees C include neoprene, cellulose, EDTA, tributylphosphate, and nitromethane. More stable compounds such as benzoic acid, polyethylene, oils, and resins have been completely decomposed below 200 degrees C and 10 psig. The process uses dilute nitric acid in a concentrated phosphoric acid media as the main oxidant for the organic compounds. Phosphoric acid allow nitric acid to be retained in solution well above its normal boiling point. The reaction forms NOx vapors which can be reoxidized and recycled using air and water. The addition of 0.001M Pd(II) reduces CO generation to near 1% of the released carbon gases. The advantages of this process are that it is straightforward, uses relatively inexpensive reagents, operates at relatively low temperature and pressure, and produces final solutions which are compatible with stainless steel equipment. For organic wastes, all carbon, hydrogen, and nitrogen are converted to gaseous products. If interfaced with an acid recovery system which converts NOx back to nitric acid, the net oxidizer would be oxygen from air

Characterization and application of expanded graphite modified with phosphoric acid and glucose for the removal of Ni(II) from aqueous solution

Science.gov (United States)

Jiang, Li; Zhang, Jian; Xu, Xiaoli; Zhang, Jie; Liu, Hai; Guo, Zizhang; Kang, Yan; Li, Yiran; Xu, Jingtao

2015-12-01

Three kinds of modified expanded graphite (EG), impregnated with phosphoric acid (H3PO4) (P-EG), impregnated with glucose (G-EG), and impregnated with H3PO4 and glucose (G-P-EG), were prepared under a low temperature (150 °C). The adsorption capacity of G-P-EG (Qm = 7.016 mg/g) is much higher than original expanded graphite (EG Qm = 0.423 mg/g) and other two kinds of modified expanded graphite (P-EG Qm = 0.770 mg/g; G-EG Qm = 0.507 mg/g). The physicochemical properties of EG and G-P-EG were characterized by N2 adsorption/desorption, Boehm's titration and X-ray photoelectron spectroscopy (XPS). EG exhibited higher values of BET surface area (11.357 m2/g) and total pore volume (0.0303 cm3/g) than that of G-P-EG (4.808 m3/g and 0.0109 cm3/g). However, the results of Bohm's titration and XPS showed that G-P-EG contained more surface oxygen-containing functional groups. The Ni(II) adsorption equilibrium data agreed well with the Langmuir model. And the experimental data of EG and G-P-EG fitted better by pseudo-second order model. Based on the results of batch adsorption experiments and XPS analysis, there were several possible mechanisms for Ni(II) adsorption on the G-P-EG, including chemical adsorption, cation exchange, electrostatic attraction and surface complication.

Activated carbon from peach stones using phosphoric acid activation at medium temperatures.

Science.gov (United States)

Kim, Dong-Su

2004-01-01

In the present study, the activation features of phosphoric acid have been investigated using waste peach stones as the raw material in the production of granular activated carbon. Thermogravimetry/differential thermal analysis was conducted to characterize the thermal behavior of peach stone and titration method was used to evaluate the adsorption capacity of the produced activated carbon. It was observed that the iodine value of the activated carbon increased with activation temperature. However, temperatures higher than 500 degrees C caused a thermal destruction, which resulted in the decrease of the adsorption capacity. Activation longer than 1.5 h at 500 degrees C resulted in thermal degradation of the porous structure of the activated carbon. The adsorption capacity was enhanced with increasing of amounts of phosphoric acid, however, excessive phosphoric acid caused a decrease in the iodine value. In addition, it was found that the carbon yields generally decreased with activation temperature and activation time. Scanning electron microscopy analysis was conducted to observe the changes in the poros structure of the activated carbon produced in different temperatures. Activation of carbon by phosphoric acid was found to be superior to that by CaCl2 and gas activation. The activated carbon produced from peach stone was applied as an adsorbent in the treatment of synthesized wastewater containing cadmium ion and its adsorption capacity was found to be as good as that of the commercial one.

Application of a precipitation method for uranium recovery from Abu-Zaabal phosphoric acid plant, egypt

International Nuclear Information System (INIS)

El-Hazek, N.M.T.; Hussein, E.M.

1997-01-01

Current industrial recovery of uranium from 30% phosphoric acid-produced by the dihydrate process-is based on solvent extraction method. Uranium recovery from concentrated phosphoric acid (45-52% P 2 O 5 ) produced by evaporation of the 30% acid or directly produced by the hemihydrate process, by solvent extraction is difficult to apply in practice. In addition to possible contamination of the acid by the organic solvents and/or their deterioration. This paper investigates the possibility of applying a precipitation method (Weterings and Janssen, 1985) for uranium recovery from both low (28% P 2 O 2 ) and high (48% P 2 O 5 ) concentration phosphoric acids produced by abu-Zaabal phosphoric acid plant (abu-Zaabal fertilizers and chemicals Co., Egypt). The 28% acid produced by H 2 SO 4 dihydrate method and the 48% acid produced by evaporation of the 28% acid

Study of the mechanism and kinetics of the reduction of uranyl ions in phosphoric acid solutions

International Nuclear Information System (INIS)

El Kacemi, K.; Tyburce, B.; Belcadi, S.

1982-01-01

The electrochemical reduction of uranyl ions in 0.1 to 9 M phosphoric acid has been investigated by polarography, cyclic voltammetry, chronopotentiometry and potentiostatic coulometry. In concentrated phosphoric acid solutions (H 3 PO 4 3 PO 4 concentrations. So, when the concentration of U(VI) increases and/or that of H 3 PO 4 reduces, the system becomes reversible. (author)

Inorganic-Organic hybrid materials for uranium extraction from phosphoric acid

International Nuclear Information System (INIS)

El-Mourabit, Sabah

2013-01-01

Phosphate rocks are industrially processed in large quantities to produce phosphoric acid and fertilisers. These rocks contain significant concentration of uranium (50 to 300 ppm) which could be interesting for nuclear industry. This work deals with the valorisation of uranium as a by-product from fertiliser industry. The aim of this study is to develop a hybrid material, constituted of an inorganic solid support grafted with an extractant (complexing molecule), which can extract selectively uranium from phosphoric acid medium. The first step of our approach was to identify an inorganic support which is stable under these particular conditions (strong acidity and complexing medium). The chemical and mechanical stability of different meso-porous materials, such as silica, glass and carbon was studied. In a second phase, we focused on the identification and the optimisation of complexing molecules, specific of uranium in phosphoric acid. These ligands were then grafted on the most stable solids. Finally, the efficiency of these hybrid systems was evaluated through different tests of extraction, selectivity and de-extraction. (author) [fr

Characterization and application of expanded graphite modified with phosphoric acid and glucose for the removal of Ni(II) from aqueous solution

International Nuclear Information System (INIS)

Jiang, Li; Zhang, Jian; Xu, Xiaoli; Zhang, Jie; Liu, Hai; Guo, Zizhang; Kang, Yan; Li, Yiran; Xu, Jingtao

2015-01-01

Highlights: • Glucose and H 3 PO 4 , single or together, were used to modify expanded graphite. • The modified condition was at a low temperature (150 °C). • The properties of EG and the highest adsorption ability modified EG were compared. • G-P-EG has the highest adsorption ability, which is much higher than that of EG. - Abstract: Three kinds of modified expanded graphite (EG), impregnated with phosphoric acid (H 3 PO 4 ) (P-EG), impregnated with glucose (G-EG), and impregnated with H 3 PO 4 and glucose (G-P-EG), were prepared under a low temperature (150 °C). The adsorption capacity of G-P-EG (Q m = 7.016 mg/g) is much higher than original expanded graphite (EG Q m = 0.423 mg/g) and other two kinds of modified expanded graphite (P-EG Q m = 0.770 mg/g; G-EG Q m = 0.507 mg/g). The physicochemical properties of EG and G-P-EG were characterized by N 2 adsorption/desorption, Boehm's titration and X-ray photoelectron spectroscopy (XPS). EG exhibited higher values of BET surface area (11.357 m 2 /g) and total pore volume (0.0303 cm 3 /g) than that of G-P-EG (4.808 m 3 /g and 0.0109 cm 3 /g). However, the results of Bohm's titration and XPS showed that G-P-EG contained more surface oxygen-containing functional groups. The Ni(II) adsorption equilibrium data agreed well with the Langmuir model. And the experimental data of EG and G-P-EG fitted better by pseudo-second order model. Based on the results of batch adsorption experiments and XPS analysis, there were several possible mechanisms for Ni(II) adsorption on the G-P-EG, including chemical adsorption, cation exchange, electrostatic attraction and surface complication.

Regio-, Diastereo-, and Enantioselective Nitroso-Diels-Alder Reaction of 1,3-Diene-1-carbamates Catalyzed by Chiral Phosphoric Acids.

Science.gov (United States)

Pous, Jonathan; Courant, Thibaut; Bernadat, Guillaume; Iorga, Bogdan I; Blanchard, Florent; Masson, Géraldine

2015-09-23

Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels-Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels-Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

Influence of pH-control in phosphoric acid treatment of zinc oxide

Energy Technology Data Exchange (ETDEWEB)

Onoda, H., E-mail: onoda@kpu.ac.jp [Department of Informatics and Environmental Sciences, Kyoto Prefectural University (Japan); Chemel, M. [Ecole de Biologie Industrielle, CERGY Cedex (France)

2017-04-15

Zinc oxide is often used as a white pigment for cosmetics; however, it shows photocatalytic activity that causes decomposition of sebum on the skin when exposed to the ultraviolet radiation in sunlight. In this work, zinc oxide was reacted with phosphoric acid at various pH values to synthesize a novel white pigment for cosmetics. The chemical composition, powder properties, photocatalytic activities, colors, and smoothness of these pigments were studied. The obtained materials exhibited X-ray diffraction peaks relating to zinc oxide and phosphate after phosphoric acid treatment. The ratio of zinc phosphate to zinc oxide was estimated from inductively coupled plasma - atomic emission spectroscopy results. Samples treated at pH 4-7 yielded small particles with sub-micrometer sizes. The photocatalytic activity of zinc oxide became lower after phosphoric acid treatment. Samples treated at pH 4-7 showed the same reflectance as zinc oxide in both the ultraviolet and visible ranges. Adjustment of the pH was found to be important in the phosphoric acid treatment of zinc oxide. (author)

(Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

Science.gov (United States)

Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

2014-01-01

The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the oxalic acid molecule shows a significantly smaller bend angle (∼7°). In the crystal, the components are connected by strong O—H⋯O and much weaker N—H⋯O hydrogen bonds, leading to the formation of layers extending parallel to (001). The structure was refined from a racemically twinned crystal with twin components in an approximate 1:1 ratio. PMID:24765013

Shear bond strength of self-etch adhesives to enamel with additional phosphoric acid etching.

Science.gov (United States)

Lührs, Anne-Katrin; Guhr, Silke; Schilke, Reinhard; Borchers, Lothar; Geurtsen, Werner; Günay, Hüsamettin

2008-01-01

This study evaluated the shear bond strength of self-etch adhesives to enamel and the effect of additional phosphoric acid etching. Seventy sound human molars were randomly divided into three test groups and one control group. The enamel surfaces of the control group (n=10) were treated with Syntac Classic (SC). Each test group was subdivided into two groups (each n=10). In half of each test group, ground enamel surfaces were coated with the self-etch adhesives AdheSe (ADH), Xeno III (XE) or Futurabond NR (FNR). In the remaining half of each test group, an additional phosphoric acid etching of the enamel surface was performed prior to applying the adhesives. The shear bond strength was measured with a universal testing machine at a crosshead speed of 1 mm/minute after storing the samples in distilled water at 37 degrees C for 24 hours. Fracture modes were determined by SEM examination. For statistical analysis, one-way ANOVA and the two-sided Dunnett Test were used (p>0.05). Additional phosphoric etching significantly increased the shear bond strength of all the examined self-etch adhesives (padhesive fractures. For all the self-etch adhesives, a slight increase in mixed fractures occurred after conditioning with phosphoric acid. An additional phosphoric acid etching of enamel should be considered when using self-etch adhesives. More clinical studies are needed to evaluate the long-term success of the examined adhesives.

Green synthetic strategy of BCNO nanostructure and phosphor-based light – Emitting diodes

Energy Technology Data Exchange (ETDEWEB)

Kang, Yue [The Quartermaster Research Institute of General Logistics Department, Beijing 100010 (China); Yuan, Bo [Chemical Defense Institute of China, Beijing 100010 (China); Zhang, Dongjiu [Key Laboratory of Space Launching Site Reliability Technology, Hainan 570100 (China); Ma, Tian; Huang, Xiancong [The Quartermaster Research Institute of General Logistics Department, Beijing 100010 (China); Chu, Zengyong [College of Science, National University of Defense Technology, Changsha 410073 (China); Lai, Kan [The Quartermaster Research Institute of General Logistics Department, Beijing 100010 (China)

2016-11-15

BCNO phosphor has been paid much attention due to their unique physical, electronic and optical properties. Here we have successfully obtained BCNO nano-particle phosphor by microwave treating from boric acid, urea, and glucose at low temperatures and in short reaction time. Glucose decomposed into graphene quantum dots (GQDs), which facilitated the formation of hexagonal boron nitride (h-BN). Through our method, GQDs domains were uniformly incorporated into h-BN, leading to the formation of BCNO and decrease of bandgap. BCNO demonstrated excellent performance in light emitting diodes (LEDs) with green and blue light. We envision that this BCNO phosphor will enable the next generation blue and green LED devices due to the easiness of large scale fabrication at an economic cost.

Green synthetic strategy of BCNO nanostructure and phosphor-based light – Emitting diodes

International Nuclear Information System (INIS)

Kang, Yue; Yuan, Bo; Zhang, Dongjiu; Ma, Tian; Huang, Xiancong; Chu, Zengyong; Lai, Kan

2016-01-01

BCNO phosphor has been paid much attention due to their unique physical, electronic and optical properties. Here we have successfully obtained BCNO nano-particle phosphor by microwave treating from boric acid, urea, and glucose at low temperatures and in short reaction time. Glucose decomposed into graphene quantum dots (GQDs), which facilitated the formation of hexagonal boron nitride (h-BN). Through our method, GQDs domains were uniformly incorporated into h-BN, leading to the formation of BCNO and decrease of bandgap. BCNO demonstrated excellent performance in light emitting diodes (LEDs) with green and blue light. We envision that this BCNO phosphor will enable the next generation blue and green LED devices due to the easiness of large scale fabrication at an economic cost.

Reactivity of the cadmium ion in concentrated phosphoric acid solutions.

Science.gov (United States)

De Gyves, J; Gonzales, J; Louis, C; Bessiere, J

1989-07-01

The solvation transfer coefficients which characterize the changes of ion reactivity with phosphoric acid concentration have been calculated for cadmium from the constants of the successive chloride complexes, and for silver and diethyldithiophosphate from potentiometric measurements. They evidence the strong desolvation of the cadmium species in concentrated phosphoric acid media, causing a remarkable increase of its reactivity. They allow the results of liquid-liquid extraction, precipitation and flotation reactions to be correctly interpreted and their changes to be foreseen when the reagents are modified.

Pretreatment of phosphoric acid of Annaba

International Nuclear Information System (INIS)

Kada, R.

1990-03-01

The most important step in the process of uranium recovery from phosphoric acid is the pretreatment operation. In this study, the adsorption of organic matters on activated carbon was carried out in a batch process and in a fixed bed column. First, the chemical and physical characterization of phosphoric acid, activated carbon and gypsum were performed. In addition, the organic matters were qualitatively analysed and a new and original quantitative method was experimented. Next, the various operating parameters such as agitation speed, granulometry, temperature, solid/liquid ratio, initial concentration, acid flowrate, and bed height were optimized. The experimental equilibrium isotherm was compared to the Langmuir, Freundlich, and Redlich-Peterson theoretical isotherms. It was noticed that the three models did not fit the experimental isotherm in the total concentration range. Thus, an original bilinear model was proposed. The influence of the operating conditions on the adsorption kinetics was also investigated. As a result of that, a new mathematical model was proposed to determine both the liquid and solid phases mass transfer and the solid phase diffusion coefficient. Finally, adsorption of organic matters on a fixed bed process allowed computation of the number of transfer units (NTU), the height of adsorption zone and the degree of saturation of activated carbon

The preparation of 32P labelled phosphorous acid

International Nuclear Information System (INIS)

Henderson, D.; Jenkinson, A.; Sorby, P.

1986-11-01

Phosphorous acid labelled with 32 P has been prepared, on a small scale, starting from neutron-irradiated phosphorus. The compound is intended for tracer studies in the development of novel fungicides

Uranium recovery from wet process phosphoric acid

International Nuclear Information System (INIS)

1980-01-01

In the field of metallurgy, specifically processes for recovering uranium from wet process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores, problems of imbalance of ion exchange agents, contamination of recycled phosphoric acid with process organics and oxidizing agents, and loss and contamination of uranium product, are solved by removing organics from the raffinate after ion exchange conversion of uranium to uranous form and recovery thereof by ion exchange, and returning organics to the circuit to balance mono and disubstituted ester ion exchange agents; then oxidatively stripping uranium from the agent using hydrogen peroxide; then after ion exchange recovery of uranyl and scrubbing, stripping with sodium carbonate and acidifying the strip solution and using some of it for the scrubbing; regenerating the sodium loaded agent and recycling it to the uranous recovery step. Economic recovery of uranium as a by-product of phosphate fertilizer production is effected. (author)

Method for recovery of uranium from phosphoric acid

International Nuclear Information System (INIS)

Duarte Neto, J.

1984-01-01

The results of a method for recuperation of uranium from phosphoric acid by humid way are presented. The extracting mixture used was di-ethylhexylphosphoric acid (D 2 EHPA) and trioctylphosphine oxide (TOPO). An installation in micro-pilot scale was made to get and visualize data for continuous process. (M.A.C.) [pt

Complexity in Acid?Base Titrations: Multimer Formation Between Phosphoric Acids and Imines

OpenAIRE

Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

2017-01-01

Abstract Solutions of Br?nsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Br?nsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid?base aggregates challenging. Here, we track such acid?base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by u...

Kinetic study of ion exchange in phosphoric acid chelating resin

International Nuclear Information System (INIS)

Brikci-Nigassa, Mounir; Hamouche, Hafida

1995-11-01

Uranium may be recovered as a by product of wet phosphoric acid using a method based on specific ion exchange resins. These resins called chelates contain amino-phosphonic functional groups. The resin studied in this work is a purolite S-940; uranium may be loaded on this resin from 30% P2O5 phosphoric acid in its reduced state. The influence of different parameters on the successive steps of the process have been studied in batch experiments: uranium reduction, loading and oxydation. Uranium may be eluted with ammonium carbonate and the resin regeneration may be done with hydrochloric acid.Ferric ions reduce the effective resin capacity considerably and inert fixation conditions are proposed to enhance uranium loading

Temperature dependence and P/Ti ratio in phosphoric acid treatment of titanium dioxide and powder properties.

Science.gov (United States)

Onoda, H; Matsukura, A

2015-02-01

Titanium dioxide has photocatalytic activity and is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium dioxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Titanium dioxide was treated with 0.1 mol/L of phosphoric acid at various P/Ti molar ratios, and then shaken in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, colour phase, and smoothness of the obtained powder were studied. The obtained materials indicated XRD peaks of titanium dioxide, however the peaks diminished subsequent to phosphoric acid treatment. The samples included small particles with sub-micrometer size. The photocatalytic activity of the obtained powders decreased, decomposing less sebum on the skin. Samples prepared at high P/Ti ratio with high shaking temperature indicated low whiteness in in L*a*b* colour space. The shaking and heating temperature and P/Ti ratio had influence on the smoothness of the obtained materials. Phosphoric acid treatment of titanium dioxide is an effective method to inhibit photocatalytic activity for a white pigment. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Process for the winning of a concentrate containing uranium and purified phosphoric acid, as well as the concentrate containing uranium and purified phosphoric acid obtained by this process

International Nuclear Information System (INIS)

1980-01-01

The uranium containing concentrate and purified phosphoric acid are obtained by treating wet phosphoric acid with an inorganic fluorine compound (ammonium fluoride) and an aliphatic ketone (acetone) in the presence of a reducing agent (finely divided iron). The ketone is added first and the formed uranium precipitate is separated from the solution. If the fluorine compound is added first, the yield is lowered by a factor of 2. (Th.P.)

Semitechnical studies of uranium recovery from wet process phosphoric acid by liquid-liquid-extraction method

International Nuclear Information System (INIS)

Poczynajlo, A.; Wlodarski, R.; Giers, M.

1987-01-01

A semitechnical installation for uranium recovery from wet process phosphoric acid has been built. The installation is based on technological process comprising 2 extraction cycles, the first with a mixture of mono- and dinonylphenylphosphoric acids (NPPA) and the second with a synergic mixture of di-/2-ethylhexyl/-phosphoric acid (D2EHPA) and trioctylphosphine oxide (TOPO). The installation was set going and the studies on the concentration distributions of uranium and other components of phosphoric acid have been performed for all technological circuits. 23 refs., 15 figs., 3 tabs. (author)

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

International Nuclear Information System (INIS)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun; Seo, Jong Hyun; Choe, HeeHwan; Jeon, Jae-Hong; Hong, Munpyo; Lee, Yong Uk; Winkler, Joerg

2011-01-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm 2 to 26 mA/cm 2 , indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO 2 passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

Energy Technology Data Exchange (ETDEWEB)

Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Seo, Jong Hyun, E-mail: jhseo@kau.ac.kr [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Choe, HeeHwan; Jeon, Jae-Hong [School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Hong, Munpyo [Display and Semiconductor Physics, Korea University (Korea, Republic of); Lee, Yong Uk [PETEC (The Printable Electronics Technology Centre) (United Kingdom); Winkler, Joerg [PLANSEE Metal GmbH, Metallwerk-Plansee-Str. 71A-6600, Reutte (Austria)

2011-08-01

Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm{sup 2} to 26 mA/cm{sup 2}, indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO{sub 2} passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

Bace1 activity impairs neuronal glucose metabolism: rescue by beta-hydroxybutyrate and lipoic acid

Directory of Open Access Journals (Sweden)

John A Findlay

2015-10-01

Full Text Available Glucose hypometabolism and impaired mitochondrial function in neurons have been suggested to play early and perhaps causative roles in Alzheimer’s disease (AD pathogenesis. Activity of the aspartic acid protease, beta-site amyloid precursor protein (APP cleaving enzyme 1 (BACE1, responsible for beta amyloid peptide generation, has recently been demonstrated to modify glucose metabolism. We therefore examined, using a human neuroblastoma (SH-SY5Y cell line, whether increased BACE1 activity is responsible for a reduction in cellular glucose metabolism. Overexpression of active BACE1, but not a protease-dead mutant BACE1, protein in SH-SY5Y cells reduced glucose oxidation and the basal oxygen consumption rate, which was associated with a compensatory increase in glycolysis. Increased BACE1 activity had no effect on the mitochondrial electron transfer process but was found to diminish substrate delivery to the mitochondria by inhibition of key mitochondrial decarboxylation reaction enzymes. This BACE1 activity-dependent deficit in glucose oxidation was alleviated by the presence of beta hydroxybutyrate or α-lipoic acid. Consequently our data indicate that raised cellular BACE1 activity drives reduced glucose oxidation in a human neuronal cell line through impairments in the activity of specific tricarboxylic acid cycle enzymes. Because this bioenergetic deficit is recoverable by neutraceutical compounds we suggest that such agents, perhaps in conjunction with BACE1 inhibitors, may be an effective therapeutic strategy in the early-stage management or treatment of AD.

Solid-state actinide acid phosphites from phosphorous acid melts

International Nuclear Information System (INIS)

Oh, George N.; Burns, Peter C.

2014-01-01

The reaction of UO 3 and H 3 PO 3 at 100 °C and subsequent reaction with dimethylformamide (DMF) produces crystals of the compound (NH 2 (CH 3 ) 2 )[UO 2 (HPO 2 OH)(HPO 3 )]. This compound crystallizes in space group P2 1 /n and consists of layers of uranyl pentagonal bipyramids that share equatorial vertices with phosphite units, separated by dimethylammonium. In contrast, the reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup. Subsequent dilution in solvents and use of standard solution-state methods results in the crystallization of two polymorphs of the actinide acid phosphites An(HPO 2 OH) 4 (An=U, Th) and of the mixed acid phosphite–phosphite U(HPO 3 )(HPO 2 OH) 2 (H 2 O)·2(H 2 O). α- and β-An(HPO 2 OH) 4 crystallize in space groups C2/c and P2 1 /n, respectively, and comprise a three-dimensional network of An 4+ cations in square antiprismatic coordination corner-sharing with protonated phosphite units, whereas U(HPO 3 )(HPO 2 OH) 2 (H 2 O) 2 ·(H 2 O) crystallizes in a layered structure in space group Pbca that is composed of An 4+ cations in square antiprismatic coordination corner-sharing with protonated phosphites and water ligands. We discuss our findings in using solid inorganic reagents to produce a solution-workable precursor from which solid-state compounds can be crystallized. - Graphical abstract: Reaction of UO 3 and H 3 PO 3 at 100 °C and subsequent reaction with DMF produces crystals of (NH 2 (CH 3 ) 2 )[UO 2 (HPO 2 OH)(HPO 3 )] with a layered structure. Reaction of phosphorous acid and actinide oxides at 210 °C produces a viscous syrup and further solution-state reactions result in the crystallization of the actinide acid phosphites An(HPO 2 OH) 4 (An=U, Th), with a three-dimensional network structure, and the mixed acid phosphite–phosphite U(HPO 3 )(HPO 2 OH) 2 (H 2 O) 2 ·(H 2 O) with a layered structure. - Highlights: • U(VI), U(IV) and Th(IV) phosphites were synthesized by solution

Complexity in Acid-Base Titrations: Multimer Formation Between Phosphoric Acids and Imines.

Science.gov (United States)

Malm, Christian; Kim, Heejae; Wagner, Manfred; Hunger, Johannes

2017-08-10

Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid-base aggregates challenging. Here, we track such acid-base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid-base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid-base association constant is only around six times larger than that for the acid binding to an acid-base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Continuous tests of Phosphoric Acid - dihydrate process - from phosphatic concentrate of Itataia-CE ore

International Nuclear Information System (INIS)

Santos Benedetto, J. dos.

1984-01-01

A consolidation of principal studies and continuous tests done with phosphatic concentrated of Itataia ore intending phosphoric acid production by humid-route dihydrate way process is presented. The production of phosphoric acid is applied in uranium extraction process by solvents. (author) [pt

Oxidizer in phosphoric reactors

International Nuclear Information System (INIS)

Santos Benedetto, J. dos

1985-01-01

Oxidation during the manufacture of wet-process phosphoric acid affected the distribution of uranium and impurities between phosphoric acid and gypsum, by decreasing the uranium loss to gypsum and the impurities solubilization in phosphoric acid. (Author) [pt

Kinetic studies on uranium stripping in D2EHPA+TBP/phosphoric acid system

International Nuclear Information System (INIS)

Yadav, K.K.; Singh, D.K.; Kotekar, M.K.; Anitha, M.; Vijayalakshmi, R.; Singh, H.

2010-01-01

Full text: A novel process based on synergistic mixture of 1.5 M D2EHPA (di 2 ethyl hexyl phosphoric acid) + 0.2 M TBP (tri-n-butyl phosphate) to recover uranium from wet process phosphoric acid (WPA) has been developed. Though the equilibrium study for the above process has been investigated in detail its kinetic behavior has not been reported so far. The work presented in the paper is an attempt to study the kinetics of U(VI) stripping from extractant phase to aqueous phase in a constant interfacial area cell (Lewis cell). Kinetic study of the solvent extraction process helps in designing of equipment and optimizing process condition for the better utilization of solvent inventory. Mass transfer kinetics of stripping of U(VI) from loaded 1.5M D2EHPA+ 0.2M TBP with phosphoric acid (AR) has been studied over a wide range of experimental conditions such as stirring speed, interfacial contact area, phosphoric acid concentration, uranium concentration, extractant concentration in organic phase and temperature. Investigation on effect of stirring speed (100-500 rpm) on stripping of U(VI) showed that the rate constant (k) values increases linearly with increase in stirring speeds from 100 to 300 rpm (0.03 to 0.075 cm/min), while the k values were almost constant (0.0819 cm/min) in 300 to 400 rpm range, beyond 450 rpm the k values again increased due to increased turbulence at the interface. The rate constant value (∼0.0814 cm/min) was found to be independent of interfacial contact area (24.6 to 67.02 cm 2 ) available for mass transfer. The rate constants were found to increase with increase in phosphoric acid concentration (6-10M) and temperature (30-60 deg C), the values being in the range of 0.01 to 0.082 cm/min. The slopes of ln-ln plot showed that the stripping of U(VI) has a second order dependence on phosphoric acid concentration (slope∼2) at temperatures ranging from 30 to 60 deg C. The activation energy value for uranium stripping was found to be in the

Study of uranium(VI) speciation in phosphoric acid solutions and of its recovery by solvent extraction

International Nuclear Information System (INIS)

Dartiguelongue, Adrien

2014-01-01

Because small amounts of uranium are present in phosphate rocks, wet phosphoric acids may contain up to 300 ppm of uranium(VI). Therefore, such acids are a cost-effective unconventional source of this metal. Its recovery is a challenge for metallurgical firms which must develop reliable and selective solvent extraction processes. Such processes need to know the chemical equilibria involved in the extraction process, the speciation of uranium and its thermodynamics in solution. These two last points have been investigated in this work. Firstly, the most probable species of uranium(VI) in phosphoric acid solutions have been selected thanks to a detailed review of the literature. Then, a thermodynamic model founded on an equation of state for electrolytes has been built according these hypotheses. It has been validated with speciation data coming from original ATR-IR spectroscopy measurements. Finally, the composition of the aqueous phosphoric acid solutions and the activity coefficients obtained have been combined with a chemical model of uranium(VI) extraction into an organic phase containing a synergistic mixture of bis(2-ethylhexyl)phosphoric acid (D2EHPA) and tri-n-octylphosphine oxide (TOPO) in order to represent the variation of the distribution coefficient of uranium(VI) with H 3 PO 4 concentration. This model had been previously developed at Chimie ParisTech at a given concentration of H 3 PO 4 (i.e., 5,3 mol/L), but in the present study we have tested its validity in an extended range of phosphoric acid concentrations (i.e., 1-7 mol/L) and improved it. (author)

Development of an improved two-cycle process for recovering uranium from wet-process phosphoric acid

International Nuclear Information System (INIS)

Chen, H.M.; Chen, H.J.; Tsai, Y.M.; Lee, T.W.; Ting, G.

1987-01-01

An improved two-cycle separation process for the recovery of uranium from wet-process phosphoric acid by extraction with bis(2-ethylhexyl)phosphoric acid (D2EHPA) plus dibutyl butylphosphonate (DBBP) in kerosene has been developed and demonstrated successfully in bench-scale, continuous mixer-settler tests. The sulfuric acid and water scrubbing steps for the recycled extraction in the second cycle solve the problems of the contamination and dilution of the phosphoric acid by the ammonium ion and water and also avoid the formation of undesirable phosphatic precipitates during the subsequent extraction of uranium by recycled organic extractant

Direct uranium extraction from dihydrate and hemi-dihydrate wet process phosphoric acids by liquid emulsion membrane

International Nuclear Information System (INIS)

El-Hazek, N.T.; El Sayed, M.S.

2003-01-01

A new liquid emulsion membrane (LEM) process for uranium extraction from either dihydrate 28-30% P 2 O 5 (DH) or hemi-dihydrate 42-45% P 2 O 5 (HDH) wet process phosphoric acid is proposed. In this process, the organic component of the LEM is composed of a synergistic mixture of 0.1M di-2-ethyl hexyl phosphoric acid (DEHPA) and 0.025M trioctyl phosphine oxide (TOPO) with 4% Span 80. The internal or the strip acid phase is composed of 0.5M citric acid. The prepared LEM was proved to be stable in 42-45% P 2 O 5 acid concentration range and can, therefore, be applied to the phosphoric acid produced by the hemi-dihydrate process. After breakdown of the loaded emulsion, the uranyl citrate in the internal strip phase is separated by adding methanol followed by its calcination to the orange oxide. Most of the reagents used are recycled. The proposed process is characterized by simplicity, practically closed operation cycle in addition to lower capital and operating costs. (author)

Nitric-phosphoric acid oxidation of organic waste materials

International Nuclear Information System (INIS)

Pierce, R.A.; Smith, J.R.

1995-01-01

A wet chemical oxidation technology has been developed to address issues facing defense-related facilities, private industry, and small-volume generators such as university and medical laboratories. Initially tested to destroy and decontaminate a heterogenous mixture of radioactive-contaminated solid waste, the technology can also remediate other hazardous waste forms. The process, unique to Savannah River, offers a valuable alternative to incineration and other high-temperature or high-pressure oxidation processes. The process uses nitric acid in phosphoric acid; phosphoric acid allows nitric acid to be retained in solution well above its normal boiling point. The reaction converts organics to carbon dioxide and water, and generates NO x vapors which can be recycled using air and water. Oxidation is complete in one to three hours. In previous studies, many organic compounds were completely oxidized, within experimental error, at atmospheric pressure below 180 degrees C; more stable compounds were decomposed at 200 degrees C and 170 kPa. Recent studies have evaluated processing parameters and potential throughputs for three primary compounds: EDTA, polyethylene, and cellulose. The study of polyvinylchloride oxidation is incomplete at this time

Determination of anions in pure and commercial phosphoric acid by ion chromatography and manual of 792 basic IC

International Nuclear Information System (INIS)

Al-Kabani, F.; Abdulbaki, M. K.

2007-01-01

A method for determination of anions in pure and concentrated phosphoric and samples (85%) and commercial phosphoric acid ion chromatography was developed, in order to control the specification of phosphoric acid produced in the pilot plant for phosphoric acid purification. The accuracy of the method was studied and the standard deviation was found to be between 0.09 and 0.10. Operation instructions of 792 Basic IC was described. (author)

Process for extracting uranium from phosphoric acid solutions

International Nuclear Information System (INIS)

1977-01-01

The description is given of a method for extracting uranium from phosphoric acid solutions whereby the previously oxided acid is treated with an organic solvent constituted by a mixture of dialkylphosphoric acid and trialkylphosphine oxide in solution in a non-reactive inert solvent so as to obtain de-uraniated phosphoric acid and an organic extract constituted by the solvent containing most of the uranium. The uranium is then separated from the extract as uranyl ammonium tricarbonate by reaction with ammonia and ammonium carbonate and the extract de-uraniated at the extraction stage is recycled. The extract is treated in a re-extraction apparatus comprising not less than two stages. The extract to be treated is injected at the top of the first stage. At the bottom of the first stage, ammonia is introduced counter current as gas or as an aqueous solution whilst controlling the pH of the first stage so as to keep it to 8.0 or 8.5 and at the bottom of the last stage an ammonium carbonate aqueous solution is injected in a quantity representing 50 to 80% of the stoichiometric quantity required to neutralize the dialkylphosphoric acid contained in the solvent and transform the uranium into uranyl ammonium tricarbonate [fr

Removal of uranium(VI) from aqueous solutions by new phosphorus-containing carbon spheres synthesized via one-step hydrothermal carbonization of glucose in the presence of phosphoric acid

International Nuclear Information System (INIS)

Zhi-bin Zhang; East China Institute of Technology, Fuzhou; China University of Geosciences, Wuhan; Zhi-wei Zhou; Xiao-hong Cao; Yun-hai Liu; Guo-xuan Xiong; East China Institute of Technology, Fuzhou; Ping Liang; East China Institute of Technology, Fuzhou; China University of Geosciences, Wuhan

2014-01-01

The novel phosphorus-rich hydrothermal carbon spheres (HCSs-PO 4 ) have been synthesized via one-step hydrothermal carbonization of glucose in the presence of phosphoric acid. The textural and surface chemistry properties were characterized using Boehm titrations, scanning electron microscopy and Fourier transform infrared spectrometer. The content of oxygen-containing functional groups on the surface of HCSs increased from 0.053 to 1.009 mmol g -1 by phosphate group modification. The adsorption ability of HCSsPO 4 has been explored for the removal of uranium from aqueous solutions. The adsorption kinetic data were best described by the pseudo-second-order equation. Adsorption process could be well defined by the Langmuir isotherm, the adsorption capacity of HCSs increased from 80.00 to 285.70 mg g -1 after phosphate group modification. And thermodynamic parameters indicated the adsorption process was feasible,endothermic and spontaneous. Selective adsorption studies showed that the HCSs-PO 4 could selectively remove U(VI), and the selectivity coefficients had been improved in the presence of co-existing ions, Na(I), Ni(II), Sr(II), Mn(II), Mg(II) and Zn(II). Complete removal (99.9 %) of U(VI) from 1.0 L industry wastewater containing 15.0 mg U(VI) ions was possible with 12.0 g HCSs-PO 4 . (author)

The Effect of Phosphoric Acid Pre-etching Times on Bonding Performance and Surface Free Energy with Single-step Self-etch Adhesives.

Science.gov (United States)

Tsujimoto, A; Barkmeier, W W; Takamizawa, T; Latta, M A; Miyazaki, M

2016-01-01

The purpose of this study was to evaluate the effect of phosphoric acid pre-etching times on shear bond strength (SBS) and surface free energy (SFE) with single-step self-etch adhesives. The three single-step self-etch adhesives used were: 1) Scotchbond Universal Adhesive (3M ESPE), 2) Clearfil tri-S Bond (Kuraray Noritake Dental), and 3) G-Bond Plus (GC). Two no pre-etching groups, 1) untreated enamel and 2) enamel surfaces after ultrasonic cleaning with distilled water for 30 seconds to remove the smear layer, were prepared. There were four pre-etching groups: 1) enamel surfaces were pre-etched with phosphoric acid (Etchant, 3M ESPE) for 3 seconds, 2) enamel surfaces were pre-etched for 5 seconds, 3) enamel surfaces were pre-etched for 10 seconds, and 4) enamel surfaces were pre-etched for 15 seconds. Resin composite was bonded to the treated enamel surface to determine SBS. The SFEs of treated enamel surfaces were determined by measuring the contact angles of three test liquids. Scanning electron microscopy was used to examine the enamel surfaces and enamel-adhesive interface. The specimens with phosphoric acid pre-etching showed significantly higher SBS and SFEs than the specimens without phosphoric acid pre-etching regardless of the adhesive system used. SBS and SFEs did not increase for phosphoric acid pre-etching times over 3 seconds. There were no significant differences in SBS and SFEs between the specimens with and without a smear layer. The data suggest that phosphoric acid pre-etching of ground enamel improves the bonding performance of single-step self-etch adhesives, but these bonding properties do not increase for phosphoric acid pre-etching times over 3 seconds.

