Extraction of magnesium from calcined dolomite ore using hydrochloric acid leaching

NASA Astrophysics Data System (ADS)

Royani, Ahmad; Sulistiyono, Eko; Prasetiyo, Agus Budi; Subagja, Rudi

2018-05-01

Magnesium is widely used in varieties industrial sector. Dolomite is one source of magnesium besides seawater. The extraction of magnesium from dolomite ores can be done by leaching process. In this work, the dolomite leaching to extract magnesium by hydrochloric acid was investigated. The leaching experiments were performed in a spherical glass batch reactor having a capacity of 1000 ml. The effects of the stirring speed, acid concentration, reaction temperature and liquid-solid ratio for each reaction time of 1; 2; and 3 h on the Mg leaching have been evaluated. 5 ml of solution sample were collected from the leached solutions, then it was filtered prior to analysis by ICP OES. The experimental results show that the magnesium extraction increases along with the increase of acid concentration, liquid-solid ratio and temperature. The optimum conditions for magnesium extraction were achieved at temperature 75 °C, extraction time 3 h, the HCl concentration of 2 M, the liquid-solid ratio 20 ml/g and stirring speed of 400 rpm. At this condition 98, 82 % of magnesium were extracted from dolomite. The conclusion obtained from this leaching process is that the magnesium can be extracted from dolomite by using hydrochloric acid solutions.

46 CFR 153.557 - Special requirements for hydrochloric acid.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and... system that carries hydrochloric acid must be lined with: (1) Natural rubber; (2) Neoprene; or (3) A material approved for hydrochloric acid tanks by the Commandant (CG-522). (b) Containment systems for...

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

PubMed

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

2014-05-15

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 (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 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. Copyright © 2014 Elsevier B.V. All rights reserved.

Surface roughness of composite resins subjected to hydrochloric acid.

PubMed

Roque, Ana Carolina Cabral; Bohner, Lauren Oliveira Lima; de Godoi, Ana Paula Terossi; Colucci, Vivian; Corona, Silmara Aparecida Milori; Catirse, Alma Blásida Concepción Elizaur Benitez

2015-01-01

The purpose of this study was to determine the influence of hydrochloric acid on surface roughness of composite resins subjected to brushing. Sixty samples measuring 2 mm thick x 6 mm diameter were prepared and used as experimental units. The study presented a 3x2 factorial design, in which the factors were composite resin (n=20), at 3 levels: microhybrid composite (Z100), nanofilled composite (FiltekTM Supreme), nanohybrid composite (Ice), and acid challenge (n=10) at 2 levels: absence and presence. Acid challenge was performed by immersion of specimens in hydrochloric acid (pH 1.2) for 1 min, 4 times per day for 7 days. The specimens not subjected to acid challenge were stored in 15 mL of artificial saliva at 37 oC. Afterwards, all specimens were submitted to abrasive challenge by a brushing cycle performed with a 200 g weight at a speed of 356 rpm, totaling 17.8 cycles. Surface roughness measurements (Ra) were performed and analyzed by ANOVA and Tukey test (p≤0.05). Surface roughness values were higher in the presence (1.07±0.24) as compared with the absence of hydrochloric acid (0.72±0.04). Surface roughness values were higher for microhybrid (1.01±0.27) compared with nanofilled (0.68 ±0.09) and nanohybrid (0.48±0.15) composites when the specimens were not subjects to acid challenge. In the presence of hydrochloric acid, microhybrid (1.26±0.28) and nanofilled (1.18±0,30) composites presents higher surface roughness values compared with nanohybrid (0.77±0.15). The hydrochloric acid affected the surface roughness of composite resin subjected to brushing.

Extraction of Gold(III) from Hydrochloric Acid Solutions with a PVC-based Polymer Inclusion Membrane (PIM) Containing Cyphos(®) IL 104.

PubMed

Bonggotgetsakul, Ya Ya Nutchapurida; Cattrall, Robert W; Kolev, Spas D

2015-12-08

Poly(vinyl chloride) (PVC) based polymer inclusion membranes (PIMs), with different concentrations of Cyphos® IL 104 as the membrane extractant/carrier, were studied for their ability to extract Au(III) from hydrochloric acid solutions. Some of the PIMs also contained one of the following plasticizers or modifiers: 2-nitrophenyloctyl ether, dioctylphthalate, 1-dodecanol, 1-tetradecanol, or tri(2-ethylhexyl) phosphate. The best performance, in terms of extraction rate and amount of Au(III) extracted, was exhibited by a PIM consisting of 25 wt% Cyphos(®) IL 104, 5 wt% 1-dodecanol, and 70 wt% PVC. An almost complete back-extraction of the Au(III) extracted from this membrane was achieved by using a 0.10 mol L(-1) Na₂SO₃ receiver solution at pH 8. The stoichiometry of the extracted Au(III)/Cyphos® IL 104 adduct was determined as [P]⁺ [AuCl₄](-) H⁺ [PO₂](-) where [P]⁺ and [PO₂](-) represent trihexyl(tetradecyl) phosphonium and bis(2,4,4-trimethylpentyl) phosphinate ions, respectively. Back-extraction of Au(III) is suggested to occur by reduction of Au(III) to Au(I), with the formation of the species [Au(SO₃)₂](3-) in the aqueous receiver solution. Loss of 1-dodecanol from the newly developed PIM to the aqueous solutions in contact with it was observed, which indicated that this membrane was suitable for single use in the efficient recovery of Au(III) from hydrochloric acid solutions of electronic scrap or recycled jewelry.