Systematically controlled pore system of ordered mesoporous carbons using phosphoric acid as the in situ generated catalysts for carbonization and activation

Energy Technology Data Exchange (ETDEWEB)

Jin, Xing; Lee, Chang Hyun; Kim, Jin Hoe; You, Dae Jong; Shon, Jeong Kuk; Kim, Ji Man [Dept. of Chemistry, Sungkyunkwan University, Suwon (Korea, Republic of); Pak, Chan Ho [Fuel Cell Group, Corporate R and D Center, Samsung SDI Co. Ltd., Yongin (Korea, Republic of)

2015-08-15

We report on a facile synthesis of the ordered mesoporous carbon (OMC) materials with systematically controlled microporosity and mesoporosity simultaneously through the nano-replication route using phosphoric acid as the acid catalyst and activation agent. The use of phosphoric acid affects the pore structures of OMC materials, such as the formation of numerous micropores by activation of the carbon framework and the enlargement of mesopores by spontaneous phase separation during the carbonization. The mesopore sizes, surface areas, total pore volumes, and micropore volumes of the OMC materials are highly dependent on the phosphoric acid content and can be systematically controlled in the range 3.7–7.5 nm, 1027–2782 m{sup 2} g{sup -1}, 1.12–3.53 cm{sup 3} g{sup -1} and 0.34–0.95 cm{sup 3} g{sup -1}, respectively. OMC materials with systematically controlled pore structures were successfully synthesized using phosphoric acid as the carbonization catalyst and mesoporous silica materials with cubic Ia3d and 2-D hexagonal mesostructures as the templates. The phosphoric acid in the synthesis of ordered mesoporous carbon materials acts as the chemical activating agent for micropore generation of the carbon framework and pore-expanding agent for controlling of mesopore size, in addition to functioning as the acid catalyst. The present synthesis pathway is very useful for preparing OMC materials with tunable mesopore sizes and well-developed microporosities at the same time.

Unexpected 226Ra build-up in wet-process phosphoric-acid plants.

Science.gov (United States)

Lardinoye, M H; Weterings, K; van de Berg, W B

1982-04-01

During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filtres. This higher radiation level is caused by radium, which, as a decay product in the 238U series, is present in very low concentrations (1-50 pCi 226R/g) in the phosphates used for fertilizer production. Specific research later on established that there were detectable radiation levels around vessels and piping in other phosphoric-acid works as well. It turned out that in all factories the filter part, and especially the washing-acid section showed the highest radiation-level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of bariumsulphate and calciumsulphate with a higher radiumconcentration (+/- 0.1 Ci/g) is formed. The radium ions appeared to be incorporated in the bariumsulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal pollution, for example in cleaning operations by radio-active intake or inhallation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning (every 1-3 yr) the equipment in which the radio-active scaling is formed.

Characterization and application of expanded graphite modified with phosphoric acid and glucose for the removal of Ni(II) from aqueous solution

Energy Technology Data Exchange (ETDEWEB)

Jiang, Li [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Zhang, Jian, E-mail: zhangjian00@sdu.edu.cn [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Xu, Xiaoli [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Zhang, Jie [Shandong Experimental High School, Jinan 250100 (China); Liu, Hai; Guo, Zizhang; Kang, Yan; Li, Yiran [Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Jinan 250100 (China); Xu, Jingtao [School of Municipal and Environmental Engineering, Shandong Jianzhu University, Jinan 250100 (China)

2015-12-01

Highlights: • Glucose and H{sub 3}PO{sub 4}, single or together, were used to modify expanded graphite. • The modified condition was at a low temperature (150 °C). • The properties of EG and the highest adsorption ability modified EG were compared. • G-P-EG has the highest adsorption ability, which is much higher than that of EG. - Abstract: Three kinds of modified expanded graphite (EG), impregnated with phosphoric acid (H{sub 3}PO{sub 4}) (P-EG), impregnated with glucose (G-EG), and impregnated with H{sub 3}PO{sub 4} and glucose (G-P-EG), were prepared under a low temperature (150 °C). The adsorption capacity of G-P-EG (Q{sub m} = 7.016 mg/g) is much higher than original expanded graphite (EG Q{sub m} = 0.423 mg/g) and other two kinds of modified expanded graphite (P-EG Q{sub m} = 0.770 mg/g; G-EG Q{sub m} = 0.507 mg/g). The physicochemical properties of EG and G-P-EG were characterized by N{sub 2} adsorption/desorption, Boehm's titration and X-ray photoelectron spectroscopy (XPS). EG exhibited higher values of BET surface area (11.357 m{sup 2}/g) and total pore volume (0.0303 cm{sup 3}/g) than that of G-P-EG (4.808 m{sup 3}/g and 0.0109 cm{sup 3}/g). However, the results of Bohm's titration and XPS showed that G-P-EG contained more surface oxygen-containing functional groups. The Ni(II) adsorption equilibrium data agreed well with the Langmuir model. And the experimental data of EG and G-P-EG fitted better by pseudo-second order model. Based on the results of batch adsorption experiments and XPS analysis, there were several possible mechanisms for Ni(II) adsorption on the G-P-EG, including chemical adsorption, cation exchange, electrostatic attraction and surface complication.

Phosphoric acid pretreatment of Achyranthes aspera and Sida acuta weed biomass to improve enzymatic hydrolysis.

Science.gov (United States)

Siripong, Premjet; Duangporn, Premjet; Takata, Eri; Tsutsumi, Yuji

2016-03-01

Achyranthes aspera and Sida acuta, two types of weed biomass are abundant and waste in Thailand. We focus on them as novel feedstock for bio-ethanol production because they contain high-cellulose content (45.9% and 46.9%, respectively) and unutilized material. Phosphoric acid (70%, 75%, and 80%) was employed for the pretreatment to improve by enzymatic hydrolysis. The pretreatment process removed most of the xylan and a part of the lignin from the weeds, while most of the glucan remained. The cellulose conversion to glucose was greater for pretreated A. aspera (86.2 ± 0.3%) than that of the pretreated S. acuta (82.2 ± 1.1%). Thus, the removal of hemicellulose significantly affected the efficiency of the enzymatic hydrolysis. The scanning electron microscopy images showed the exposed fibrous cellulose on the cell wall surface, and this substantial change of the surface structure contributed to improving the enzyme accessibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

Search for a developed method for the determination of Fe2 and Fe3 in Syrian Phosphoric acid

International Nuclear Information System (INIS)

Elian, Nuzhat; Kalak, Issam

1988-08-01

Phosphoric acid is the most important precursor for uranium production in Syria. Uranium extraction from phosphoric acid depends on the chemical composition of the acid, and most important is the relation between the proportions of iron I I/iron I II, and uranium I V/uranium V I, this proportion plays a very important role in different steps of the extraction. For this purposes two methods for determination of Iron I I and Iron I II in Syrian wet phosphoric acid spectrophotometrically were studied. The first one used 1.10 phenanthroline as complex agent. Iron I I formed red complex with 1.10 phenonstholine in the range of pH between 4 and 6, for determination of total iron. Iron I II was reduced to Iron I I with hydroxylamine hydrochloride. The second method used sulfosalycilic acid, Iron I II formed a yellow complex with sulfosalycilic acid. Total iron was determined in ammonium medium, but Iron I II was determined in pH=1.5. The sensibility of the tow methods and stability of their complex have been studied in normal laboratory conditions. 45 refs., 4 figs. (author)

Ionic flotation of uranium contained in industrial phosphoric acid

International Nuclear Information System (INIS)

Jdid; Blazy; Bessiere

1983-01-01

A new process for uranium recovery from industrial phosphoric acid at 30% of P 2 O 5 is applied by the ionic flotation process. Research is carried out on determination of the nature of ionic species of U in H 3 PO 4 5.5 M and the behavior of reagents from CECA Co. in very acid media. Reagents able to form complexes directly with uranium and stable in phosphoric acid selected are: potassium ethylene diamine tetra (methylene phosphonate) (INIPOL AD32) and sodium dialkyldiphosphonate (34S). Uranium IV, obtained by reduction of uranium VI with iron powder, is precipitated by these reagents. Flotation of the precipitate obtained with INIPOL AD 32 is realized by addition of hexylamino bis (methylene phosphonic acid). A recovery of 80 wt% is obtained. Flotation of the coprecipitate 34S-U(IV) is obtained without any other additions because 34S is a surfactant. Metal recovery is better than 90% and the coprecipitate contains more than 10% U. The process is fast precipitation 10 minutes and flotation 5 minutes and is efficient even at 60 0 C [fr

Dissociation constants of phosphoric acid in dimethylformamide-water mixtures at 298.15 K

Science.gov (United States)

Safonova, L. P.; Fadeeva, Yu. A.; Pryakhin, A. A.

2009-10-01

The dissociation constants of phosphoric acid (p K 1 and p K 2) in water-dimethylformamide (DMFA) mixtures (0-0.65 mole fractions of DMFA) were determined at 298.15 K by potentiometric titration. The extrapolation of these data to pure DMFA and the comparative calculation method were used to estimate the dissociation constants of the acid in DMFA.

Effect of EDTA and phosphoric Acid pretreatment on the bonding effectiveness of self-etch adhesives to ground enamel.

Science.gov (United States)

Ibrahim, Ihab M; Elkassas, Dina W; Yousry, Mai M

2010-10-01

This in vitro study determined the effect of enamel pretreatment with phosphoric acid and ethylenediaminetetraacetic acid (EDTA) on the bond strength of strong, intermediary strong, and mild self-etching adhesive systems. Ninety sound human premolars were used. Resin composite cylinders were bonded to flat ground enamel surfaces using three self-etching adhesive systems: strong Adper Prompt L-Pop (pH=0.9-1.0), intermediary strong AdheSE (pH=1.6-1.7), and mild Frog (pH=2). Adhesive systems were applied either according to manufacturer instructions (control) or after pretreatment with either phosphoric acid or EDTA (n=10). After 24 hours, shear bond strength was tested using a universal testing machine at a cross-head speed of 0.5 mm/minute. Ultra-morphological characterization of the surface topography and resin/enamel interfaces as well as representative fractured enamel specimens were examined using scanning electron microscopy (SEM). Neither surface pretreatment statistically increased the mean shear bond strength values of either the strong or the intermediary strong self-etching adhesive systems. However, phosphoric acid pretreatment significantly increased the mean shear bond strength values of the mild self-etching adhesive system. SEM examination of enamel surface topography showed that phosphoric acid pretreatment deepened the same etching pattern of the strong and intermediary strong adhesive systems but converted the irregular etching pattern of the mild self-etching adhesive system to a regular etching pattern. SEM examination of the resin/enamel interface revealed that deepening of the etching pattern was consistent with increase in the length of resin tags. EDTA pretreatment had a negligible effect on ultra-morphological features. Use of phosphoric acid pretreatment can be beneficial with mild self-etching adhesive systems for bonding to enamel.

Influence of anodization parameters on the volume expansion of anodic aluminum oxide formed in mixed solution of phosphoric and oxalic acids

Science.gov (United States)

Kao, Tzung-Ta; Chang, Yao-Chung

2014-01-01

The growth of anodic alumina oxide was conducted in the mixed solution of phosphoric and oxalic acids. The influence of anodizing voltage, electrolyte temperature, and concentration of phosphoric and oxalic acids on the volume expansion of anodic aluminum oxide has been investigated. Either anodizing parameter is chosen to its full extent of range that allows the anodization process to be conducted without electric breakdown and to explore the highest possible volume expansion factor. The volume expansion factors were found to vary between 1.25 and 1.9 depending on the anodizing parameters. The variation is explained in connection with electric field, ion transport number, temperature effect, concentration, and activity of acids. The formation of anodic porous alumina at anodizing voltage 160 V in 1.1 M phosphoric acid mixed with 0.14 M oxalic acid at 2 °C showed the peak volume expansion factor of 1.9 and the corresponding moderate growth rate of 168 nm/min.

Absorption characteristics of Kupravas deposit clays modified by phosphoric acid

International Nuclear Information System (INIS)

Ruplis, A.; Mezinskis, G.; Chaghuri, M.

1998-01-01

Literature data suggested that clays may be used as sorbents for waste water treatment. The surface and sorption properties of minerals changes due to the influence of acid rains. The process of recession of clay properties has been modeled in laboratory by treatment of clays with mineral acids at higher temperature that in natural conditions. The present paper is devoted to the study of influence of phosphoric acid on the sorption properties of Kupravas deposit clays. Natural clay samples and samples treated with phosphoric acid were characterized by means of x-ray diffraction an differential thermal analysis (DTA) methods These methods were used also to identify the sample of Lebanese clays. X-ray diffraction analysis data show that the samples of clays from the deposit of Kuprava contain illite and kaolinite while sample of Lebanese clay contains quartz, calcite, and montmorillonite. DTA results show characteristic features of Kuprava clays described in reference with DTA of Lebanese clay clearly demonstrate the presence of large quantity of calcite

Fluoride removal performance of phosphoric acid treated lime ...

African Journals Online (AJOL)

Fluoride in drinking water above permissible levels is responsible for dental and skeletal fluorosis. In this study, removal of fluoride ions from water using phosphoric acid treated lime was investigated in continuous and point-of-use system operations. In the continuous column operations, fluoride removal performance was ...

Structural and morphological changes in supramolecular-structured polymer electrolyte membrane fuel cell on addition of phosphoric acid

Science.gov (United States)

Hendrana, S.; Pryliana, R. F.; Natanael, C. L.; Rahayu, I.

2018-03-01

Phosphoric acid is one agents used in membrane fuel cell to modify ionic conductivity. Therefore, its distribution in membrane is a key parameter to gain expected conductivity. Efforts have been made to distribute phosphoric acid in a supramolecular-structured membrane prepared with a matrix. To achieve even distribution across bulk of the membrane, the inclusion of the polyacid is carried out under pressurized chamber. Image of scanning electron microscopy (SEM) shows better phosphoric acid distribution for one prepared in pressurized state. It also leads in better performing in ionic conductivity. Moreover, data from differential scanning calorimetry (DSC) indicate that the addition of phosphoric acid is prominent in the change of membrane structure, while morphological changes are captured in SEM images.

Preparation and physical properties of (PVA0.7(NaBr0.3(H3PO4xM solid acid membrane for phosphoric acid – Fuel cells

Directory of Open Access Journals (Sweden)

F. Ahmad

2013-03-01

Full Text Available A solid acid membranes based on poly (vinyl alcohol (PVA, sodium bromide (NaBr and phosphoric acid (H3PO4 were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA0.7(NaBr0.3(H3PO4xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10−3 S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA0.7(NaBr0.3(H3PO4xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications.

Evaluation of Bio-phosphor and HumicAcid on Growth Parameters and Oil Content in Evening Primrose (Oenotherabiennis L.

Directory of Open Access Journals (Sweden)

Zeinab Aghakhani

2017-12-01

Full Text Available Introduction: Evening primrose (OenotherabiennisL. is a relatively new and valuable oilseed crop for temperate region. Its oilseed is important because of high levels of unsaturated fatty acids, especially gamma-linolenic acid. Seeds contain 20-30% oil which includes 70% linoleic acid (LA and 10% gamma linolenic acid (GLA. Oil content in O. biennis is a quantitative trait which controlled by many genes and similar to any other quantitative traits varies with environmental conditionssuch factors as age of seed and growth conditions. Evening primrose oil, especially gamma-linolenic acid, has many therapeutic properties, and it uses as cure for many diseases such as Diabetes, Eczema, inflammation, Cardiovascular, Cancer, Autoimmune diseases, Rheumatoid Arthritis, Depression. Studies on Medicinal Plants in nature and farmlands show that the use of sustainable agriculturae andnatural sources are two suitable methods for producing healthy plants.Additionally, the use of bio-fertilizers lead to maximum yield and quality in these plants. Azizi et al.(6 showed that interactions of vermicompost and plant density had significant effect on oil content, oil density and refractive index of evening primrose oil. The best treatments were also including 2 Kg/m2 of vermicompost,20 plants/ m2in terms of oil production,9 plants/ m2in terms of oil quality and ratio of unsaturated fatty acids to saturated, respectively. Material and Method: The aim of this research was to determine the effect of humic acid and bio-phosphor application on growth parameters in O. biennis. The experiment was conducted based on randomized complete block design with 8 treatments and three replicates during 2013-2014 growing season, at the experimental farm of the faculty of Agriculture, Ferdowsi University of Mashhad.. Treatments consisted of 4 levels of humic acid (0, 1, 3, 5 ml/L and 2 levels of bio-phosphor (without bio-phosphor or with bio-phosphor. Liquid form of humic acid was used

Procedure for recovery from an uranium containing concentrate and phosphoric acid, as well as an uranium containing concentrate and phosphoric acid obtained by this procedure

International Nuclear Information System (INIS)

1980-01-01

The phosphate ore is dissolved in sulphuric acid and the formed calcium sulphate is separated from the solution. The uranium is then precipitated by adding ammonium fluoride solution to the remaining phosphoric acid solution. When the phosphate ore is dissolved in sulphuric acid, fluorine gas is liberated and this is then used to produce the ammonium fluoride solution. (Th.P.)

Interim solidification of SRP waste with silica, bentonite, or phosphoric acid

International Nuclear Information System (INIS)

Thompson, G.H.

1976-03-01

One option for interim waste management at the Savannah River Plant is in-tank solidification of the liquid waste solutions. This would reduce the mobility of these highly radioactive solutions until techniques for their long-term immobilization and storage are developed and implemented. Interim treatments must permit eventual retrieval of waste and subsequent incorporation into a high-integrity form. This study demonstrated the solidification of simulated alkaline waste solutions by reaction with silica, bentonite, and phosphoric acid. Alkaline waste can be solidified by reaction with silica gel, silica flour, or sodium silicate solution. Solidified products containing waste salt can be retrieved by slurrying with water. Alkaline supernate (solution in equilibrium with alkaline sludge in SRP waste tanks) can be solidified by reaction with bentonite to form cancrinite powder. The solidified waste can be retrieved by slurrying with water. Alkaline supernate can be solidified by partial evaporation and reaction with phosphoric acid. Water is incorporated into hydrated complexes of trisodium phosphate. The product is soluble, but actual plant waste would not solidify completely because of decay heat. Reaction of simulated alkaline waste solutions with silica gel, silica flour, or bentonite increases the volume by a factor of approximately 6 over that of evaporated waste; reaction with phosphoric acid results in a volume 1.5 times that of evaporated waste. At present, the best method for in-tank solidification is by evaporation, a method that contributes no additional solids to the waste and does not compromise any waste management options

Recent Advances in Fluorescent Arylboronic Acids for Glucose Sensing

Directory of Open Access Journals (Sweden)

Jon Stefan Hansen

2013-12-01

Full Text Available Continuous glucose monitoring (CGM is crucial in order to avoid complications caused by change in blood glucose for patients suffering from diabetes mellitus. The long-term consequences of high blood glucose levels include damage to the heart, eyes, kidneys, nerves and other organs, among others, caused by malign glycation of vital protein structures. Fluorescent monitors based on arylboronic acids are promising candidates for optical CGM, since arylboronic acids are capable of forming arylboronate esters with 1,2-cis-diols or 1,3-diols fast and reversibly, even in aqueous solution. These properties enable arylboronic acid dyes to provide immediate information of glucose concentrations. Thus, the replacement of the commonly applied semi-invasive and non-invasive techniques relying on glucose binding proteins, such as concanavalin A, or enzymes, such as glucose oxidase, glucose dehydrogenase and hexokinases/glucokinases, might be possible. The recent progress in the development of fluorescent arylboronic acid dyes will be emphasized in this review.

Distribution of lanthanum and neodymium in Di(2-ethlhexyl) phosphoric acid and tributylphosphate

International Nuclear Information System (INIS)

Kraikaew, J.; Suparith, N.; Pruantonsai, P.

1994-01-01

Lanthanum and neodymium are among the high quantity elements in mixed rare earth from monazite processing. The popular rare earth separation process is liquid-liquid extraction. This research was carried out to study lanthanum and neodymium distribution in two extractants, di(2-ethylhexyl) phosphoric acid and tributylphosphate. The experimental results show that neodymium distributes in both extractants better than lanthanum. The distribution of both elements are higher at low acidity than at high acidity. Quick and rough investigation by calculating the ratio of distribution coefficient of neodymium to lanthanum in each extractant indicated that La-nd separation efficiency of Di(2-ethylhexyl) phosphoric acid is higher than that of tributylphosphate

Unexpected /sup 226/Ra build-up in wet-process phosphoric-acid plants

Energy Technology Data Exchange (ETDEWEB)

Lardinoye, M.H.; Weterings, K.; van de Berg, W.B.

1982-04-01

During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filtres. This higher radiation level is caused by radium, which, as a decay product in the /sup 238/U series, is present in very low concentrations (1-50 pCi 226R/g) in the phosphates used for fertilizer production. Specific research later on established that there were detectable radiation levels around vessels and piping in other phosphoric-acid works as well. It turned out that in all factories the filter part, and especially the washing-acid section showed the highest radiation-level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of bariumsulfate and calciumsulfate with a higher radium concentration (+/- 0.1 Ci/g) is formed. The radium ions appeared to be incorporated in the bariumsulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal pollution, for example in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning (every 1-3 yr) the equipment in which the radioactive scaling is formed.

Production of activated carbon from peanut hill using phosphoric acid and microwave activation

Directory of Open Access Journals (Sweden)

Weerawat Clowutimon

2015-06-01

Full Text Available The optimum conditions for preparing activated carbon from peanut hulls by phosphoric acid and microwave activation were studied. Factors investigated in this study were temperature of carbonization at 300, 350, 400 and 450๐ C, and time of carbonization at 30, 60 and 90 minutes. The optimum yield was observed that carbonization temperature of 400๐ C and time at 60 minutes, respectively. The yield of charcoal was 39% and the f ix carbon was 69%. Then the charcoal was activated by phosphoric acid and microwave irradiation, respectively. The effect of the weight per volume ratios of charcoal to activating acid (1:1, 1:2 and 2:1(W/V, microwave power at (activated 300, 500 and 700 watts, and activated time (30, 60 and 90 seconds were studied. The results showed that the optimum conditions for activating peanut charcoal were 1:2 (W/V charcoal per activating acid, microwave power 700 watts for 90 seconds. The results yielding maximum surface area by BET method was 303.1 m2 /g and pore volume was 0.140 cm3 /g. An efficiency of maximum iodine adsorption was 418 mg iodine/g activated carbon. Comparing the adsorption efficiency of non- irradiated and irradiated activated carbon, the efficiency of irradiated activated carbon improved up to 31%, due to its larger surface area and pore volume.

Determination of formal potential of Amsup((4))/Amsup((3)) pair in phosphoric-acid solutions

International Nuclear Information System (INIS)

Mikhajlov, V.M.; Myasoedov, B.F.

1977-01-01

Values of formal potentials of the system Amsup((4))/Amsup((3)) in 12 and 15 M phosphoric acid at 20+-2 deg C are determined by potentiometric method. The effect is studied of metallic platinum on the process of self-reduction of tetravalent americium, and the optimum conditions are found for potentiostatic oxidation of Amsup((3)) to Amsup((4)) in 12 M phosphoric acid

Purification of Industrial Phosphoric Acid using Silica Produced from Rice Husk (Part 1)

International Nuclear Information System (INIS)

Gad, H.M.H.; Awwad, N.S.; El-Khalafawy, A.; Daifullah, A.A.M.; El-Reefy, S.A.; Aly, H.F.

2008-01-01

In this work, silica was extracted from rice husk (RH) by different techniques and used for removal of some heavy metals from industrial phosphoric acid. The data obtained, showed that removal of Cu(II), Cd(II) and Pb(II) is efficient when the silica used is obtained by acidic treatment, while the removal of Fe(III) and Zn(II) is efficient when the silica used was obtained by alkaline treatment of RH. On the other hand, if silica used is obtained from rice husk ash (RHA) it was found more efficient for the removal of Mn. In all cases, the concentration of silica has been characterized by UV-Spectrophotometry. FTIR, SEM and EDX were used for predication of sorption mechanism

(Di­methyl­phosphor­yl)methanaminium hydrogen oxalate–oxalic acid (2/1)

OpenAIRE

Bialek, Sebastian; Clemens, Rebecca; Reiss, Guido J.

2014-01-01

The reaction of (di­methyl­phosphor­yl)methanamine (dpma) with oxalic acid in ethanol yielded the title solvated salt, C3H11NOP+·C2HO4 −·0.5C2H2O4. Its asymmetric unit consists of one dpmaH+ cation, one hydrogen oxalate anion and a half-mol­ecule of oxalic acid located around a twofold rotation axis. The H atom of the hydrogen oxalate anion is statistically disordered over two positions that are trans to each other. The hydrogen oxalate monoanion is not planar (bend angle ∼16°) whereas the ox...

Study of phosphoric acid crystallization using a focused beam reflectance measurement method

Energy Technology Data Exchange (ETDEWEB)

Ma, Yong [School of Chemistry and Resource Environment, Linyi Normal University, Linyi Shandong 276005 (China); Chen, Kui; Wu, Yanyang; Zhu, Jiawen [Chemical Engineering Research Center, East China University of Science and Technology, Shanghai 200237 (China); Sheng, Yong [SINOCHEN Fuling Chemical Industrial Co., Ltd, Chongqing 226005 (China)

2010-10-15

A way for restoring the crystal size distributions (CSD) from measured chord length distributions (CLD) was reported in this paper. The kinetics of phosphoric acid crystallization process was investigated in cooling mode using focused beam reflectance measurement (FBRM) and digital photo technique. In order to restore the CSD from measured CLD and verify the reliability of FBRM data, digital photo technique in real time and optical microscope were applied in large crystal size and small range, respectively. Results indicated a converting constant A existed between CLD and CSD when crystal growth follows size-independent growth (Mcabe's {delta}L law) law. It was verified by Malvern particles size analysis method. The converting constant A varied with crystal morphology. The crystal growth order increased with the stirring increasing speed during phosphoric acid crystallization process. The trend was especially notable at higher speed situations. It can illustrate that the state of phosphoric acid hemihydrate crystal growth was controlled by both diffusion and surface-integration with the increasing stirring speed. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Improvement of Haramay Fiber by Pre-treatment of Retting Process withPhosphoric Acid

International Nuclear Information System (INIS)

Kuntari-Sasas; Neni-Rustini Eriawati

2000-01-01

Haramay as bast fiber contains of cellulose fiber as the main part, mixedwith hemi cellulose, pectin, and lignin as binding material for cellulosefiber to keep it together in the bundle form. For textile material, this bastfiber has to be freed from its binding material, called as retting process,before subjecting to scouring, dyeing and finishing process in textileindustry. In the retting process the dissolve of binding material can be doneeither by using enzyme in bio technology or extraction with strong alkalinecondition in common technology. Using sodium hydroxide for dissolving thebinding material can be carried out easily with good dissolving ability, butcan render the strength retention of the cellulose fiber. Pre-treatment ofthe bast fiber with phosphoric acid (H 3 PO 4 ), is expected to hydrolyze someof the binding materials that can not be dissolved in alkaline condition,including natural pigment that colored the fiber with creamy white. In thisstudy, the pre-treatment process before retting with phosphoric acid wascarried out in various condition, such as concentration of phosphoric acid (5ml/l- 25 ml/l), time and temperature of pre-treatment (1-3 hours at 50 o C or12-24 hours at room temperature), followed by neutralization in dilutealkaline. The retting process was carried out by means of scouring in variousconcentration of sodium hydroxide (NaOH 38 o Be, 10 ml/l-30 m/l), and then wascontinued with bleaching process in hydrogen peroxide solution. Aftercarrying out those experiment, the bast fiber that called haramay wassubjected to testing for weight reduction, strength retention and degree ofwhiteness. From the testing results it is concluded that pre-treatment withphosphoric acid can increase the weight reduction, strength retention ortenacity and degree of whiteness of haramay fiber compared to the oneswithout pre-treatment with phosphoric acid. The best result was obtained bypre-treatment with 5 ml/l H 3 PO 4 at 50 o C for 2 hours, continued by

Studies on the interference of hydrofluoric acid and phosphoric acid in the determination of uranium using Ti(III) reduction method-biamperometry end point

International Nuclear Information System (INIS)

Shiny, T.S.; Rajalakshmi, A.; Phal, D.G.; Charyulu, M.M.; Ramakumar, K.L.

2007-01-01

Accurate and precise determination of uranium in nuclear materials is necessary for chemical quality control as well as for nuclear material accounting purposes. Different types of uranium samples are received for the measurements. Depending upon the nature of the sample dissolution procedure is selected. Mixed oxide samples of uranium and plutonium, for example, are dissolved in nitric acid containing hydrofluoric acid under IR lamp. The fluoride ions are removed by repeated evaporation of the solution. However, some fluoride ions are left in the solutions depending on the conditions of evaporation. Uranium samples and alloy samples are dissolved in dilute hydrochloric acid. The rate of dissolution depends on concentration of acid. Sometimes a mixture of hydrochloric acid and hydrofluoric acid is used for the dissolution metal alloy samples, which may contain silica. Another method of dissolution of these samples is using a mixture of phosphoric acid and 1% hydrofluoric acid. It is necessary to study the interference of hydrofluoric acid and phosphoric acid on the determination of uranium

Extractants for uranium recovery from wet phosphoric acid

International Nuclear Information System (INIS)

Musikas, C.; Benjelloun, N.; Lours, S.

1982-01-01

Synergistic mixtures containing phosphine oxide plus one of the acidic extractants: dialkyldithiophosphoric acid, dialkylthiophosphoric acid and dialkylphosphoric acid have been compared with respect to U(VI) and Fe(III) extraction from wet phosphoric acid. Distribution curves slope analysis showed that U(VI) extraction mechanisms are totally different. It has been found that U(VI) is extracted as: UO 2 (H 2 PO 4 )(DEHDTP)(TOPO) ; UO 2 (H 2 PO 4 )(DBTP)(POX) 2 and UO 2 (DEHP)(HDEHP) 2 TOPO in dodecane solutions containing di 2 ethylhexyldithiophosphoric acid (HDEHDTP) or dibutylthiophosphoric acid (HDBTP) or di-2-ethylhexylphosphoric acid (HDEHP) plus a phosphine oxide (TOPO or dihexylmethoxyoctylphosphine oxide (POX 11)). The synergistic mixtures containing HDEHDTP gave the highest U(VI) distribution coefficients. Back extraction with oxalic solutions can be achieved only with the synergistic mixtures containing the acidic thiophosphoric donors

Synthesis of novel acid electrolytes for phosphoric acid fuel cells

Science.gov (United States)

Adcock, James L.

1988-11-01

A 40 millimole per hour scale aerosol direct fluorination reactor was constructed. F-Methyl F-4-methoxybutanoate and F-4-methoxybutanoyl fluoride were synthesized by aerosol direct fluorination of methyl 4-methoxybutanoate. Basic hydrolysis of the perfluorinated derivatives produce sodium F-4 methoxybutanoate which was pyrolyzed to F-3-methoxy-1-propene. Purification and shipment of 33 grams of F-3-methoxy-1-propene followed. Syntheses by analogous methods allowed production and shipment of 5 grams of F-3-ethoxy 1-propene, 18 grams of F-3-(2-methoxy.ethoxy) 1-propene, and 37 grams of F-3,3-dimethyl 1-butene. Eighteen grams of F-2,2-dimethyl 1-chloropropane was produced directly and shipped. As suggested by other contractors, 5 grams of F-3-methoxy 1-iodopropane, and 5 grams of F-3-(2-methoxy.ethoxy) 1-iodopropane were produced by converting the respective precursor acid sodium salts produced for olefin synthesis to the silver salts and pyrolyzing them with iodine. Each of these compounds was prepared for the first time by the aerosol fluorination process during the course of the contract. These samples were provided to other Gas Research Institute (GRI) contractors for synthesis of perfluorinated sulfur (VI) and phosphorous (V) acids.

Synthesis of new polyphosphonic acids, uranium extracting agents in a phosphoric medium

International Nuclear Information System (INIS)

Pensec, T.

1981-04-01

Synthesis of organic phosphorus compounds for liquid-liquid extraction of traces of uranium in concentrated phosphoric acid is studied in view of industrial applications. Diphosphonic acids and monoesters and also triphosphonic acids and related compounds are synthetized. Extraction tests show a better efficiency than OPPA [fr

Optimizing Phosphoric Acid plus Hydrogen Peroxide (PHP) Pretreatment on Wheat Straw by Response Surface Method for Enzymatic Saccharification.

Science.gov (United States)

Qiu, Jingwen; Wang, Qing; Shen, Fei; Yang, Gang; Zhang, Yanzong; Deng, Shihuai; Zhang, Jing; Zeng, Yongmei; Song, Chun

2017-03-01

Wheat straw was pretreated by phosphoric acid plus hydrogen peroxide (PHP), in which temperature, time, and H 3 PO 4 proportion for pretreatment were investigated by using response surface method. Results indicated that hemicellulose and lignin removal positively responded to the increase of pretreatment temperature, H 3 PO 4 proportion, and time. H 3 PO 4 proportion was the most important variable to control cellulose recovery, followed by pretreatment temperature and time. Moreover, these three variables all negatively related to cellulose recovery. Increasing H 3 PO 4 proportion can improve enzymatic hydrolysis; however, reduction on cellulose recovery results in decrease of glucose yield. Extra high temperature or long time for pretreatment was not beneficial to enzymatic hydrolysis and glucose yield. Based on the criterion for minimizing H 3 PO 4 usage and maximizing glucose yield, the optimized pretreatment conditions was 40 °C, 2.0 h, and H 3 PO 4 proportion of 70.2 % (H 2 O 2 proportion of 5.2 %), by which glucose yielded 299 mg/g wheat straw (946.2 mg/g cellulose) after 72-h enzymatic hydrolysis.

The use of ion chromatography for the determination of impurities in crude phosphoric acid

International Nuclear Information System (INIS)

Pires, M.A.F.; Atalla, L.T.; Abrao, A.

1988-07-01

The determination of fluoride, nitrate, sulphate and phosphate ions in crude phosphoric acid by means of ion chromatography is described. A previous separation of interferent cations was made by using a cationic resin or EDTA complexation. The last alternative allowed more reproductible results. The technique described is very quick and is being applied for the simultaneous determination of impurities in phosphoric acid and its own phosphospate concentration. The method is quick and has good reprodutibility. (author) [pt

Physical-Mechanical Properties and Micromorphology of Calcium Cements Exposed to Polyacrylic and Phosphoric Acids.

Science.gov (United States)

de Souza, Gustavo Fernandes; Arrais, Ana Beatriz; Aragão, Cícero Flávio Soares; Ferreira, Isana Alvares; Borges, Boniek Castillo Dutra

2018-01-01

To evaluate if physical and mechanical properties of self-curing calcium hydroxide cements were affected by contact with polyacrylic and phosphoric acids. Resin-containing (Life (LF)) and resin-free (Hydro C (HyC)) materials were subjected to polyacrylic acid conditioning and rinsing (POL); phosphoric acid conditioning and rinsing (PHO); rinsing only; and no treatment ( n = 10). Water sorption/solubility, release of hydroxyl ions (pH), roughness (Ra), and impact resistance were evaluated. Additional samples ( n = 1) were prepared for scanning electron microscopy (SEM) analysis of the surface morphology. Data were analyzed by two-way ANOVA and Tukey post hoc test ( P < 0.05). Water sorption was significantly higher for LF when in contact with PHO and lower for POL ( P < 0.05). The mean solubility was higher with POL for both cements ( P < 0.05). PHO increased the mean surface roughness for HyC ( P < 0.01); a significant decrease was noted for LF after contact with both acids ( P < 0.01). PHO promoted lower release of hydroxyl ions on both cements ( P < 0.05). For LF, rinsing, PHO, and POL presented similar morphology, differing from the control group. For HyC, PHO and POL presented similar morphology, differing from the control group. PHO had a negative effect on the physical properties of the cements tested, except for the solubility test. POL affected roughness and solubility of HyC cement. Clinical procedures that require polyacrylic and phosphoric acid conditioning must be done carefully on self-curing calcium hydroxide cements in order to avoid negative impact on their properties.

Effect of Phosphoric Acid Pre-etching on Fatigue Limits of Self-etching Adhesives.

Science.gov (United States)

Takamizawa, T; Barkmeier, W W; Tsujimoto, A; Scheidel, D D; Erickson, R L; Latta, M A; Miyazaki, M

2015-01-01

The purpose of this study was to use shear bond strength (SBS) and shear fatigue limit (SFL) testing to determine the effect of phosphoric acid pre-etching of enamel and dentin prior to application of self-etch adhesives for bonding resin composite to these substrates. Three self-etch adhesives--1) G- ænial Bond (GC Corporation, Tokyo, Japan); 2) OptiBond XTR (Kerr Corp, Orange, CA, USA); and 3) Scotchbond Universal (3M ESPE Dental Products, St Paul, MN, USA)--were used to bond Z100 Restorative resin composite to enamel and dentin surfaces. A stainless-steel metal ring with an inner diameter of 2.4 mm was used to bond the resin composite to flat-ground (4000 grit) tooth surfaces for determination of both SBS and SFL. Fifteen specimens each were used to determine initial SBS to human enamel/dentin, with and without pre-etching with a 35% phosphoric acid (Ultra-Etch, Ultradent Products Inc, South Jordan, UT, USA) for 15 seconds prior to the application of the adhesives. A staircase method of fatigue testing (25 specimens for each test) was then used to determine the SFL of resin composite bonded to enamel/dentin using a frequency of 10 Hz for 50,000 cycles or until failure occurred. A two-way analysis of variance and Tukey post hoc test were used for analysis of SBS data, and a modified t-test with Bonferroni correction was used for the SFL data. Scanning electron microscopy was used to examine the area of the bonded restorative/tooth interface. For all three adhesive systems, phosphoric acid pre-etching of enamel demonstrated significantly higher (padhesives clearly demonstrated different tendencies between enamel and dentin. The effect of using phosphoric acid, prior to the application of the self-etching adhesives, on SBS and SFL was dependent on the adhesive material and tooth substrate and should be carefully considered in clinical situations.

46 CFR 153.558 - Special requirements for phosphoric acid.

Science.gov (United States)

2010-10-01

... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and... containment system must be: (a) Lined with natural rubber or neoprene; (b) Lined with a material approved for phosphoric acid tanks by the Commandant (CG-522); or (c) Made of a stainless steel that resists corrosion by...

Analytical applications of condensed phosphoric acid-I Determination of ferrous and total iron in iron ores after decomposition with condensed phosphoric acid.

Science.gov (United States)

Mizoguchi, T; Ishii, H

1978-06-01

A simple method is described for the determination of ferrous and total iron in iron ores. Iron ores are dissolved by condensed phosphoric acid (CPA) very rapidly without any tedious and time-consuming manipulations such as elimination of silica and filtration. Under the proposed conditions (amount of sample 100 mg, amount of CPA added 10 g, heating temperature 290 degrees , heating time 30 min), magnetite, limonite and hematite are completely dissolved. The iron content can be determined in the presence of condensed phosphoric acid by titration with dichromate solution, if a slight modification is made. The total iron in iron ores, determined by the present method, is in agreement with that found by the JIS method. The ferrous iron in iron ores can be determined by dissolving the samples with CPA in a nitrogen atmosphere and titrating with dichromate solution. Chelatometric titration of iron after solvent extraction with MIBK from solutions prepared by use of CPA is found to be accurate for samples such as pyrite cinder. The ability of CPA to dissolve various materials has been investigated.

Comparison of enamel bond fatigue durability between universal adhesives and two-step self-etch adhesives: Effect of phosphoric acid pre-etching.

Science.gov (United States)

Suda, Shunichi; Tsujimoto, Akimasa; Barkmeier, Wayne W; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2018-03-30

The effect of phosphoric acid pre-etching on enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives was investigated. Four universal adhesives and three two-step self-etch adhesives were used. The initial shear bond strengths and shear fatigue strengths to enamel with and without phosphoric acid pre-etching using the adhesives were determined. SEM observations were also conducted. Phosphoric acid pre-etching of enamel was found to increase the bond fatigue durability of universal adhesives, but its effect on two-step self-etch adhesives was material-dependent. In addition, some universal adhesives with phosphoric acid pre-etching showed similar bond fatigue durability to the two-step self-etch adhesives, although the bond fatigue durability of universal adhesives in self-etch mode was lower than that of the two-step self-etch adhesives. Phosphoric acid pre-etching enhances enamel bond fatigue durability of universal adhesives, but the effect of phosphoric acid pre-etching on the bond fatigue durability of two-step self-etch adhesives was material-dependent.

Gel Electrolytes of Covalent Network Polybenzimidazole and Phosphoric Acid by Direct Casting

DEFF Research Database (Denmark)

Kirkebæk, Andreas; Aili, David; Henkensmeier, Dirk

2017-01-01

for preparing mechanically robust covalent network polybenzimidazole membranes containing up to 95 wt% phosphoric acid. Diamino-terminal pre-polymers of different chain lengths are first prepared, followed by addition of a trifunctional carboxylic acid. The crude solutions are cast and subsequently heat treated...

Determination of uranium content in phosphoric and sulfuric acids used by the phosphatized fertilizers industry

International Nuclear Information System (INIS)

Ramos, M.M.O.

1984-05-01

Uranium content in phosphoric and sulfuric acids is determined. The uranium was measured through the fission track registration technique, using Makrofol KG, 10 μg thick, as detector. The so-called 'wet' method was adopted and the acid samples were used directly as irradiation medium. This proceeding showed the advantages of simple sample preparation and avoided the need of changing the acid samples media to nitric medium, as commonly used. The analysis of the sulfuric acid samples showed uranium contents under the detection limit of the technique (4 ppb). The results found for phosphoric acid samples ranged from 31 to 845 ppm, with experimental errors between 7.9 and 9.7%. (Author) [pt

On the reaction of iron oxides and oxyhydroxides with tannic and phosphoric acid and their mixtures

Energy Technology Data Exchange (ETDEWEB)

Beltran, J. J., E-mail: jjbj08@yahoo.com; Novegil, F. J.; Garcia, K. E.; Barrero, C. A. [Universidad de Antioquia, Sede de Investigacion Universitaria, Grupo de Estado Solido, Instituto de Fisica (Colombia)

2010-01-15

The actions of tannic acid, phosphoric acid and their mixture on lepidocrocite, goethite, superparamagnetic goethite, akaganeite, magnetite, hematite and maghemite for 1 day and 1 month were explored. It was found that these acids form iron tannates and phosphates. Lepidocrocite and magnetite were the iron phases more easily transformed with the mixture of the acids after 1 month of reaction, whereas hematite was the most resistant phase. In the case of goethite, our results suggest that in order to understand properly the action of these acids, we have to take into account its stoichiometry, surface area and degree of crystallinity.

Corrosion of graphite composites in phosphoric acid fuel cells

Science.gov (United States)

Christner, L. G.; Dhar, H. P.; Farooque, M.; Kush, A. K.

1986-01-01

Polymers, polymer-graphite composites and different carbon materials are being considered for many of the fuel cell stack components. Exposure to concentrated phosphoric acid in the fuel cell environment and to high anodic potential results in corrosion. Relative corrosion rates of these materials, failure modes, plausible mechanisms of corrosion and methods for improvement of these materials are investigated.

230Th, 232Th and 238U determinations in phosphoric acid fertilizer and process products by ICP-MS

International Nuclear Information System (INIS)

Nascimento, Marcos R.L. do; Guerreiro, Luisa M.R.; Bonifacio, Rodrigo L.; Taddei, Maria H.T.

2015-01-01

Through processing of Santa Quiteria-CE mine phosphate rock, Brazil has established a project for production of phosphoric acid fertilizer and uranium as a by-product. Under leaching conditions of phosphate rock with sulfuric acid, which is the common route for preparing phosphoric acid fertilizer, a large part of uranium, thorium and their decay products naturally present in the rock are solubilized. In order to assess the contamination potential in phosphoric acid and others process products, this paper describes a previous precipitation and direct methods for routine analysis of thorium and uranium isotopes by ICP-MS. In all samples, 230 Th, 232 Th and 238 U were directly determined after dilution, except 230 Th in phosphoric acid loaded with uranium sample, which to overcome equipment contamination effect, was determined after its separation by oxalate precipitation using lanthanum as a carrier. The results obtained by the proposed method by ICP-MS, were in good agreement when compared to alpha spectrometry for 230 Th, and ICP-OES and spectrophotometry with arsenazo III for elementary uranium and thorium determinations. (author)

Unexpected 226Ra build-up in wet-process phosphoric-acid plants

International Nuclear Information System (INIS)

Lardinoye, M.H.; Weterings, K.; Berg, W.B. van de

1982-01-01

During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filters. This higher radiation level is caused by radium which is present in very low concentrations in the phosphates used for fertilizer production. Detectable radiation levels around vessels and piping in other phosphoric-acid works have since been determined. In all factories the filter part and especially the washing-acid section showed the highest radiation level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of barium sulphate and calcium sulphate with a higher radium concentration is formed. The radium ions appeared to be incorporated in the barium sulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal contamination in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning the equipment in which the radioactive scaling is formed. (author)

Glucose and fatty acid metabolism in normal and diabetic rabbit cerebral microvessels

International Nuclear Information System (INIS)

Hingorani, V.; Brecher, P.

1987-01-01

Rabbit cerebral microvessels were used to study fatty acid metabolism and its utilization relative to glucose. Microvessels were incubated with either [6- 14 C]glucose or [1- 14 C]oleic acid and the incorporation of radioactivity into 14 CO 2 , lactate, triglyceride, cholesterol ester, and phospholipid was determined. The inclusion of 5.5 mM glucose in the incubation mixture reduced oleate oxidation by 50% and increased esterification into both phospholipid and triglyceride. Glucose oxidation to CO 2 was reduced by oleate addition, whereas lactate production was unaffected. 2'-Tetradecylglycidic acid, an inhibitor of carnitine acyltransferase I, blocked oleic acid oxidation in the presence and absence of glucose. It did not effect fatty acid esterification when glucose was absent and eliminated the inhibition of oleate on glucose oxidation. Glucose oxidation to 14 CO 2 was markedly suppressed in microvessels from alloxan-treated diabetic rabbits but lactate formation was unchanged. Fatty acid oxidation to CO 2 and incorporation into triglyceride, phospholipid, and cholesterol ester remained unchanged in the diabetic state. The experiments show that both fatty acid and glucose can be used as a fuel source by the cerebral microvessels, and the interactions found between fatty acid and glucose metabolism are similar to the fatty acid-glucose cycle, described previously

PROPERTIES OF NEW SALTS OF 2-(5-(ADAMANTANE-1-YL-4-R-1,2,4-TRIAZOLE-3-YLTIOACETIC ACIDS IN THE GLUCOSE TOLERANCE TEST

Directory of Open Access Journals (Sweden)

V. M. Odyntsova

2015-04-01

Full Text Available The concentration of glucose in the blood is one of the integral indicators of the internal environment that reflects the metabolism of carbohydrates, proteins and fats in the body. Glucose is a key component of human metabolism. The level of blood sugar is one of the most important controlled constants of body that defines homeostasis and displays the status of carbohydrate metabolism. Low blood sugar (hypoglycemia is a dangerous condition when blood glucose is critically low. The aim of research. The aim of our study was pharmacological screening of the effects of the newly synthesized salts of 2-(5-adamantane-1-yl-4-R-1,2,4-tirazol-3-yltioacetic acids on glucose blood level in experimental animals. Materials and methods. The compounds have been synthesized at the Department of Inorganic Chemistry and Toxicology of Zaporozhye State Medical University (the Head of the chair, Professor Panasenko O.I.. Blood glucose levels of saults of2-(5-adamantane-1-yl-4-R-1,2,4-tirazol-3-yltioacetic acids in rats have been evaluated by intraperitoneal glucose tolerance test (IGTT. IGTT was reproduced by glucose load on animals in a dose of 2 g / kg of rat’s body weight. White nonlinear rats weighing 160-230 g were involved in experiments. Animals were divided into 13 groups of 7 animals in each group: the 1st is intact one; the 2nd is control one with glycemia (untreated, the 3rd group of the animals received glibenclamide in the dose of 1 mg / kg; the groups 3-13 received 1,2,4-triazole derivatives. The compounds were dissolved in purified water at the rate of 1 ml per 100 g of animals’ weight and were injected intraperitoneally. Glucose content in blood has been measured by glucosidase method using glucometer «Accu Chek Active» in 30 minutes from the load moment. The research results have been processed by modern statistical methods of analysis on a personal computer using a standard software package Microsoft Office 2010 (Microsoft Excel and �

A process for uranium recovery in phosphoric acid

International Nuclear Information System (INIS)

Duarte Neto, J.

1984-01-01

Results are presented about studies carried out envisaging the development of a process for uranium recovery from phosphoric acid, produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). This process uses a mixture of DEPA-TOPO as extractant and the extraction cycle involves the following stages: acid pre-treatment; adjustment of the oxidation potential so to ensure that all uranium is hexavalent; extraction of uranium from the acid; screening of the solvent to remove undesirable impurities; uranium re-extraction and precipitation; solvent recovery. A micro-pilot plant for continuous processing was built up. Data collected showed that uranium can be recovered with an yield greater than 99%, thus proving the feasibility of the process and encouraging the construction of a bigger scale plant. (Author) [pt

Extraction of americium from acid aqueous solutions by diethyl-2-hexyl-pyro-phosphoric acid

International Nuclear Information System (INIS)

Guillaume, Bernard

1971-02-01

After having outlined the interesting properties of americium and the difficulties of its recovery, the author reports the study of the mechanism of extraction of americium from acid aqueous solutions by using the diethyl-2hexyl-pyro-phosphoric acid. Several aspects are thus discussed: influence of concentration of H 2 DEHPP, influence of the acidity of the aqueous phase, saturation of extracting agent, influence of the diluting agent, complexing of americium, influence of other cations. In a second part, the author reports the application to the recovery of americium from effluents, and discusses the obtained results

Phosphoric acid doped AB-PBI membranes and its applications in high temperature PEMFC

DEFF Research Database (Denmark)

He, Ronghuan; Qingfeng, Li; Bjerrum, Niels

2005-01-01

Poly(2,5-benzimidazole) (ab-PBI) was prepared from 3，4-diaminobenzoic acid via a polymerisation reaction. The obtained polymer exhibits excellent thermal stability in a temperature range ….. The membrane of ab-PBI when doped with phosphoric acid at room temperaturepresents high proton conductivity...

Online Automatic Titration of Chromic Acid in Chromium Plating Solutions and Phosphoric and Sulfuric Acids in Electropolishing Solutions

National Research Council Canada - National Science Library

Sopok, Samuel

1991-01-01

.... The analytical chemistry literature lacks an adequate online automatic titration method for the monitoring of chromic acid in chromium plating solutions and the monitoring of phosphoric and sulfuric...

Phosphoric acids as amplifiers of molecular chirality in liquid crystalline media

NARCIS (Netherlands)

Eelkema, R; Feringa, BL

2006-01-01

A new system for the double amplification of the molecular chirality of simple chiral amines in achiral liquid crystalline media is described. It involves a conformationally flexible phosphoric acid based receptor that by binding to chiral amines induces chirality in the liquid crystalline matrix.

Uric Acid or 1-Methyl Uric Acid in the Urinary Bladder Increases Serum Glucose, Insulin, True Triglyceride, and Total Cholesterol Levels in Wistar Rats

Directory of Open Access Journals (Sweden)

T. Balasubramanian

2003-01-01

Full Text Available In animals deprived of food for a long period, a drop in the fat mass below 5% of the total body mass results in an increase in blood glucocorticoids and uric acid levels, followed by foraging activity. Since the glucocorticoids increase the uric acid excretion, an increase in the level of uric acid in the bladder urine could be the signal for this feeding behaviour and subsequent fat storage. Accumulation of fat is associated with hyperglycaemia, hyperinsulinaemia, hyperlipidaemia, and hypercholesterolaemia as seen in the metabolic syndrome or hibernation. It is hypothesized that uric acid or its structurally related compound, 1-methyl uric acid (one of the metabolites of the methyl xanthines namely caffeine, theophylline, and theobromine present in coffee, tea, cocoa, and some drugs, can act on the urinary bladder mucosa and increases the blood glucose, insulin, triglyceride, and cholesterol levels. In rats, perfusion of the urinary bladder with saturated aqueous solution of uric acid or 1-methyl uric acid results in a significant increase in the serum levels of glucose, insulin, true triglyceride, and total cholesterol in comparison with perfusion of the bladder with distilled water at 20, 40, and 80 min. The uric acid or the 1-methyl uric acid acts on the urinary bladder mucosa and increases the serum glucose, insulin, true triglyceride, and total cholesterol levels.

Impact of pH and application time of meta-phosphoric acid on resin-enamel and resin-dentin bonding.

Science.gov (United States)

Cardenas, A F M; Siqueira, F S F; Bandeca, M C; Costa, S O; Lemos, M V S; Feitora, V P; Reis, A; Loguercio, A D; Gomes, J C

2018-02-01

To evaluate the immediate microshear resin-enamel bond strength (μSBS) and the immediate and 6-month microtensile bond strength (μTBS) and nanoleakage (NL) of the adhesive interface performed by different pHs of 40% meta-phosphoric acid (MPA) were compared with conventional 37% ortho-phosphoric acid (OPA) under different application times. Additionally, the enamel etching patterns were evaluated and the chemical/morphological changes induced by these differents groups were evaluated. One hundred and ninety-eight extracted human molars were randomly assigned into experimental groups according to the combination of independent variables: Acid [37% ortho-phosphoric acid (OPA), 40% meta-phosphoric acid (MPA) at pHs of: 0.5, 1 and 2] and Application Time [7, 15 and 30s]. Enamel-bond specimens were prepared and tested under μSBS. Resin-dentin beams were tested under μTBS tested immediately or after 6-months of water storage. Nanoleakage was evaluated using bonded-beams of each tooth/time-period. Enamel etching pattern and chemical and ultra-morphology analyses were also performed. The μSBS (MPa) data were subjected to a two-way repeated measures ANOVA (Acid vs. Application time). For μTBS, Acid vs application time vs storage time data were subjected to three-way ANOVA and Tukey's test (α = 0.05). MPA pH 0.5 showed μTBS similar to OPA, independently of the application time on enamel (p>0.05) or dentin (p>0.05). OPA provided higher nanoleakage values than MPA (p = 0.003). Significant decreases in TBS and increases in NL were only observed for OPA after 6 months (p = 0.001). An increase in the application time resulted in a more pronounced etching pattern for MPA. Chemical analysis showed that dentin demineralized by MPA depicted peaks of brushite and octacalcium phosphate. MPA exposed less collagen than OPA. However, optimal results for MPA were dependent on pH/application time. The use of 40% meta-phosphoric acid with a pH of 0.5 is an alternative acid

Alternative processes for uranium recovery from phosphoric acid

International Nuclear Information System (INIS)

Duarte Neto, J.; Santos Benedetto, J. dos; Aquino, J.A. de

1987-01-01

Two processes of solvent extraction using D 2 EHPATOPO synergistic mixture, in order to recover uranium from phosphoric acid proceeding from physical and chemical treatments of the phosphorus-uraniferous ore of Itataia-CE, Brazil, are studied. The steps of each process were studied in laboratory and pilot scales. The flow charts for both processes with detailed description of each step, the operational conditions, the mass balances, the results obtained and the description of pilot units, are presented. (M.C.K.) [pt

Wet Chemical Oxidation of Organic Waste Using Nitric-Phosphoric Acid Technology

Energy Technology Data Exchange (ETDEWEB)

Pierce, R.A.

1998-10-06

Experimental progress has been made in a wide range of areas which support the continued development of the nitric-phosphoric acid oxidation process for combustible, solid organic wastes. An improved understanding of the overall process operation has been obtained, acid recovery and recycle systems have been studied, safety issues have been addressed, two potential final waste forms have been tested, preliminary mass flow diagrams have been prepared, and process flowsheets have been developed. The flowsheet developed is essentially a closed-loop system which addresses all of the internally generated waste streams. The combined activities aim to provide the basis for building and testing a 250-400 liter pilot-scale unit. Variations of the process now must be evaluated in order to address the needs of the primary customer, SRS Solid Waste Management. The customer is interested in treating job control waste contaminated with Pu-238 for shipment to WIPP. As a result, variations for feed preparation, acid recycle, and final form manufacturing must be considered to provide for simpler processing to accommodate operations in high radiation and contamination environments. The purpose of this program is to demonstrate a nitric-phosphoric acid destruction technology which can treat a heterogeneous waste by oxidizing the solid and liquid organic compounds while decontaminating noncombustible items.

Influence of multi-step washing using Na2EDTA, oxalic acid and phosphoric acid on metal fractionation and spectroscopy characteristics from contaminated soil.

Science.gov (United States)

Wei, Meng; Chen, Jiajun

2016-11-01

A multi-step soil washing test using a typical chelating agent (Na 2 EDTA), organic acid (oxalic acid), and inorganic weak acid (phosphoric acid) was conducted to remediate soil contaminated with heavy metals near an arsenic mining area. The aim of the test was to improve the heavy metal removal efficiency and investigate its influence on metal fractionation and the spectroscopy characteristics of contaminated soil. The results indicated that the orders of the multi-step washing were critical for the removal efficiencies of the metal fractions, bioavailability, and potential mobility due to the different dissolution levels of mineral fractions and the inter-transformation of metal fractions by XRD and FT-IR spectral analyses. The optimal soil washing options were identified as the Na 2 EDTA-phosphoric-oxalic acid (EPO) and phosphoric-oxalic acid-Na 2 EDTA (POE) sequences because of their high removal efficiencies (approximately 45 % for arsenic and 88 % for cadmium) and the minimal harmful effects that were determined by the mobility and bioavailability of the remaining heavy metals based on the metal stability (I R ) and modified redistribution index ([Formula: see text]).

Recovery of uranium from phosphoric acid medium by polymeric composite beads encapsulating organophosphorus extractants

Energy Technology Data Exchange (ETDEWEB)

Singh, D.K.; Yadav, K.K.; Varshney, L.; Singh, H. [Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2013-07-01

The present study deals with the preparation and evaluation of the poly-ethersulfone (PES) based composite beads encapsulating synergistic mixture of D2EHPA and Cyanex 923 (at 4:1 mole ratio) for the separation of uranium from phosphoric acid medium. SEM was used for the characterization of the composite materials. Addition of 1% PVA (polyvinyl alcohol) improved the internal morphology and porosity of the beads. Additionally, microscopic examination of the composite bead confirmed central coconut type cavity surrounded by porous polymer layer of the beads through which exchange of metal ions take place. Effect of various experimental variables including aqueous acidity, metal ion concentration in aqueous feed, concentration of organic extractant inside the beads, extractant to polymer ratio, liquid to solid (L/S) ratio and temperature on the extraction of uranium was studied. Increase in acidity (1-6 M), L/S ratio (1- 10), metal ion concentration (0.2-3 g/L U{sub 3}O{sub 8}) and polymer to extractant ratio (1:4 -1:10) led to decrease in extraction of uranium. At 5.5 M (comparable to wet process phosphoric acid concentration) the extraction of uranium was about 85% at L/S ratio 5. Increase in extractant concentration inside the bead resulted in enhanced extraction of metal ion. Increase in temperature in the range of 30 to 50 Celsius degrees increased the extraction, whereas further increase to 70 C degrees led to the decrease in extraction of uranium. Amongst various reagents tested, stripping of uranium was quantitative by 12% Na{sub 2}CO{sub 3} solution. Polymeric beads were found to be stable and reusable up-to 10 cycles of extraction/stripping. (authors)

Unexpected /sup 226/Ra build-up in wet-process phosphoric-acid plants

Energy Technology Data Exchange (ETDEWEB)

Lardinoye, M.H.; Weterings, K. (Stamicarbon B.V., Geleen (Netherlands)); van de Berg, W.B. (Unie van Kunstmestfabrieken, Utrecht (Netherlands))

1982-04-01

During an investigation of the distribution of radium and uranium over the different process streams in phosphoric-acid production and in the nitrophosphate route, a higher than average radiation level was detected in the vicinity of some piping and vessels near the gypsum filters. This higher radiation level is caused by radium which is present in very low concentrations in the phosphates used for fertilizer production. Detectable radiation levels around vessels and piping in other phosphoric-acid works have since been determined. In all factories the filter part and especially the washing-acid section showed the highest radiation level. In the piping of the gypsum filter, through which the washing acid is discharged, a scaling of barium sulphate and calcium sulphate with a higher radium concentration is formed. The radium ions appeared to be incorporated in the barium sulphate lattice, hence the solubility of the radium precipitate is very low. The danger of internal contamination in cleaning operations by radioactive intake or inhalation of radon is very small in the cases described. The risk of external radiation can be prevented by periodically cleaning the equipment in which the radioactive scaling is formed.

Proton conductivity of phosphoric acid doped polybenzimidazole and its composites with inorganic proton conductors

DEFF Research Database (Denmark)

He, Ronghuan; Qingfeng, Li; Gang, Xiao

2003-01-01

Phosphoric acid doped polybenzimidazole (PBI) and PBI composite membranes have been prepared in the present work. The PBI composites contain inorganic proton conductors including zirconium phosphate (ZrP), (Zr(HPO4)2·nH2O), phosphotungstic acid (PWA), (H3PW12O40·nH2O) and silicotungstic acid (Si...

Complexity in Acid–Base Titrations: Multimer Formation Between Phosphoric Acids and Imines

Science.gov (United States)

Malm, Christian; Kim, Heejae; Wagner, Manfred

2017-01-01

Abstract Solutions of Brønsted acids with bases in aprotic solvents are not only common model systems to study the fundamentals of proton transfer pathways but are also highly relevant to Brønsted acid catalysis. Despite their importance the light nature of the proton makes characterization of acid–base aggregates challenging. Here, we track such acid–base interactions over a broad range of relative compositions between diphenyl phosphoric acid and the base quinaldine in dichloromethane, by using a combination of dielectric relaxation and NMR spectroscopy. In contrast to what one would expect for an acid–base titration, we find strong deviations from quantitative proton transfer from the acid to the base. Even for an excess of the base, multimers consisting of one base and at least two acid molecules are formed, in addition to the occurrence of proton transfer from the acid to the base and simultaneous formation of ion pairs. For equimolar mixtures such multimers constitute about one third of all intermolecular aggregates. Quantitative analysis of our results shows that the acid‐base association constant is only around six times larger than that for the acid binding to an acid‐base dimer, that is, to an already protonated base. Our findings have implications for the interpretation of previous studies of reactive intermediates in organocatalysis and provide a rationale for previously observed nonlinear effects in phosphoric acid catalysis. PMID:28597513

Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

Energy Technology Data Exchange (ETDEWEB)

Kouril, M. [Institute of Chemical Technology, Technicka 5, 166 28 Prague (Czech Republic); Christensen, E. [Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby (Denmark); Eriksen, S.; Gillesberg, B. [Tantaline A/S, Nordborgvej 81, 6430 Nordborg (Denmark)

2012-04-15

The paper is focused on selection of a proper material for construction elements of water electrolysers, which make use of a 85% phosphoric acid as an electrolyte at temperature of 150 C and which might be loaded with anodic polarization up to 2.5 V versus a saturated Ag/AgCl electrode (SSCE). Several grades of stainless steels were tested as well as tantalum, niobium, titanium, nickel alloys and silicon carbide. The corrosion rate was evaluated by means of mass loss at free corrosion potential as well as under various levels of polarization. The only corrosion resistant material in 85% phosphoric acid at 150 C and at polarization of 2.5 V/SSCE is tantalum. In that case, even a gentle cathodic polarization is harmful in such an acidic environment. Hydrogen reduction leads to tantalum hydride formation, to loss of mechanical properties and to complete disintegration of the metal. Contrary to tantalum, titanium is free of any corrosion resistance in hot phosphoric acid. Its corrosion rate ranges from tens of millimetres to metres per year depending on temperature of the acid. Alloy bonded tantalum coating was recognized as an effective corrosion protection for both titanium and stainless steel. Its serviceability might be limited by slow dissolution of tantalum that is in order of units of mm/year. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Proton conductivity of phosphoric acid doped polybenzimidazole and its composites with inorganic protontic conductors

DEFF Research Database (Denmark)

Li, Qingfeng

2003-01-01

contain inorganic protonic conductors including zirconium phosphate (ZrP), (Zr(HPO4)2. nH2O); phosphotungstic acid (PWA), (H3PW12O40. nH2O); and silicotungstic acid (SiWA), (H4SiW12O40 . nH2O). The conductivity of phosphoric acid doped PBI and PBI composite membranes was found to be dependent on the acid...

Radiotracer investigation of phosphoric acid and phosphatic fertilizers production process

International Nuclear Information System (INIS)

Ben Abdelouahed, H.; Reguigui, N.

2011-01-01

In the phosphoric acid production process, the time a particle spends inside the chemical reactor (residence time) is of paramount importance to process engineers. Residence time distribution (RTD) gives information on the efficiency of the chemical reactor, on the efficiency of the process, and also the availabilities of the reactive volume for the reaction (active volume vs. dead volume). Traditionally, chemical engineers used chemical tracer to determine the RTD. However, first disadvantage is that the chemical tracer could not allow an online diagnosis: the samples containing chemical tracer have to go to a lab for analysis, second disadvantage is that the chemical tracer is less sensitive than radioactive ones because of its adsorption onto strata or its retention in rocks. Consequently, chemical tracer results are not always precise and cannot convincingly explain the multiple flow-path model. Radioactive tracers are the only tracers capable of measuring the active RTD with high degree of precision and give information on the internal recirculation rate. In this work, we will describe the application of radiotracer method for RTD measurement in the phosphoric acid production process and give results and discussion of each case encountered. (author)

Optimization of cellulose nanocrystal length and surface charge density through phosphoric acid hydrolysis

Science.gov (United States)

Vanderfleet, Oriana M.; Osorio, Daniel A.; Cranston, Emily D.

2017-12-01

Cellulose nanocrystals (CNCs) are emerging nanomaterials with a large range of potential applications. CNCs are typically produced through acid hydrolysis with sulfuric acid; however, phosphoric acid has the advantage of generating CNCs with higher thermal stability. This paper presents a design of experiments approach to optimize the hydrolysis of CNCs from cotton with phosphoric acid. Hydrolysis time, temperature and acid concentration were varied across nine experiments and a linear least-squares regression analysis was applied to understand the effects of these parameters on CNC properties. In all but one case, rod-shaped nanoparticles with a high degree of crystallinity and thermal stability were produced. A statistical model was generated to predict CNC length, and trends in phosphate content and zeta potential were elucidated. The CNC length could be tuned over a relatively large range (238-475 nm) and the polydispersity could be narrowed most effectively by increasing the hydrolysis temperature and acid concentration. The CNC phosphate content was most affected by hydrolysis temperature and time; however, the charge density and colloidal stability were considered low compared with sulfuric acid hydrolysed CNCs. This study provides insight into weak acid hydrolysis and proposes `design rules' for CNCs with improved size uniformity and charge density. This article is part of a discussion meeting issue `New horizons for cellulose nanotechnology'.

Feasibility studies on supercritical fluid extraction of uranium from phosphoric acid

International Nuclear Information System (INIS)

Dubey, B.P.; Agarwal, A.K.

2014-01-01

Supercritical fluid extraction (SFE) is a promising novel technology for extraction of many materials. Work has been carried out worldwide on SFE of uranium from various matrices. However, there are no references indicating the R and D on uranium extraction from phosphoric acid using this technology. Heavy Water Board is involved in technology development for recovery of uranium from secondary source, hence it was considered prudent to investigate the technology of SFE for this purpose. Various experiments were carried out with both WPA (P 2 O 5 content 28%) and MGPA (P 2 O 5 content 54%) using bench scale facility available with one of the private party. Extraction experiments were carried out using several chelating agents including TBP, D2EHPA, D2EHPA+TBP/TOPO, TTA, TTA+TBP etc. Feasibility studies revealed the hydrodynamics of operation indicating liquid expansion by about three times during flow of super critical (SC) CO 2 . No flooding was observed when the extraction column filled 20% of its volume capacity, no carryover of entrained/extracted liquid with SC CO 2 with MGPA, material balance of inputs and outputs established i.e. 100% recovery of MGPA and chelating agent, No operational problems with raw MGPA (untreated). No significant extraction of impurities from phosphoric acid to SC CO 2 , 40℃ temperature and 160 bar pressure found ideal for extraction experiments since no other materials found extracted at these conditions and no apparent change/deterioration in PA and chelating agents. Experiments established feasibility of SCE with CO 2 , proper recovery of PA and chelating agents, no need for pretreatment/gunk removal from PA; however, extraction of uranium was found inadequate even though ORP of feed acid was boosted by H 2 O 2 addition. Investigations revealed that SCE column created reducing environment in phosphoric acid, which was not favourable for uranium extraction, which resulted in difficulty in extraction of Uranium. HWB has now designed

Methyl phosphate formation as a major degradation mode of direct methanol fuel cells with phosphoric acid based electrolytes

DEFF Research Database (Denmark)

Aili, David; Vassiliev, Anton; Jensen, Jens Oluf

2015-01-01

Phosphoric acid and phosphoric acid doped polymer membranes are widely used as electrolytes in hydrogen based fuel cells operating at elevated temperatures. Such electrolytes have been explored for direct oxidation of methanol to further increase the versatility of the systems, however......, with demonstrated lifetimes of only a few days to weeks. In this work the methyl phosphate formation from the acid and methanol is identified and proposed to be a major mechanism for the cell degradation. Proton conductivity and fuel cell durability tests validate the mechanism at high methanol contents....

Developmental, gustatory, and behavioral responses of leafroller larvae, Choristoneura rosaceana, to tannic acid and glucose.

Science.gov (United States)

Panzuto, M; Mauffette, Y; Alber, P J

2002-01-01

Soluble sugars are essential nutrients generally perceived as phagostimulants to most insects studied. However, tannins are known as digestibility reducers, hence deleterious to caterpillar development, and as deterrents as well. Previous work demonstrated that larvae of the polyphagous oblique-banded leafroller, Choristoneura rosaceana, performed better when reared on a control + 0.5% tannic acid diet than on the standard control diet and that larvae reared on a control + 5% glucose diet had slower development and reduced survival. This study was designed to elucidate the behavioral and neurophysiological components of the larval responses to tannic acid and glucose. C. rosaceana larvae were reared individually from the first to the sixth instar on one of four different artificial diets: (1) control; (2) control + 5% glucose; (3) control + 0.5% tannic acid; (4) control + 5% glucose + 0.5% tannic acid. After 14 days, larvae reared on the control + 5% glucose diet had not developed past the fourth instar, whereas a considerable proportion of larvae reared on the control + 0.5% tannic acid diet had already attained the pupal stage. Insects reared on the control or the control + 5% glucose + 0.5% tannic acid diet had intermediate development. with most larvae in the fifth instar. In addition, once the mid-sixth instar was reached, the feeding preferences to 25 and 300 mM glucose, 25 mM tannic acid, and 25 mM glucose + 25 mM tannic acid over water were assessed in two-choice tests. Feeding affected preference. Control-reared insects preferred feeding on treatments containing glucose and were not deterred by tannic acid. However, larvae that had been exposed to tannic acid during their development were deterred by tannic acid and their glucose discrimination was impaired. The sensitivity to glucose was also examined from neurophysiological recordings by stimulating the sugar-sensitive cell (cell 1) on the lateral styloconic sensillum of the maxillary galea with

Production of caffeoylmalic acid from glucose in engineered Escherichia coli.

Science.gov (United States)

Li, Tianzhen; Zhou, Wei; Bi, Huiping; Zhuang, Yibin; Zhang, Tongcun; Liu, Tao

2018-07-01

To achieve biosynthesis of caffeoylmalic acid from glucose in engineered Escherichia coli. We constructed the biosynthetic pathway of caffeoylmalic acid in E. coli by co-expression of heterologous genes RgTAL, HpaBC, At4CL2 and HCT2. To enhance the production of caffeoylmalic acid, we optimized the tyrosine metabolic pathway of E. coli to increase the supply of the substrate caffeic acid. Consequently, an E. coli-E. coli co-culture system was used for the efficient production of caffeoylmalic acid. The final titer of caffeoylmalic acid reached 570.1 mg/L. Microbial production of caffeoylmalic acid using glucose has application potential. In addition, microbial co-culture is an efficient tool for producing caffeic acid esters.

Synthesis of Fluorite (CaF2 Crystal from Gypsum Waste of Phosphoric Acid Factory in Silica Gel

Directory of Open Access Journals (Sweden)

Mohammad Misbah Khunur

2012-06-01

Full Text Available This paper report the synthesis and characterization of fluorite single crystal prepared from gypsum waste of phosphoric acid production in silica gel. Instead of its high calcium, gypsum was used to recycle the waste which was massively produces in the phosphoric acid production. The gypsum waste, the raw material of CaCl2 supernatant, was dissolved in concentrated HCl and then precipitated as calcium oxalate (CaC2O4 by addition of ammonium oxalate. The CaCl2 was obtained by dissolving the CaC2O4 with HCl 3M. The crystals were grown at room temperature in silica gel and characterized by AAS, FTIR and powder XRD. The optimum crystal growth condition, which is pH of gel, CaCl2 concentration and growth time, were investigated. The result shows that at optimum condition of pH 5.80, CaCl2 concentrations of 1.2 M, and growth time of 144 hours, colorless crystals with the longest size of 3 mm, were obtained (72.57%. Characterization of the synthesized crystal by AAS indicates that the obtained crystal has high purity. Meanwhile, analysis by FTIR spectra shows a Ca–F peak at 775 cm-1, and powder-XRD analysis confirms that the obtained crystal was fluorite (CaF2. © 2012 BCREC UNDIP. All rights reservedReceived: 11st April 2012; Revised: 4th June 2012; Accepted: 13rd June 2012[How to Cite: M.M. Khunur, A. Risdianto, S. Mutrofin, Y.P. Prananto. (2012. Synthesis of Fluorite (CaF2 Crystal from Gypsum Waste of Phosphoric Acid Factory in Silica Gel. Bulletin of Chemical Reaction Engineering & Catalysis, 7 (1: 71-77.  doi:10.9767/bcrec.7.1.3171.71-77 ][How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.1.3171.71-77 ] | View in 

Survey on aging on electrodes and electrocatalysts in phosphoric acid fuel cells

Science.gov (United States)

Stonehart, P.; Hochmuth, J.

1981-01-01

The processes which contribute to the decay in performance of electrodes used in phosphoric acid fuel cell systems are discussed. Loss of catalytic surface area, corrosion of the carbon support, electrode structure degradation, electrolyte degradation, and impurities in the reactant streams are identified as the major areas for concern.

Measurement of the oxidation-extraction of uranium from wet-process phosphoric acid

International Nuclear Information System (INIS)

Lawes, B.C.

1985-01-01

The present invention relates to processes for the recovery of uranium from wet-process phosphoric acid and more particularly to the oxidation-extraction steps in the DEPA-TOPO process for such recovery. A more efficient use of oxidant is obtained by monitoring the redox potential during the extraction step

Amino-Functional Polybenzimidazole Blends with Enhanced Phosphoric Acid Mediated Proton Conductivity as Fuel Cell Electrolytes

DEFF Research Database (Denmark)

Aili, David; Javakhishvili, Irakli; Han, Junyoung

2016-01-01

A new amino-functional polybenzimidazole copolymer is synthesized by homogeneous solution condensation polymerization from a novel monomer, N,N′-bis (2,4-diaminophenyl)-1,3-diaminopropane. The copolymer readily dissolves in organic solvents and shows good film forming characteristics. To balance...... the phosphoric acid uptake and to obtain mechanically robust membranes, the amino-functional polybenzimidazole derivative is blended with high molecular weight poly [2,2′-(m-phenylene)-5,5′-bisbenzimidazole] at different ratios. Due to the high acid uptake, the homogenous blend membranes show enhanced proton...

Effects of glucose, glucose plus branched-chain amino acids, or placebo on bike performance over 100 km

DEFF Research Database (Denmark)

Madsen, Klavs; MacLean, David A; Kiens, Bente

1996-01-01

This study was undertaken to determine the effects of ingesting either glucose (trial G) or glucose plus branched-chain amino acids (BCAA: trial B), compared with placebo (trial P), during prolonged exercise. Nine well-trained cyclists with a maximal oxygen uptake of 63.1 +/- 1.5 ml O2. min-1.kg-...

Separation of uranium and other metals from commercial phosphoric acid by ion-exchange and voltammetric determination of uranium

International Nuclear Information System (INIS)

Ferreira, J.B.C.; Carvalho, F.M.S. de; Abrao, A.