Effect of Hydrochloric Acid Concentration on the Conversion of Sugarcane Bagasse to Levulinic Acid

NASA Astrophysics Data System (ADS)

Anggorowati, Heni; Jamilatun, Siti; Cahyono, Rochim B.; Budiman, Arief

2018-01-01

Levulinic acid is a new green platform chemical used to the synthesis of a variety of materials for numerous applications such as fuel additives, polymers and resins. It can be produced using renewable resources such as biomass like sugarcane bagasse which are cheap and widely available as waste in Indonesia. In this study, sugarcane bagasse was hydrolyzed using hydrochloric acid with a solid liquid ratio 1:10. The effects of hydrochloric acid concentration at temperature of 180 °C and reaction time of 30 min were studied. The presence of levulinic acid in product of hydrolysis was measured with gas chromatography (GC). It was found that the highest concentration of levulinic acid was obtained at 1 M hydrochloric acid in 25.56 yield%.

Electrochemical studies of novel corrosion inhibitor for mild steel in 1 M hydrochloric acid

NASA Astrophysics Data System (ADS)

Al-Amiery, Ahmed A.; Ahmed, Mohammed H. Othman; Abdullah, Thamer Adnan; Gaaz, Tayser Sumer; Kadhum, Abdul Amir H.

2018-06-01

The electrochemical performance of a novel organic corrosion inhibitor 6-(4-hydroxyphenyl)-3-mercapto-7,8-dihydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine [HT3], for mild steel in 1 M hydrochloric acid is evaluated by potentiodynamic curves. The experimental results show that the investigated inhibitor [HT3], which can effectively retard the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing a protective coating for the mild steel that, can be weakened by increasing the temperature. Furthermore, the inhibition efficiency of [HT3] increased with increasing the concentrations of the inhibitors and decreased with increasing temperature.

Persistent Ion Pairing in Aqueous Hydrochloric Acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baer, Marcel D.; Fulton, John L.; Balasubramanian, Mahalingam

2014-07-03

For strong acids, like hydrochloric acid, the complete dissociation into an excess proton and conjugated base as well as the formation of independent solvated charged fragments is assumed. The existence of a chloride-Hyronium (Cl-H3O+) contact ion pairs even in moderate concentration hydrochloric acid (2.5 m) demonstrates that the counter ions do not behave merely as spectators. Through the use of modern extended X-ray absorption fine structure (EXAFS) measurements in conjunction with state-of-the-art density functional theory (DFT) simulations, we are able to obtain an unprecedented view into the molecular structure of medium to high concentrated electrolytes. Here we report that themore » Cl-H3O+ contact ion pair structure persists throughout the entire concentration range studied and that these structures differ significantly from moieties studied in micro-solvated hydrochloric acid clusters. Characterizing distinct populations of these ion pairs gives rise to a novel molecular level description of how to think about the activity of the proton that impacts our picture of the pH scale. Funding for CJM, GKS, and JLF was provided by DOE Office of Science, Office of Basic Energy Science, Division of Chemical Sciences, Geosciences, and Biosciences. Funding for MDB was provided throught the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MB was funded through Argonne National Laboratory.« less

Study on tea leaves extract as green corrosion inhibitor of mild steel in hydrochloric acid solution

NASA Astrophysics Data System (ADS)

Hamdan, A. B.; Suryanto; Haider, F. I.

2018-01-01

Corrosion inhibitor from extraction of plant has been considered as the most preferable and most chosen technique to prevent corrosion of metal in acidic medium because of the environmental friendly factor. In this study, black tea leaves extraction was tested as corrosion inhibitor for mild steel in 0.1M of hydrochloric acid (HCl) with the absence and presence of corrosion inhibitor. The efficiency and effectiveness of black tea as corrosion inhibitor was tested by using corrosion weight loss measurement experiment was carried out with varies parameters which with different concentration of black tea extract solution. The extraction of black tea solution was done by using aqueous solvent method. The FT-IR result shows that black tea extract containing compounds such as catechin, caffeine and tannins that act as anti-corrosive reagents and responsible to enhance the effectiveness of black tea extract as corrosion inhibitor by forming the hydrophobic thin film through absorption process. As a result of weight loss measurement, it shows that loss in weight of mild steel reduces as the concentration of inhibitor increases. The surface analysis was done on the mild steel samples by using SEM.

Integrated Computational and Experimental Protocol for Understanding Rh(III) Speciation in Hydrochloric and Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samuels, Alex C.; Boele, Cherilynn A.; Bennett, Kevin T.

2014-12-01

A combined experimental and theoretical approach has investigated the complex speciation of Rh(III) in hydrochloric and nitric acid media, as a function of acid concentration. This has relevance to the separation and isolation of Rh(III) from dissolved spent nuclear fuel, which is an emergent and attractive alternative source of platinum group metals, relative to traditional mining efforts.

46 CFR 151.50-22 - Hydrochloric acid.

Code of Federal Regulations, 2010 CFR

2010-10-01

...), compressed air may be used to discharge hydrochloric acid from gravity type cargo tanks only if the tanks are of cylindrical shape with dished heads, provided the air pressure does not exceed the design pressure...

Venus Clouds: A dirty hydrochloric acid model

NASA Technical Reports Server (NTRS)

Hapke, B.

1971-01-01

The spectral and polarization data for Venus are consistent with micron-sized, aerosol cloud particles of hydrochloric acid containing soluble and insoluble iron compounds, whose source could be volcanic or crustal dust. The ultraviolet features could arise from variations in the Fe-HCl concentration in the cloud particles.