1985-11-01

The separation of metals from crude commercial phosphoric acid is achieved by simple dilution and percolation through a strong cationic ion exchanger. Uranium, calcium, magnesium, manganese, iron and aluminum are quantitatively fixed by the exchanger and can be detected or analysed after their complete elution with 6 M HCI. Titanium and zirconium are only partially retained. Specially for its separation and determination uranium is retained selectively by the resin from the phosphoric acid-EDTA solution, the column is washed with water and then eluted with hydrochloric acid. Uranium is analyzed by voltametry with the hanging drop mercury electrode. (Author) [pt

An extremely sensitive monoboronic acid based fluorescent sensor for glucose

International Nuclear Information System (INIS)

Sun Xiangying; Liu Bin; Jiang Yunbao

2004-01-01

An extremely sensitive monoboronic acid based fluorescent sensor for glucose was developed. This was carried out by assembling a fluorescent monoboronic acid, 3-aminophenylboronic acid (PBA) indirectly onto gold surface via its electrostatic interaction with cysteine (Cys) that was directly assembled on the gold surface. The formation of self-assembled bilayers (SAB) was confirmed and primarily characterized by cyclic voltammetry and X-ray photoelectron spectra (XPS). The SAB containing PBA was found fluorescent and its fluorescence showed an extremely high sensitivity to the presence of glucose and other monosaccharides such as galactose and fructose with quenching constants at 10 8 M -1 order of magnitude compared to those at 10 2 M -1 in bulk solutions. The quenching constants were found to vary in the order of D-glucose>D-galactose>D-fructose>D-mannose that is different from that in bulk solution which shows the highest binding affinity toward D-fructose and very low sensitivity toward glucose. The reported monoboronic acid based SAB fluorescent sensor showed the highest sensitivity towards glucose with the capacity of detecting saccharides of concentration down to nanomolar level. It was also demonstrated that the fluorescence from PBA/Cys/Au can be easily recovered after each measurement event and therefore also represents a new reusable method for immobilizing reagent in fabricating chemosensors

Evaluation of human dental loss caused by carbamide peroxide bleacher compared with phosphoric acid conditioning - radioactive method

International Nuclear Information System (INIS)

Adachi, Eduardo Makoto; Yousseff, Michel Nicolau; Saiki, Mitiko

2002-01-01

The radiometric method was applied to the evaluation of dental loss caused by carbamide peroxide when it is applied on the surface layers of enamel and dentin tissues. Also the dental loss caused by the etching with 37% phosphoric acid procedure used in aesthetic restoration was assessed for comparison with those results obtained. The tooth samples irradiated with a P standard in a thermal neutron flux of the nuclear reactor were placed in contact with 10% carbamide peroxide or with 37% phosphoric acid solution. The radioactivity of 32 P transferred from the radioactive teeth to the bleaching gel or to etching acid was measured using a Geiger Muller detector to calculate the mass of P removed in this treatment and losses were calculated after obtaining their P concentrations. Results obtained indicated that enamel and dentin exposed to carbamide peroxide bleaching agent lose phosphorus. The extent of enamel loss was smaller than that obtained for dentin. In the case of acid etching, there was no difference between the results obtained for enamel and dentin loss. Also the dentin loss obtained after a treatment of 30 applications of 10% carbamide peroxide was the same magnitude of that one application of 37% phosphoric acid. (author)

Process for recovering uranium from wet process phosphoric acid (III)

International Nuclear Information System (INIS)

Pyrih, R.Z.; Rickard, R.S.; Carrington, O.F.

1983-01-01

Uranium is conventionally recovered from wet-process phosphoric acid by two liquid ion exchange steps using a mixture of mono- and disubstituted phenyl esters of orthophosphoric acid (OPPA). Efficiency of the process drops as the mono-OPPA is lost preferentially to the aqueous phase. This invention provides a process for the removal of the uranium process organics (OPPA and organic solvents) from the raffinate of the first liquid ion exchange step and their return to the circuit. The process organics are removed by a combination flotation and absorption step, which results in the recovery of the organics on beads of a hydrophobic styrene polymer

Process of converting starch to glucose and glucose to lactic acid

Energy Technology Data Exchange (ETDEWEB)

Tsai, TenLin; Sanville, C.Y.; Coleman, R.D.; Schertz, W.W.

1990-01-01

This document describes a method for converting starch into lactic acid of sufficient purity for use as a substrate for biodegradable plastics. The process is designed to work on industrial food waste streams such as potato wastes or cheese whey permeate. For potato waste, {alpha}-amylase and calcium chloride are added to the starch containing waste and incubated at a pH of 4--7, a temperature of 90--130{degree}C, and a pressure above 15 psi for not less than 15 minutes. At this point, glucoamylase is added and the mixture is incubated at a temperature of 50--70{degree}C and a pH below 6.5 for 4 hours. This results in the conversion of more than 90% of the starch into glucose, which is substantially free of microbial contamination. The hydrolysate is filtered, and introduced with additional nutrients to a fermentor containing a lactose producing microorganism to form a fermentation broth. This results in the fermentation of glucose to lactose, which is filtered and subjected to electrodialysis for purification. Conversion of glucose to lactic acid or lactate occurs with an efficiency of over 95%. 1 fig. (MHB)

Spectrophotometric Analysis of Phosphoric Acid Leakage in High-Temperature Phosphoric Acid-Doped Polybenzimidazole Membrane Fuel Cell Application

Directory of Open Access Journals (Sweden)

Seungyoon Han

2016-01-01

Full Text Available High-temperature proton exchange membrane fuel cells (HT-PEMFCs utilize a phosphoric acid- (PA- doped polybenzimidazole (PBI membrane as a polymer electrolyte. The PA concentration in the membrane can affect fuel cell performance, as a significant amount of PA can leak from the membrane electrode assembly (MEA by dissolution in discharged water, which is a byproduct of cell operation. Spectrophotometric analysis of PA leakage in PA-doped polybenzimidazole membrane fuel cells is described here. This spectrophotometric analysis is based on measurement of absorption of an ion pair formed by phosphomolybdic anions and the cationoid color reagent. Different color reagents were tested based on PA detection sensitivity, stability of the formed color, and accuracy with respect to the amount of PA measured. This method allows for nondestructive analysis and monitoring of PA leakage during HT-PEMFCs operation.

Solid phosphoric acid oligomerisation: Manipulating diesel selectivity by controlling catalyst hydration

International Nuclear Information System (INIS)

Prinsloo, Nicolaas M.

2006-01-01

Solid phosphoric acid (SPA) catalyst is traditionally used in crude oil refineries to produce unhydrogenated motor-gasoline by propene and butene oligomerisation. SPA is also used in High-Temperature Fischer-Tropsch refineries (HTFT) to produce synthetic fuels albeit with a different emphasis. The petrol/diesel ratio of an HTFT refinery is very different from crude refining and it is often necessary to shift this ratio depending on market requirements. The influence of hydration was investigated as a means of improving diesel selectivity. This was achieved by studying SPA over a hydration range of 99-110% H 3 PO 4 , a temperature range of 140-230 o C and using C 3 -C 6 model and synthetic FT-derived olefinic feedstocks. A direct correlation was found between the selectivity towards diesel range products and the distribution of the phosphoric acid species viz. H 3 PO 4 , H 4 P 2 O 7 and H 5 P 3 O 10 . For various olefinic feedstocks, diesel selectivity increased with decreasing catalyst hydration with a maximum around 108% H 3 PO 4 for propene oligomerisation. Commercial tests confirmed the increase in diesel selectivity with lowered catalyst hydration. (author)

Synergic extraction of some lanthanide and actinide elements by a mixture of bis(2-ethyl hexyl) phosphoric acid and dinonylnapthalene - sulfonic acid in aromatic diluents

International Nuclear Information System (INIS)

Raieh, M.A.; El-Dessouky, M.M.

1985-01-01

Extraction of lanthanides and actinides were found to be synergetically enhanced by a mixture of bis(2-ethyl hexyl) phosphoric acid (HA) and dinonylnaphthalene sulfonic acid (HD) in aromatic diluents covering a wide range of dielectric constants. The main extracted species is found to be MAsub(2)Hsub(m-1)Dsub(m). Experimental results indicate that the extraxtion mechanism is governed by the extraction of HD in the organic phase. (author)

Phosphoric acid doped polysulfone membranes with aminopyridine pendant groups and imidazole cross-links

DEFF Research Database (Denmark)

Hink, Steffen; Elsøe, Katrine; Cleemann, Lars Nilausen

2015-01-01

Udel polysulfone based membranes with 4-aminopyridine pendant groups and cross-linking imidazole units are synthesized in a simple two step reaction. The ratio of 4-aminopyridine and imidazole is varied and the materials are extensively characterized. The average phosphoric acid uptake (in 85 wt%...

Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

DEFF Research Database (Denmark)

Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf

2018-01-01

Phosphoric acid is the common electrolyte for high-temperature polymer electrolyte fuel cells (HT-PEMFCs) that have advantages such as enhanced CO tolerance and simplified heat and water management. The currently used rotating disk electrode technique is limited to tests in dilute solutions at lo...

Natural Radiation in byproducts of the production of phosphoric acid; Radiacao natural em residuos gerados no processo de producao de acido fosforico

Energy Technology Data Exchange (ETDEWEB)

Silveira, Marcilei A. Guazzelli da; Cardoso, L.L., E-mail: marcilei@fei.edu.br [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil); Medina, N.H. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Institutlo de Fisica

2014-07-01

Natural radiation is the largest source of radiation exposure to which man is subject. It is formed basically by cosmic radiation and the radionuclides present in the Earth crust, as {sup 40}K and the elements of the decay series of {sup 232}Th and {sup 238}U. Phosphate ores, which constitutes the raw material for the production of phosphoric acid, have a high rate of natural radiation from the decay series of {sup 232}Th and {sup 238}U. Phosphogypsum, which is naturally radioactivity, is a by-product of the production of phosphoric acid by the wet method. For each ton of phosphoric acid it is produced about 4.5 tons of phosphogypsum. This work presents the analysis of samples collected in all stages of the manufacturing process of phosphoric acid, which generates the phosphogypsum. Gamma-ray spectrometry was used to measure the concentration of the elements of the decay series of {sup 232}Th and {sup 238}U. All analyzed samples showed a high concentration of radionuclides, promoting the need for further steps in the process in order to reduce the presence of such radionuclides in the phosphogypsum. The results indicate the radionuclide {sup 238}U has higher contribution in some samples of the intermediate stages of the process. All samples exceeded the international average range of human exposure to terrestrial gamma radiation, which is 0.3 to 1.0 mSv/year. (author)

Ferulic acid depletion by cultured soybean seedlings under action of glucose and methionine

Directory of Open Access Journals (Sweden)

Herrig Vanessa

2000-01-01

Full Text Available Cultured soybean seedlings were used to investigate how glucose or methionine influenced depletion of ferulic acid. Three-day-old seedlings were grown in hydroponic solution containing ferulic acid plus glucose or methionine, and the level of the phenolic acid were monitored in the nutrient culture. The results showed that ferulic acid depletion was more rapid in the presence of those compounds. After 6 h, the increase caused by glucose (0.01 and 0.05 mM was more pronounced than methionine in the same concentrations. On the other hand, methionine (0.1 and 0.2 mM increased depletion more significantly than glucose. Results suggested that both compounds might to increase the allelopathic effects of ferulic acid in the seedlings.

A selective glucose sensor: the cooperative effect of monoboronic acid-modified poly(amidoamine) dendrimers.

Science.gov (United States)

Tsai, Ching-Hua; Tang, Yi-Hsuan; Chen, Hui-Ting; Yao, Yi-Wen; Chien, Tun-Cheng; Kao, Chai-Lin

2018-05-01

Selective glucose binding was identified through five generations of monoboronic acid-functionalized PAMAM dendrimers. The best selectivity obtained when using G3 dendrimers (1b) generated 71.1, 94.9, and 1309 times stronger binding than when using galactose, fructose, and lactose, respectively. Further experiments using dendrimer analogues and glucose derivatives suggested that two nearby monoboronic acids cooperatively bound one glucose.

Trans-Fatty Acids Aggravate Obesity, Insulin Resistance and Hepatic Steatosis in C57BL/6 Mice, Possibly by Suppressing the IRS1 Dependent Pathway

Directory of Open Access Journals (Sweden)

Xiaona Zhao

2016-05-01

Full Text Available Trans-fatty acid consumption has been reported as a risk factor for metabolic disorders and targeted organ damages. Nonetheless, little is known about the roles and mechanisms of trans-fatty acids in obesity, insulin resistance (IR and hepatic steatosis. Adult C57BL/6 male mice were fed with four different diets for 20 weeks: normal diet (ND, high fat diet (HFD, low trans-fatty acids diet (LTD and high trans-fatty acid diet (HTD. The diet-induced metabolic disorders were assessed by evaluating body weight, glucose tolerance test, hepatic steatosis and plasma lipid profiles post 20-week diet. Histological (H&E, Oil-Red-O staining and western blot analysis were employed to assess liver steatosis and potential signaling pathways. After 20-weeks of diet, the body weights of the four groups were 29.61 ± 1.89 g (ND, 39.04 ± 4.27 g (HFD, 34.09 ± 2.62 g (LTD and 43.78 ± 4.27 g (HTD (p < 0.05, respectively. HFD intake significantly impaired glucose tolerance, which was impaired further in the mice consuming the HTD diet. The effect was further exacerbated by HTD diet. Moreover, the HTD group exhibited significantly more severe liver steatosis compared with HFD group possibly through regulating adipose triglyceride lipase. The group consuming the HTD also exhibited significantly reduced levels of IRS1, phosphor-PKC and phosphor-AKT. These results support our hypothesis that consumption of a diet high in trans-fatty acids induces higher rates of obesity, IR and hepatic steatosis in male C57BL/6 mice, possibly by suppressing the IRS1dependent pathway.

Nanomolar Caffeic Acid Decreases Glucose Uptake and the Effects of High Glucose in Endothelial Cells.

Directory of Open Access Journals (Sweden)

Lucia Natarelli

Full Text Available Epidemiological studies suggest that moderate and prolonged consumption of coffee is associated with a reduced risk of developing type 2 diabetes but the molecular mechanisms underlying this effect are not known. In this study, we report the effects of physiological concentrations of caffeic acid, easily achievable by normal dietary habits, in endothelial cells cultured in 25 mM of glucose (high glucose, HG. In HG, the presence of 10 nM caffeic acid was associated with a decrease of glucose uptake but not to changes of GLUT-1 membrane localization or mRNA levels. Moreover, caffeic acid countered HG-induced loss of barrier integrity, reducing actin rearrangement and FITC-dextran passage. The decreased flux of glucose associated to caffeic acid affected HG induced apoptosis by down-regulating the expression of initiator (caspase 8 and 9 and effector caspases (caspase 7 and 3 and by increasing the levels of phosphorylated Bcl-2. We also observed that caffeic acid in HG condition was associated to a reduction of p65 subunit nuclear levels with respect to HG alone. NF-κB activation has been shown to lead to apoptosis in HG treated cells and the analysis of the expression of a panel of about 90 genes related to NF-κB signaling pathway revealed that caffeic acid significantly influenced gene expression changes induced by HG. In conclusion, our results suggest that caffeic acid, decreasing the metabolic stress induced by HG, allows the activation of survival mechanisms mediated by a different modulation of NF-κB-related signaling pathways and to the activation of anti-apoptotic proteins.

Ascorbic acid prevents vascular dysfunction induced by oral glucose load in healthy subjects.

Science.gov (United States)

De Marchi, Sergio; Prior, Manlio; Rigoni, Anna; Zecchetto, Sara; Rulfo, Fanny; Arosio, Enrico

2012-01-01

To examine the effects of oral glucose load on forearm circulatory regulation before and after ascorbic acid administration in healthy subjects. Microcirculation study with laser Doppler was performed at the hand in basal conditions, after ischemia and after acetylcholine and nitroprusside; strain gauge plethysmography was performed at basal and after ischemia. The tests were repeated in the same sequence 2 hour after oral administration of glucose (75 g). The subjects were randomised for administration of ascorbic acid (1 g bid) or placebo (sodium bicarbonate 1 g bid) for 10 days. After that, the tests were repeated before and after a new oral glucose load. Blood pressure and heart rate were monitored. Macrocirculatory flux, pressure values and heart rate were unvaried throughout the study. The glucose load caused a reduction in the hyperemic peak flow with laser Doppler and plethysmography; it reduced flux recovery time and hyperemic curve area after ischemia; acetylcholine elicited a minor increase in flux with laser Doppler. The response to nitroprusside was unvaried after glucose load as compared to basal conditions. Treatment with ascorbic acid prevented the decrease in hyperemia after glucose, detected with laser Doppler and plethysmography. Ascorbic acid prevented the decreased response to acetylcholine after glucose, the response to nitroprusside was unaffected by ascorbic acid. Results after placebo were unvaried. Oral glucose load impairs endothelium dependent dilation and hyperaemia at microcirculation, probably via oxidative stress; ascorbic acid can prevent it. Copyright © 2011 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Catalyst evaluation for oxygen reduction reaction in concentrated phosphoric acid at elevated temperatures

Science.gov (United States)

Hu, Yang; Jiang, Yiliang; Jensen, Jens Oluf; Cleemann, Lars N.; Li, Qingfeng

2018-01-01

Phosphoric acid is the common electrolyte for high-temperature polymer electrolyte fuel cells (HT-PEMFCs) that have advantages such as enhanced CO tolerance and simplified heat and water management. The currently used rotating disk electrode technique is limited to tests in dilute solutions at low temperatures and hence is not suitable for catalyst evaluation for HT-PEMFCs. In this study, we have designed and constructed a half-cell setup to measure the intrinsic activities of catalysts towards the oxygen reduction reaction (ORR) in conditions close to HT-PEMFC cathodes. By optimization of the hydrophobic characteristics of electrodes and the catalyst layer thickness, ORR activities of typical Pt/C catalysts are successfully measured in concentrated phosphoric acid at temperatures above 100 °C. In terms of mass-specific activities, the catalyst exhibits about two times higher activity in the half-cell electrode than that observed in fuel cells, indicating the feasibility of the technique as well as the potential for further improvement of fuel cell electrode performance.

The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis

Science.gov (United States)

Aldersley, Michael Frank; Joshi, Prakash C.; Huang, Yixing

2017-09-01

The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

Phosphoric acid doped imidazolium polysulfone membranes for high temperature proton exchange membrane fuel cells

DEFF Research Database (Denmark)

Yang, Jingshuai; Li, Qingfeng; Jensen, Jens Oluf

2012-01-01

A novel acid–base polymer membrane is prepared by doping of imidazolium polysulfone with phosphoric acid for high temperature proton exchange membrane fuel cells. Polysulfone is first chloromethylated, followed by functionalization of the chloromethylated polysulfone with alkyl imidazoles i.e. me...

A contribution to the study of mass transfer: uranium extraction from phosphoric acid

International Nuclear Information System (INIS)

Maher, A.

1985-12-01

Liquid-liquid extraction of uranium (VI) contained in phosphoric acid is examined. Synergism and thermodynamical equilibria are studied. Influence of drop size, extractant concentration and temperature on reaction kinetics are determined. The experimental study concerns extraction by HDEHP, TOPO and the mixture of both. Reaction mechanisms are interpreted [fr

Interfacial characteristics of an epoxy composite reinforced with phosphoric acid-functionalized Kevlar fibers

Science.gov (United States)

Li, J.; Xia, Y. C.

2010-07-01

A Kevlar fiber was functionalized with the phosphoric acid (PA) of different concentrations. The surface characteristics of the fiber were examined by using the X-ray photoelectron spectroscopy. It was found that the PA functionalization considerably increased the bond strength between the Kevlar fiber and an epoxy matrix.

Pyroelectric properties of phosphoric acid-doped TGS single crystals

International Nuclear Information System (INIS)

Saxena, Aparna; Fahim, M; Gupta, Vinay; Sreenivas, K

2003-01-01

Pyroelectric properties of phosphoric acid (H 3 PO 4 )-doped triglycine sulfate (TGSP) single crystals grown from solutions containing 0.1-0.5 mol of H 3 PO 4 have been studied. Incorporation of H 3 PO 4 into the crystal lattice is found to induce an internal bias field (E b ) and is observed through the presence of a sustained polarization and pyroelectricity beyond the transition temperature. The internal bias field has been estimated theoretically by fitting the experimentally measured data on temperature dependence of the pyroelectric coefficient (λ), dielectric constant (ε') and polarization (P). A high E b value in the range 9 x 10 3 -15.5 x 10 4 V m -1 is obtained for crystals grown with 0.1-0.5 mol of H 3 PO 4 in the solution, and a specific concentration of 0.2-0.25 mol of H 3 PO 4 in the solution during crystal growth is found to be optimum for a high figure of merit for detectivity, F d = 428 μC m -2 K -1

Extraction of uranium from wet process phosphoric acid in centrifugal and mixer-settler batteries

International Nuclear Information System (INIS)

Poczynajlo, A.; Giers, M.

1986-01-01

Five stage countercurrent batteries were comparatively applied for the extraction of uranium from wet phosphoric acid (Chemical Works, Police) in semitechnical scale. As an extractant phase the 0.16 M equimolar solution of mono- and dinonylphenyolphosphoric acids in kerosene was used. The optimum hydrodynamic and extraction conditions for the batteries were found. Process efficiencies of the apparatus were also determined. 5 refs., 5 figs., 2 tabs. (author)

Polymeric supported sorbents for decreasing hazardous metal ions content in wet process phosphoric acid

International Nuclear Information System (INIS)

El-Zahhar, A.A.; El-Naggar, H.A.; Ahmed, M.

2005-01-01

Procedure for preparation of polymeric supported silica, and their usage for decreasing hazardous metal ion content in wet process phosphoric acid was developed. The procedure is based firstly on extraction silica from rice straw by alkaline treatment , secondly supporting the produced silica on binding polyacrylonitrile (PAN). The produced polymer based sorbent was used for decreasing hazardous metal ions (especially iron) present as inorganic impurities in crud Egyptian phosphoric acid (green acid). Different factors affecting the sorption equilibrium ( contact time, temperature , sorbent mass and batch factor ) were studied. Studying the sorption isotherm revealed that the adsorption data could favorably fit the Langmuir adsorption isotherm. In the dynamic study , the sorption capacity at (Cξ/Cο = 50%) was found to be 28.5 mg/g and the loaded column could be regenerated using 50ml of 0.15 M HNO 3 . The regenerated column could undergo sorption regeneration cycles up to four cycles without significant decrease in the sorption capacity , weight loss or change in the physical properties of the sorbent

Tensile bond strength and SEM analysis of enamel etched with Er:YAG laser and phosphoric acid: a comparative study in vitro

International Nuclear Information System (INIS)

Sasaki, Luis H.; Tanaka, Celso Shin-Ite; Lobo, Paulo D.C.; Villaverde, Antonio B.; Moriyama, Eduardo H.; Brugnera Junior, Aldo; Moriyama, Yumi; Watanabe, Ii-Sei

2008-01-01

Er:YAG laser has been studied as a potential tool for restorative dentistry due to its ability to selectively remove oral hard tissue with minimal or no thermal damage to the surrounding tissues. The purpose of this study was to evaluate in vitro the tensile bond strength (TBS) of an adhesive/composite resin system to human enamel surfaces treated with 37% phosphoric acid, Er:YAG laser (λ=2.94 μm) with a total energy of 16 J (80 mJ/pulse, 2Hz, 200 pulses, 250 ms pulse width), and Er:YAG laser followed by phosphoric acid etching. Analysis of the treated surfaces was performed by scanning electron microscopy (SEM) to assess morphological differences among the groups. TBS means (in MPa) were as follows: Er:YAG laser + acid (11.7 MPa) > acid (8.2 MPa) > Er:YAG laser (6.1 MPa), with the group treated with laser+acid being significantly from the other groups (p=0.0006 and p= 0.00019, respectively). The groups treated with acid alone and laser alone were significantly different from each other (p=0.0003). The SEM analysis revealed morphological changes that corroborate the TBS results, suggesting that the differences in TBS means among the groups are related to the different etching patterns produced by each type of surface treatment. The findings of this study indicate that the association between Er:YAG laser and phosphoric acid can be used as a valuable resource to increase bond strength to laser-prepared enamel. (author)

Comparison of palmitic acid kinetics during glucose or ketone body infusions

Energy Technology Data Exchange (ETDEWEB)

Birkhahn, R.H.; Block, D.J.; Birkhahn, G.C.; Thomford, N.R.

1986-03-05

Ketone body interactions can be observed for extended ketosis by infusion by monoacetoacetin (the monoglyceride of acetoacetic acid). Palmitic acid kinetics were compared on the 5th day of glucose or ketone body-glucose infusions. 20 rats were fed complete diets intravenously at the rate of 50 ml/day. All diets contained vitamins, trace minerals, electrolytes, amino acids and 1 kcal/ml of non-protein energy. Rats were divided by energy source: Group A (n = 10) received energy from glucose and Group B (n = 10) from 72% monoacetoacetin plus 28% glucose. Diets were given at 1/2 and 3/4 rats on days 1 and 2, respectively and at full rate for days 3-5. Urinary nitrogen losses, body weight and dietary intake were measured daily. Palmitate kinetics was measured on day 5 using a continuous infusion of (1-/sup 14/C) palmitate and measuring C-14 in breath and plasma and plasma palmitate by GC. The two groups had similar body weight changes and urinary nitrogen losses over the 3 days of full intake Group A had lower plasma palmitate (88 +/- 7 vs 105 +/- 6 micromol/l) but similar turnover (17.1 +/- 2.4 vs 15.0 +/- 1.9 mmol/hr) and oxidation 2.3 +/- 0.3 vs 2.2 +/- 0.05 mmol/hr) compared to Group B. These data show that feeding monoacetoacetin intravenously does not stimulate fatty acid metabolism in the well nourished rat.

Comparison of palmitic acid kinetics during glucose or ketone body infusions

International Nuclear Information System (INIS)

Birkhahn, R.H.; Block, D.J.; Birkhahn, G.C.; Thomford, N.R.

1986-01-01

Ketone body interactions can be observed for extended ketosis by infusion by monoacetoacetin (the monoglyceride of acetoacetic acid). Palmitic acid kinetics were compared on the 5th day of glucose or ketone body-glucose infusions. 20 rats were fed complete diets intravenously at the rate of 50 ml/day. All diets contained vitamins, trace minerals, electrolytes, amino acids and 1 kcal/ml of non-protein energy. Rats were divided by energy source: Group A (n = 10) received energy from glucose and Group B (n = 10) from 72% monoacetoacetin plus 28% glucose. Diets were given at 1/2 and 3/4 rats on days 1 and 2, respectively and at full rate for days 3-5. Urinary nitrogen losses, body weight and dietary intake were measured daily. Palmitate kinetics was measured on day 5 using a continuous infusion of [1- 14 C] palmitate and measuring C-14 in breath and plasma and plasma palmitate by GC. The two groups had similar body weight changes and urinary nitrogen losses over the 3 days of full intake Group A had lower plasma palmitate (88 +/- 7 vs 105 +/- 6 micromol/l) but similar turnover (17.1 +/- 2.4 vs 15.0 +/- 1.9 mmol/hr) and oxidation 2.3 +/- 0.3 vs 2.2 +/- 0.05 mmol/hr) compared to Group B. These data show that feeding monoacetoacetin intravenously does not stimulate fatty acid metabolism in the well nourished rat

Manual of phosphoric acid fuel cell power plant cost model and computer program

Science.gov (United States)

Lu, C. Y.; Alkasab, K. A.

1984-01-01

Cost analysis of phosphoric acid fuel cell power plant includes two parts: a method for estimation of system capital costs, and an economic analysis which determines the levelized annual cost of operating the system used in the capital cost estimation. A FORTRAN computer has been developed for this cost analysis.

Liquid-liquid extraction of uranium from Egyptian phosphoric acid using a synergistic D2EHPA-DBBP mixture

International Nuclear Information System (INIS)

Abdel-Khalek, A.A.

2011-01-01

Extraction of uranium from Egyptian phosphoric acid with synergistic mixture of di-2-ethylhexylphosphoric acid (D2EHPA) and di-butyl butyl phosphonate (DBBP) is reported in this paper. The influence of various factors such as D2EHPA concentration, DBBP concentration, phosphoric acid concentration, contact time, aqueous: organic phase's ratio (aq:org) and temperature on the degree of extraction has been established. The data on the effect of temperature on the extraction showed that the enthalpy change is -23.12 kJ/mol. Uranium extracted by D2EHPA- DBBP is further subjected to a second cycle of extraction and scrubbing impurities. The uranium is finally converted to a high purity UO 3 product using precipitation with hydrogen peroxide and heat treatment at 375 deg C. (author)

On the fractionation of natural radioactivity in the production of phosphoric acid by the wet acid method

International Nuclear Information System (INIS)

Bolivar, J.P.; Garcia-Tenorio, R.; Garcia-Leon, M.

1996-01-01

The fractionation of different natural radionuclides (U-isotopes, 226 Ra and 210 Po) in the process used for the production of phosphoric acid in some factories located in the south-west of Spain is analyzed. As a consequence, different ways of natural radionuclide liberation to the environment can be evaluated due to these industrial activities. (author). 9 refs., 2 figs., 3 tabs

A glucose-responsive pH-switchable bioelectrocatalytic sensor based on phenylboronic acid-diol specificity

International Nuclear Information System (INIS)

Gao, Peiyi; Wang, Zhihua; Yang, Lele; Ma, Tengfei; Yang, Ling; Guo, Qianqiong; Huang, Shasheng

2015-01-01

Graphical abstract: A pH-switchable bioelectrocatayltic sensor was developed, which exhibited an obvious anodic current in acidic conditions as “ON” state, yet a prohibited signal in alkaline conditions as “OFF” state. With the change of pH and/or the presence of glucose, our proposed biosensor produced the corresponding amplified signal, providing a better sensitivity. - Abstract: Aminophenylboronic acid moieties were covalently grafted onto mercaptobenzoic acid moieties, and glucose oxidase was then immobilized through boronic acid-diol specific recognition to form a pH-sensitive electrosensor switching between pH 5.8 and pH 8.0 base solution. Using potassium ferricyanide as electroactive probe, the response was intensified in acidic condition while hindered in alkaline condition. The sharp and stable contrast in current was performed alternately upon the change of pH like a “pH switch”. In the presence of glucose, the response to glucose was further amplified catalytically by glucose oxidase on “ON” state, while electron transfer was inhibited on “OFF” state. Furthermore, when our sensor was on “ON” state, it showed a good linearity ranging from 0 to 30 μmol L −1 of glucose, with a detection limit of 348 nmol L −1 (S/B = 3) and a dynamic range extending to 50 μmol L −1 . Glucose-responsive, pH-switchable and catalytically-amplified, our biosensor provided a new method for the detection of glucose in the form of pH switch in human serum sample, and was promising to more complicated environment

Passivation behaviour of stainless steel (UNS N-08028) in industrial or simplified phosphoric acid solutions at different temperatures

International Nuclear Information System (INIS)

Ben Salah, M.; Sabot, R.; Refait, Ph.; Liascukiene, I.; Méthivier, C.; Landoulsi, J.; Dhouibi, L.

2015-01-01

Highlights: • Industrial phosphoric acid is less aggressive than simulated industrial acid. • Polyphosphate film in Industrial acid is reinforced by calcium and sulfate. • Passive film thickness is obtained by the power law model from EIS measurements. • Passive film of Sanicro28 becomes more resistive towards corrosion with exposure time in industrial acid. • XPS measurements coupled to Raman spectroscopy reveal the corrosion products formed in simulated acid. - Abstract: The corrosion behaviour of Sanicro28, in industrial phosphoric acid and simplified solution of pure H_3PO_4 containing sulphates and chlorides, is investigated during 48 h between 20 and 80 °C. Results show higher corrosion resistance in the industrial medium. Film thickness evaluated by EIS remains constant in industrial acid due to polyphosphate that promotes crystallisation of the Cr_2O_3 inner layer. Conversely, the passive film is partially destroyed at 80 °C in simplified acid. XPS and Raman analysis show that phosphate and molybdenum are both present in the passive film and in corrosion products. The role of Ca present in the industrial acid is discussed.

Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line

Energy Technology Data Exchange (ETDEWEB)

Zhang, Leshuai W.; McMahon Tobin, Grainne A.; Rouse, Rodney L., E-mail: rodney.rouse@fda.hhs.gov

2012-10-15

The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in “on-target” RIN-5mF (islet) cells as well as in “off-target” AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4 mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-L-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment. -- Highlights: ► Exenatide did not inhibit islet, acinar or ductal cell proliferation. ► GLP1R protein decreased after glucose stimulation in oleic acid-treated ductal cells. ► Oleic acid treatment altered localization of GLP1R with early and recycling

Oleic acid and glucose regulate glucagon-like peptide 1 receptor expression in a rat pancreatic ductal cell line

International Nuclear Information System (INIS)

Zhang, Leshuai W.; McMahon Tobin, Grainne A.; Rouse, Rodney L.

2012-01-01

The glucagon-like peptide 1 receptor (GLP1R) plays a critical role in glucose metabolism and has become an important target for a growing class of drugs designed to treat type 2 diabetes. In vitro studies were designed to investigate the effect of the GLP1R agonist, exenatide (Ex4), in “on-target” RIN-5mF (islet) cells as well as in “off-target” AR42J (acinar) and DSL-6A/C1 (ductal) cells in a diabetic environment. Ex4 increased islet cell proliferation but did not affect acinar cells or ductal cells at relevant concentrations. A high caloric, high fat diet is a risk factor for impaired glucose tolerance and type-2 diabetes. An in vitro Oleic acid (OA) model was used to investigate the effect of Ex4 in a high calorie, high fat environment. At 0.1 and 0.4 mM, OA mildly decreased the proliferation of all pancreatic cell types. Ex4 did not potentiate the inhibitory effect of OA on cell proliferation. Akt phosphorylation in response to Ex4 was diminished in OA-treated ductal cells. GLP1R protein detected by western blot was time and concentration dependently decreased after glucose stimulation in OA-treated ductal cells. In ductal cells, OA treatment altered the intracellular localization of GLP1R and its co-localization with early endosome and recycling endosomes. Chloroquine (lysosomal inhibitor), N-acetyl-L-cysteine (reactive oxygen species scavenger) and wortmannin (a phosphatidylinositol-3-kinase inhibitor), fully or partially, rescued GLP1R protein in OA-pretreated, glucose-stimulated ductal cells. The impact of altered regulation on phenotype/function is presently unknown. However, these data suggest that GLP1R regulation in ductal cells can be altered by a high fat, high calorie environment. -- Highlights: ► Exenatide did not inhibit islet, acinar or ductal cell proliferation. ► GLP1R protein decreased after glucose stimulation in oleic acid-treated ductal cells. ► Oleic acid treatment altered localization of GLP1R with early and recycling

The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis.

Science.gov (United States)

Aldersley, Michael Frank; Joshi, Prakash C; Huang, Yixing

2017-09-01

The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

Fatty acid and amino acid modulation of glucose cycling in isolated rat hepatocytes

NARCIS (Netherlands)

Gustafson, LA; Neeft, M; Reijngoud, DJ; Kuipers, F; Sauerwein, HP; Romijn, JA; Herling, AW; Burger, HJ; Meijer, AJ

2001-01-01

We studied the influence of glucose/glucose 6-phosphate cycling on glycogen deposition from glucose in fasted-rat hepatocytes using S4048 and CP320626, specific inhibitors of glucose-6-phosphate translocase and glycogen phosphorylase respectively. The effect of amino acids and oleate was also

Molecular cloning and characterization of glucose transporter 1 ...

African Journals Online (AJOL)

Glucose transporter type-1 (glut1) and citrate synthase plays crucial role in glucose transport and regulation of tricarboxylic acid cycle (TCA) cycle in mammalian energy metabolism. The present study was aimed to clone and characterize glut1 and citrate synthase cDNA in water buffalo (Bubalus bubalis). Total of 90 ...

Heteropoly acid catalyzed hydrolysis of glycogen to glucose

International Nuclear Information System (INIS)

Klein, Miri; Pulidindi, Indra Neel; Perkas, Nina; Gedanken, Aharon

2015-01-01

Complete conversion of glycogen to glucose is achieved by using H 3 PW 12 O 40 ·nH 2 O (HPW) and H 4 SiW 12 O 40 ·nH 2 O (HSiW) as catalysts for the hydrolysis under optimized hydrothermal conditions (mass fraction of catalyst 2.4%, 373 K and 2 h reaction time). The reusability of the catalyst (HPW) was demonstrated. In addition to carrying out the glycogen hydrolysis in an autoclave, other novel methods such as microwave irradiation and sonication have also been investigated. At higher mass fraction of the heteropoly acids (10.5%), glycogen could be completely converted to glucose under microwave irradiation. Sonication of an aqueous solution of glycogen in the presence of HPW and HSiW also yielded glucose. Thus, heteropoly acids are efficient, environmentally friendly and reusable catalysts for the conversion of glycogen to glucose. - Highlights: • Hydrothermal, microwave and sonication based methods of hydrolysis. • Heteropoly acids are green catalysts for glycogen hydrolysis. • Glycogen from cyanobacteria is demonstrated as a potential feedstock for glucose

A metabolic switch in brain: glucose and lactate metabolism modulation by ascorbic acid.

Science.gov (United States)

Castro, Maite A; Beltrán, Felipe A; Brauchi, Sebastián; Concha, Ilona I

2009-07-01

In this review, we discuss a novel function of ascorbic acid in brain energetics. It has been proposed that during glutamatergic synaptic activity neurons preferably consume lactate released from glia. The key to this energetic coupling is the metabolic activation that occurs in astrocytes by glutamate and an increase in extracellular [K(+)]. Neurons are cells well equipped to consume glucose because they express glucose transporters and glycolytic and tricarboxylic acid cycle enzymes. Moreover, neuronal cells express monocarboxylate transporters and lactate dehydrogenase isoenzyme 1, which is inhibited by pyruvate. As glycolysis produces an increase in pyruvate concentration and a decrease in NAD(+)/NADH, lactate and glucose consumption are not viable at the same time. In this context, we discuss ascorbic acid participation as a metabolic switch modulating neuronal metabolism between rest and activation periods. Ascorbic acid is highly concentrated in CNS. Glutamate stimulates ascorbic acid release from astrocytes. Ascorbic acid entry into neurons and within the cell can inhibit glucose consumption and stimulate lactate transport. For this switch to occur, an ascorbic acid flow is necessary between astrocytes and neurons, which is driven by neural activity and is part of vitamin C recycling. Here, we review the role of glucose and lactate as metabolic substrates and the modulation of neuronal metabolism by ascorbic acid.

PEM steam electrolysis at 130 °C using a phosphoric acid doped short side chain PFSA membrane

DEFF Research Database (Denmark)

Hansen, Martin Kalmar; Aili, David; Christensen, Erik

2012-01-01

Steam electrolysis test with a phosphoric acid doped Aquivion™ membrane was successfully conducted and current densities up to 775 mA cm-2 at 1.8 V was reached at 130 ºC and ambient pressure. A new composite membrane system using a perfluorosulfonic acid membrane (Aquivion™) as matrix and phospho...... implied that a new and highly corrosion resistant construction material was needed. Tantalum coated stainless steel felt was tested and found suitable as the anode gas diffusion layer. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved....

Study of the interference of uranium, vanadium, aluminium and molebdenum in the determination of FeII, FeIII in Syrian phosphoric acid by spectrophotometry

International Nuclear Information System (INIS)

Zaizafoun, Ghadir; Elian, Nazha

1991-04-01

The spectrophotometric determination of the ratio of iron I I to iron I II in crude phosphoric acid is of great importance because of its influence on the redox potential in the different stages which lead to the extraction of uranium from crude phosphoric acid. The suitability of a number of reagents for this determination was examined and only 1,10-phenanthroline, 5-sulfosalicylic acid and 2,2'-bipyridine were selected for further experimentation. 1-10-phenanthroline can give a deep red complex with Fe I I, in phosphoric acid medium at PH 4-6, absorbs at λ = 510 nm. The total iron was determined by reducing Fe I II to Fe I I using hydroxylamine hydrochloride. The second reagent was found capable of forming a yellow complex absorbs light at λ = 430 nm in amonia medium at PH 8.5 - 11 with Fe I II. The adopted procedure was to determine total iron first by oxidation with nitric acid. Then iron I I was determined in a second test at PH 1.5 and at λ = 500 nm. The third reagent i.e. 2-2' bipyridine is capable of forming a red complex with iron I I absorbs at λ = 522 nm. The interference of U, V, Al, and Mo was investigated. These elements were selected because of their presence in considerable amounts in Syrian commercial phosphoric acid. The work was designed so that the effect of the presence of each element as well as the presence of all possible combinations of these elements can be estimated. The investigation revealed that the interference is very high in the case of 2-2' bipyridine in addition to the instability of the complex. In the case of 1,10-phenanthroline the interference was also found high. Thus these two reagents were disregarded. The 5-sulfosalicylic reagent was found satisfactory when determining iron I II, However when Fe I I is considered the error resulting from interference ranges between 17.5 - 50%. This error was found very dependent on the PH of the medium and further work is in progress in order to lower the value of interferences

Hydroxycitric acid delays intestinal glucose absorption in rats

NARCIS (Netherlands)

Wielinga, PY; Wachters-Hagedoorn, RE; Bouter, B; van Dijk, TH; Stellaard, F; Nieuwenhuizen, AG; Verkade, HJ; Scheurink, AJW; Nieuwenhuizen, Arie G.; Verkade, Henkjan J.

In this study, we investigated in rats if hydroxycitric acid (HCA) reduces the postprandial glucose response by affecting gastric emptying or intestinal glucose absorption. We compared the effect of regulator HCA (310 mg/kg) and vehicle (control) on the glucose response after an intragastric or

Mechanocatalytic Production of Lactic Acid from Glucose by Ball Milling

Directory of Open Access Journals (Sweden)

Luyang Li

2017-06-01

Full Text Available A solvent-free process was developed for the direct production of lactic acid from glucose in a mechanocatalytic process in the presence of Ba(OH2, and a moderate lactic acid yield of 35.6% was obtained. Glucose conversion and lactic acid formation were favorable at higher catalyst/glucose mass ratios. However, at relatively lower catalyst/glucose mass ratios, they were greatly inhibited, and the promotion of fructose formation was observed. The mechanocatalytic process was applicable for various carbohydrates such as C5 sugars, C6 sugars, and disaccharides with 20–36% lactic acid yields achieved. This work provides a new pathway for the production of value-added chemicals from biomass resources.

Separation of uranium from molybdenum by alkyl phosphoric acid extraction

Energy Technology Data Exchange (ETDEWEB)

Zhongshi, Li

1986-08-01

The regularities of separation of uranium from molybdenum by alkyl phosphoric acid extraction are described. Two parameters, i.e., density ratio of uranium to molybdenum in organic phase at first stage and density of uranium in raffinate at last stage are presented. The relationship between these parameters and purity of molybdenum and uranium products is given. The method of adjusting and controlling these parameters in experiments and production is worked out. The technical key problem in comprehensive utilization of sedimentary type uranium ore containing molybdenum with close concentration of these to elements has been solved.

Potential radiological impacts of recovery of uranium from wet-process phosphoric acid. Final report to the Environmental Protection Agency

International Nuclear Information System (INIS)

Davis, W. Jr.; Haywood, F.F.; Danek, J.L.; Moore, R.E.; Wagner, E.B.; Rupp, E.M.

1979-01-01

A study was made to determine the radiological impacts associated with recovery of uranium from wet-process (WP) phosphoric acid in central Florida. Removal of U and other radionuclides from phosphoric acid prevents their distribution on farm lands and urban gardens and grasses via fertilizers; this results in a positive impact (decreased dose commitment) on the associated populations. This study considers the potential negative impacts of current and project recovery processes in a site-specific manner using detailed state-of-the-art methodologies. Positive impacts are treated in a generic sense using U.S. average values for important variables such as average and maximum fertilizer application rates and quantities of radionuclides in fertilizer. Three model plants to recover U from WP phosphoric acid were selected and source terms for release of radionuclides are developed for all three and for two treatment methods for airborne particulates. Costs for radwaste treatment were developed. Field measurements were conducted at the only commercial uranium recovery plant in operation. Radiological doses to the population surrounding release points during plant operation were estimated

Trans-Fatty Acids Aggravate Obesity, Insulin Resistance and Hepatic Steatosis in C57BL/6 Mice, Possibly by Suppressing the IRS1 Dependent Pathway.

Science.gov (United States)

Zhao, Xiaona; Shen, Cheng; Zhu, Hong; Wang, Cong; Liu, Xiangwei; Sun, Xiaolei; Han, Shasha; Wang, Peng; Dong, Zhen; Ma, Xin; Hu, Kai; Sun, Aijun; Ge, Junbo

2016-05-30

Trans-fatty acid consumption has been reported as a risk factor for metabolic disorders and targeted organ damages. Nonetheless, little is known about the roles and mechanisms of trans-fatty acids in obesity, insulin resistance (IR) and hepatic steatosis. Adult C57BL/6 male mice were fed with four different diets for 20 weeks: normal diet (ND), high fat diet (HFD), low trans-fatty acids diet (LTD) and high trans-fatty acid diet (HTD). The diet-induced metabolic disorders were assessed by evaluating body weight, glucose tolerance test, hepatic steatosis and plasma lipid profiles post 20-week diet. Histological (H&E, Oil-Red-O) staining and western blot analysis were employed to assess liver steatosis and potential signaling pathways. After 20-weeks of diet, the body weights of the four groups were 29.61 ± 1.89 g (ND), 39.04 ± 4.27 g (HFD), 34.09 ± 2.62 g (LTD) and 43.78 ± 4.27 g (HTD) (p steatosis compared with HFD group possibly through regulating adipose triglyceride lipase. The group consuming the HTD also exhibited significantly reduced levels of IRS1, phosphor-PKC and phosphor-AKT. These results support our hypothesis that consumption of a diet high in trans-fatty acids induces higher rates of obesity, IR and hepatic steatosis in male C57BL/6 mice, possibly by suppressing the IRS1dependent pathway.

Phosphoric acid as a matrix additive for MALDI MS analysis of phosphopeptides and phosphoproteins

DEFF Research Database (Denmark)

Kjellström, Sven; Jensen, Ole Nørregaard

2004-01-01

Phosphopeptides are often detected with low efficiency by MALDI MS analysis of peptide mixtures. In an effort to improve the phosphopeptide ion response in MALDI MS, we investigated the effects of adding low concentrations of organic and inorganic acids during peptide sample preparation in 2,5-di...... acid to 2,5-DHB were also observed in LC-MALDI-MS analysis of tryptic phosphopeptides of B. subtilis PrkC phosphoprotein. Finally, the mass resolution of MALDI mass spectra of intact proteins was significantly improved by using phosphoric acid in 2,5-DHB matrix....

Pyroelectric properties of phosphoric acid-doped TGS single crystals

Energy Technology Data Exchange (ETDEWEB)

Saxena, Aparna; Fahim, M; Gupta, Vinay; Sreenivas, K [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2003-12-21

Pyroelectric properties of phosphoric acid (H{sub 3}PO{sub 4})-doped triglycine sulfate (TGSP) single crystals grown from solutions containing 0.1-0.5 mol of H{sub 3}PO{sub 4} have been studied. Incorporation of H{sub 3}PO{sub 4} into the crystal lattice is found to induce an internal bias field (E{sub b}) and is observed through the presence of a sustained polarization and pyroelectricity beyond the transition temperature. The internal bias field has been estimated theoretically by fitting the experimentally measured data on temperature dependence of the pyroelectric coefficient ({lambda}), dielectric constant ({epsilon}') and polarization (P). A high E{sub b} value in the range 9 x 10{sup 3}-15.5 x 10{sup 4} V m{sup -1} is obtained for crystals grown with 0.1-0.5 mol of H{sub 3}PO{sub 4} in the solution, and a specific concentration of 0.2-0.25 mol of H{sub 3}PO{sub 4} in the solution during crystal growth is found to be optimum for a high figure of merit for detectivity, F{sub d} = 428 {mu}C m{sup -2} K{sup -1}.

Process for recovering uranium from wet process phosphoric acid

International Nuclear Information System (INIS)

Pyrih, R.Z.; Rickard, S.; Carrington, F.

1982-01-01

A process for recovering uranium from phosphoric acid solutions uses an acidified alkali metal carbonate solution for the second-stage strip of uranyl uranium from the ion-exchange solution. The stripped solution is then recycled to the ion-exchange circuit. In the first stripping stage the ion-exchange solution containing the recovered uranyl uranium and an inert organic diluent is stripped with ammonium carbonate, producing a slurry of ammonium uranyl tricarbonate. The second strip, with a solution of 50-200 grams per litre of sodium carbonate eliminates the problems of inadequate removal of phosphorus, iron and vanadium impurities, solids accumulation, and phase separation in the strip circuit

Glucagon-like peptide-1 reduces contractile function and fails to boost glucose utilization in normal hearts in the presence of fatty acids.

Science.gov (United States)

Nguyen, T Dung; Shingu, Yasushige; Amorim, Paulo A; Schwarzer, Michael; Doenst, Torsten

2013-10-09

GLP-1 and exendin-4, which are used as insulin sensitizers or weight reducing drugs, were shown to improve glucose uptake in the heart. However, the direct effects of GLP-1 or exendin-4 on normal hearts in the presence of fatty acids, the main cardiac substrates, have never been investigated. We therefore assessed the effects of GLP-1 or exendin-4 on myocardial glucose uptake (GU), glucose oxidation (GO) and cardiac performance (CP) under conditions of fatty acid utilization. Rat hearts were perfused with only glucose (5 mM) or glucose (5 mM) plus oleate (0.4 mM) as substrates for 60 min. After 30 min, GLP-1 or exendin-4 (0.5 nM or 5 nM) was added. In the absence of oleate, GLP-1 increased both GU and GO. Exendin-4 increased GO but showed no effect on GU. Neither GLP-1 nor exendin-4 affected CP. However, when oleate was present, GLP-1 failed to stimulate glucose utilization and exendin-4 even decreased GU. Furthermore, now GLP-1 reduced CP. In contrast to prior reports, this negative inotropic effect could not be blocked by the protein kinase A inhibitor H-89. We then measured myocardial GO and CP in rats receiving a 4-week GLP-1 infusion. Interestingly, this chronic treatment resulted in a significant reduction in both GO and CP. Under the influence of oleate, GLP-1 reduces contractile function and fails to stimulate glucose utilization in normal hearts. Exendin-4 may acutely reduce cardiac glucose uptake but not contractility. We suggest advanced investigation of heart function and metabolism in patients treating with these peptides. © 2013.

Behaviors of glucose decomposition during acid-catalyzed hydrothermal hydrolysis of pretreated Gelidium amansii.

Science.gov (United States)

Jeong, Tae Su; Choi, Chang Ho; Lee, Ji Ye; Oh, Kyeong Keun

2012-07-01

Acid-catalyzed hydrothermal hydrolysis is one path to cellulosic glucose and subsequently to its dehydration end products such as hydroxymethyl furfural (HMF), formic acid and levulinic acid. The effect of sugar decomposition not only lowers the yield of fermentable sugars but also forms decomposition products that inhibit subsequent fermentation. The present experiments were conducted with four different acid catalysts (H(2)SO(4), HNO(3), HCl, and H(3)PO(4)) at various acid normalities (0.5-2.1N) in batch reactors at 180-210 °C. From the results, H(2)SO(4) was the most suitable catalyst for glucose production, but glucose decomposition occurred during the hydrolysis. The glucose production was maximized at 160.7 °C, 2.0% (w/v) H(2)SO(4), and 40 min, but resulted in a low glucan yield of 33.05% due to the decomposition reactions, which generated formic acid and levulinic acid. The highest concentration of levulinic acid, 7.82 g/L, was obtained at 181.2 °C, 2.0% (w/v) H(2)SO(4), and 40 min. Copyright © 2012 Elsevier Ltd. All rights reserved.

Brewer’s Spent Grain Valorization Using Phosphoric Acid Pretreatment for Second Generation Bioethanol Production

DEFF Research Database (Denmark)

Romero, I.; Ruiz, E.; Cara, C.

the effect of phosphoric acid concentration (2-6% w/v) and pretreatment temperature (140-180ºC). The influence of these factors on the hemicellulosic sugar solubilisation and the subsequent enzymatic hydrolysis was evaluated. Optimal pretreatment conditions were determined by maximizing both...... hemicellulosic sugar recovery in liquids and enzymatic hydrolysis yield....

Liquid-liquid extraction for purification of wet process phosphoric acid

International Nuclear Information System (INIS)

Lotfollahi, Mohammad Nader; Bakshi, Mahdi

2006-01-01

The Wet Process Phosphoric Acid (WPA) is used to produce fertilizers and alimentary supplies for cattle. In each of these applications, the impurities contained in acid must be in standard range. In this paper purification of WPA by solvent extraction is performed and the effect of the mass ratio of solvent to feed on extraction efficiency is studied. The working solvents are Methyl Iso Butyl Ketone (MIBK), Iso Amyl Alcohol (IAA) and the mixture of them. The results show that the IAA is better than other solvents in extraction of WPA. This solvent can extract 82.2% of acid after two extraction stages but MIBK can extract only 73.5% of acid after three extraction stages. For all of these solvents, the Pb and Cd concentrations go down to trace. The experimental results show that the maximum separation of Mg with MIBK is 87.5% which occurs at the mass ratio of solvent to feed eual to 4. In the case of IAA solvent the percent is 91.7% and the ratio is 8

Effect of Reduced Phosphoric Acid Pre-etching Times 
on Enamel Surface Characteristics and Shear Fatigue Strength Using Universal Adhesives.

Science.gov (United States)

Tsujimoto, Akimasa; Fischer, Nicholas; Barkmeier, Wayne; Baruth, Andrew; Takamizawa, Toshiki; Latta, Mark; Miyazaki, Masashi

2017-01-01

To examine the effect of reduced phosphoric acid pre-etching times on enamel fatigue bond strength of universal adhesives and surface characteristics by using atomic force microscopy (AFM). Three universal adhesives were used in this study (Clearfil Universal Bond [C], G-Premio Bond [GP], Scotchbond Universal Adhesive [SU]). Four pre-etching groups were employed: enamel pre-etched with phosphoric acid and immediately rinsed with an air-water spray, and enamel pre-etched with phosphoric acid for 5, 10, or 15 s. Ground enamel was used as the control group. For the initial bond strength test, 15 specimens per etching group for each adhesive were used. For the shear fatigue test, 20 specimens per etching group for each adhesive were loaded using a sine wave at a frequency of 20 Hz for 50,000 cycles or until failure occurred. Initial shear bond strengths and fatigue shear strengths of composite adhesively bonded to ground and pre-etched enamel were determined. AFM observations of ground and pre-etched enamel were also conducted, and surface roughness as well as surface area were evaluated. The initial shear bond strengths and fatigue shear strengths of the universal adhesives in the pre-etched groups were significantly higher than those of the control group, and were not influenced by the pre-etching time. Significantly higher surface roughness and surface area of enamel surfaces in pre-etched groups were observed compared with those in the control group. While the surface area was not significantly influenced by etching time, surface roughness of the enamel surfaces in the pre-etched groups significantly increased with pre-etching time. The results of this in vitro study suggest that reduced phosphoric acid pre-etching times do not impair the fatigue bond strength of universal adhesives. Although fatigue bond strength and surface area were not influenced by phosphoric-acid etching times, surface roughness increased with increasing etching time.

Transcription factor Nrf1 is topologically repartitioned across membranes to enable target gene transactivation through its acidic glucose-responsive domains.

Science.gov (United States)

Zhang, Yiguo; Ren, Yonggang; Li, Shaojun; Hayes, John D

2014-01-01

The membrane-bound Nrf1 transcription factor regulates critical homeostatic and developmental genes. The conserved N-terminal homology box 1 (NHB1) sequence in Nrf1 targets the cap'n'collar (CNC) basic basic-region leucine zipper (bZIP) factor to the endoplasmic reticulum (ER), but it is unknown how its activity is controlled topologically within membranes. Herein, we report a hitherto unknown mechanism by which the transactivation activity of Nrf1 is controlled through its membrane-topology. Thus after Nrf1 is anchored within ER membranes, its acidic transactivation domains (TADs), including the Asn/Ser/Thr-rich (NST) glycodomain situated between acidic domain 1 (AD1) and AD2, are transiently translocated into the lumen of the ER, where NST is glycosylated in the presence of glucose to yield an inactive 120-kDa Nrf1 glycoprotein. Subsequently, portions of the TADs partially repartition across membranes into the cyto/nucleoplasmic compartments, whereupon an active 95-kDa form of Nrf1 accumulates, a process that is more obvious in glucose-deprived cells and may involve deglycosylation. The repartitioning of Nrf1 out of membranes is monitored within this protein by its acidic-hydrophobic amphipathic glucose-responsive domains, particularly the Neh5L subdomain within AD1. Therefore, the membrane-topological organization of Nrf1 dictates its post-translational modifications (i.e. glycosylation, the putative deglycosylation and selective proteolysis), which together control its ability to transactivate target genes.

Glucose-Sensitive Hydrogel Optical Fibers Functionalized with Phenylboronic Acid.

Science.gov (United States)

Yetisen, Ali K; Jiang, Nan; Fallahi, Afsoon; Montelongo, Yunuen; Ruiz-Esparza, Guillermo U; Tamayol, Ali; Zhang, Yu Shrike; Mahmood, Iram; Yang, Su-A; Kim, Ki Su; Butt, Haider; Khademhosseini, Ali; Yun, Seok-Hyun

2017-04-01

Hydrogel optical fibers are utilized for continuous glucose sensing in real time. The hydrogel fibers consist of poly(acrylamide-co-poly(ethylene glycol) diacrylate) cores functionalized with phenylboronic acid. The complexation of the phenylboronic acid and cis-diol groups of glucose enables reversible changes of the hydrogel fiber diameter. The analyses of light propagation loss allow for quantitative glucose measurements within the physiological range. © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A new oxidimetric reagent: potassium dichromate in a strong phosphoric acid medium--VII. Photometric titration of vanadium(IV) and of cerium(III) alone and in mixtures with iroN(II).

Science.gov (United States)

Rao, G G; Rao, P K

1967-01-01

Vanadium(IV) can be accurately titrated with potassium dichromate in media containing phosphoric acid of 3-12M concentration: the change in absorption of vanadium(IV) is followed in the region 660 mmicro using a red filter. It is more convenient to carry out the titration in 3M phosphoric acid because at higher concentrations chloride, nitrate, cerium(III) and manganese(II) may interfere. Photoelcetric titration is more convenient than potentiometric because the former can be made in a 3M phosphoric acid medium, whereas the latter is possible only in 12M phosphoric acid. The simultaneous differential photometric titration of iron(II) and vanadium(IV) is also possible. Conditions have been found for the photometric titration of cerium(III) and of cerium(III) plus iron(II). The titration is carried out (at 450 mmicro or with a blue filter) in about 10.5M phosphoric acid. Application of the method to a cerium mineral is considered.

Woking Park phosphoric acid fuel cell CHP monitoring

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-09-15

A phosphoric acid fuel (PC25) delivering up to 200kw of electrical power and commensurate heat was installed in Woking Park UK in late 2006 and has been monitored over a period of one year. The system supplies electric power to a leisure centre and swimming pool via a private wires network. This report gives details of the monitoring and shows a schematic of the system, data on electrical and thermal efficiencies, stack voltage variations and gaseous emissions. Extended monitoring is now taking place to provide a complete picture of the economics and operation of the fuel cell in the developing combined heat and power unit and private wires system. The contractor is Advantica of Loughborough and detailed results of the monitoring are available on the DTI website.

Uranium problem in production of wet phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Gorecka, H; Gorecki, H [Politechnika Wroclawska (Poland)

1980-01-01

The balance of the uranium in the wet dihydrate method was presented. This balance shows that a large quantity of the uranium compounds shift from mineral phosphate rock to liquid phase of decomposition pulp (about 70-85% U) and the rest moves to phosphogypsum (about 15-25% U). The contents of uranium in phosphate rock imported for our country and in products and by-products of the fertilizer industry, were determined. Concentration of uranium in the phosphogypsum is dependent on the type of mineral rock and the process of phosphogypsum crystallization. Analysis of the uranium contents in phosphogypsum samples and results of the sedimentation analysis indicated influence of the specific surface of phosphogypsum crystals on the uranium concentration. Investigation of the sets of samples obtained in the industrial plant proved that phosphogypsum cake washed counter-currently on the filter contained from 10 to 20 ..mu..g U/g. The radioactivity of these samples fluctuated from 35 to 60 pCi/g. Using solution sulphuric acid of concentration in range 2-4% by weight H/sub 2/SO/sub 4/ to washing and repulpation of the phosphogypsum enables to reduce its radioactivity to level below 25 pCi/g. This processing makes possible to utilize this waste material in the building industry. Extraction of uranium from the wet phosphoric acid using kerosen solution of the reaction product between octanol -1 and phosphorus pentaoxide showed possibility to recover over 80% of uranium contained in phosphate rock.

Study of the properties of dialkyl thiophosphoric acids. Application to the extraction of U, in phosphoric and nitric solutions

International Nuclear Information System (INIS)

Benjelloun, N.

1983-09-01

A study is made of complex formation and liquid-liquid extraction of uranium (VI) by dialkyl-thiophosphoric acids of formula (RO) 2 POSH and by the synergic mixtures: dialkylthiophosphoric acids-phosphine oxides. The aqueous phases studied consist of concentrated phosphoric acid solutions and nitric acid solutions. Several methods, including distribution coefficient measurements, U.V., visible and infrared absorption spectrophotometries and magnetic resonance, were used to study the extraction mechanisms and the structures of species formed in the organic phase. The influence of different parameters (partition of extraction agent, dimerisation, acid ligand-phosphine oxide association, extraction of inorganic acids...) on the uranium (VI) distribution coefficients enabled the constants of complex formation in the aqueous phase and extraction in the organic phase to be determined. These various properties were compared with those of dialkyl phosphoric and dithiophosphoric acids. The mechanisms established prove that sulfur donors ligands form stable complexes with UO 2 2+ ions although U(VI) is considered as a ''hard class a'' acceptor according to Ahrland's classification [fr

Influence of duration of phosphoric acid pre-etching on bond durability of universal adhesives and surface free-energy characteristics of enamel.

Science.gov (United States)

Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

2016-08-01

The purpose of this study was to evaluate the influence of duration of phosphoric acid pre-etching on the bond durability of universal adhesives and the surface free-energy characteristics of enamel. Three universal adhesives and extracted human molars were used. Two no-pre-etching groups were prepared: ground enamel; and enamel after ultrasonic cleaning with distilled water for 30 s to remove the smear layer. Four pre-etching groups were prepared: enamel pre-etched with phosphoric acid for 3, 5, 10, and 15 s. Shear bond strength (SBS) values of universal adhesive after no thermal cycling and after 30,000 or 60,000 thermal cycles, and surface free-energy values of enamel surfaces, calculated from contact angle measurements, were determined. The specimens that had been pre-etched showed significantly higher SBS and surface free-energy values than the specimens that had not been pre-etched, regardless of the aging condition and adhesive type. The SBS and surface free-energy values did not increase for pre-etching times of longer than 3 s. There were no significant differences in SBS values and surface free-energy characteristics between the specimens with and without a smear layer. The results of this study suggest that phosphoric acid pre-etching of enamel improves the bond durability of universal adhesives and the surface free-energy characteristics of enamel, but these bonding properties do not increase for phosphoric acid pre-etching times of longer than 3 s. © 2016 Eur J Oral Sci.

Effect of chenodeoxycholic acid and the bile acid sequestrant colesevelam on glucagon-like peptide-1 secretion

DEFF Research Database (Denmark)

Hansen, Morten; Scheltema, Matthijs J; Sonne, David P

2016-01-01

AIMS: In patients with type 2 diabetes, rectal administration of bile acids increases glucagon-like peptide-1 (GLP-1) secretion and reduces plasma glucose. In addition, oral bile acid sequestrants (BASs) reduce blood glucose by an unknown mechanism. In this study we evaluated the effects...... of the primary human bile acid, chenodeoxycholic acid (CDCA), and the BAS, colesevelam, instilled into the stomach, on plasma levels of GLP-1, glucose-dependent insulinotropic polypeptide, glucose, insulin, C-peptide, glucagon, cholecystokinin and gastrin as well as gastric emptying, gallbladder volume, appetite......, and delayed gastric emptying. We speculate that bile acid-induced activation of TGR5 on L cells increases GLP-1 secretion, which in turn may result in amplification of glucose-stimulated insulin secretion. Furthermore our data suggest that colesevelam does not have an acute effect on GLP-1 secretion in humans....

Electrolytes for methanol-air fuel cells. I. The performance of methanol electro-oxidation catalysts in sulphuric acid and phosphoric acid electrolytes

Energy Technology Data Exchange (ETDEWEB)

Andrew, M.R.; McNicol, B.D.; Short, R.T.; Drury, J.S.

1977-03-01

Phosphoric acid and sulphuric acid have been compared as potential electrolytes for methanol-air fuel cells. The performances of typical electro-oxidation catalysts were measured in both electrolytes over a range of concentrations. With all catalysts the activity falls with increasing acid concentration. While this is to some extent due to the decrease in water activity at higher concentrations it seems that with both acids there is significant poisoning of the catalyst. The results can be explained for both electrolytes by assuming that adsorption of undissociated acid poisons the catalyst surfaces and that the reaction rate on the poisoned surfaces is proportional to the water activity.

Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, {alpha}-D-Glucose and Tannic acid)

Energy Technology Data Exchange (ETDEWEB)

Ostovari, A. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of)], E-mail: A.Ostovari@gmail.com; Hoseinieh, S.M.; Peikari, M. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Shadizadeh, S.R. [Petroleum Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Hashemi, S.J. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of)

2009-09-15

The inhibitive action of henna extract (Lawsonia inermis) and its main constituents (lawsone, gallic acid, {alpha}-D-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > {alpha}-D-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.

Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, α-D-Glucose and Tannic acid)

International Nuclear Information System (INIS)

Ostovari, A.; Hoseinieh, S.M.; Peikari, M.; Shadizadeh, S.R.; Hashemi, S.J.

2009-01-01

The inhibitive action of henna extract (Lawsonia inermis) and its main constituents (lawsone, gallic acid, α-D-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > α-D-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.

External radiation assessment in a wet phosphoric acid production plant

Energy Technology Data Exchange (ETDEWEB)

Bolivar, J.P.; Perez-Moreno, J.P. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Mas, J.L. [Dept. Fisica Aplicada I, Escuela Universitaria Politecnica, Universidad de Sevilla, 41012 Sevilla (Spain)], E-mail: ppmasb@us.es; Martin, J.E.; San Miguel, E.G. [Dept. Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Huelva, 21012 Huelva (Spain); Garcia-Tenorio, R. [Dept. Fisica Aplicada II, Escuela Tecnica Superior de Arquitectura, Universidad de Sevilla, 41012 Sevilla (Spain)

2009-10-15

The factories dedicated to the production of phosphoric acid by the so-called wet acid method are usually considered typical NORM industries, because the phosphate rock used as raw material usually contains high concentrations of {sup 238}U-series radionuclides. The magnitude and behaviour of the radionuclides involved in the production process revealed the need to determine its dosimetric impact on workers. This work aims to partially compensate this lack of knowledge through the determination of external effective dose rates at different zones in the process at a typical plant located in the southwest of Spain. To this end, two dosimetric sampling campaigns have been carried out at this phosphoric acid production plant. The first sampling was carried out when phosphate rocks originating in Morocco were processed, and the second one when phosphate rock processed came from the Kola Peninsula (Russia Federation). This differentiation was necessary because the activity concentrations are almost one order of magnitude higher in Moroccan phosphate rock than in Kola phosphate rock. The results obtained have reflected external dose rate enhancements as high as 1.4 {mu}Sv h{sup -1} (i.e., up to thirty times the external exposition due to radionuclides in unperturbed soils) at several points in the facility, particularly where the digested rock (pulp) is filtered. However, the most problematic points are characterised by a small occupation factor. That means that the increment in the annual effective external gamma dose received by the most-exposed worker is clearly below 1 mSv (European Commission limit for the general population) under normal production. Nevertheless, special care in the design and schedule of cleaning and maintaining work in the areas with high doses should be taken in order to avoid any possibility of exceeding the previously mentioned general population limit. In addition, the results of the dosimetric campaign showed no clear correlation between {sup

Study of the solubility of yttrium, praseodymium, neodymium, and gadolinium sulfates in the presence of sodium and potassium in sulfuric-phosphoric acid solutions at 20 deg C

International Nuclear Information System (INIS)

Lokshin, Eh.P.; Tareeva, O.A.; Kashulina, T.G.

2007-01-01

The solubility of yttrium, praseodymium, neodymium, and gadolinium sulfates in the presence of sodium and potassium ions and the composition of solid phases were studied at 20 deg C in relation to the concentration of acids in sulfuric acid, phosphoric acid, and sulfuric-phosphoric acid solutions containing up to 36 wt % H 2 SO 4 and 33.12 g 1 -1 H 3 PO 4 . The formation of double sulfates of praseodymium and neodymium with sodium and potassium ions, as well as of gadolinium sulfate with sodium ions of the composition 1 : 1 was revealed. In water at 20 deg C, the solubility products of PrNa(SO 4 ) 2 ·H 2 O, NdNa(SO 4 ) 2 ·H 2 O, GdNa(SO 4 ) 2 ·H 2 O, PrK(SO 4 ) 2 ·H 2 O, and NdK(SO 4 ) 2 ·H 2 O are found to be 7.28x10 -8 , 7.84x10 -8 , 3.09x10 -6 , 3.02x10 -6 , and 1.70x10 -6 , respectively [ru

New Trident Molecule with Phosphoric Acid Functionality for Trivalent Rare Earth Extraction

Directory of Open Access Journals (Sweden)

Keisuke Ohto

2017-11-01

Full Text Available Tripodal extraction reagent with three phosphoric acid groups, together with the corresponding monopodal molecule has been prepared to investigate some metals extraction behavior, in particular, trivalent rare earth elements (REEs. The tripodal reagent exhibited extremely high selectivity for metals with high valency such as Zr(IV, In(III, Lu(III, and Fe(III. Tripodal reagent also exhibited exceptionally high extraction ability compared with the corresponding monopodal one in the extraction of trivalent rare earths. The result for the stoichiometry of tripodal reagent to heavy rare earths showed the inflection point between Er (2:1 for a ligand with ion and Tm (1:1. The extraction reactions were determined for all rare earths with both reagents. The extraction equilibrium constants (Kex, the separation factors (β, half pH values (pH1/2, difference half pH values (ΔpH1/2 for extraction of REEs with both reagents are estimated.

Phosphorous gettering in acidic textured multicrystalline solar cells

Energy Technology Data Exchange (ETDEWEB)

Montesdeoca-Santana, A. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Fraunhofer Institut fuer Solare Energiesysteme ISE, Laboratory and Servicecenter Gelsenkirchen, Auf der Reihe 2, 45884 Gelsenkirchen (Germany); Jimenez-Rodriguez, E.; Diaz-Herrera, B.; Hernandez-Rodriguez, C. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Gonzalez-Diaz, B. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Departamento de Energia Fotovoltaica, Instituto Tecnologico y de Energias Renovables. Poligono Industrial de Granadilla s/n, 38600 San Isidro-Granadilla de Abona, S/C de Tenerife (Spain); Rinio, M.; Borchert, D. [Fraunhofer Institut fuer Solare Energiesysteme ISE, Laboratory and Servicecenter Gelsenkirchen, Auf der Reihe 2, 45884 Gelsenkirchen (Germany); Guerrero-Lemus, R. [Departamento de Fisica Basica, Universidad de La Laguna (ULL), Avenida Astrofisico Francisco Sanchez 2, 38206 La Laguna, S/C de Tenerife (Spain); Fundacion de Estudios de Economia Aplicada, Catedra Focus-Abengoa, Jorge Juan 46, 28001 Madrid (Spain)

2011-03-15

The influence of phosphorus gettering is studied in this work applied to an acidic textured multicrystalline silicon substrate. The texturization was achieved with an HF/HNO{sub 3} solution leading to nanostructures on the silicon surface. It has been demonstrated in previous works that this textured surface decreases the reflectance on the solar cell and increases the surface area improving the photon collection and enhancing the short circuit current. The present study investigates the effect on the minority carrier lifetime of the phosphorous diffusion when it is carried out on this textured surface. The lifetime is measured by means microwave photoconductance decay and quasi steady state phototoconductance devices. The diffused textured wafers are used to fabricate solar cells and their electrical parameters are analyzed. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Glucose-stimulated acrolein production from unsaturated fatty acids.

Science.gov (United States)

Medina-Navarro, R; Duran-Reyes, G; Diaz-Flores, M; Hicks, J J; Kumate, J

2004-02-01

Glucose auto-oxidation may be a significant source of reactive oxygen species (ROS), and also be important in the lipid peroxidation process, accompanied by the release of toxic reactive products. We wanted to demonstrate that acrolein can be formed directly and actively from free fatty acids in a hyperglycemic environment. A suspension of linoleic and arachidonic acids (2.5 mM) was exposed to different glucose concentrations (5, 10 and 15 mmol/L) in vitro. The samples were extracted with organic solvents, partitioned, followed at 255-267 nm, and analysed using capillary electrophoresis and mass spectroscopy. The total release of aldehydes significantly (P products, acrolein (5% of total) and its condensing product, 4-hydroxy-hexenal, were identified. From the results presented here, it was possible to demonstrate the production of acrolein, probably as a fatty acid product, due to free radicals generated from the glucose auto-oxidation process. The results led us to propose that acrolein, which is one of the most toxic aldehydes, is produced during hyperglycemic states, and may lead to tissue injury, as one of the initial problems to be linked to high levels of glucose in vivo.

A new planetary structure fabrication process using phosphoric acid

Science.gov (United States)

Buchner, Christoph; Pawelke, Roland H.; Schlauf, Thomas; Reissner, Alexander; Makaya, Advenit

2018-02-01

Minimising the launch mass is an important aspect of exploration mission planning. In-situ resource utilisation (ISRU) can improve this by reducing the amount of terrestrial materials needed for planetary exploration activities. We report on a recently concluded investigation into the requirements and available technologies for creating hardware on extra-terrestrial bodies, using the limited resources available on site. A trade-off of ISRU technologies for hardware manufacturing was conducted. A new additive manufacturing process suitable for fabricating structures on the Moon or Mars was developed. The process uses planetary regolith as the base material and concentrated phosphoric acid as the liquid binder. Mixing the reagents creates a sticky construction paste that slowly solidifies into a hard, rock-like material. Prior to solidification, the paste is extruded in layers, creating the desired structures in a 3D printing process. We used Martian regolith simulant JSC-Mars-1A, but the process is not selective towards regolith composition. Samples were exposed to thermal cycles and were mechanically characterised. Reduced-scale demonstrator structures were printed to demonstrate structure fabrication using the developed process.

The optimisation study of tbp synthesis process by phosphoric acid

International Nuclear Information System (INIS)

Amedjkouh, A.; Attou, M.; Azzouz, A.; Zaoui, B.

1995-07-01

The present work deals with the optimisation study of TBP synthesis process by phosphoric acid. This way of synthesis is more advantageous than POCL3 or P2O5 as phosphatant agents. these latters are toxic and dangerous for the environnement. The optimisation study is based on a series of 16 experiences taking into account the range of variation of the following parameters : temperature, pressure, reagents mole ratio, promoter content. the yield calculation is based on the randomisation of an equation including all parameters. the resolution of this equation gave a 30% TBP molar ratio. this value is in agreement with that of experimental data

Carbon components in the phosphoric acid fuel cell-an overview

International Nuclear Information System (INIS)

Appleby, J.

1983-01-01

The single breakthrough that has made the phosphoric acid fuel cell a practical reality has been the use of carbon or graphite components for the repeat parts of the cell stack. While the thermodynamic stability of carbon is such that rapid corrosion would be expected at the cathode at fuel cell operating temperature, its kinetic stability is remarkable despite the absence of passivating layers analogous to those on, for example, the Group VA elements niobium and tantalum. This happy accident, combined with the adequate electronic conductivity of the carbon materials used, has provided the opportunity to reduce fuel cell cost to attractive levels. The development of these carbon compounds is reviewed

Method for the recovery of uranium from phosphoric acid, originating from the wet-process of uraniferous phosphate ores

International Nuclear Information System (INIS)

Pyrih, R.Z.; Rickard, R.S.; Carrington, O.F.

1978-01-01

Improvement in the process for recoverying uranium from wet-process phosphoric acid solution derived from the acidulation of uraniferous phosphate ores by the use of two ion exchange circuits is described. (Auth.)

Uranium(VI) and ruthenium extraction by dialkyldithio-phosphoric acids

International Nuclear Information System (INIS)

Fitoussi, R.; Musikas, C.

1980-01-01

Oxygen donors like dialkylphosphoric acids are good extractants for actinide ions, but little is known about their sulfur homologs. Investigations of U(VI) and Ru extraction from various aqueous media are reported. This includes extraction of U(VI) from nitric, perchloric, and phosphoric acids by solutions of dialkyldithiophosphoric acids in dodecane or benzene. Extraction of U(VI) by synergistic mixtures, of which at least one of the components is a sulfur donor, has been investigated. The extracted species have been identified, and a comparison with the complexes obtained by extraction with the homologous oxygen donors is made. The sulfur-actinide bond is weaker than the oxygen-actinide one, but in some synergistic extractions the dialkyldithiophosphonates are more efficient than the oxygen donors. In addition to size effects, this behavior could be attributed to the weakness of the hydrogen bonds of the SH groups, which allows a greater variety of the ligands to enter the coordination sphere of the metal. Ruthenium, like the d-transition elements, gives strong bonds with the sulfur donors. However, its extraction from nitric acid is slow. We investigated the influence of several parameters on the distribution coefficients and found that the presence of a reagent which destroys nitrous ions is necessary to achieve quantitative extraction. The role of RuNO groups is also discussed

Contribution to the study of dialcoylphosphates. The dibenzyl-phosphoric acid and its application to liquid-liquid extraction

International Nuclear Information System (INIS)

Courtemanche, Pierre V.

1966-01-01

This research thesis is a contribution to the knowledge of organophosphate compounds, and more particularly dialcoylphosphates, and even more particularly the dibenzyl-phosphoric acid or dibenzyl-phosphate (HDBzP). In a first part, the author reports studies on the synthesis of this compound by solving the specific analytic problem raised by simple organophosphates regarding their separation and identification. He also reports the study of some specific metallic derived compounds. The second part addresses the study of a specific feature of dialcoylphosphates: their interesting power of extraction with respect to metallic cations. The author shows that, through specific operational conditions (solvent nature, concentration of the extraction agent, composition of the aqueous phase containing the metallic ion), it is even possible to obtain a selective extraction. Thus, the author reports a physical-chemical study of the extraction agent, the dibenzyl-phosphoric acid

1-/sup 11/C-D-glucose and related compounds

Energy Technology Data Exchange (ETDEWEB)

Shiue, C.Y.; Wolf, A.P.

1982-01-26

The novel compounds 1-/sup 11/C-D-glucose, 1-/sup 11/C-D-mannose, 1-/sup 11/C-D-galactose, 2-/sup 11/C-D-glucose, 2-/sup 11/C-D-mannose and 2-/sup 11/C-D-galactose which can be used in nuclear medicine to monitor the metabolism of glucose and galactose can be rapidly prepared by reaction of the appropriate aldose substrate with an alkali metal /sup 11/C-labeled cyanide followed by reduction with a Raney alloy in formic acid.