Synthesis and characterization of a novel organic corrosion inhibitor for mild steel in 1 M hydrochloric acid

NASA Astrophysics Data System (ADS)

Ahmed, Mohammed H. Othman; Al-Amiery, Ahmed A.; Al-Majedy, Yasmin K.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Gaaz, Tayser Sumer

2018-03-01

The synthesis and characterization of a novel organic corrosion inhibitor (4-(3-mercapto-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazin-6-yl)phenol), for mild steel in 1 M hydrochloric acid (HCl) has been successfully reported for the first time. The inhibitor evaluated as corrosion inhibitor for mild steel in 1 M of Hydrochloric acid solution using electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurement techniques. Changes in the impedance parameters suggested an adsorption of the inhibitor onto the mild steel surface, leading to the formation of protective films. The results show that the inhibition efficiencies increased with increasing the concentrations of the inhibitors and decreased with increasing temperature. The maximum inhibition efficiency up to 67% at the maximum concentration 0.5 mM. This shows that those inhibitors are effective in helping to reduce and slowing down the corrosion process that occurs to mild steel with a hydrochloric acid solution by providing an organic inhibitor for the mild steel that can be weakened by increasing the temperature. The adsorption process of the synthesized organic inhibitor depends on its electronic characteristics in addition to steric effects and the nature of metal surface, temperature degree and the varying degrees of surface-site activity. The synthesized inhibitor molecules were absorbed by metal surface and follow Langmuir isotherms.

Electrochemical and surface analysis of the Fe-Cr-Ru system in non-oxidizing acid solutions

NASA Astrophysics Data System (ADS)

Tjong, S. C.

1990-03-01

The effect of ruthenium addition on the spontaneous passivation behaviour of Fe-40Cr alloy in 0.5M H 2SO 4 and 0.5M HCl acid solutions has been studied. Auger and XPS techniques were also used to investigate the surface chemistries of the spontaneously passivated film. Electrochemical measurements indicate that the Fe-40Cr-0.1Ru and Fe-40Cr-0.2Ru alloys exhibit spontaneous passivation upon exposing them in both hydrochloric and sulphuric acid solutions from 25 to 85 ° C. However, the transition time for spontaneous passivation reduces dramatically with an increase in the ruthenium content and solution temperature. Furthermore, this transition time also decreases for the investigated alloys exposed in a less aggressive sulphuric acid solution. AES results show that ruthenium and chromium are enriched in the spontaneous passive films formed on the Fe-40Cr-0.1Ru alloy in both hydrochloric and sulphuric acid solutions at 25 °C, and also in the spontaneous passive film formed on the Fe-40Cr-0.2Ru alloy in hydrochloric acid solution at 25 ° C. AES does not detect the presence of ruthenium in the spontaneous passive film formed on the Fe-40Cr-0.2Ru alloy in sulphuric acid solution. However, XPS analysis shows that ruthenium and chromium are incorporated into the spontaneous passive films formed on the Fe-40Cr-0.1Ru and Fe-40Cr-0.2Ru alloys in both hydrochloric and sulphuric acid solutions as Ru 4+ and Cr 3+ species.

Effect of beverages on bovine dental enamel subjected to erosive challenge with hydrochloric acid.

PubMed

Amoras, Dinah Ribeiro; Corona, Silmara Aparecida Milori; Rodrigues, Antonio Luiz; Serra, Mônica Campos

2012-01-01

This study evaluated by an in vitro model the effect of beverages on dental enamel previously subjected to erosive challenge with hydrochloric acid. The factor under study was the type of beverage, in five levels: Sprite® Zero Low-calorie Soda Lime (positive control), Parmalat® ultra high temperature (UHT) milk, Ades® Original soymilk, Leão® Ice Tea Zero ready-to-drink low-calorie peach-flavored black teaand Prata® natural mineral water (negative control). Seventy-five bovine enamel specimens were distributed among the five types of beverages (n=15), according to a randomized complete block design. For the formation of erosive wear lesions, the specimens were immersed in 10 mL aqueous solution of hydrochloric acid 0.01 M for 2 min. Subsequently, the specimens were immersed in 20 mL of the beverages for 1 min, twice daily for 2 days at room temperature. In between, the specimens were kept in 20 mL of artificial saliva at 37ºC. The response variable was the quantitative enamel microhardness. ANOVA and Tukey's test showed highly significant differences (p<0.00001) in the enamel exposed to hydrochloric acid and beverages. The soft drink caused a significantly higher decrease in microhardness compared with the other beverages. The black tea caused a significantly higher reduction in microhardness than the mineral water, UHT milk and soymilk, but lower than the soft drink. Among the analyzed beverages, the soft drink and the black tea caused the most deleterious effects on dental enamel microhardness.

Reactive airways dysfunction syndrome in housewives due to a bleach-hydrochloric acid mixture.