Intracerebroventricular Kainic Acid-Induced Damage Affects Blood Glucose Level in d-glucose-fed Mouse Model.

Science.gov (United States)

Kim, Chea-Ha; Hong, Jae-Seung

2015-03-01

We have previously reported that the intracerebroventricular (i.c.v.) administration of kainic acid (KA) results in significant neuronal damage on the hippocampal CA3 region. In this study, we examined possible changes in the blood glucose level after i.c.v. pretreatment with KA. The blood glucose level was elevated at 30 min, began to decrease at 60 min and returned to normal at 120 min after D-glucose-feeding. We found that the blood glucose level in the KA-pretreated group was higher than in the saline-pretreated group. The up-regulation of the blood glucose level in the KA-pretreated group was still present even after 1~4 weeks. The plasma corticosterone and insulin levels were slightly higher in the KA-treated group. Corticosterone levels decreased whereas insulin levels were elevated when mice were fed with D-glucose. The i.c.v. pretreatment with KA for 24 hr caused a significant reversal of D-glucose-induced down-regulation of corticosterone level. However, the insulin level was enhanced in the KA-pretreated group compared to the vehicle-treated group when mice were fed with D-glucose. These results suggest that KA-induced alterations of the blood glucose level are related to cell death in the CA3 region whereas the up-regulation of blood glucose level in the KA-pretreated group appears to be due to a reversal of D-glucose feeding-induced down-regulation of corticosterone level.

Phosphors for LED lamps

Science.gov (United States)

Murphy, James Edward; Manepalli, Satya Kishore; Kumar, Prasanth Nammalwar

2013-08-13

A phosphor, a phosphor blend including the phosphor, a phosphor prepared by a process, and a lighting apparatus including the phosphor blend are disclosed. The phosphor has the formula (Ca.sub.1-p-qCe.sub.pK.sub.q).sub.xSc.sub.y(Si.sub.1-rGa.sub.r).sub.zO.su- b.12+.delta. or derived from a process followed using disclosed amounts of reactants. In the formula, (01.ltoreq..delta..ltoreq.0.4. In one embodiment, 31; 2.ltoreq.y.ltoreq.2.15; and 3.ltoreq.z.ltoreq.3.2. Similarly, in another embodiment, 3.ltoreq.x.ltoreq.3.1; 2

Synthesis of a chelate resin with amido and phosphoric acid and its character in uranium extraction

International Nuclear Information System (INIS)

Qiu Yueshuang; Zhang Jianguo; Feng Yu; Zhao Chaoya

2013-01-01

A chelate resin (D814) with amido and phosphoric acid functional group was synthetized by means of the reactions of stytene-divinyl benzene chloromethylated sphere with ethylenedianmine and orth-phosphorous acid and formaldehyde. This resin can be used to adsorb uranium from leaching solution with high chloride ion in the rang of pH l.33-9.05, and the adsorption rate of uranium was above 95%. D814 resin had a good ability resistant to high chloride ion. The loading capacity for uranium was not apparently effected when chlorid ion concentration in solution was 60 g/L. The results of the adsorption experiment show that when the ratio of saturation volume to breakthrough volume was l.82, the uranium saturation capacity of D814 was 40.5 mg/g dry resin. NaCl + NaHCO 3 was used for eluting agent, and the eluting rate of uranium was 96.7%. Adsorption uranium mechanism by D814 was also discussed. (authors)

Synthesis and characterization of new biopolymeric microcapsules containing DEHPA-TOPO extractants for separation of uranium from phosphoric acid solutions.

Science.gov (United States)

Outokesh, Mohammad; Tayyebi, Ahmad; Khanchi, Alireza; Grayeli, Fatemeh; Bagheri, Ghodrat

2011-01-01

A novel microcapsule adsorbent for separation of uranium from phosphoric acid solutions was developed by immobilizing the di(2-ethylhexyl) phosphoric acid-trioctyl phosphine oxide extractants in the polymeric matrix of calcium alginate. Physical characterization of the microcapsules was accomplished by scanning electron microscopy and thermogravimetric techniques. Equilibrium experiments revealed that both ion exchange and solvent extraction mechanisms were involved in the adsorption of [Formula: see text] ions, but the latter prevailed in a wider range of acid concentration. According to the results of kinetics study, at low acidity level, the rate controlling step was slow chemical reaction of [Formula: see text] ions with the microdroplets of extractant, whereas it changed to intraparticle diffusion at higher acid concentration. The study also attempted identification of the diffusion paths of the ions within the microcapsules, and the mechanism of change of mass transfer rate during the uptake process. The prepared microcapsules preserved their entire capacity after three cycles of adsorption, and their breakthrough behaviour was well fitted by a new formula derived from shrinking core model.

Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

DEFF Research Database (Denmark)

Kouril, M.; Christensen, Erik; Eriksen, S.

2011-01-01

The paper is focused on selection of a proper material for construction elements of water electrolysers, which make use of a 85% phosphoric acid as an electrolyte at temperature of 150 8C and which might be loaded with anodic polarization up to 2.5 V versus a saturated Ag/AgCl electrode (SSCE...

Corrosion inhibition of austenitic stainless steel by clay in polluted phosphoric acid with presence of SiC abrasif

Directory of Open Access Journals (Sweden)

Skal S.

2018-01-01

Full Text Available Stainless steels have many properties mechanical and chemical resistances resulting from the formation of the protective layer (passive film on their surface which prevents the metal to react with corrosive environments such as, phosphoric acid. This acid contains various impurities, including agressive agents and solid particles of gypsum, increase the risk of corrosion damage depending on the type of stainless steel used. In addition, it has been show that abrasion-corrosion causes an acceleration electrochemical process leading to a decrease in the resistance of materials. This work is to find a solution through an ecological inhibitor. That why we have been studied the effect of crude clay on corrosion behavior of Alloy 31 in polluted phosphoric acid with abrasive by electrochemical impedance spectroscopy (EIS . The clay was characterized by X-ray fluorescence spectroscopy (FX, X-ray diffraction (DRX and infrared spectroscopy (IR. EIS exhibited that resistance of Alloy 31 increased with increase the concentration of inhibitor.

Spectrophotometric and potentiometric studies of oxidation of Mo(III) by Mo(VI) in phosphoric acid medium

Energy Technology Data Exchange (ETDEWEB)

Kumar, A; Verma, G S.P. [Ranchi Coll. (India). Dept. of Chemistry

1975-12-01

Oxidation of Mo(III) (green) by Mo(VI) in an inert atmosphere and in orthophosphoric acid medium at various acid concentrations is reported. Potentiometric and spectrophotometric data suggest that oxidation of Mo(III) proceeds to Mo(V) through a binuclear species Mo(III) Mo(IV) absorbing at 400 nm. The formation of this species is facilitated at high acid concentrations. It is further found that quantitative conversion of Mo(III) into Mo(V) takes place at fairly high acid concentrations. In high phosphoric acid concentrations, solution of Mo(III) has been found to be oxidized to Mo(VI) by air and hence this can be used as a good oxygen absorber.

A Novel Method for Fabricating Double Layers Porous Anodic Alumina in Phosphoric/Oxalic Acid Solution and Oxalic Acid Solution

Directory of Open Access Journals (Sweden)

Yanfang Xu

2016-01-01

Full Text Available A novel method for fabricating ordered double layers porous anodic alumina (DL-PAA with controllable nanopore size was presented. Highly ordered large pore layer with interpore distance of 480 nm was fabricated in phosphoric acid solution with oxalic acid addition at the potential of 195 V and the small pore layer was fabricated in oxalic acid solution at the potential from 60 to 100 V. Experimental results show that the thickness of large pore layer is linearly correlative with anodizing time, and pore diameter is linearly correlative with pore widening time. When the anodizing potential in oxalic acid solution was adjusted from 60 to 100 V, the small pore layers with continuously tunable interpore distance from 142 to 241 nm and pore density from 1.94×109 to 4.89×109 cm−2 were obtained. And the interpore distance and the pore density of small pore layers are closely correlative with the anodizing potential. The fabricated DL-PAA templates can be widely utilized for fabrication of ordered nanomaterials, such as superhydrophobic or gecko-inspired adhesive materials and metal or semiconductor nanowires.

Nanoporous anodic aluminum oxide with a long-range order and tunable cell sizes by phosphoric acid anodization on pre-patterned substrates

Science.gov (United States)

Surawathanawises, Krissada; Cheng, Xuanhong

2014-01-01

Nanoporous anodic aluminum oxide (AAO) has been explored for various applications due to its regular cell arrangement and relatively easy fabrication processes. However, conventional two-step anodization based on self-organization only allows the fabrication of a few discrete cell sizes and formation of small domains of hexagonally packed pores. Recent efforts to pre-pattern aluminum followed with anodization significantly improve the regularity and available pore geometries in AAO, while systematic study of the anodization condition, especially the impact of acid composition on pore formation guided by nanoindentation is still lacking. In this work, we pre-patterned aluminium thin films using ordered monolayers of silica beads and formed porous AAO in a single-step anodization in phosphoric acid. Controllable cell sizes ranging from 280 nm to 760 nm were obtained, matching the diameters of the silica nanobead molds used. This range of cell size is significantly greater than what has been reported for AAO formed in phosphoric acid in the literature. In addition, the relationships between the acid concentration, cell size, pore size, anodization voltage and film growth rate were studied quantitatively. The results are consistent with the theory of oxide formation through an electrochemical reaction. Not only does this study provide useful operational conditions of nanoindentation induced anodization in phosphoric acid, it also generates significant information for fundamental understanding of AAO formation. PMID:24535886

Salvianolic acid B Relieves Oxidative Stress in Glucose Absorption ...

African Journals Online (AJOL)

Absorption and Utilization of Mice Fed High-Sugar Diet ... Salvianolic acid B, Blood glucose, Reactive oxygen species, Oxidative stress, Sugar diet. ... protein expression in human aortic smooth ... induced by glucose uptake and metabolism [8].

Chemoenzymatic combination of glucose oxidase with titanium silicalite -1

DEFF Research Database (Denmark)

Vennestrøm, Peter Nicolai Ravnborg; Taarning, Esben; Christensen, Claus H.

2010-01-01

Zeozymes: A proof-of-concept is presented for the chemoenzymatic combination of titanium silicalite-1 zeolite with glucose oxidase. In this combination, glucose is oxidized to gluconic acid and the H2O2 byproduct formed in situ is used for the simultaneous oxidation of chemical substrates. Both...... a soluble glucose oxidase and a truly integrated heterogeneous combination whereby the oxidase enzyme is anchored onto the zeolite surface are reported....

Ion flotation of uranium contained in industrial phosphoric acid with collector recycling

International Nuclear Information System (INIS)

Jdid, E.; Blazy, P.; Bessiere, J.

1985-01-01

Uranium has been recovered from wet-process phosphoric acid (30% P 2 O 5 ) by ion flotation with an anionic organophosphorous collector. Recoveries greater than 90% were obtained even at temperatures of about 60 C, the uranium concentrate, which was collected in the froth as a precipitate, containing 7 to 10% U. Collector consumption without recycling of the surface-active reagent was about 12 kg/kg U. Much of the reagent, however, can be recovered for recycling by attack with sodium hydroxide on the floated phase after filtration. This enables a precipitate containing about 30% U to be produced and decreases collector consumption to about 3 kg/kg U. The results were obtained in laboratory-scale experiments on industrial wet-process acid. (author)

Color stable manganese-doped phosphors

Science.gov (United States)

Lyons, Robert Joseph [Burnt Hills, NY; Setlur, Anant Achyut [Niskayuna, NY; Deshpande, Anirudha Rajendra [Twinsburg, OH; Grigorov, Ljudmil Slavchev [Sofia, BG

2012-08-28

A process for preparing color stable Mn.sup.+4 doped phosphors includes providing a phosphor of formula I; A.sub.x[MF.sub.y]:Mn.sup.+4 I and contacting the phosphor in particulate form with a saturated solution of a composition of formula II in aqueous hydrofluoric acid; A.sub.x[MF.sub.y]; II wherein A is Li, Na, K, Rb, Cs, NR.sub.4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7. In particular embodiments, M is Si, Ge, Sn, Ti, Zr, or a combination thereof. A lighting apparatus capable of emitting white light includes a semiconductor light source; and a phosphor composition radiationally coupled to the light source, and which includes a color stable Mn.sup.+4 doped phosphor.

Phosphoric acid fuel cell platinum use study

Science.gov (United States)

Lundblad, H. L.

1983-05-01

The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

A novel glucose biosensor based on phosphonic acid-functionalized silica nanoparticles for sensitive detection of glucose in real samples

International Nuclear Information System (INIS)

Zhao, Wenbo; Fang, Yi; Zhu, Qinshu; Wang, Kuai; Liu, Min; Huang, Xiaohua; Shen, Jian

2013-01-01

An effective strategy for preparation amperometric biosensor by using the phosphonic acid-functionalized silica nanoparticles (PFSi NPs) as special modified materials is proposed. In such a strategy, glucose oxidase (GOD) was selected as model protein to fabricate glucose biosensor in the presence of phosphonic acid-functionalized silica nanoparticles (PFSi NPs). The PFSi NPs were first modified on the surface of glassy carbon (GC) electrode, then, GOD was adsorbed onto the PFSi NPs film by drop-coating. The PFSi NPs were characterized by transmission electron microscopy (TEM) and nuclear magnetic resonance (NMR) spectra. The interaction of PFSi NPs with GOD was investigated by the circular dicroism spectroscopy (CD). The results showed PFSi NPs could essentially maintain the native conformation of GOD. The direct electron transfer of GOD on (PFSi NPs)/GCE electrode exhibited excellent electrocatalytic activity for the oxidation of glucose. The proposed biosensor modified with PFSi NPs displayed a fast amperometric response (5 s) to glucose, a good linear current–time relation over a wide range of glucose concentrations from 5.00 × 10 −4 to 1.87 × 10 −1 M, and a low detection limit of 2.44 × 10 −5 M (S/N = 3). Moreover, the biosensor can be used for assessment of the concentration of glucose in many real samples (relative error < 3%). The GOD biosensor modified with PFSi NPs will have essential meaning and practical application in future that attributed to the simple method of fabrication and good performance

Effects of free fatty acids per se on glucose production, gluconeogenesis, and glycogenolysis

DEFF Research Database (Denmark)

Staehr, Peter; Hother-Nielsen, Ole; Landau, Bernard R

2003-01-01

Insulin-independent effects of a physiological increase in free fatty acid (FFA) levels on fasting glucose production, gluconeogenesis, and glycogenolysis were assessed by administering [6,6-(2)H(2)]-glucose and deuteriated water ((2)H(2)O) in 12 type 1 diabetic patients, during 6-h infusions...

The use of Syrian bentonite to remove organics and other ions from commercial Syrian phosphoric acid

International Nuclear Information System (INIS)

Khorfan, S.; Abdulbaki, M.; Zein, A.

2006-01-01

Using of activated carbon to remove organic matter from phosphoric acid in uranium and P 2 O 5 extraction units has high cost. A new study was conducted to establish a new material instead of activated carbon. Experiments were carried out on removing organic matter by adsorption on Syrian bentonite. The experiments of the removal of humic acid by Syrian bentonite gave good results and showed that the chemical and thermal activation of bentonite increased the adsorption efficiency. (Authors)

The use of Syrian bentonite to remove organics and other ions from commercial Syrian phosphoric acid

International Nuclear Information System (INIS)

Khorfan, S.; Abdulbaki, M.; Zein, A.

2005-03-01

Using of activated carbon to remove organic matter from phosphoric acid in uranium and P 2 O 5 extraction units has high cost. A new study was conducted to establish a new material instead of activated carbon. Experiments were carried out on removing organic matter by adsorption on Syrian bentonite. The experiments of the removal of humic acid by Syrian bentonite gave good results and showed that the chemical and thermal activation of bentonite increased the adsorption efficiency. (Authors)

Inhibitors of Fatty Acid Synthesis Induce PPAR α -Regulated Fatty Acid β -Oxidative Genes: Synergistic Roles of L-FABP and Glucose.

Science.gov (United States)

Huang, Huan; McIntosh, Avery L; Martin, Gregory G; Petrescu, Anca D; Landrock, Kerstin K; Landrock, Danilo; Kier, Ann B; Schroeder, Friedhelm

2013-01-01

While TOFA (acetyl CoA carboxylase inhibitor) and C75 (fatty acid synthase inhibitor) prevent lipid accumulation by inhibiting fatty acid synthesis, the mechanism of action is not simply accounted for by inhibition of the enzymes alone. Liver fatty acid binding protein (L-FABP), a mediator of long chain fatty acid signaling to peroxisome proliferator-activated receptor- α (PPAR α ) in the nucleus, was found to bind TOFA and its activated CoA thioester, TOFyl-CoA, with high affinity while binding C75 and C75-CoA with lower affinity. Binding of TOFA and C75-CoA significantly altered L-FABP secondary structure. High (20 mM) but not physiological (6 mM) glucose conferred on both TOFA and C75 the ability to induce PPAR α transcription of the fatty acid β -oxidative enzymes CPT1A, CPT2, and ACOX1 in cultured primary hepatocytes from wild-type (WT) mice. However, L-FABP gene ablation abolished the effects of TOFA and C75 in the context of high glucose. These effects were not associated with an increased cellular level of unesterified fatty acids but rather by increased intracellular glucose. These findings suggested that L-FABP may function as an intracellular fatty acid synthesis inhibitor binding protein facilitating TOFA and C75-mediated induction of PPAR α in the context of high glucose at levels similar to those in uncontrolled diabetes.

Influence of free fatty acids on glucose uptake in prostate cancer cells

International Nuclear Information System (INIS)

Andersen, Kim Francis; Divilov, Vadim; Sevak, Kuntalkumar; Koziorowski, Jacek; Lewis, Jason S.; Pillarsetty, NagaVaraKishore

2014-01-01

Introduction: The study focuses on the interaction between glucose and free fatty acids (FFA) in malignant human prostate cancer cell lines by an in vitro observation of uptake of fluoro-2-deoxy-D-glucose (FDG) and acetate. Methods: Human prostate cancer cell lines (PC3, CWR22Rv1, LNCaP, and DU145) were incubated for 2 h and 24 h in glucose-containing (5.5 mM) Dulbecco’s Modified Eagle’s Medium (DMEM) with varying concentrations of the free fatty acid palmitate (0–1.0 mM). Then the cells were incubated with [ 18 F]-FDG (1 μCi/mL; 0.037 MBq/mL) in DMEM either in presence or absence of glucose and in presence of varying concentrations of palmitate for 1 h. Standardized procedures regarding cell counting and measuring for 18 F radioactivity were applied. Cell uptake studies with 14 C-1-acetate under the same conditions were performed on PC3 cells. Results: In glucose containing media there was significantly increased FDG uptake after 24 h incubation in all cell lines, except DU145, when upper physiological levels of palmitate were added. A 4-fold increase of FDG uptake in PC3 cells (15.11% vs. 3.94%/10 6 cells) was observed in media with 1.0 mM palmitate compared to media with no palmitate. The same tendency was observed in PC3 and CWR22Rv1 cells after 2 h incubation. In glucose-free media no significant differences in FDG uptake after 24 h incubation were observed. The significant differences after 2 h incubation all pointed in the direction of increased FDG uptake when palmitate was added. Acetate uptake in PC3 cells was significantly lower when palmitate was added in glucose-free DMEM. No clear tendency when comparing FDG or acetate uptake in the same media at different time points of incubation was observed. Conclusions: Our results indicate a FFA dependent metabolic boost/switch of glucose uptake in PCa, with patterns reflecting the true heterogeneity of the disease

Glucose and amino acid metabolism in rat brain during sustained hypoglycemia

International Nuclear Information System (INIS)

Wong, K.L.; Tyce, G.M.

1983-01-01

The metabolism of glucose in brains during sustained hypoglycemia was studied. [U- 14 C]Glucose (20 microCi) was injected into control rats, and into rats at 2.5 hr after a bolus injection of 2 units of insulin followed by a continuous infusion of 0.2 units/100 g rat/hr. This regimen of insulin injection was found to result in steady-state plasma glucose levels between 2.5 and 3.5 mumol per ml. In the brains of control rats carbon was transferred rapidly from glucose to glutamate, glutamine, gamma-aminobutyric acid and aspartate and this carbon was retained in the amino acids for at least 60 min. In the brains of hypoglycemic rats, the conversion of carbon from glucose to amino acids was increased in the first 15 min after injection. After 15 min, the specific activity of the amino acids decreased in insulin-treated rats but not in the controls. The concentrations of alanine, glutamate, and gamma-amino-butyric acid decreased, and the concentration of aspartate increased, in the brains of the hypoglycemic rats. The concentration of pyridoxal-5'-phosphate, a cofactor in many of the reactions whereby these amino acids are formed from tricarboxylic acid cycle intermediates, was less in the insulin-treated rats than in the controls. These data provide evidence that glutamate, glutamine, aspartate, and GABA can serve as energy sources in brain during insulin-induced hypoglycemia

The impact of water concentration on the catalytic oxidation of ethanol on platinum electrode in concentrated phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Camargo, A.P.M.; Previdello, B.A.F.; Varela, H.; Gonzalez, E.R. [Instituto de Quimica de Sao Carlos, Universidade de Sao Paulo, C.P. 780, CEP 13560-970 Sao Carlos, SP (Brazil)

2010-01-15

The electro-oxidation of ethanol on platinum in phosphoric acid opens the door to promote the oxidation reaction at higher temperatures. However, the effect of the presence of water is not well understood. In this work, the electro-oxidation of ethanol on platinum was studied in concentrated phosphoric acid containing different concentrations of water at room temperature. The results show that effect of bulk water on the rate electro-oxidation is highest at 0.60 V and decreases for increasing potentials. This was suggested as due to the increasing formation of oxygenated species on the electrode surface with potential, which in turn is more efficient than the increase of water content in the electrolyte. Altogether, these results were interpreted as an evidence of a Langmuir-Hinshelwood step involving oxygenated species as one of the adsorbed partners. (author)

Enantioselective Synthesis of α-Mercapto-β-amino Esters via Rh(II)/Chiral Phosphoric Acid-Cocatalyzed Three-Component Reaction of Diazo Compounds, Thiols, and Imines.

Science.gov (United States)

Xiao, Guolan; Ma, Chaoqun; Xing, Dong; Hu, Wenhao

2016-12-02

An enantioselective method for the synthesis of α-mercapto-β-amino esters has been developed via a rhodium(II)/chiral phosphoric acid-cocatalyzed three-component reaction of diazo compounds, thiols, and imines. This transformation is proposed to proceed through enantioselective trapping of the sulfonium ylide intermediate generated in situ from the diazo compound and thiol by the phosphoric acid-activated imine. With this method, a series of α-mercapto-β-amino esters were obtained in good yields with moderate to good stereoselectivities.

Circulating Glucagon 1-61 Regulates Blood Glucose by Increasing Insulin Secretion and Hepatic Glucose Production

Directory of Open Access Journals (Sweden)

Nicolai J. Wewer Albrechtsen

2017-11-01

Full Text Available Glucagon is secreted from pancreatic α cells, and hypersecretion (hyperglucagonemia contributes to diabetic hyperglycemia. Molecular heterogeneity in hyperglucagonemia is poorly investigated. By screening human plasma using high-resolution-proteomics, we identified several glucagon variants, among which proglucagon 1-61 (PG 1-61 appears to be the most abundant form. PG 1-61 is secreted in subjects with obesity, both before and after gastric bypass surgery, with protein and fat as the main drivers for secretion before surgery, but glucose after. Studies in hepatocytes and in β cells demonstrated that PG 1-61 dose-dependently increases levels of cAMP, through the glucagon receptor, and increases insulin secretion and protein levels of enzymes regulating glycogenolysis and gluconeogenesis. In rats, PG 1-61 increases blood glucose and plasma insulin and decreases plasma levels of amino acids in vivo. We conclude that glucagon variants, such as PG 1-61, may contribute to glucose regulation by stimulating hepatic glucose production and insulin secretion.

Influence of free fatty acids on glucose uptake in prostate cancer cells

DEFF Research Database (Denmark)

Andersen, Kim Francis; Divilov, Vadim; Sevak, Kuntalkumar

2014-01-01

The study focuses on the interaction between glucose and free fatty acids (FFA) in malignant human prostate cancer cell lines by an in vitro observation of uptake of fluoro-2-deoxy-d-glucose (FDG) and acetate.......The study focuses on the interaction between glucose and free fatty acids (FFA) in malignant human prostate cancer cell lines by an in vitro observation of uptake of fluoro-2-deoxy-d-glucose (FDG) and acetate....

Determination of elemental impurities in phosphoric acid by INAA employing a novel method of phosphate precipitation

Czech Academy of Sciences Publication Activity Database

Kameník, Jan; Amsil, H.; Kučera, Jan

2014-01-01

Roč. 2014, AUG (2014), s. 3455 ISSN 1588-2780 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(XE) LM2011019 Institutional support: RVO:61389005 Keywords : instrumental neutron activation analysis * phosphoric acid * elemental impurities * isothermal distillation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

Spectrophotometric and potentiometric studies of oxidation of Mo(III) by Mo(VI) in phosphoric acid medium

International Nuclear Information System (INIS)

Kumar, Arvind; Verma, G.S.P.

1975-01-01

Oxidation of Mo(III) (green) by Mo(VI) in an inert atmosphere and in orthophosphoric acid medium at various acid concentrations is reported. Potentiometric and spectrophotometric data suggest that oxidation of Mo(III) proceeds to Mo(V) through a binuclear species Mo(III) Mo(IV) absorbing at 400 nm. The formation of this species is facilitated at high acid concentrations. It is further found that quantitative conversion of Mo(III) into Mo(V) takes place at fairly high acid concentrations. In high phosphoric acid concentrations, solution of Mo(III) has been found to be oxidized to Mo(VI) by air and hence this can be used as a good oxygen absorber. (author)

Proton exchange in systems: Glucose-water and uric acid-water

International Nuclear Information System (INIS)

Maarof, S.

2007-01-01

It is clear that formation of glucose-water and uric acid-water solutions is related in principle to interaction accepter - donor between hydrogen atom in water and oxygen atom in glucose or uric acid. The proton exchange in hydrogen bond system is an integral process and it goes by tunnel mechanism (transfer of proton within the hydrogen bridge in these structures). Proton exchange process goes very quickly at low concentrations for glucose and uric acid solutions, because these compounds are able to form more than one hydrogen bond, which helps the proton transfer within obtained structure. However, at its high concentrations, the process becomes very slow due to higher viscosity of its solutions, which result in break down of the structures, and more hydrogen bonds. (author)

Evaluation of two processes for the production of phosphoric acid in pilot scale

International Nuclear Information System (INIS)

Santos Benedetto, J. dos.

1984-01-01

Two processes for the production of phosphoric acid, based on dihydrate route and hemihydrate route, have been evaluated. The processes were tested in a pilot plant using the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). Results were evaluated from the data obtained from phosphorus and uranium solubilizations. Also presented, although in a summarised way, are the description of the construction of the pilot plants and the analytical methods for the follow-up of processes. (Author) [pt

Determination of elemental impurities in phosphoric acid by INAA employing a novel method of phosphate precipitation

Czech Academy of Sciences Publication Activity Database

Kameník, Jan; Amsil, H.; Kučera, Jan

2015-01-01

Roč. 304, APR (2015), s. 157-162 ISSN 0236-5731 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : instrumental neutron activation analysis * phosphoric acid * elemental impurities * isothermal distillation Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 0.983, year: 2015

Solvent Extraction of Rare Earths by Di-2 Ethylhexyl Phosphoric Acid

International Nuclear Information System (INIS)

Srinuttrakul, Wannee; Kranlert, Kannika; Kraikaew, Jarunee; Pongpansook, Surasak; Chayavadhanangkur, Chavalek; Kranlert, Kannika

2004-10-01

Solvent extraction has been widely applied for individual rare earth separation because the separation time is rapid and a large quantity of products is obtained. In this work, this technique was utilized to extract mixed rare earths, obtained from monazite digestion process. Di-2-ethylhexyl phosphoric acid (D2EHPA) was used as an extractant. The factors affected the extraction including HNO 3 concentration in mixed rare earth nitrate solution and the amount of D2EHPA were studied. The appropriate concentrations of HNO 3 and D2EHPA were found to be 0.01 and 1.5 M, respectively. From the result of equilibrium curve study, it was observed that heavy rare earths were extracted more efficient than light rare earths. A 6-stage continuous countercurrent solvent extraction was simulated for rare earth extraction. The optimum ratio of solvent to feed solution (S/F) was 2. Because of the high cost of D2EHPA, 1.0 M of D2EHPA was suitable for the rare earth extraction by the continuous countercurrent solvent extraction

Thermal Effect on the phosphoric Acid Impregnated Activated Carbon Fiber and Adsorption Properties Toward Isoprene

Energy Technology Data Exchange (ETDEWEB)

Hwang, Taek Sung; Lee, Jin Hyok; Kang, Kyung suk [Department of Chemical Engineering, College of Engineering, Chungnam National University, Taejon (Korea); Kim, Kwang Young [Ace Lab. Co. Ltd. Taejon (Korea); Rhee, Moon Soo [Korea Ginseng and Tobacoo Research Institute, Taejon (Korea)

2001-05-01

To introduce chemisorption property and improve adsorption capacities for isoprene, ACF (Activated Carbon Fiber) was impregnated by phosphoric acid. As the impregnated ACF was dried by programmed temperature from 300 degree C to 500 degree C, degree of impregnation, surface area, thermal stability and adsorption properties for isoprene were observed. The degree of impregnation of the ACF, dried at the 400 degree C, was 12.7 w/w% and surface area was 1148 m{sup 2}/g. Over the temperature range of 450 degree C to 700 degree C, there was one-step thermal degradation by the thermal decomposition of phosphonyl group. The adsorption rate of phosphoric acid on the impregnated ACF, which was dried at 400 degree C, was the fastest. The breakthrough time of ACF that was dried at 400 degree C was 18 min., and its adsorption capacity improved roughly 7.2 times in comparison to the pure ACF. In addition, it was observed the adsorption properties persisted even after the regeneration. The adsorption efficiency of regenerated ACF was 66 percent compared to the unused impregnated ACF. 21 refs., 7 figs., 3 tabs.

Physicochemical properties of carbons prepared from pecan shell by phosphoric acid activation.

Science.gov (United States)

Guo, Yanping; Rockstraw, David A

2007-05-01

Activated carbons were prepared from pecan shell by phosphoric acid activation. The pore structure and acidic surface groups of these carbons were characterized by nitrogen adsorption, Boehm titration and transmittance Fourier infrared spectroscopy (FTIR) techniques. The characterization results demonstrated that the development of pore structure was apparent at temperatures 250 degrees C, and reached 1130m(2)/g and 0.34cm(3)/g, respectively, at 500 degrees C. Impregnation ratio and soaking time at activation temperature also affected the pore development and pore size distribution of final carbon products. At an impregnation ratio of 1.5, activated carbon with BET surface area and micropore volume as high as 861m(2)/g and 0.289cm(3)/g was obtained at 400 degrees C. Microporous activated carbons were obtained in this study. Low impregnation ratio (less than 1.5) and activation temperature (less than 300 degrees C) are favorable to the formation of acidic surface functional groups, which consist of temperature-sensitive (unstable at high temperature) and temperature-insensitive (stable at high temperature) two parts. The disappearance of temperature-sensitive groups was significant at temperature 300 degrees C; while the temperature-insensitive groups are stable even at 500 degrees C. FTIR results showed that the temperature-insensitive part was mostly phosphorus-containing groups as well as some carbonyl-containing groups, while carbonyl-containing groups were the main contributor of temperature-sensitive part.

Research and development of a phosphoric acid fuel cell/battery power source integrated in a test-bed bus. Final report

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-05-30

This project, the research and development of a phosphoric acid fuel cell/battery power source integrated into test-bed buses, began as a multi-phase U.S. Department of Energy (DOE) project in 1989. Phase I had a goal of developing two competing half-scale (25 kW) brassboard phosphoric acid fuel cell systems. An air-cooled and a liquid-cooled fuel cell system were developed and tested to verify the concept of using a fuel cell and a battery in a hybrid configuration wherein the fuel cell supplies the average power required for operating the vehicle and a battery supplies the `surge` or excess power required for acceleration and hill-climbing. Work done in Phase I determined that the liquid-cooled system offered higher efficiency.

Retrobiosynthetic NMR studies with 13C-labeled glucose. Formation of gallic acid in plants and fungi

International Nuclear Information System (INIS)

Werner, I.; Bacher, A.; Eisenreich, W.

1997-01-01

The biosynthesis of gallic acid was studied in cultures of the fungus Phycomyces blakesleeanus and in leaves of the tree Rhus typhina. Fungal cultures were grown with [1-13C]glucose or with a mixture of unlabeled glucose and [U-13C6]glucose. Young leaves of R. typhina were kept in an incubation chamber and were supplied with a solution containing a mixture of unlabeled glucose and [U-13C6]glucose via the leaf stem. Isotope distributions in isolated gallic acid and aromatic amino acids were analyzed by one-dimensional 1H and 13C NMR spectroscopy. A quantitative analysis of the complex isotopomer composition of metabolites was obtained by deconvolution of the 13C13C coupling multiplets using numerical simulation methods. This approach required the accurate analysis of heavy isotope chemical shift effects in a variety of different isotopomers and the analysis of long range 13C13C coupling constants. The resulting isotopomer patterns were interpreted using a retrobiosynthetic approach based on a comparison between the isotopomer patterns of gallic acid and tyrosine. The data show that both in the fungus and in the plant all carbon atoms of gallic acid are biosynthetically equivalent to carbon atoms of shikimate. Notably, the carboxylic group of gallic acid is derived from the carboxylic group of an early intermediate of the shikimate pathway and not from the side chain of phenylalanine or tyrosine. It follows that the committed precursor of gallic acid is an intermediate of the shikimate pathway prior to prephenate or arogenate, most probably 5-dehydroshikimate. A formation of gallic acid via phenylalanine, the lignin precursor, caffeic acid, or 3,4, 5-trihydroxycinnamic acid can be ruled out as major pathways in the fungus and in young leaves of R. typhina. The incorporation of uniformly 13C-labeled glucose followed by quantitative NMR analysis of isotopomer patterns is suggested as a general method for biosynthetic studies. As shown by the plant experiment, this

Yields of 2-deoxy-D-gluconic, D-gluconic and other sugar acids in gamma-irradiated aqueous solutions of D-glucose. [Gamma rays

Energy Technology Data Exchange (ETDEWEB)

Esterbauer, H; Schubert, J; Sanders, E B; Sweeley, C C [Pittsburgh Univ., Pa. (USA); Michigan State Univ., East Lansing (USA). Dept. of Biochemistry)

1977-03-01

The yields of 2-deoxy-D-gluconic, D-gluconic and other sugar acids from /sup 60/Co-gamma irradiated (dose-rate = 4 Krads/min) D-glucose solutions are reported. The acids produced upon radiolysis were separated from glucose and neutral products by anion exchange, assayed by gas chromatography of the trimethylsilyl derivatives, and definitive identification made by mass spectrometry. In He degassed, irradiated 0.055 M glucose G(2-deoxy-D-gluconic acid) = 0.62 and G(D-gluconic acid) = 0.20. The approximate G values for the other identified acids are: glyceric acid 0.03, 2-deoxy-tetronic acid 0.04, tetronic acid 0.03, 4-deoxypentonic acid 0.02, deoxyketogluconic acid 0.17. In N/sub 2/O saturated glucose solutions D-gluconic acid yields increased by a factor of approximately 1.9 while that of 2-deoxy-D-gluconic acid increased by a factor of only approximately 1.1.

Experiences from Swedish demonstration projects with phosphoric acid fuel cells; Erfarenheter fraan svenska demonstrationsprojekt med fosforsyrabraensleceller

Energy Technology Data Exchange (ETDEWEB)

Carlsson, Per [Sycon Energikonsult AB, Stockholm (Sweden); Sarkoezi, Laszlo [Vattenfall Utveckling AB, Stockholm (Sweden)

1999-10-01

In Sweden, there are today two phosphoric acid fuel cells installed, one PC25A which have been in operation in more than 4 years, and one PC25C which have been in operation for two years. The aim with this project has been two compare operation characteristics, performance, and operation experiences for these two models.

Progress report on nitric-phosphoric acid oxidation

International Nuclear Information System (INIS)

Pierce, R.A.

1994-01-01

The purpose of this program has been to demonstrate a nitric-phosphoric acid destruction technology which can treat a heterogeneous waste stream. This technology is being developed to convert hazardous liquid and solid organics to inorganic gases and salts while simultaneously performing a surface decontamination of the noncombustible items. Pu-238 waste is an issue because it must be shipped to WIPP. However, the presence of organics and Pu-238 waste is an issue because it must be shipped to WIPP. However, the presence of organics and Pu-238 exceeds packaging requirements because of concerns of hydrogen generation. If the TRU can be separated from the organics, the allowable heat load of a container increases a factor of 25. More importantly, since the current shipping package is limited by volume and not heat loading, destroying the organic compounds and decontaminating noncombustible can potentially create a three-order magnitude decrease in the number of shipments that must be made to WIPP. The process envisioned will be configured to handle 1 million pounds (as of 12/91) of a wide range of solid TRU-contaminated waste of which 600,000 pounds is combustible. The process will oxidize the combustibles (a mixture of 14% cellulose, 3% rubber, 64% plastics, 9% absorbed oil, 4% resins and sludges, and 6% miscellaneous organics) without requiring separation from the 400,000 pounds of noncombustibles. The system is being developed to operate below 200 C at moderate pressures (0--15 psig). This report primarily discusses results obtained over the past 3 1/2 months and their impact on the feasibility of a pilot-scale system

Liquid–liquid equilibria study of the (water + phosphoric acid + hexyl or cyclohexyl acetate) systems at T = (298.15, 308.15, and 318.15) K: Measurement and thermodynamic modelling

International Nuclear Information System (INIS)

Ghanadzadeh Gilani, A.; Ghanadzadeh Gilani, H.; Shekarsaraee, S.; Nasiri-Touli, E.; Seyed Saadat, S.L.

2016-01-01

Highlights: • Tie line data for aqueous solutions of phosphoric acid with esters were obtained. • The LLE data were correlated using the UNIQUAC and NRTL models. • The quality of the LLE data was validated using the appropriate equations. • Separation factors were calculated for the chosen solvents. - Abstract: Liquid–liquid equilibrium (LLE) data for the (water + phosphoric acid + n-hexyl acetate or cyclohexyl acetate) ternary systems were determined at T = (298.15, 308.15 and 318.15) K and p = 101.3 kPa. The cloud point method was used to obtain the solubility and the Karl-Fischer, acidimetric titration, and refractive index methods were used to determine the tie-line values. Both the ternary systems exhibit type-1 behavior of LLE. The experimental values were regressed and acceptably correlated using the UNIQUAC and NRTL models. The reliability of the experimental tie lines was confirmed using the Othmer–Tobias plot. Experimental distribution coefficients and separation factors were fitted using the Kamlet–Taft LSER model. The influence of temperature on the biphasic area and separation factor was found to be minor. As a result, both the esters are suitable separating agents for aqueous phosphoric acid mixtures.

Optimization of lactic acid production from glucose using geobacillus stearothermophilus strain 15

Science.gov (United States)

Kunasundari, Balakrishnan; Naresh, Sandrasekaran; Safie, Mohammad Farhan Mohd

2017-09-01

This study investigated the conversion efficiency of glucose to lactic acid by Geobacillus stearothermophilus strain 15. Six parameters (temperature, pH, incubation time, agitation speed, carbon and nitrogen concentrations) were screened to identify the most significant factors in affecting lactic acid production using glucose. Three most significant factors (temperature, pH and incubation time) were further optimized in this experiment to determine the optimal production of lactic acid. Numerical optimization gave the point prediction of lactic acid concentration produced at 9.95 g/L with the desirability of 0.979 at 40°C, pH 8.5, 24 h, 100 rpm with 5% glucose and 3% yeast extract.

Re-processing CRT phosphors for mercury-free applications

International Nuclear Information System (INIS)

Dexpert-Ghys, Jeannette; Regnier, Sophie; Canac, Sophie; Beaudette, Tristan; Guillot, Philippe; Caillier, Bruno; Mauricot, Robert; Navarro, Julien; Sekhri, Salem

2009-01-01

This study is part of an operation in the framework of treatment and revalorization of IEEE (Informatics, Electronics and related) wastes. It aims to recover the active phosphors in cathode ray tubes (CRTs) and to re-cycle these powders by appropriate treatments as phosphors for mercury-free applications such as plasma display panels, flat lamps, advertising and lighting. The studied waste comes from a large panel of CRTs from any supplier. Several thermo-chemical treatments have been investigated. The removal of zinc sulfide-based phosphors and the recovery of a red phosphor Y 2 O 3 :Eu 3+ has been achieved by one (basic attack) route. The photoluminescence efficiency under VUV excitation of the obtained powders is at most 30% that of a commercial phosphor. The second route (acid attack) appears less promising. It has been established that silicate-based impurities could prevent isolating the yttrium based phosphor.

Re-processing CRT phosphors for mercury-free applications

Energy Technology Data Exchange (ETDEWEB)

Dexpert-Ghys, Jeannette, E-mail: jdexpert@cemes.f [CEMES, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse cedex 4 (France); Regnier, Sophie; Canac, Sophie [ICAM, 75 avenue de Grande Bretagne, 31300 Toulouse (France); Beaudette, Tristan; Guillot, Philippe; Caillier, Bruno [DPHE, Universite Jean Francois Champollion, place de Verdun, 81012 Albi cedex 9 (France); Mauricot, Robert; Navarro, Julien [CEMES, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse cedex 4 (France); Sekhri, Salem [ENVOI, Cheminement Glueck, 31100 Toulouse (France)

2009-12-15

This study is part of an operation in the framework of treatment and revalorization of IEEE (Informatics, Electronics and related) wastes. It aims to recover the active phosphors in cathode ray tubes (CRTs) and to re-cycle these powders by appropriate treatments as phosphors for mercury-free applications such as plasma display panels, flat lamps, advertising and lighting. The studied waste comes from a large panel of CRTs from any supplier. Several thermo-chemical treatments have been investigated. The removal of zinc sulfide-based phosphors and the recovery of a red phosphor Y{sub 2}O{sub 3}:Eu{sup 3+} has been achieved by one (basic attack) route. The photoluminescence efficiency under VUV excitation of the obtained powders is at most 30% that of a commercial phosphor. The second route (acid attack) appears less promising. It has been established that silicate-based impurities could prevent isolating the yttrium based phosphor.

Influence of Amino Acids in Dairy Products on Glucose Homeostasis: The Clinical Evidence.

Science.gov (United States)

Chartrand, Dominic; Da Silva, Marine S; Julien, Pierre; Rudkowska, Iwona

2017-06-01

Dairy products have been hypothesized to protect against type 2 diabetes because of their high content of whey proteins, rich in branched-chain amino acids (BCAAs) - leucine, isoleucine and valine - and lysine, which may decrease postprandial glucose responses and stimulate insulin secretion. Paradoxically, epidemiologic studies also show that higher levels of plasma BCAAs have been linked to insulin resistance and type 2 diabetes. Therefore, the objective was to review the recent clinical evidence concerning the intake of amino acids found in dairy proteins so as to determine their impact on glucose homeostasis in healthy persons and in those with prediabetes and type 2 diabetes. Clinical studies have reported that the major dairy amino acids, namely, leucine, isoleucine, glutamine, phenylalanine, proline and lysine, have beneficial effects on glucose homeostasis. Yet the reported doses of amino acids investigated are too elevated to be reached through adequate dairy product intake. The minor dairy amino acids, arginine and glycine, may improve glucose homeostasis by improving other risk factors for type 2 diabetes. Further, the combination of amino acids may also improve glucose-related outcomes, suggesting additive or synergistic effects. Nevertheless, additional long-term studies in individuals with prediabetes and type 2 diabetes are needed to ascertain the benefits for glucose homeostasis of amino acids found in dairy foods. Copyright © 2017 Diabetes Canada. Published by Elsevier Inc. All rights reserved.

Quality parameters evaluation for the determination of available phosphorous in soils

International Nuclear Information System (INIS)

Garcia Galvis, John Brynner; Ballesteros, Maria Ines

2006-01-01

There are some colorimetric procedures for determining available phosphorous in soils, and phosphorous is evaluated by means of a blue complex (phosphomolybdic acid); in one of the methods, color appear when ascorbic acid is used as reductor agent, and in the other when stannous chloride is used. Both methods use the same extractive solution bray i i due to its good response for acid soil cultures, like most Colombian soils are. When the two methodologies were compared it was found that the most sensible method and with the best limit of detection and quantification was the one that uses ascorbic acid, antimonious and potassium tartrate. Its variation coefficients and standard deviation were lower, and for this reason it is considered as the most precise method for phosphorous determination

The extraction of uranium from wet process phosphoric acid using a liquid surfactant membrane system

International Nuclear Information System (INIS)

Dickens, N.; Davies, G.A.

1984-01-01

A liquid membrane extraction process is examined for the extraction of uranium from wet process phosphoric acid. Uranium is present in the acid in concentrations up to 100 ppm which in principle makes it ideal for treatment with a membrane process. The membrane system studied is based on extraction using DEHPA-TOPO reagents which are contained within the organic phase of a water in oil emulsion. Formulations of the emulsion membrane system have been studied, the limitations of acid temperature, P 2 O 5 concentration and solid dispersed impurities in the acid have been studied in laboratory batch experiments and in a continuous pilot plant unit capable of treating 5l of concentrated acid per minute. Data from the pilot plant work has been used to develop a flowsheet for a commercial unit based on this process. (author)

Use of a pulsed column with discs and crowns for uranium extraction from phosphoric acid

International Nuclear Information System (INIS)

1982-04-01

The physico-chemistry of the system phosphoric acid-uranium-dioctylpyrophosphoric acid is studied for the determination of analytical methods and extraction parameters (oxidation state of uranium and iron, phosphorus concentration, extractant concentration). Extraction is then realized on a pilot scale with a liquid-liquid extraction column 4m high and of 50 mm in diameter with a column packing made of discs and crowns. Column efficiency is evaluated by studying uranium transfer as a function of operating conditions. The results obtained are extrapolated to an industrial scale and a comparative economic evaluation is made between a pulsed column and a mixer-settler [fr

Separation of transuranium elements from high-level waste by extraction with diisodecyl phosphoric acid

International Nuclear Information System (INIS)

Morita, Y.; Kubota, M.; Tani, S.

1991-01-01

Separation of transuranic elements (TRU) by extraction with diisodecyl phosphoric acid (DIDPA) has been studied to develop a partitioning process for high-level waste (HLW). In the present study, experiments of counter-current continuous extraction and back-extraction using a miniature mixer-settler were carried out to find the optimum process condition for the separation of Np initially in the pentavalent state and to examine the extraction behaviors of fission and corrosion products. (J.P.N.)

Effect of Ramadan fasting on glucose level, lipid profile, HbA1c and uric acid among medical students in Karachi, Pakistan.

Science.gov (United States)

Khan, Nazeer; Rasheed, Abdur; Ahmed, Hassaan; Aslam, Faiza; Kanwal, Fatima

2017-06-14

To assess the effect of Ramadan fasting on blood pressure, fasting glucose, lipid profile, uric acid, HbA1c, body mass index, body adiposity index and visceral adiposity index among fasting medical students, 35 students were recorded before, during and after Ramadan (August) 2011, for their blood pressure, anthropometric measurements, questionnaire response and blood sample. A blood sample was taken at each visit for glucose, lipid profile and HbA1c. Total physical activity, weight-to-height ratio, body adiposity index and visceral adiposity index were calculated for insulin sensitivity. Changes in anthropometric measurements were not statistically significant. However, physical activities increased significantly after Ramadan. Changes in blood pressure, fasting blood sugar, total cholesterol, HbA1c, uric acid and triglyceride were not statistically significant. Mean high density lipoprotein decreased significantly in Ramadan, while low density lipoprotein increased significantly.

Determination of Water Vapor Pressure Over Corrosive Chemicals Versus Temperature Using Raman Spectroscopy as Exemplified with 85.5% Phosphoric Acid

DEFF Research Database (Denmark)

Rodier, Marion; Li, Qingfeng; Berg, Rolf W.

2016-01-01

A method to determine the water vapor pressure over a corrosive substance was developed and tested with 85.5 ± 0.4% phosphoric acid. The water vapor pressure was obtained at a range of temperatures from ∼25 ℃ to ∼200 ℃ using Raman spectrometry. The acid was placed in an ampoule and sealed...... with a reference gas (either hydrogen or methane) at a known pressure (typically ∼0.5 bar). By comparing the Raman signals from the water vapor and the references, the water pressure was determined as a function of temperature. A considerable amount of data on the vapor pressure of phosphoric acid are available...... in the literature, to which our results could successfully be compared. A record value of the vapor pressure, 3.40 bar, was determined at 210 ℃. The method required a determination of the precise Raman scattering ratios between the substance, water, and the used reference gas, hydrogen or methane. In our case...

Decommissioning of Phosphoric Acid Purification Facility, PT Petrokimia Gresik

International Nuclear Information System (INIS)

Zainus Salimin; Nanang TS; Zaid, Ach.; Chotimah; Karyono

2008-01-01

Decommissioning of phosporic acid purification facility was the administrative and technical actions taken to allow the removal of some or all of the regulatory control from that facility exploit the phosphoric acid containing uranium. The site location of facility was cleaned up as the clean previous site (green land) for another site project utilization. Decommissioning activities covers the draining of solution or solid powder of remaining process on the equipment, decontamination of site location and equipment wall, dismantling of equipment, decontamination of equipment after dismantling, and decontamination of concrete floor and wall. Uranium contaminated liquid waste and organic solution was treated by bio-oxidation process using bacteria. Remaining solid powder from process (28 drums), contaminated material and equipment after decontamination (60 drums of fire brick, 31 pieces of equipment cut, 2 drums of ashes, 10 drums of active sludge from bio-oxidation process) and concrete splinter of 10 drums of 200 l volume per drum are the radioactive waste that must be sent to Radioactive Waste Technology Centre for its treatment. The non contaminated material and equipment (908 ton) can be reused for reprocessing, some of non contaminated sludge (14.4 m 3 ) and all of non contaminated filtrate water (353 m 3 ) from bio-oxidation process with toxic matters qualification which comply to the its limit values are released on the effluent release drain system of the plant. Clearance level utilizing for filtering contaminated material or equipment was an activity concentration of 1 Bq/g, surface contamination of 1 Bq/cm 2 , effective dose on the 50 cm distance from surface of contaminated material of 0.5 μSv/h (BAPETEN Regulation Letter No. 1459A/P101/PIBN/2008). Limit values for toxic matter are pH 6-9, COD 100 ppm and BOD 50 ppm (Gov. Regulation of East Java No. 45 year of 2002). (author)

Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells by a Potential Decay Method

DEFF Research Database (Denmark)

Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage

1995-01-01

The reduction of gaseous oxygen on carbon supported platinum electrodes has been studied at 150 degrees C with polarization and potential decay measurements. The electrolyte was either 100 weight percent phosphoric acid or that acid with a fluorinated additive, potassium perfluorohexanesulfonate ......6F13SO3K). The pseudo-Tafel curves of the overpotential vs. log (ii(L)/(i(L) - i)) show a two-slope behavior, probably due to different adsorption mechanisms. The potential relaxations as functions of log (t + tau) and log (-d eta/dt) have been plotted. The variations of these slopes...

Recovery of fluorine, uranium, and rare earth metal values from phosphoric acid by-product brine raffinate

International Nuclear Information System (INIS)

Wamser, C.A.; Bruen, C.P.

1976-01-01

A method for recovering substantially all of the fluorine and uranium values and at least 90 percent of the rare earth metal values from brine raffinate obtained as by-product in the production of phosphoric acid by the hydrochloric acid decomposition of tricalcium phosphate minerals is described. A basically reacting compound is added to the brine raffinate to effect a pH 9 or greater, whereby fluorine, uranium and rare earth metal values are simultaneously precipitated. These values may then be separately recovered from the precipitate by known processes

Associations of fatty acids in cerebrospinal fluid with peripheral glucose concentrations and energy metabolism.

Directory of Open Access Journals (Sweden)

Reiner Jumpertz

Full Text Available Rodent experiments have emphasized a role of central fatty acid (FA species, such as oleic acid, in regulating peripheral glucose and energy metabolism. Thus, we hypothesized that central FAs are related to peripheral glucose regulation and energy expenditure in humans. To test this we measured FA species profiles in cerebrospinal fluid (CSF and plasma of 32 individuals who stayed in our clinical inpatient unit for 6 days. Body composition was measured by dual energy X-ray absorptiometry and glucose regulation by an oral glucose test (OGTT followed by measurements of 24 hour (24EE and sleep energy expenditure (SLEEP as well as respiratory quotient (RQ in a respiratory chamber. CSF was obtained via lumbar punctures; FA concentrations were measured by liquid chromatography/mass spectrometry. As expected, FA concentrations were higher in plasma compared to CSF. Individuals with high concentrations of CSF very-long-chain saturated FAs had lower rates of SLEEP. In the plasma moderate associations of these FAs with higher 24EE were observed. Moreover, CSF monounsaturated long-chain FA (palmitoleic and oleic acid concentrations were associated with lower RQs and lower glucose area under the curve during the OGTT. Thus, FAs in the CSF strongly correlated with peripheral metabolic traits. These physiological parameters were most specific to long-chain monounsaturated (C16:1, C18:1 and very-long-chain saturated (C24:0, C26:0 FAs.Together with previous animal experiments these initial cross-sectional human data indicate that central FA species are linked to peripheral glucose and energy homeostasis.

Performance Degradation Tests of Phosphoric Acid Doped Polybenzimidazole Membrane Based High Temperature Polymer Electrolyte Membrane Fuel Cells

DEFF Research Database (Denmark)

Zhou, Fan; Araya, Samuel Simon; Grigoras, Ionela

2015-01-01

Degradation tests of two phosphoric acid (PA) doped PBI membrane based HT-PEM fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation of the HT-PEM fuel cell. Continuous tests with pure dry H2 and meth...

Studies on the solvent extraction behaviour of Pu(IV) from nitric acid, nitric-perchloric acid and hydrochloric acids, by di,2-ethylhexyl phosphoric acid (HDEHP)

International Nuclear Information System (INIS)

Phal, D.G.; Kannan, S.K.; Ramakrishna, V.V.

1994-01-01

Extraction of plutonium (IV) from aqueous nitric acid, nitric-perchloric acid and hydrochloric acids by di,2-ethylhexyl phosphoric acid, the dimeric form of which is represented as H 2 Y 2 , in different diluents (dodecane, toluene and chloroform) was investigated. The composition of the extracted Pu(IV) species were found to be Pu(NO 3 ) 2 (HY) 2 , Pu(NO 3 )(ClO 4 )(HY 2 ) 2 , PuClY(HY 2 ) 2 and PuCl 2 (HY 2 ) 2 from nitric, nitric-perchloric and hydrochloric acids respectively, the last one being pre-dominant at high aqueous acidities (i.e. 5M HCl). Synergic enhancement in the extraction of Pu(IV) from different aqueous media, by the addition of thenoyltrifluoroacetone (HTTA) to HDEHP was also investigated and was attributed to the formation and extraction of the species PuX(TTA)(HY 2 ) 2 , and Pu(TTA) 2 (HY 2 ) 2 where X=Cl - or NO 3 - . The addition of the neutral extractant TOPO to H 2 Y 2 also resulted in synergism. The possible equilibria in these systems were inferred and the corresponding equilibrium constants determined. (author). 24 refs., 10 figs., 10 tabs

Phosphoric acid activation of sugarcane bagasse for removal of o-toluidine and benzidine

Science.gov (United States)

Adib, M. R. M.; Attahirah, M. H. M. N.; Amirza, A. R. M.

2018-04-01

In the effort to find alternatives for low cost adsorbent, activated carbon using sugarcane bagasse (SBAC) has been introduced in this study that has undergo chemical treatment using phosphoric acid to determine the effectiveness of adsorption process in removing o-toluidine and benzidine. Throughout this study, 92.9% of o-toluidine has been successfully removed by SBAC at optimum value of 1.1 g of dosage with contact time of 10 minutes and concentration of 10 mg/L. While benzidine was remove by 83.1% at optimum dosage of 1.1 g with 60 minutes of contact time and at 20 mg/L concentrations. Testing of SEM proves that SBAC has high porosity and comparable to CAC. In FTIR results, shows that CAC has high number of double bond while SBAC shows no double bond at all. Presence of double bond in CAC lead to increase in percentage of removal of adsorbate. After considering other factor such as cost, energy and environmental friendly, it shows that SBAC was considerable to replaced CAC.

Kinetics of Maleic Acid and Aluminum Chloride Catalyzed Dehydration and Degradation of Glucose

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ximing; Hewetson, Barron B.; Mosier, Nathan S.

2015-04-16

We report the positive effect of maleic acid, a dicarboxylic acid, on the selectivity of hexose dehydration to 5-hydroxymethyfurfural (HMF) and subsequent hydrolysis to levulinic and formic acids. We also describe the kinetic analysis of a Lewis acid (AlCl3) alone and in combination with HCl or maleic acid to catalyze the isomerization of glucose to fructose, dehydration of fructose to HMF, hydration of HMF to levulinic and formic acids, and degradation of these compounds to humins. The results show that AlCl3 significantly enhances the rate of glucose conversion to HMF and levulinic acid in the presence of both maleic acid and HCl. In addition, the degradation of HMF to humins, rather than levulinic and formic acids, is reduced by 50% in the presence of maleic acid and AlCl3 compared to HCl combined with AlCl3. The results suggest different reaction mechanisms for the dehydration of glucose and rehydration of HMF between maleic acid and HCl.

Encapsulation of strontium aluminate phosphors to enhance water resistance and luminescence

International Nuclear Information System (INIS)

Zhu Yong; Zeng Jianghua; Li Wenyu; Xu Li; Guan Qiu; Liu Yingliang

2009-01-01

Strontium aluminate SrAl 2 O 4 :Eu 2+ ,Dy 3+ phosphors are chemically unstable against water or even moisture. To enhance the water resistance of the phosphors, an encapsulation was performed by direct surface reactions with phosphoric acid (H 3 PO 4 ). The morphology, surface structure, surface element composition, water resistance, luminescence, and photoacoustic spectrum of the phosphors before and after encapsulation were discussed. Experimental results showed that phosphors were perfectly encapsulated by amorphous layers in nanoscale and crystalline layers in microscale under different conditions. The water resistance of phosphors was greatly enhanced by the two types of layer. More importantly, the amorphous layers enhanced the luminescence of phosphors markedly. The possible mechanism for the enhancements was also proposed.

OPTIMIZATION OF PRODUCTION OF 5-HYDROXYMETHYLFURFURAL FROM GLUCOSE IN A WATER: ACETONE BIPHASIC SYSTEM

Directory of Open Access Journals (Sweden)

A. D. M. Mendonça

2015-06-01

Full Text Available Abstract5-Hydroxymethylfurfural (HMF is considered to be an important building block for biorefineries and has a high potential for the production of chemicals and fuels. Production of HMF from glucose was studied using phosphoric acid as catalyst, in a water:acetone system with volume ratio of 1:2 and NaCl. An experimental design was applied to examine the influence of temperature, time and concentration of catalyst on the HMF yield. HMF yields of more than 50 % were obtained when using 200 ºC, 8.4 min and 0.8% of catalyst. The temperature is the main factor influencing the HMF yield.

Enhancement of hydrolysis of Chlorella vulgaris by hydrochloric acid.

Science.gov (United States)

Park, Charnho; Lee, Ja Hyun; Yang, Xiaoguang; Yoo, Hah Young; Lee, Ju Hun; Lee, Soo Kweon; Kim, Seung Wook

2016-06-01

Chlorella vulgaris is considered as one of the potential sources of biomass for bio-based products because it consists of large amounts of carbohydrates. In this study, hydrothermal acid hydrolysis with five different acids (hydrochloric acid, nitric acid, peracetic acid, phosphoric acid, and sulfuric acid) was carried out to produce fermentable sugars (glucose, galactose). The hydrothermal acid hydrolysis by hydrochloric acid showed the highest sugar production. C. vulgaris was hydrolyzed with various concentrations of hydrochloric acid [0.5-10 % (w/w)] and microalgal biomass [20-140 g/L (w/v)] at 121 °C for 20 min. Among the concentrations examined, 2 % hydrochloric acid with 100 g/L biomass yielded the highest conversion of carbohydrates (92.5 %) into reducing sugars. The hydrolysate thus produced from C. vulgaris was fermented using the yeast Brettanomyces custersii H1-603 and obtained bioethanol yield of 0.37 g/g of algal sugars.

Determination of the activity concentration of {sup 230}Th in phosphoric acids produced in Brazil; Determinação da concentração de atividade de {sup 230}Th em ácidos fosfóricos produzidos no Brasil

Energy Technology Data Exchange (ETDEWEB)

Taddei, M.H.T.; Ferreira, M.T.; Fukuma, H.T.; Xavier, T.T.; Sousa, F.V.T.S., E-mail: tatianattx@gmail.com [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas. Radioquimica

2017-07-01

The high uranium phosphate rock from Itataia, Brazil, was processed using the wet route in the dihydrate system to manufacture phosphoric acid. The uranium contained in phosphoric acid was recovered by the solvent extraction technique. The distribution of the long half-life radionuclides from the decay series of {sup 238}U and {sup 232}Th were evaluated in these processes. The {sup 26}Ra, {sup 228}Ra and {sup 210}Pb radionuclides were found predominantly in phosphogypsum, while the isotopes of {sup 228}Th, {sup 230}Th and {sup 232}Th predominated in phosphoric acid after extracting uranium. The main concern in the commercialization of phosphoric acid that will be produced in the Itataia plant is in relation to the content of {sup 230}Th. This work determined the content of these radionuclides in phosphoric acid from different locations in the country in order to compare.

Study on the kinetics of high-energy phosphates in myocardium by phosphorous nuclear magnetic resonance

Energy Technology Data Exchange (ETDEWEB)

Kusuoka, Hideo; Tsuneoka, Yutaka; Inoue, Michitoshi; Abe, Hiroshi [Osaka Univ. (Japan). Faculty of Medicine; Watari, Hiroshi

1982-12-01

Effect of artificial blood, FC 43 (Perfluorochemicals) on the kinetics of high-energy phosphate in the myocardium was evaluated by /sup 31/P-NMR which permits a continuous and non-invasive assessment of in vivo phosphorus compounds. Cardiac perfusion was carried out on a excised rat heart with a Krebs-Henseleit modified solution and FC 43 alternately. Under the normal condition, ischemic condition, and at second perfusion amounts of intramyocardial creatine phosphoric acid, ATP, and inorganic phosphorus were determined by /sup 31/P-NMR. Coronary flow was simultaneously estimated. The ischemic state due to interruption of perfusion resulted in a decrease in creatine phosphoric acid, which was associated with an increase in inorganic phosphorus and intracellular acidosis. No change of ATP amount was observed under ischemic state. With resumption of perfusion, the levels of creatine phosphoric acid and inorganic phosphorus rapidly returned to the normal. In the group of FC 43, coronary flow was 2.68 ml/min/g of the heart weight, about 1/2 of that of the Krebs-Henseleit group (5.68 ml/min/g of the heart weight). In controls, there was no difference between the two groups concerning creatine phosphoric acid level and recovery of creatine phospohric acid level after ischemia. These results showed that FC 43 supplies sufficient oxygen, and has no effect on the kinetics of energy in the myocardium.

Anaerobic digestion of glucose with separated acid production and methane formation

Energy Technology Data Exchange (ETDEWEB)

Cohen, R J; Zoetemeyer, R J; Van Deursen, A; Van Andel, J G

1979-01-01

In a two-phase anaerobic-digestion system, with separate reactors for the acidification and methane fermentation phases, the glucose of a 1% glucose solution was almost completely converted into biomass and gases. The acid reactor was operated at 30/sup 0/C and a pH of 6.0, with a retention time of 10 h. The main products of the acid-forming phase were hydrogen, carbon dioxide, butyrate and acetate. On a molar base, these products represented over 96% of all products formed. On average, 12% of the COD content of the influent was evolved as hydrogen. The effluent of the first reactor was pumped to the methane reactor after passing through a storage vessel. The methane reactor was operated at 30/sup 0/C, pH 7.8 and a retention time of 100 h. Approximately 98% of the organic substances fed to this reactor were converted to methane, carbon dioxide and biomass. About 11% of the glucose fed to the digesting system was converted to bacterial mass.

Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid

Science.gov (United States)

2012-01-01

The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing. PMID:23272786

Chemical process for recovery of uranium values contained in phosphoric mineral lixivia

International Nuclear Information System (INIS)

Conceicao, E.L.H. da; Awwal, M.A.; Coelho, S. V.

1980-01-01

A recovery process of uranium values from phosporic mineral lixivia for obtaining uranio oxide concentrate adjusted to specifications of purity for its commercialization the process consists of the adjustment of electromotive force of lixiviem to suitable values for uranium extraction, extraction with organic solvent containing phosphoric acid ester and oxidant reextraction from this solvent with phosphoric acid solution, suggesting a new solvent extraction containing synergetic mixture of di-2-ethyl hexyl phosphoric acid and tri-octyl phosphine, leaching this solvent with water and re-extraction/precipitation with ammonium carbonate solution, resulting in the formation of uranyl tricarbonate and ammonium, that by drying and calcination gives the uranium oxide with purity degree for commercialization. (M.C.K.) [pt

Unactivated yttrium tantalate phosphor

International Nuclear Information System (INIS)

Reddy, V.B.; Cheung, H.K.

1992-01-01

This patent describes an unactivated yttrium tantalate phosphor having M prime monoclinic structure and containing one or more additives of Rb and Al in an amount of between about 0.001 to 0.1 moles per mole of yttrium tantalate to improve brightness under X-radiation. This patent also describes an unactivated yttrium tantalate phosphor having M prime monoclinic structure and containing additives of Sr in an amount of between 0.001 to 0.1 moles per mole of yttrium tantalate and one or more of Rb and Al in an amount of between 0.001 to 0.1 moles per mole of yttrium tantalate the phosphor exhibiting a greater brightness under X-radiation than the phosphor absent Rb and Al

Comparison of arsenic acid with phosphoric acid in the interaction with a water molecule and an alkali/alkaline-earth metal cation.

Science.gov (United States)

Park, Sung Woo; Kim, Chang Woo; Lee, Ji Hyun; Shim, Giwoong; Kim, Kwang S

2011-10-20

Recently, Wolfe-Simon has discovered a bacterium which is able to survive using arsenic(V) rather than phosphorus(V) in its DNA. Thus it is important to investigate some important structural and chemical similarities and dissimilarities between phosphate and arsenate. We compared the monohydrated structures and the alkali/alkaline-earth metal (Na(+), K(+), Mg(2+) and Ca(2+)) complexes of the arsenic acid/anions with those of the phosphoric acid/anions [i.e., H(m)PO(4)(-(3-m)) vs H(m)AsO(4)(-(3-m)) (m = 1-3)]. We carried out geometry optimization along with harmonic frequency calculations using ab initio calculations. Despite the increased van der Waals radius of As, the hydrated structures of both P and As systems show very close similarity (within 0.25 Å in the P/As···O(water) distance and within a few kJ/mol in binding energy) because of the increased induction energies by more polar arsenic acid/anons and slightly increased dispersion energy by a larger size of the As atom. In the metal complexes, the arsenic acid has a slightly larger binding distance (by 0.07-1.0 Å) and weaker binding energy because the As(V) ion has a slightly larger radius than the P(V) ion, and the electrostatic interaction is the dominating feature in these systems.

High temperature thermometric phosphors

Science.gov (United States)

Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

1999-03-23

A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

Glucose-induced lipogenesis in pancreatic beta-cells is dependent on SREBP-1

DEFF Research Database (Denmark)

Sandberg, Maria B; Fridriksson, Jakob; Madsen, Lise

2005-01-01

High concentrations of glucose induce de novo fatty acid synthesis in pancreatic beta-cells and chronic exposure of elevated glucose and fatty acids synergize to induce accumulation of triglycerides, a phenomenon termed glucolipotoxicity. Here we investigate the role of sterol-regulatory element......, de novo fatty acid synthesis and lipid accumulation are induced primarily through sterol-regulatory elements (SREs) and not E-Boxes. Adenoviral expression of a dominant negative SREBP compromises glucose induction of some lipogenic genes and significantly reduces glucose-induction of de novo fatty...... acid synthesis. Thus, we demonstrate for the first time that SREBP activity is necessary for full glucose induction of de novo fatty acid synthesis in pancreatic beta-cells....

Insulin Sensitivity and Glucose Homeostasis Can Be Influenced by Metabolic Acid Load

Directory of Open Access Journals (Sweden)

Lucio Della Guardia

2018-05-01

Full Text Available Recent epidemiological findings suggest that high levels of dietary acid load can affect insulin sensitivity and glucose metabolism. Consumption of high protein diets results in the over-production of metabolic acids which has been associated with the development of chronic metabolic disturbances. Mild metabolic acidosis has been shown to impair peripheral insulin action and several epidemiological findings suggest that metabolic acid load markers are associated with insulin resistance and impaired glycemic control through an interference intracellular insulin signaling pathways and translocation. In addition, higher incidence of diabetes, insulin resistance, or impaired glucose control have been found in subjects with elevated metabolic acid load markers. Hence, lowering dietary acid load may be relevant for improving glucose homeostasis and prevention of type 2 diabetes development on a long-term basis. However, limitations related to patient acid load estimation, nutritional determinants, and metabolic status considerably flaws available findings, and the lack of solid data on the background physiopathology contributes to the questionability of results. Furthermore, evidence from interventional studies is very limited and the trials carried out report no beneficial results following alkali supplementation. Available literature suggests that poor acid load control may contribute to impaired insulin sensitivity and glucose homeostasis, but it is not sufficiently supportive to fully elucidate the issue and additional well-designed studies are clearly needed.

Enhanced amino acid utilization sustains growth of cells lacking Snf1/AMPK

DEFF Research Database (Denmark)

Nicastro, Raffaele; Tripodi, Farida; Guzzi, Cinzia

2015-01-01

when grown with glucose excess. We show that loss of Snf1 in cells growing in 2% glucose induces an extensive transcriptional reprogramming, enhances glycolytic activity, fatty acid accumulation and reliance on amino acid utilization for growth. Strikingly, we demonstrate that Snf1/AMPK-deficient cells...... remodel their metabolism fueling mitochondria and show glucose and amino acids addiction, a typical hallmark of cancer cells....

Bond strength of compomers to dentin using acidic primers.

Science.gov (United States)

Tate, W H; You, C; Powers, J M

1999-10-01

To determine the in vitro bond strengths of seven compomer/bonding agent restorative systems to human dentin. Seven compomer/bonding agents were bonded to human dentin, stored in water at 37 degrees C for 24 hours, and debonded in tension. Bonding conditions were with and without phosphoric acid etching, with and without the use of combined primer/bonding agents, and under moist and wet bond interfaces. Without phosphoric acid etching, F2000/F2000 Compomer Primer/Adhesive and F2000/Single Bond Dental Adhesive System were less sensitive to dentin wetness. With moist dentin, bond strengths of Dyract/Prime & Bond 2.1, Dyract AP/Prime & Bond 2.1, Hytac/OSB light-curing, one-component bonding agent, F2000/Single Bond, and Freedom/STAE single component light-cured dentin/enamel adhesive system, were improved with phosphoric acid etching. Also, with moist dentin, the bond strength of F2000/F2000 Compomer Primer/Adhesive in the 3M Clicker dispensing system was higher without phosphoric acid etching, whereas bonds of Compoglass/Syntac Single-component were not affected by phosphoric acid etching. Bonding did not occur without primer/bonding agent, regardless of surface condition or use of phosphoric acid etching.

Recovery of uranium contained in phosphoric acid by a wet method and its transformation in a high-purity uraniferous concentrates

International Nuclear Information System (INIS)

Davister, A.; Dubreucq, A.; Granville, G.; Gray, H.

1984-01-01

There are altogether three plants in active operation today for the recovery of uranium contained in the phosphoric acid, two in the USA and one in Prayon in Belgium. All three utilize the same solvant, i.e. the Depa-Topo mixture. The Prayon plant was started up in May 1980. Phosphoric acid is desaturated before the extraction for a long time at a low temperature, totally free from mineral and organic solids and rid of its soluble humic matter until a clear acid of very low optical density is obtained. During the re-extraction of the first cycle, the reduction of U 6+ into U 4+ is effected by metallic iron, according to an original patented process which permits the reduction of the introduced iron to a strict minimum. At the end of the second cycle, an original technique permits the precipitation of a uranium and ammonium hydroxide, starting from the aqueous phase, first separated from the organic phase and purified as regards iron; because of this, the concentrate requires no roasting [fr

Limiting Current of Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells

DEFF Research Database (Denmark)

Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage

1994-01-01

on polytetrafluorine-ethyl bonded gas-diffusion electordes in phosphoric acid with and without fluorinated additives. This provides an alternative to estimate the film thickness by combining it with the acid-adsorption measurements and the porosity analysis of the catalyst layer. It was noticed that the limiting......Various models have been devoted to the operation mechanism of porous diffusion electrodes. They are, however, suffering from the lack of accuracy concerning the acid-film thickness on which they are based. In the present paper the limiting current density has been measured for oxygen reduction...... current density can be accomplished either by gas-phase diffusion or liquid-phase diffusion, and it is the latter that can be used in the film-thickness estimation. It is also important to mention that at such a limiting condition, both the thin-film model and the filmed agglomerate model reach the same...

Study of corrosion-erosion behaviour of stainless alloys in industrial phosphoric acid medium

Energy Technology Data Exchange (ETDEWEB)

Guenbour, Abdellah [Laboratory of Electrochemistry-Corrosion, Av. Ibn Batouta, BP1014-Faculty of Science, Rabat (Morocco)]. E-mail: guenbour@fsr.ac.ma; Hajji, Mohamed-Adil [Group Corrosion and Protection of Materials, ENIM, Rabat (Morocco); Jallouli, El Miloudi [Group Corrosion and Protection of Materials, ENIM, Rabat (Morocco); Bachir, Ali Ben [Laboratory of Electrochemistry-Corrosion, Av. Ibn Batouta, BP1014-Faculty of Science, Rabat (Morocco)

2006-12-30

The corrosion and corrosion-abrasion resistance of some stainless steels in industrial phosphoric acid 30% P{sub 2}O{sub 5} has been studied using electrochemical techniques. The corrosion rate of materials increases with the increase of temperature. Alloys which contain chromium, molybdenum and nitrogen in sufficient quantities present the best behaviour. In the abrasion-corrosion conditions, the experimental device set up allowed to follow continually samples electrochemical behaviour. Under dynamic conditions and without solid particles, the increase of acid projection speed has no effect on the alloys corrosion behaviour. The adding of abrasive leads to a general increase of corrosion rate and to a decrease of material resistance. Under these conditions, materials attack is controlled by synergistic effect between the abrasion and the impurities. The cast 30% Cr shows good resistance according to his high chromium content.

Study of corrosion-erosion behaviour of stainless alloys in industrial phosphoric acid medium

International Nuclear Information System (INIS)

Guenbour, Abdellah; Hajji, Mohamed-Adil; Jallouli, El Miloudi; Bachir, Ali Ben

2006-01-01

The corrosion and corrosion-abrasion resistance of some stainless steels in industrial phosphoric acid 30% P 2 O 5 has been studied using electrochemical techniques. The corrosion rate of materials increases with the increase of temperature. Alloys which contain chromium, molybdenum and nitrogen in sufficient quantities present the best behaviour. In the abrasion-corrosion conditions, the experimental device set up allowed to follow continually samples electrochemical behaviour. Under dynamic conditions and without solid particles, the increase of acid projection speed has no effect on the alloys corrosion behaviour. The adding of abrasive leads to a general increase of corrosion rate and to a decrease of material resistance. Under these conditions, materials attack is controlled by synergistic effect between the abrasion and the impurities. The cast 30% Cr shows good resistance according to his high chromium content

Efficacy of fungicide combinations, phosphoric acid, and plant extract from stinging nettle on potato late blight management and tuber yield

Science.gov (United States)

Late blight, caused by Phytophthora infestans is a major constraint to potato production. Inadequate management of the disease has often resulted in heavy losses in various production regions. We assessed the efficacy of fungicides, phosphoric acid, and stinging nettle plant extract combinations for...

Photoassist-phosphorylated TiO2 as a catalyst for direct formation of 5-(hydroxymethyl)furfural from glucose.

Science.gov (United States)

Hattori, Masashi; Kamata, Keigo; Hara, Michikazu

2017-02-01

Photo-assisted phosphorylation of an anatase TiO 2 catalyst was examined to improve its catalytic performance for the direct production of 5-(hydroxymethyl)furfural (HMF), a versatile chemical platform, from glucose. In phosphorylation based on simple esterification between phosphoric acid and surface OH groups on anatase TiO 2 with water-tolerant Lewis acid sites, the density of phosphates immobilized on TiO 2 is limited to 2 phosphates nm -2 , which limits selective HMF production. Phosphorylation of the TiO 2 surface under fluorescent light irradiation increases the surface phosphate density to 50%, which is higher than the conventional limit, thus preventing the adsorption of hydrophilic glucose molecules on TiO 2 and resulting in a more selective HMF production over photoassist-phosphorylated TiO 2 .

A study on the kinetics of high-energy phosphates in myocardium by phosphorous nuclear magnetic resonance

International Nuclear Information System (INIS)

Kusuoka, Hideo; Tsuneoka, Yutaka; Inoue, Michitoshi; Abe, Hiroshi; Watari, Hiroshi.