PubMed

Gorguner, Metin; Aslan, Sahin; Inandi, Tacettin; Cakir, Zeynep

2004-02-01

The sudden onset of asthmalike symptoms and persistence of airway reactivity following an acute exposure to an irritant gas or vapor has been termed reactive airways dysfunction syndrome (RADS). A mixture of sodium hypochlorite (bleach, 40%) and hydrochloric acid (18%) is commonly used as a household cleaning solution in our region. From this mixture, chlorine gas is produced, which can cause airway damage and ensuing RADS. Here we describe findings of patients with RADS due to this cleaning mixture, and determine factors associated with a favorable outcome. Data were collected retrospectively on 55 symptomatic patients presenting to our emergency department after inhalation exposure to a mixture of bleach and hydrochloric acid. Symptoms, past medical and smoking history, details of the exposure, initial peak expiratory flow rate (PEFR) and oxygenation, and acute reversibility of airways obstruction were documented. All patients met previously defined criteria for the diagnosis of RADS, but did not undergo methacholine challenge testing and bronchoalveolar lavage or histopathologic study. Fifty patients were followed over the course of 3 mo. The majority of exposures (64%) occurred in the bathroom or kitchen. Only 21 of 55 (38%) patients showed an improvement in PEFR of 15% or greater following two beta(2)-agonist inhalation treatments. In follow-up, 48 patients (87%) improved clinically and functionally (FEV(1)). Seven patients (13%) deteriorated, with ARDS developing in two, one of whom died from respiratory failure. Advanced age, initial low PEFR, exposure in a small enclosed area, use immediately after mixing, and prolonged short- and long-term exposures were associated with a poorer prognosis. This descriptive study is the largest case series in the literature of RADS developing after exposure to a bleach-hydrochloric acid mixture. The optimum acute treatment and long-term outcomes for patients with RADS due to this combination still need to be determined.

Heavy metal recovery from electric arc furnace steel slag by using hydrochloric acid leaching

NASA Astrophysics Data System (ADS)

Wei, Lim Jin; Haan, Ong Teng; Shean Yaw, Thomas Choong; Chuah Abdullah, Luqman; Razak, Mus'ab Abdul; Cionita, Tezara; Toudehdehghan, Abdolreza

2018-03-01

Electric Arc Furnace steel slag (EAFS) is the waste produced in steelmaking industry. Environmental problem such as pollution will occur when dumping the steel slag waste into the landfill. These steel slags have properties that are suitable for various applications such as water treatment and wastewater. The objective of this study is to develop efficient and economical chlorination route for EAFS extraction by using leaching process. Various parameters such as concentration of hydrochloric acid, particle size of steel slag, reaction time and reaction temperature are investigated to determine the optimum conditions. As a result, the dissolution rate can be determined by changing the parameters, such as concentration of hydrochloric acid, particle size of steel slag, reaction time and reaction temperature. The optimum conditions for dissolution rates for the leaching process is at 3.0 M hydrochloric acid, particle size of 1.18 mm, reaction time of 2.5 hour and the temperature of 90°C.

Cetyltrimethyl Ammonium Bromide as Corrosion Inhibitor for Zinc Used in Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Sun, C. X.; Du, J. J.; Ma, Z. W.; Huang, C. S.; Wu, J. Y.

2018-05-01

A compound inhibitor composed of cetyltrimethyl ammonium bromide (CTAB) and bromohexadecyl pyridine was tested as corrosion inhibitor for zinc in hydrochloric acid. The results of static coupon test show that the compound inhibitor can effectively protect zinc from corrosion and the best concentration ratio is CTAB 50 mg/L and bromohexadecyl pyridine 200 mg/L. The polarization results show that the compound inhibitor will cause a negative shift of E0 of zinc in hydrochloric acid. The EIS (electrchemical impedance spectra) results show that the inhibitor leads to a bigger radius and has one time constant. SEM results show that the CTAB and bromohexadecyl pyridine form a uniform and compact membrane on the surface of zinc that can protect zinc from corroding effectively.

Physicochemical and in vitro antioxidant properties of pectin extracted from hot pepper (Capsicum annuum L. var. acuminatum (Fingerh.)) residues with hydrochloric and sulfuric acids.

PubMed

Xu, Honggao; Tai, Kedong; Wei, Tong; Yuan, Fang; Gao, Yanxiang

2017-11-01

Transformation of hot pepper residues to value-added products with concomitant benefits on environmental pollution would be of great value to capsicum oleoresin manufacturers. Pectin, a soluble dietary fiber with multiple functions, from hot pepper residues was investigated in this study. The extraction of hot pepper pectin using hydrochloric acid was first optimized using response surface methodology (RSM). The most efficient parameters for maximum hot pepper pectin yield (14.63%, dry basis) were a pH of 1.0, a temperature of 90 °C, an extraction time of 2 h and a liquid-to-solid ratio of 20 L g -1 . The pectin was mainly composed of uronic acids, and the major neutral sugars were galactose and glucose. The structure of hot pepper pectin was characterized by homogalacturonan and rhamnogalacturonan I elements. The physicochemical properties of hot pepper pectin extracted by sulfuric acid and hydrochloric acid were further investigated. The content of protein and degree of esterification in hot pepper pectin extracted with sulfuric acid solution (SP) were higher (P < 0.05) than those in that extracted with hydrochloric acid solution (HP), while the mean molecular weight of SP was lower than that of HP. Compared with HP, SP exhibited higher viscosity and better emulsifying property. Based on the yield and physicochemical properties of hot pepper pectin, hot pepper residues would be a new source to obtain pectin, and SP would be more preferred than HP. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Microarray-based transcriptome of Listeria monocytogenes adapted to sublethal concentrations of acetic acid, lactic acid, and hydrochloric acid.

PubMed

Tessema, Girum Tadesse; Møretrø, Trond; Snipen, Lars; Heir, Even; Holck, Askild; Naterstad, Kristine; Axelsson, Lars

2012-09-01

Listeria monocytogenes , an important foodborne pathogen, commonly encounters organic acids in food-related environments. The transcriptome of L. monocytogenes L502 was analyzed after adaptation to pH 5 in the presence of acetic acid, lactic acid, or hydrochloric acid (HCl) at 25 °C, representing a condition encountered in mildly acidic ready-to-eat food kept at room temperature. The acid-treated cells were compared with a reference culture with a pH of 6.7 at the time of RNA harvesting. The number of genes and magnitude of transcriptional responses were higher for the organic acids than for HCl. Protein coding genes described for low pH stress, energy transport and metabolism, virulence determinates, and acid tolerance response were commonly regulated in the 3 acid-stressed cultures. Interestingly, the transcriptional levels of histidine and cell wall biosynthetic operons were upregulated, indicating possible universal response against low pH stress in L. monocytogenes. The opuCABCD operon, coding proteins for compatible solutes transport, and the transcriptional regulator sigL were significantly induced in the organic acids, strongly suggesting key roles during organic acid stress. The present study revealed the complex transcriptional responses of L. monocytogenes towards food-related acidulants and opens the roadmap for more specific and in-depth future studies.

Electrochemical investigation on the corrosion inhibition of mild steel by Quinazoline Schiff base compounds in hydrochloric acid solution.

PubMed

Khan, Ghulamullah; Basirun, Wan Jeffrey; Kazi, Salim Newaz; Ahmed, Pervaiz; Magaji, Ladan; Ahmed, Syed Muzamil; Khan, Ghulam Mustafa; Rehman, Muhammad Abdur; Badry, Ahmad Badarudin Bin Mohamad

2017-09-15

The inhibitory effect of two Schiff bases 3-(5-methoxy-2-hydroxybenzylideneamino)-2-(-5-methoxy-2-hydroxyphenyl)-2,3-dihydroquinazoline-4(1H)-one (MMDQ), and 3-(5-nitro-2-hydroxybenzylideneamino)-2(5-nitro-2-hydroxyphenyl)-2,3-dihydroquinazoline-4(1H)-one (NNDQ) on the corrosion of mild steel in 1M hydrochloric acid were studied using mass loss, potentiodynamic polarization technique and electrochemical impedance spectroscopy measurements at ambient temperature. The investigation results indicate that the Schiff Bases compounds with an average efficiency of 92% at 1.0mM of additive concentration have fairly effective inhibiting properties for mild steel in hydrochloric acid, and acts as mixed type inhibitor character. The inhibition efficiencies measured by all measurements show that the inhibition efficiencies increase with increase in inhibitor concentration. This reveals that the inhibitive mechanism of inhibitors were primarily due to adsorption on mild steel surface, and follow Langmuir adsorption isotherm. The temperature effect on the inhibition process in 1MHCl with the addition of investigated Schiff bases was studied at a temperature range of 30-60°C, and the activation parameters (Ea, ΔH and ΔS) were calculated to elaborate the corrosion mechanism. The differences in efficiency for two investigated inhibitors are associated with their chemical structures. Copyright © 2017 Elsevier Inc. All rights reserved.

46 CFR 151.50-76 - Hydrochloric acid, spent (NTE 15%).

Code of Federal Regulations, 2011 CFR

2011-10-01

... must provide for the free passage of air and gases to the vent or vents. (f) No lights may be used... 46 Shipping 5 2011-10-01 2011-10-01 false Hydrochloric acid, spent (NTE 15%). 151.50-76 Section 151.50-76 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS...

46 CFR 151.50-76 - Hydrochloric acid, spent (NTE 15%).

Code of Federal Regulations, 2012 CFR

2012-10-01

... must provide for the free passage of air and gases to the vent or vents. (f) No lights may be used... 46 Shipping 5 2012-10-01 2012-10-01 false Hydrochloric acid, spent (NTE 15%). 151.50-76 Section 151.50-76 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS...

46 CFR 151.50-76 - Hydrochloric acid, spent (NTE 15%).

Code of Federal Regulations, 2014 CFR

2014-10-01

... must provide for the free passage of air and gases to the vent or vents. (f) No lights may be used... 46 Shipping 5 2014-10-01 2014-10-01 false Hydrochloric acid, spent (NTE 15%). 151.50-76 Section 151.50-76 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS...

46 CFR 151.50-76 - Hydrochloric acid, spent (NTE 15%).

Code of Federal Regulations, 2013 CFR

2013-10-01

... must provide for the free passage of air and gases to the vent or vents. (f) No lights may be used... 46 Shipping 5 2013-10-01 2013-10-01 false Hydrochloric acid, spent (NTE 15%). 151.50-76 Section 151.50-76 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS...

Leaching of Titanium and Silicon from Low-Grade Titanium Slag Using Hydrochloric Acid Leaching

NASA Astrophysics Data System (ADS)

Zhao, Longsheng; Wang, Lina; Qi, Tao; Chen, Desheng; Zhao, Hongxin; Liu, Yahui; Wang, Weijing

2018-05-01

Acid-leaching behaviors of the titanium slag obtained by selective reduction of vanadium-bearing titanomagnetite concentrates were investigated. It was found that the optimal leaching of titanium and silicon were 0.7% and 1.5%, respectively. The titanium and silicon in the titanium slag were firstly dissolved in the acidic solution to form TiO2+ and silica sol, and then rapidly reprecipitated, forming hydrochloric acid (HCl) leach residue. Most of the silicon presented in the HCl leach residue as floccules-like silica gel, while most of the titanium was distributed in the nano-sized rod-like clusters with crystallite refinement and intracrystalline defects, and, as such, 94.3% of the silicon was leached from the HCl leach residue by alkaline desilication, and 96.5% of the titanium in the titanium-rich material with some rutile structure was then digested by the concentrated sulfuric acid. This provides an alternative route for the comprehensive utilization of titanium and silicon in titanium slag.