1982-01-01

Effect of artificial blood, FC 43 (Perfluorochemicals) on the kinetics of high-energy phosphate in the myocardium was evaluated by 31 P-NMR which permits a continuous and non-invasive assessment of in vivo phosphorus compounds. Cardiac perfusion was carried out on a excised rat heart with a Krebs-Henseleit modified solution and FC 43 alternately. Under the normal condition, ischemic condition, and at second perfusion amounts of intramyocardial creatine phosphoric acid, ATP, and inorganic phosphorus were determined by 31 P-NMR. Coronary flow was simultaneously estimated. The ischemic state due to interruption of perfusion resulted in a decrease in creatine phosphoric acid, which was associated with an increase in inorganic phosphorus and intracellular acidosis. No change of ATP amount was observed under ischemic state. With resumption of perfusion, the levels of creatine phosphoric acid and inorganic phosphorus rapidly returned to the normal. In the group of FC 43, coronary flow was 2.68 ml/min/g of the heart weight, about 1/2 of that of the Krebs-Henseleit group (5.68 ml/min/g of the heart weight). In controls, there was no difference between the two groups concerning creatine phosphoric acid level and recovery of creatine phospohric acid level after ischemia. These results showed that FC 43 supplies sufficient oxygen, and has no effect on the kinetics of energy in the myocardium. (Ueda, J.)

Investigation of uranium (VI) extraction mechanisms from phosphoric and sulfuric media by {sup 31}P-NMR

Energy Technology Data Exchange (ETDEWEB)

Fries, B.; Marie, C.; Pacary, V.; Berthon, C.; Miguirditchian, M.; Charbonnel, M.C. [CEA, Centre de Marcoule, Nuclear Energy Divison, RadioChemistry and Processes Department - DRCP, F-30207 Bagnols-sur-Ceze (France); Mokhtari, H. [AREVA Mines, Process and Analysis Department - SEPA, F-87250 Bessines-sur-Gartempe (France)

2016-07-01

Phosphate rocks contain uranium (∼1000 ppm on average) and are considered as a secondary source for uranium production. Uranium extraction using DEHCNPB (butyl-1-[N,N-bis(2-ethylhexyl)carbamoyl]nonyl phosphonic acid, a bifunctional cationic extractant) has been studied to better understand mechanism differences depending on the original acidic solution (phosphoric or sulfuric). Solvent extraction batch experiments were carried out and the organic phases were probed using {sup 31}P-NMR. This technique enabled to demonstrate that phosphoric acid is poorly extracted by DEHCNPB ([H{sub 3}PO{sub 4}]{sub org} < 2 mM), using direct quantification in the organic phase by {sup 31}P-NMR spectra integration. Moreover, in the presence of uranium in the initial phosphoric acid solution, uranyl extraction by DEHCNPB competes with H{sub 3}PO{sub 4} extraction. Average stoichiometries of U(VI)-DEHCNPB complexes in organic phases were also determined using slope analysis on uranium distribution data. Uranium seems to be extracted from a phosphoric medium by two extractant molecules, whereas more than three DEHCNPB on average would be necessary to extract uranium from a sulfuric medium. Thus, uranium is extracted according to different mechanisms depending on the nature of the initial solution. (authors)

Activation of Short and Long Chain Fatty Acid Sensing Machinery in the Ileum Lowers Glucose Production in Vivo.

Science.gov (United States)

Zadeh-Tahmasebi, Melika; Duca, Frank A; Rasmussen, Brittany A; Bauer, Paige V; Côté, Clémence D; Filippi, Beatrice M; Lam, Tony K T

2016-04-15

Evidence continues to emerge detailing the myriad of ways the gut microbiota influences host energy homeostasis. Among the potential mechanisms, short chain fatty acids (SCFAs), the byproducts of microbial fermentation of dietary fibers, exhibit correlative beneficial metabolic effects in humans and rodents, including improvements in glucose homeostasis. The underlying mechanisms, however, remain elusive. We here report that one of the main bacterially produced SCFAs, propionate, activates ileal mucosal free fatty acid receptor 2 to trigger a negative feedback pathway to lower hepatic glucose production in healthy rats in vivo We further demonstrate that an ileal glucagon-like peptide-1 receptor-dependent neuronal network is necessary for ileal propionate and long chain fatty acid sensing to regulate glucose homeostasis. These findings highlight the potential to manipulate fatty acid sensing machinery in the ileum to regulate glucose homeostasis. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

Directory of Open Access Journals (Sweden)

EDUARDO Carlos de Paula

1997-01-01

Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

Role of keto–enol tautomerization in a chiral phosphoric acid catalyzed asymmetric thiocarboxylysis of meso-epoxide: a DFT study

KAUST Repository

Ajitha, Manjaly John; Huang, Kuo-Wei

2015-01-01

The mechanism of a chiral phosphoric acid catalyzed thiocarboxylysis of meso-epoxide was investigated by density functional theory (DFT) calculations (M06-2X). The nucleophilic ring opening of epoxide by thiobenzoic acid was found to proceed via a concerted termolecular transition state with a simultaneous dual proton transfer to yield the β-hydroxy thioester product. Electrostatic interactions together with the steric environment inside the chiral catalyst play an important role in determining the enantioselectivity of the reaction.

Role of keto–enol tautomerization in a chiral phosphoric acid catalyzed asymmetric thiocarboxylysis of meso-epoxide: a DFT study

KAUST Repository

Ajitha, Manjaly John

2015-09-15

The mechanism of a chiral phosphoric acid catalyzed thiocarboxylysis of meso-epoxide was investigated by density functional theory (DFT) calculations (M06-2X). The nucleophilic ring opening of epoxide by thiobenzoic acid was found to proceed via a concerted termolecular transition state with a simultaneous dual proton transfer to yield the β-hydroxy thioester product. Electrostatic interactions together with the steric environment inside the chiral catalyst play an important role in determining the enantioselectivity of the reaction.

Determination of uranium in urine samples for workers in the phosphoric acid purification using fluorimetry technique

International Nuclear Information System (INIS)

Kharita, M. H.; Sakhita, Kh.; Aldalal, Z.

2003-10-01

There is probability of exposure to uranium for workers in the phosphoric acid purification (internal exposure) by inhalation, and the deposition of this uranium in organs and tissues, and the consequence excreation out of the body by perspiration or urine. This study focuses on the determination of uranium in urine samples of workers. All results seem to be under the detection limit of the method, therefore no routine monitoring is required. (author)

Effect of essential fatty acids on glucose-induced cytotoxicity to retinal vascular endothelial cells

Directory of Open Access Journals (Sweden)

Shen Junhui

2012-07-01

Full Text Available Abstract Background Diabetic retinopathy is a major complication of dysregulated hyperglycemia. Retinal vascular endothelial cell dysfunction is an early event in the pathogenesis of diabetic retinopathy. Studies showed that hyperglycemia-induced excess proliferation of retinal vascular endothelial cells can be abrogated by docosahexaenoic acid (DHA, 22:6 ω-3 and eicosapentaenoic acid (EPA, 20:5 ω-3. The influence of dietary omega-3 PUFA on brain zinc metabolism has been previously implied. Zn2+ is essential for the activity of Δ6 desaturase as a co-factor that, in turn, converts essential fatty acids to their respective long chain metabolites. Whether essential fatty acids (EFAs α-linolenic acid and linoleic acid have similar beneficial effect remains poorly understood. Methods RF/6A cells were treated with different concentrations of high glucose, α-linolenic acid and linoleic acid and Zn2+. The alterations in mitochondrial succinate dehydrogenase enzyme activity, cell membrane fluidity, reactive oxygen species generation, SOD enzyme and vascular endothelial growth factor (VEGF secretion were evaluated. Results Studies showed that hyperglycemia-induced excess proliferation of retinal vascular endothelial cells can be abrogated by both linoleic acid (LA and α-linolenic acid (ALA, while the saturated fatty acid, palmitic acid was ineffective. A dose–response study with ALA showed that the activity of the mitochondrial succinate dehydrogenase enzyme was suppressed at all concentrations of glucose tested to a significant degree. High glucose enhanced fluorescence polarization and microviscocity reverted to normal by treatment with Zn2+ and ALA. ALA was more potent that Zn2+. Increased level of high glucose caused slightly increased ROS generation that correlated with corresponding decrease in SOD activity. ALA suppressed ROS generation to a significant degree in a dose dependent fashion and raised SOD activity significantly. ALA suppressed

A kinetic study on the conversion of glucose to levulinic acid

NARCIS (Netherlands)

Girisuta, B; Janssen, LPBM; Heeres, HJ

Levulinic acid has been identified as a promising green. biomass derived platform chemical. A kinetic study oil one of the key steps in the conversion of biomass to levulinic acid, i.e., the acid catalysed decomposition of glucose to levulinic acid has been performed. The experiments were Performed

Radiological assessment occupational radionuclides in a phosphoric acid plant; Evaluacion radiologica ocupacional y distribucion de radionucleidos en una planta de acido fosforico

Energy Technology Data Exchange (ETDEWEB)

Bolivar, J. P.; Garcia-Tenorio, R.

2008-07-01

On the frame of a research project devoted to the control of the exposure due to natural radiation in several NORM industries located at the South of Spain, a detailed to the production of phosphoric acid has been performed. In addition, the behaviour along the mentioned process of the different radionuclides involved has been analysed. It has been concluded that the effective dose which can be received by the workers of the plant is clearly below 1 mSv/year. And it has been demonstrated that the main route of occupational exposure corresponds to the external radiation due mainly to the permanent presence of a radioactive contamination source in different zones of the plant. This contamination source is associated to the presence of scales in the inner surfaces of pipes and equipment as well as to the presence of sludges in the phosphoric acid storage tanks, which in both cases contain elevated concentrations of 226{sup R}a. Moreover, the 222{sup R}n concentrations inside the plant do not overpass 100 Bq/m{sup 3}, which not constitutes a radiological problem. (Author) 9 refs.

Nitrogenous compounds stimulate glucose-derived acid production by oral Streptococcus and Actinomyces.

Science.gov (United States)

Norimatsu, Yuka; Kawashima, Junko; Takano-Yamamoto, Teruko; Takahashi, Nobuhiro

2015-09-01

Both Streptococcus and Actinomyces can produce acids from dietary sugars and are frequently found in caries lesions. In the oral cavity, nitrogenous compounds, such as peptides and amino acids, are provided continuously by saliva and crevicular gingival fluid. Given that these bacteria can also utilize nitrogen compounds for their growth, it was hypothesized that nitrogenous compounds may influence their acid production; however, no previous studies have examined this topic. Therefore, the present study aimed to assess the effects of nitrogenous compounds (tryptone and glutamate) on glucose-derived acid production by Streptococcus and Actinomyces. Acid production was evaluated using a pH-stat method under anaerobic conditions, whereas the amounts of metabolic end-products were quantified using high performance liquid chromatography. Tryptone enhanced glucose-derived acid production by up to 2.68-fold, whereas glutamate enhanced Streptococcus species only. However, neither tryptone nor glutamate altered the end-product profiles, indicating that the nitrogenous compounds stimulate the whole metabolic pathways involving in acid production from glucose, but are not actively metabolized, nor do they alter metabolic pathways. These results suggest that nitrogenous compounds in the oral cavity promote acid production by Streptococcus and Actinomyces in vivo. © 2015 The Societies and Wiley Publishing Asia Pty Ltd.

Mild-temperature dilute acid pretreatment for integration of first and second generation ethanol processes.

Science.gov (United States)

Nair, Ramkumar B; Kalif, Mahdi; Ferreira, Jorge A; Taherzadeh, Mohammad J; Lennartsson, Patrik R

2017-12-01

The use of hot-water (100°C) from the 1st generation ethanol plants for mild-temperature lignocellulose pretreatment can possibly cut down the operational (energy) cost of 2nd generation ethanol process, in an integrated model. Dilute-sulfuric and -phosphoric acid pretreatment at 100°C was carried out for wheat bran and whole-stillage fibers. Pretreatment time and acid type influenced the release of sugars from wheat bran, while acid-concentration was found significant for whole-stillage fibers. Pretreatment led up-to 300% improvement in the glucose yield compared to only-enzymatically treated substrates. The pretreated substrates were 191-344% and 115-300% richer in lignin and glucan, respectively. Fermentation using Neurospora intermedia, showed 81% and 91% ethanol yields from wheat bran and stillage-fibers, respectively. Sawdust proved to be a highly recalcitrant substrate for mild-temperature pretreatment with only 22% glucose yield. Both wheat bran and whole-stillage are potential substrates for pretreatment using waste heat from the 1st generation process for 2nd generation ethanol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of an inducible UDP-glucose:salicylic acid O-glucosyltransferase from oat roots

International Nuclear Information System (INIS)

Yalpani, N.; Schulz, M.; Balke, N.E.

1990-01-01

Phytotoxicity of salicylic acid (SA), a phenolic acid that inhibits ion absorption in plant roots, is reduced in oat roots by the action of a UDP-glucose:SA glucosyltransferase (GTase). GTase activity, extracted from oat roots and assayed with [ 14 C]SA, was present at low constitutive levels but increased within 1.5 h of incubation of roots in 0.5 mM SA at pH 6.5. This induction was the result of de novo RNA and protein synthesis. Induction was highly specific towards SA as the inducer. The partially purified, soluble enzyme has a M t of about 50,000 and high specificity towards UDP-glucose as the sugar donor (K m = 0.28 mM) and SA as the glucose acceptor (K m = 0.11 mM). 2-D PAGE of [ 35 S]methionine-labeled proteins extracted from induced and uninduced roots revealed a candidate peptide representing the GTase. This peptide was also present on gels of partially purified GTase

Effects of dietary substitution of mixed amino acids for glucose on the splanchnic metabolism of plasma triglycerides, cholesterol, carbohydrates, and amino acids in conscious fed baboons.

Science.gov (United States)

Wolfe, B M; Redinger, R N; Marliss, E B; Grace, D M

1983-04-01

Splanchnic metabolism was studied in the fed state during prolonged constant intravenous administration of tracer amounts of [9,10]-3H palmitic acid and the calculated isocaloric intraduodenal administration (13 mg/min X kg body wt0.75) of either (1) glucose, (2) 15% mixed amino acids and 85% glucose or (3) 45% mixed amino acids and 55% glucose to conscious, restrained female baboons that had been maintained on a similar diet (supplemented in essential nutrients) for the previous 9 days. Secretion of plasma triglycerides from the splanchnic region was quantified from splanchnic flow and radiochemical measurements of transsplanchnic gradients of 3H-labeled free fatty acids and triglycerides. Mean splanchnic secretion of plasma triglycerides increased significantly as the proportion of dietary calories derived from amino acids was varied from 0 to 15 to 45% (mean values 1.1 +/- 0.1, 2.6 +/- 0.2 and 4.2 +/- 0.3 mumol/min kg body wt0.75, respectively, p less than 0.05). Increased triglyceride secretion was attributable to both significantly higher rates of esterification of free fatty acids taken up in the splanchnic region to triglycerides released into hepatic venous blood plasma (mean values 10 +/- 1, 16 +/- 2 and 34 +/- 5%, respectively) and to significantly higher rates of secretion of triglycerides derived from precursors other than free fatty acids. Higher intake of amino acids was also associated with both higher plasma concentrations of cholesterol and higher values for hepatic oxidation of cholesterol to bile acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation of rod type structures of CaSO4: Ce,P,Dy TLD phosphor using different synthesis routes

International Nuclear Information System (INIS)

Atone, M.S.; Wani, J.A.; Dhoble, S.J.

2011-01-01

Effect of Ce and P co-activation in CaSO 4 : Dy, standard TLD phosphor prepared by different synthesis root techniques and it's structural morphology is reported first time in this paper. We have already reported the sensitization of luminescence in CaSO 4 : Dy with phosphorous (P) and cerium (Ce) ions separately via acid distillation route. In the current investigation, we have doped these impurities (Ce, P, Dy) simultaneously in CaSO 4 host lattice. We have employed a well known chemical precipitation method and modified acid distillation method and have attempted to analyse the surface morphology resulted from these two synthesis routes. Chemical precipitation usually takes place at room temperature and in this way allows the reaction to take place silently. In case of acid distillation method we have reduced the synthesis temperature to 493K which is considerably less than 653K employed in previously reported literature. In case of precipitation method particle shape seems to be spherical and particle size is around one micro range or in the neighbourhood of nanorange. However, in the case of modified acid distillation method particles have shaped in to rod like structures and particle size again falls in the micro range. The photoluminescence intensity of the phosphor prepared by chemical precipitation method is weak as compared to the phosphor prepared by modified acid distillation method. Both the phosphors prepared by different methods have shown characteristic transitions of dopants. The emission spectra of prepared phosphors at 309 nm and 329 nm of Ce 3+ ions overlap well with excitation of Dy 3+ ions. Thermoluminescence (TL) property of both phosphors is again good though certain variation is observed in case of phosphor prepared by modified acid distillation method which shows rod like structure of phosphor. This variation in TL may be attributed to change in surface morphology (formation of rod type structure of particles) of the phosphor. (author)

High pressure HC1 conversion of cellulose to glucose

Energy Technology Data Exchange (ETDEWEB)

Antonoplis, Robert Alexander [Univ. of California, Berkeley, CA (United States); Blanch, Harvey W. [Univ. of California, Berkeley, CA (United States); Wilke, Charles R. [Univ. of California, Berkeley, CA (United States)

1981-08-01

The production of ethanol from glucose by means of fermentation represents a potential long-range alternative to oil for use as a transportation fuel. Today's rising oil prices and the dwindling world supply of oil have made other fuels, such as ethanol, attractive alternatives. It has been shown that automobiles can operate, with minor alterations, on a 10% ethanol-gasoline mixture popularly known as gasohol. Wood has long been known as a potential source of glucose. Glucose may be obtained from wood following acid hydrolysis. In this research, it was found that saturating wood particles with HCl gas under pressure was an effective pretreatment before subjecting the wood to dilute acid hydrolysis. The pretreatment is necessary because of the tight lattice structure of cellulose, which inhibits dilute acid hydrolysis. HCl gas makes the cellulose more susceptible to hydrolysis and the glucose yield is doubled when dilute acid hydrolysis is preceded by HCl saturation at high pressure. The saturation was most effectively performed in a fluidized bed reactor, with pure HCl gas fluidizing equal volumes of ground wood and inert particles. The fluidized bed effectively dissipated the large amount of heat released upon HCl absorption into the wood. Batch reaction times of one hour at 314.7 p.s.i.a. gave glucose yields of 80% and xylose yields of 95% after dilute acid hydrolysis. A non-catalytic gas-solid reaction model, with gas diffusing through the solid limiting the reaction rate, was found to describe the HCl-wood reaction in the fluidized bed. HCl was found to form a stable adduct with the lignin residue in the wood, in a ratio of 3.33 moles per mole of lignin monomer. This resulted in a loss of 0.1453 lb. of HCl per pound of wood. The adduct was broken upon the addition of water. A process design and economic evaluation for a plant to produce 214 tons per day of glucose from air-dried ground Populus tristi gave an estimated glucose cost of 15.14 cents per pound

Caffeic acid as active principle from the fruit of Xanthium strumarium to lower plasma glucose in diabetic rats.

Science.gov (United States)

Hsu, F L; Chen, Y C; Cheng, J T

2000-04-01

The antihyperglycemic effect of caffeic acid, one of the phenolic compounds contained in the fruit of Xanthium strumarium, was investigated. After an intravenous injection of caffeic acid into diabetic rats of both streptozotocin-induced and insulin-resistant models, a dose-dependent decrease of plasma glucose was observed. However, a similar effect was not produced in normal rats. An insulin-independent action of caffeic acid can thus be considered. Otherwise, this compound reduced the elevation of plasma glucose level in insulin-resistant rats receiving a glucose challenge test. Also, glucose uptake into the isolated adipocytes was raised by caffeic acid in a concentration-dependent manner. Increase of glucose utilization by caffeic acid seems to be responsible for the lowering of plasma glucose.

Electron-beam-pumped phosphors

International Nuclear Information System (INIS)

Goldhar, J.; Krupke, W.F.

1985-01-01

Electron-beam excitation of solid-state scintillators, or phosphors, can result in efficient generation of visible light confined to relatively narrow regions of the spectrum. The conversion efficiency can exceed 20%, and, with proper choice of phosphors, radiation can be obtained anywhere from the near infrared (IR) to the near ultraviolet (UV). These properties qualify the phosphors as a potentially useful pump source for new solid-state lasers. New phosphors are being developed for high-brightness television tubes that are capable of higher power dissipation. Here, an epitaxial film of fluorescing material is grown on a crystalline substrate with good thermal properties. For example, researchers at North American Philips Laboratories have developed a cerium-doped yttrium aluminum garnet (YAG) grown on a YAG substrate, which has operated at 1 A/cm 2 at 20 kV without observed thermal quenching. The input power is higher by almost two orders of magnitude than that which can be tolerated by a conventional television phosphor. The authors describe tests of these new phosphors

Ursolic acid increases skeletal muscle and brown fat and decreases diet-induced obesity, glucose intolerance and fatty liver disease.

Directory of Open Access Journals (Sweden)

Steven D Kunkel

Full Text Available Skeletal muscle Akt activity stimulates muscle growth and imparts resistance to obesity, glucose intolerance and fatty liver disease. We recently found that ursolic acid increases skeletal muscle Akt activity and stimulates muscle growth in non-obese mice. Here, we tested the hypothesis that ursolic acid might increase skeletal muscle Akt activity in a mouse model of diet-induced obesity. We studied mice that consumed a high fat diet lacking or containing ursolic acid. In skeletal muscle, ursolic acid increased Akt activity, as well as downstream mRNAs that promote glucose utilization (hexokinase-II, blood vessel recruitment (Vegfa and autocrine/paracrine IGF-I signaling (Igf1. As a result, ursolic acid increased skeletal muscle mass, fast and slow muscle fiber size, grip strength and exercise capacity. Interestingly, ursolic acid also increased brown fat, a tissue that shares developmental origins with skeletal muscle. Consistent with increased skeletal muscle and brown fat, ursolic acid increased energy expenditure, leading to reduced obesity, improved glucose tolerance and decreased hepatic steatosis. These data support a model in which ursolic acid reduces obesity, glucose intolerance and fatty liver disease by increasing skeletal muscle and brown fat, and suggest ursolic acid as a potential therapeutic approach for obesity and obesity-related illness.

Laser enhanced reductions of uranium(VI) ion in aqueous phosphoric acid solutions

International Nuclear Information System (INIS)

Park, Y.Y.; Harada, M.; Tomiyasu, H.; Ikeda, Y.; Takashima, Y.

1991-01-01

Photochemical reactions of U(VI) ions with inorganic anions (I - , Br - , Cl - , NCS - ) and organic compounds (1-hexene, cyclohexene, pyridine) in phosphoric acid were studied for the purpose of finding an efficient method of adjusting the oxidation states of uranium ions in nuclear fuel reprocessing. The formation of U(IV) was observed in the photoreactions with I - , Br - and NCS - , but not with Cl - . The yield of U(VI) increased in the order, Br - - - . This order was the same as the quenching rate constants of the excited U(VI) ions with these anions, and the reverse of their standard redox potentials. The rates of the formation of U(IV) in the presence of Br - were measured spectrophotometrically. It was found that the rate equation was first order in both [U(VI)] and [Br - ]. The results were reasonably interpreted by a series of reaction processes involving U(V) and Br radical. With organic molecules, 1-hexene, cyclohexene, and pyridine, the formation of U(IV) were observed. The yield of U(IV) increased in the order pyridine < 1-hexene < cyclohexene. This order is the reverse of their vertical ionization potentials, suggesting an electron transfer mechanism between these organic molecules and excited U(VI). (author)

On the complexing of phosphoric acid vinyl esters with praseodymium (3) and europium (3) nitrates in acetonitrile

International Nuclear Information System (INIS)

Goryushko, A.G.; Gololobov, Yu.G.; Boldeskul, A.E.; Oganesyan, A.S.; Yartsev, V.G.

1990-01-01

By the methods of electron, IR and PMR spectroscopy interaction of vinyl esters of phosphoric acid with praseodymium (3) and europium (3) nitrates in acetonitrile solutions has been studied. It is shown that the character of metal-ligand interaction is determined by chemical nature of the ligands: for a compound of ionic structure partially covalent bond is formed, and for a compound of betaine structure the interaction has mainly dipole character. Addition of molecule with betaine structure to praseodymium nitrate causes a change in geometry of Pr 3+ close surrounding and increase in its coordination number. The possibility of formation of the complex with metal-ligand ratio equal to 1:3 is shown

Poly(1-(2-carboxyethyl)pyrrole)/polypyrrole composite nanowires for glucose biosensor

International Nuclear Information System (INIS)

Jiang Hairong; Zhang Aifeng; Sun Yanan; Ru Xiaoning; Ge Dongtao; Shi Wei

2012-01-01

A novel glucose biosensor based on poly(1-(2-carboxyethyl)pyrrole) (PPyCOOH)/polypyrrole (PPy) composite nanowires was developed by immobilizing glucose oxidase (GOD) on the nanowires via covalent linkages. The PPyCOOH/PPy composite nanowires were fabricated by a facile two-step electrochemical synthesis route. First, PPy nanowires were synthesized in phosphate buffer solution using organic sulfonic acid, p-toluenesulfonate acid, as soft-template. Then, PPyCOOH/PPy composite nanowires were obtained by polymerizing 1-(2-carboxyethyl)pyrrole onto PPy nanowires via electrochemical method. Scanning electron microscopic, FT-IR spectra, X-ray photoelectron spectroscopy and cyclic voltammograms were used to characterize the structural and electrical behaviors of the composite nanowires. The PPyCOOH/PPy composite nanowires exhibited uniform diameter, high reactive site (-COOH), large specific surface, excellent electroactivity and good adhesion to electrode. The glucose biosensor was constructed by covalently coupling GOD to the composite nanowires. The biosensor response was rapid (5 s), highly sensitive (33.6 μA mM −1 cm −2 ) with a wide linear range (up to 10.0 mM) and low detection limit (0.63 μM); it also exhibited high stability and specificity to glucose. The attractive electrochemical and structural properties of PPyCOOH/PPy composite nanowires suggested potential application for electrocatalysis and biosensor.

Hydrogen evolution activity and electrochemical stability of selected transition metal carbides in concentrated phosphoric acid

DEFF Research Database (Denmark)

Tomás García, Antonio Luis; Jensen, Jens Oluf; Bjerrum, Niels J.

2014-01-01

phosphoric acid were investigated in a temperature range from 80 to 170°C. A significant dependence of the activities on temperature was observed for all five carbide samples. Through the entire temperature range Group 6 metal carbides showed higher activity than that of the Group 5 metal carbides......Alternative catalysts based on carbides of Group 5 (niobium and tantalum) and 6 (chromium, molybdenum and tungsten) metals were prepared as films on the metallic substrates. The electrochemical activities of these carbide electrodes towards the hydrogen evolution reaction (HER) in concentrated...

Circulating Glucagon 1-61 Regulates Blood Glucose by Increasing Insulin Secretion and Hepatic Glucose Production

DEFF Research Database (Denmark)

Wewer Albrechtsen, Nicolai J.; Kuhre, Rune E.; Hornburg, Daniel

2017-01-01

that PG 1-61 dose-dependently increases levels of cAMP, through the glucagon receptor, and increases insulin secretion and protein levels of enzymes regulating glycogenolysis and gluconeogenesis. In rats, PG 1-61 increases blood glucose and plasma insulin and decreases plasma levels of amino acids in......Glucagon is secreted from pancreatic α cells, and hypersecretion (hyperglucagonemia) contributes to diabetic hyperglycemia. Molecular heterogeneity in hyperglucagonemia is poorly investigated. By screening human plasma using high-resolution-proteomics, we identified several glucagon variants, among...... which proglucagon 1-61 (PG 1-61) appears to be the most abundant form. PG 1-61 is secreted in subjects with obesity, both before and after gastric bypass surgery, with protein and fat as the main drivers for secretion before surgery, but glucose after. Studies in hepatocytes and in β cells demonstrated...

A comparative study of serum uric acid, glucose, calcium and magnesium in pre-eclampsia and normal pregnancy

Directory of Open Access Journals (Sweden)

Arun Dhungana

2017-09-01

Full Text Available Background: Preeclampsia is associated with liver function abnormalities and renal function impairment. The objective of this study is to compare serum uric acid, glucose, calcium and magnesium in pre-eclampsia with normal pregnancy. Materials and Methods: Normal pregnant women and pre eclamptic women of age group 20-40 years were included. Serum magnesium, calcium, glucose, uric acid were analyzed.Results: Mean serum magnesium level in preeclampsia (1.83 ± 0.21mg/dl was lesser in comparison to normal pregnant women (2.03 ± 0.16 mg/dl. Serum calcium level was lower (8.10 ±0.56mg/dl than control (9.59 ±0.62 mg/dl with p<0.001. Uric acid, glucose and lactate dehydrogenase in preeclamptic women was significantly higher than that in normal pregnant women (6.14 ± 0.85 vs.4.01 ± 0.62, p=<0.001, (94.17± 18.65 vs.86.34 ± 10.19, p=0.033 and ( 466.80 ± 97.29 vs. 194.22 ± 39.76, p=<0.001 respectively.Conclusion: There were significant changes in serum magnesium, uric acid, calcium, glucose, lactate dehydrogenase and total protein in pregnant women.

Phospholipase D1 mediates AMP-activated protein kinase signaling for glucose uptake.

Directory of Open Access Journals (Sweden)

Jong Hyun Kim

2010-03-01

Full Text Available Glucose homeostasis is maintained by a balance between hepatic glucose production and peripheral glucose utilization. In skeletal muscle cells, glucose utilization is primarily regulated by glucose uptake. Deprivation of cellular energy induces the activation of regulatory proteins and thus glucose uptake. AMP-activated protein kinase (AMPK is known to play a significant role in the regulation of energy balances. However, the mechanisms related to the AMPK-mediated control of glucose uptake have yet to be elucidated.Here, we found that AMPK-induced phospholipase D1 (PLD1 activation is required for (14C-glucose uptake in muscle cells under glucose deprivation conditions. PLD1 activity rather than PLD2 activity is significantly enhanced by glucose deprivation. AMPK-wild type (WT stimulates PLD activity, while AMPK-dominant negative (DN inhibits it. AMPK regulates PLD1 activity through phosphorylation of the Ser-505 and this phosphorylation is increased by the presence of AMP. Furthermore, PLD1-S505Q, a phosphorylation-deficient mutant, shows no changes in activity in response to glucose deprivation and does not show a significant increase in (14C-glucose uptake when compared to PLD1-WT. Taken together, these results suggest that phosphorylation of PLD1 is important for the regulation of (14C-glucose uptake. In addition, extracellular signal-regulated kinase (ERK is stimulated by AMPK-induced PLD1 activation through the formation of phosphatidic acid (PA, which is a product of PLD. An ERK pharmacological inhibitor, PD98059, and the PLD inhibitor, 1-BtOH, both attenuate (14C-glucose uptake in muscle cells. Finally, the extracellular stresses caused by glucose deprivation or aminoimidazole carboxamide ribonucleotide (AICAR; AMPK activator regulate (14C-glucose uptake and cell surface glucose transport (GLUT 4 through ERK stimulation by AMPK-mediated PLD1 activation.These results suggest that AMPK-mediated PLD1 activation is required for (14C-glucose

Complete oxidative conversion of lignocellulose derived non-glucose sugars to sugar acids by Gluconobacter oxydans.

Science.gov (United States)

Yao, Ruimiao; Hou, Weiliang; Bao, Jie

2017-11-01

Non-glucose sugars derived from lignocellulose cover approximately 40% of the total carbohydrates of lignocellulose biomass. The conversion of the non-glucose sugars to the target products is an important task of lignocellulose biorefining research. Here we report a fast and complete conversion of the total non-glucose sugars from corn stover into the corresponding sugar acids by whole cell catalysis and aerobic fermentation of Gluconobacter oxydans. The conversions include xylose to xylonate, arabinose to arabonate, mannose to mannonate, and galactose to galactonate, as well as with glucose into gluconate. These cellulosic non-glucose sugar acids showed the excellent cement retard setting property. The mixed cellulosic sugar acids could be used as cement retard additives without separation. The conversion of the non-glucose sugars not only makes full use of lignocellulose derived sugars, but also effectively reduces the wastewater treatment burden by removal of residual sugars. Copyright © 2017 Elsevier Ltd. All rights reserved.

3,3'-Diaryl-BINOL phosphoric acids as enantioselective extractants of benzylic primary amines.

Science.gov (United States)

Verkuijl, Bastiaan J V; de Vries, Johannes G; Feringa, Ben L

2011-01-01

We report that 3,3'-diaryl-BINOL phosphoric acids are effective enantioselective extractants in chiral separation methods based on reactive liquid-liquid extraction. These new extractants are capable of separating racemic benzylic primary amine substrates. The effect of the nature of the substituents at the 3,3'-positions of the host were examined as well as the structure of the substrate, together with important parameters such as the organic solvent, the pH of the aqueous phase, and the host stoichiometry. Titration of the substrate with the host was monitored by FTIR, NMR, UV-Vis, and CD spectroscopy, which provided insight into the structure of the host-guest complex involved in extraction. Copyright © 2010 Wiley-Liss, Inc.

Comparison of different phosphorous adsorption models in acid ...

African Journals Online (AJOL)

This study was designed to compare the phosphorous fixation capacity of three soils series named Tyele, Minkonmingon and Mekoto in the south region of Cameroon and to determine the soil properties that are the main predictors of the P activity of those soils. Five adsorption equations viz. Linear, Langmuir, Van Huay, ...

Process for the removal of acid forming gases from exhaust gases and production of phosphoric acid

Science.gov (United States)

Chang, Shih-Ger; Liu, David K.

1992-01-01

Exhaust gases are treated to remove NO or NO.sub.x and SO.sub.2 by contacting the gases with an aqueous emulsion or suspension of yellow phosphorous preferably in a wet scrubber. The addition of yellow phosphorous in the system induces the production of O.sub.3 which subsequently oxidizes NO to NO.sub.2. The resulting NO.sub.2 dissolves readily and can be reduced to form ammonium ions by dissolved SO.sub.2 under appropriate conditions. In a 20 acfm system, yellow phosphorous is oxidized to yield P.sub.2 O.sub.5 which picks up water to form H.sub.3 PO.sub.4 mists and can be collected as a valuable product. The pressure is not critical, and ambient pressures are used. Hot water temperatures are best, but economics suggest about 50.degree. C. The amount of yellow phosphorus used will vary with the composition of the exhaust gas, less than 3% for small concentrations of NO, and 10% or higher for concentrations above say 1000 ppm. Similarly, the pH will vary with the composition being treated, and it is adjusted with a suitable alkali. For mixtures of NO.sub.x and SO.sub.2, alkalis that are used for flue gas desulfurization are preferred. With this process, better than 90% of SO.sub.2 and NO in simulated flue gas can be removed. Stoichiometric ratios (P/NO) ranging between 0.6 and 1.5 were obtained.

Environmental, health, and safety issues of fuel cells in transportation. Volume 1: Phosphoric acid fuel-cell buses

Energy Technology Data Exchange (ETDEWEB)

Ring, S

1994-12-01

The U.S. Department of Energy (DOE) chartered the Phosphoric Acid Fuel-Cell (PAFC) Bus Program to demonstrate the feasibility of fuel cells in heavy-duty transportation systems. As part of this program, PAFC- powered buses are being built to meet transit industry design and performance standards. Test-bed bus-1 (TBB-1) was designed in 1993 and integrated in March 1994. TBB-2 and TBB-3 are under construction and should be integrated in early 1995. In 1987 Phase I of the program began with the development and testing of two conceptual system designs- liquid- and air-cooled systems. The liquid-cooled PAFC system was chosen to continue, through a competitive award, into Phase H, beginning in 1991. Three hybrid buses, which combine fuel-cell and battery technologies, were designed during Phase III. After completing Phase II, DOE plans a comprehensive performance testing program (Phase HI) to verify that the buses meet stringent transit industry requirements. The Phase III study will evaluate the PAFC bus and compare it to a conventional diesel bus. This NREL study assesses the environmental, health, and safety (EH&S) issues that may affect the commercialization of the PAFC bus. Because safety is a critical factor for consumer acceptance of new transportation-based technologies the study focuses on these issues. The study examines health and safety together because they are integrally related. In addition, this report briefly discusses two environmental issues that are of concern to the Environmental Protection Agency (EPA). The first issue involves a surge battery used by the PAFC bus that contains hazardous constituents. The second issue concerns the regulated air emissions produced during operation of the PAFC bus.

Genipin Cross-Linked Glucose Oxidase and Catalase Multi-enzyme for Gluconic Acid Synthesis.

Science.gov (United States)

Cui, Caixia; Chen, Haibin; Chen, Biqiang; Tan, Tianwei

2017-02-01

In this work, glucose oxidase (GOD) and catalase (CAT) were used simultaneously to produce gluconic acid from glucose. In order to reduce the distance between the two enzymes, and therefore improve efficiency, GOD and CAT were cross-linked together using genipin. Improvements in gluconic acid production were due to quick removal of harmful intermediate hydrogen peroxide by CAT. GOD activity was significantly affected by the proportion of CAT in the system, with GOD activity in the cross-linked multi-enzyme (CLME) being 10 times higher than that in an un-cross-linked GOD/CAT mixture. The glucose conversion rate after 15 h using 15 % glucose was also 10 % higher using the CLME than was measured using a GOD/CAT mixture.

Glucose and D-Allulose contained medium to support the growth of lactic acid bacteria

Science.gov (United States)

Al-Baarri, A. N.; Legowo, A. M.; Pramono, Y. B.; Sari, D. I.; Pangestika, W.

2018-01-01

Monosaccharide has been known as support agent for the growth of lactic acid bacteria. However the combination among monosaccharides for supporting the living of bacteria has not been understood well. This research was done for analyzing the combination glucose and D-allulose for the growth of Lactobacillus acidophilus and Streptococcus thermophillus. The NaCl medium containing glucose and D-allulose was used to analyse the growth of bacteria. The study showed that glucose and D-allulose have been detected as supportive agent to L. acidophilus and S. thermophillus specifically. As conclusion, glucose and D-allulose supported the growth of lactic acid bacteria equally. This finding might provide the beneficial information for industry to utilize D-allulose as well as glucose.

Phosphors

International Nuclear Information System (INIS)

1975-01-01

This invention relates to phosphors that can be used in fluorescent lamps and display devices. The phosphor is comprised of a halophosphate of calcium and/or strontium of apatite crystal structure activated with trivalent cerium and trivalent terbium. The phosphor can further include manganese. Preferably, the phosphor includes up to 10% by weight of one or more of the alkali metals lithium, sodium and potassium in the form of a compound or compounds thereof. The emissions appear as a number of fairly narrow discrete bands. The temperature of preparation is 1000degC (as opposed to the usual 1450degC), therefore reducing costs (less energy is needed, more crucibles are readily obtainable and there is no need for special conditions to enable crucibles to overcome thermal shock)