Factors influencing preparation of polyaniline doped with hydrochloric acid

NASA Astrophysics Data System (ADS)

Chuanyu, Sun; Yu, Wang

2014-12-01

Factors influencing the reaction of chemical polymerization during aniline doping with hydrochloric acid (HCl) have been studied in this work. The optimal parameters for the preparation of polyaniline were determined as follows: aniline concentration - 4 mass %, molar ratios of oxidant (NH4)2S2O8:aniline - 1.2:1 and 1.3:1, the concentration of dopant - 1 mol/L. Fourier transform infrared spectroscopy (FT-IR) was applied to characterize the structure of polyaniline.

Corrosion Behaviour of Sn-based Lead-Free Solders in Acidic Solution

NASA Astrophysics Data System (ADS)

Nordarina, J.; Mohd, H. Z.; Ahmad, A. M.; Muhammad, F. M. N.

2018-03-01

The corrosion properties of Sn-9(5Al-Zn), Sn-Cu and SAC305 were studied via potentiodynamic polarization method in an acidic solution of 1 M hydrochloric acid (HCl). Sn-9(5Al-Zn) produced different polarization profile compared with Sn-Cu and SAC305. The morphological analysis showed that small, deep grooves shaped of corrosion product formed on top of Sn-9(5Al-Zn) solder while two distinctive structures of closely packed and loosely packed corrosion product formed on top of Sn-Cu and SAC305 solder alloys. Phase analysis revealed the formations of various corrosion products such as SnO and SnO2 mainly dominant on surface of solder alloys after potentiodynamic polarization in 1 M hydrochloric acid (HCl).

Enhanced Corrosion Resistance of Carbon Steel in Hydrochloric Acid Solution by Eriobotrya Japonica Thunb. Leaf Extract: Electrochemical Study

PubMed Central

Yang, Wenjing; Wang, Qihui; Xu, Ke; Yin, Yanjun; Bao, Hebin; Li, Xueming; Niu, Lidan; Chen, Shiqi

2017-01-01

The biodegradable inhibitors, which could effectively reduce the rate of corrosion of carbon steel, were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The mixed-type inhibitors extracted from Eriobotrya japonica Thunb. leaf exhibited excellent inhibition performance, and the inhibition efficiency for carbon steel reached 90.0% at 298 K in hydrochloric acid. Moreover, the adsorption mechanism of the inhibitors on a carbon steel surface is described by the Langmuir adsorption isotherm. Simultaneously, the corrosion morphology of the carbon steel and the inhibitor structure were analyzed by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. PMID:28812993

Enhanced Corrosion Resistance of Carbon Steel in Hydrochloric Acid Solution by Eriobotrya Japonica Thunb. Leaf Extract: Electrochemical Study.

PubMed

Yang, Wenjing; Wang, Qihui; Xu, Ke; Yin, Yanjun; Bao, Hebin; Li, Xueming; Niu, Lidan; Chen, Shiqi

2017-08-16

The biodegradable inhibitors, which could effectively reduce the rate of corrosion of carbon steel, were investigated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The mixed-type inhibitors extracted from Eriobotrya japonica Thunb. leaf exhibited excellent inhibition performance, and the inhibition efficiency for carbon steel reached 90.0% at 298 K in hydrochloric acid. Moreover, the adsorption mechanism of the inhibitors on a carbon steel surface is described by the Langmuir adsorption isotherm. Simultaneously, the corrosion morphology of the carbon steel and the inhibitor structure were analyzed by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively.

STIMULATION OF FUNDULUS BY HYDROCHLORIC AND FATTY ACIDS IN FRESH WATER, AND BY FATTY ACIDS, MINERAL ACIDS, AND THE SODIUM SALTS OF MINERAL ACIDS IN SEA WATER

PubMed Central

Allison, J. B.; Cole, William H.

1934-01-01

1. Fundulus heteroclitus was found to be a reliable experimental animal for studies on chemical stimulation in either fresh or sea water. 2. The response of Fundulus to hydrochloric, acetic, propionic, butyric, valeric, and caproic acids was determined in fresh water, while the same acids plus sulfuric and nitric, as well as the sodium salts of the mineral acids, were tested in sea water. 3. Stimulation of Fundulus by hydrochloric acid in fresh water is correlated with the effective hydrogen ion concentration. Stimulation by the n-aliphatic acids in the same environment is correlated with two factors, the effective hydrogen ion concentration and the potential of the non-polar group in the molecule. However, as the number of CH2 groups increases the stimulating effect increases by smaller and smaller amounts, approaching a maximum value. 4. Stimulation of Fundulus by hydrochloric, sulfuric, and nitric acids in sea water is correlated with the forces of primary valence which in turn are correlated with the change in hydrogen ion concentration of the sea water. The n-aliphatic acids increase in stimulating efficiency in sea water as the length of the carbon chain increases, but a limiting value is not reached as soon as in fresh water. 5. Only a slight difference in stimulation by hydrochloric acid is found in sea water and in fresh water. However, there is a significant difference in stimulation by the fatty acids in fresh and in sea water, which is partly explained by the different buffering capacities of the two media. It is to be noted that in the same environment two different fish, Fundulus and Eupomotis, give different results, while the same fish (Fundulus) in two different environments responds similarly to mineral acids but differently to fatty acids. These results illustrate that stimulation is a function of the interaction between environment and receptors, and that each is important in determining the response. 6. Stimulation by sodium chloride, nitrate

Hydrochloric acid: an overlooked driver of environmental change.

PubMed

Evans, Chris D; Monteith, Don T; Fowler, David; Cape, J Neil; Brayshaw, Susan

2011-03-01

Research on the ecosystem impacts of acidifying pollutants, and measures to control them, has focused almost exclusively on sulfur (S) and nitrogen (N) compounds. Hydrochloric acid (HCl), although emitted by coal burning, has been overlooked as a driver of ecosystem change because most of it was considered to redeposit close to emission sources rather than in remote natural ecosystems. Despite receiving little regulatory attention, measures to reduce S emissions, and changes in energy supply, have led to a 95% reduction in United Kingdom HCl emissions within 20 years. Long-term precipitation, surface water, and soil solution data suggest that the near-disappearance of HCl from deposition could account for 30-40% of chemical recovery from acidification during this time, affecting both near-source and remote areas. Because HCl is highly mobile in reducing environments, it is a more potent acidifier of wetlands than S or N, and HCl may have been the major driver of past peatland acidification. Reduced HCl loadings could therefore have affected the peatland carbon cycle, contributing to increases in dissolved organic carbon leaching to surface waters. With many regions increasingly reliant on coal for power generation, HCl should be recognized as a potentially significant constituent of resulting emissions, with distinctive ecosystem impacts.

Partial liquid ventilation reduces fluid filtration of isolated rabbit lungs with acute hydrochloric acid-induced edema.

PubMed

Loer, S A; Tarnow, J

2001-06-01

Hydrochloric acid aspiration increases pulmonary microvascular permeability. The authors tested the hypothesis that partial liquid ventilation has a beneficial effect on filtration coefficients in acute acid-induced lung injury. Isolated blood-perfused rabbit lungs were assigned randomly to one of four groups. Group 1 (n = 6) served as a control group without edema. In group 2 (n = 6), group 3 (n = 6), and group 4 (n = 6), pulmonary edema was induced by intratracheal instillation of hydrochloric acid (0.1 N, 2 ml/kg body weight). Filtration coefficients were determined 30 min after this injury (by measuring loss of perfusate after increase of left atrial pressure). Group 2 lungs were gas ventilated, and group 3 lungs received partial liquid ventilation (15 ml perfluorocarbon/kg body weight). In group 4 lungs, the authors studied the immediate effects of bronchial perfluorocarbon instillation on ongoing filtration. Intratracheal instillation of hydrochloric acid markedly increased filtration coefficients when compared with non-injured control lungs (2.3 +/- 0.7 vs. 0.31 +/- 0.08 ml.min(-1). mmHg(-1).100 g(-1) wet lung weight, P < 0.01). Partial liquid ventilation reduced filtration coefficients of the injured lungs (to 0.9 +/- 0.3 ml.min(-1).mmHg(-1).100 g(-1) wet lung weight, P = 0.022). Neither pulmonary artery nor capillary pressures (determined by simultaneous occlusion of inflow and outflow of the pulmonary circulation) were changed by hydrochloric acid instillation or by partial liquid ventilation. During ongoing filtration, bronchial perfluorocarbon instillation (5 ml/kg body weight) immediately reduced the amount of filtered fluid by approximately 50% (P = 0.027). In the acute phase after acid injury, partial liquid ventilation reduced pathologic fluid filtration. This effect started immediately after bronchial perfluorocarbon instillation and was not associated with changes in mean pulmonary artery, capillary, or airway pressures. The authors suggest that

Acidic and basic solutions dissolve protein plugs made of lithostathine complicating choledochal cyst/pancreaticobiliary maljunction.

PubMed

Kaneko, Kenitiro; Ono, Yasuyuki; Tainaka, Takahisa; Sumida, Wataru; Ando, Hisami

2009-07-01

Symptoms of choledochal cysts are caused by protein plugs made of lithostathine, which block the long common channel and increase pancreaticobiliary ductal pressure. Agents that dissolve protein plugs can provide relief from or prevent symptoms. In the present study, drugs reportedly effective for pancreatic and biliary stones were used in dissolution tests. Protein plugs were obtained from choledochal cysts during surgery in two children (5- and 6-year-old girls). Plugs approximately 2 mm in diameter were immersed in citric acid, tartaric acid, dimethadione, bromhexine, dehydrocholic acid, sodium citrate, hydrochloric acid, and sodium hydroxide solutions under observation with a digital microscope. The pH of each solution was measured using a pH meter. Plugs dissolved in citric acid (5.2 mM; pH 2.64), tartaric acid (6.7 mM; pH 2.51), dimethadione (75 mM; pH 3.70), hydrochloric acid (0.5 mM; pH 3.13), and sodium hydroxide (75 mM; pH 12.75) solutions. Plugs did not dissolve in dimethadione (7.5 mM; pH 4.31), bromhexine (0.1%; pH 4.68), dehydrocholic acid (5%; pH 7.45), and sodium citrate (75 mM; pH 7.23) solutions. Protein plugs in choledochal cysts are dissolved in acidic and basic solutions, which may eliminate longitudinal electrostatic interactions of the lithostathine protofibrils.

Model Experiment of Thermal Runaway Reactions Using the Aluminum-Hydrochloric Acid Reaction

ERIC Educational Resources Information Center

Kitabayashi, Suguru; Nakano, Masayoshi; Nishikawa, Kazuyuki; Koga, Nobuyoshi

2016-01-01

A laboratory exercise for the education of students about thermal runaway reactions based on the reaction between aluminum and hydrochloric acid as a model reaction is proposed. In the introductory part of the exercise, the induction period and subsequent thermal runaway behavior are evaluated via a simple observation of hydrogen gas evolution and…

Pretreatment of corn stover for sugar production using dilute hydrochloric acid followed by lime.

PubMed

Zu, Shuai; Li, Wen-zhi; Zhang, Mingjian; Li, Zihong; Wang, Ziyu; Jameel, Hasan; Chang, Hou-min

2014-01-01

In this study, a two stage process was evaluated to increase the sugar recovery. Firstly, corn stover was treated with diluted hydrochloric acid to maximize the xylose yield, and then the residue was treated with lime to alter the lignin structure and swell the cellulose surface. The optimal condition was 120 °C and 40 min for diluted hydrochloric acid pretreatment followed by lime pretreatment at 60 °C for 12h with lime loading at 0.1 g/g of substrate. The glucose and xylose yield was 78.0% and 97.0%, respectively, with cellulase dosage at 5 FPU/g of substrate. The total glucose yield increased to 85.9% when the cellulase loading was increased to 10 FPU/g of substrate. This two stage process was effective due to the swelling of the internal surface, an increase in the porosity and a decrease in the degree of polymerization. Copyright © 2013 Elsevier Ltd. All rights reserved.

EDTA and hydrochloric acid effects on mercury accumulation by Lupinus albus.

PubMed

Rodríguez, Luis; Alonso-Azcárate, Jacinto; Villaseñor, José; Rodríguez-Castellanos, Laura

2016-12-01

The efficiency of white lupine (Lupinus albus) to uptake and accumulate mercury from a soil polluted by mining activities was assessed in a pot experiment with chemically assisted phytoextraction. The mobilizing agents tested were ethylenediaminetetracetic acid (EDTA) and hydrochloric acid (HCl). Two doses of each amendment were used (0.5 and 1.0 g of amendment per kg of soil), and unamended pots were used as a control. Addition of HCl to the soil did not negatively affect plant biomass, while the use of EDTA led to a significant decrease in plant growth when compared to that found for non-treated pots, with plants visually showing symptoms of toxicity. The addition of hydrochloric acid increased root, shoot and total plant Hg uptake of white lupine by 3.7 times, 3.1 times and 3.5 times, respectively, in relation to non-amended plants. The greatest efficiency was obtained for the highest HCl dose. EDTA led to higher concentrations of total plant Hg than that found with the control, but, due to the aforementioned decrease in plant biomass, the Hg phytoextraction yield was not significantly increased. These results were attributed to the capability of both amendments to form stable Hg complexes. The concentration of Hg in the water of the soil pores after the phytoextraction experiment was very low for all treatments, showing that risks derived from metal leaching could be partially avoided by using doses and chemicals suitable to the concentration of metal in the soil and plant performance.

Interaction of Benzimidazoles and Benzotriazole: Its Corrosion Protection Properties on Mild Steel in Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Ramya, K.; Mohan, Revathi; Joseph, Abraham

2014-11-01

Synergistic hydrogen-bonded interaction of alkyl benzimidazoles and 1,2,3-benzotrizole and its corrosion protection properties on mild steel in hydrochloric acid at different temperatures have been studied using polarization, EIS, adsorption, surface studies, and computational methods. The extent of synergistic interaction increases with temperature. Quantum chemical approach is used to calculate some electronic properties of the molecules and to ascertain the synergistic interaction, inhibitive effect, and molecular structures. The corrosion inhibition efficiencies and the global chemical reactivity relate to some parameters, such as total energy, E HOMO, E LUMO, and gap energy (Δ E). 1,2,3-Benzotrizole interacts with benzimidazoles derivatives up to a bond length of approximately 1.99 Å. This interaction represents the formation of a hydrogen bond between the 1,2,3-benzotrizole and benzimidazoles. This synergistic interaction of 1,2,3-benzotrizole and benzimidazole derivatives offers extended inhibition efficiency toward mild steel in hydrochloric acid.

Leaching lithium from the anode electrode materials of spent lithium-ion batteries by hydrochloric acid (HCl).

PubMed

Guo, Yang; Li, Feng; Zhu, Haochen; Li, Guangming; Huang, Juwen; He, Wenzhi

2016-05-01

Spent lithium-ion batteries (LIBs) are considered as an important secondary resource for its high contents of valuable components, such as lithium and cobalt. Currently, studies mainly focus on the recycling of cathode electrodes. There are few studies concentrating on the recovery of anode electrodes. In this work, based on the analysis result of high amount of lithium contained in the anode electrode, the acid leaching process was applied to recycle lithium from anode electrodes of spent LIBs. Hydrochloric acid was introduced as leaching reagent, and hydrogen peroxide as reducing agent. Within the range of experiment performed, hydrogen peroxide was found to have little effect on lithium leaching process. The highest leaching recovery of 99.4wt% Li was obtained at leaching temperature of 80°C, 3M hydrochloric acid and S/L ratio of 1:50g/ml for 90min. The graphite configuration with a better crystal structure obtained after the leaching process can also be recycled. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fact Sheet - Final Air Toxics Rule for Steel Pickling and HCI Process Facilities and Hydrochloric Acid Regeneration Plants

EPA Pesticide Factsheets

Fact Sheet summarizing the main points of the national emssions standard for hazaradous air pollutants (NESHAP) for Steel Pickling— HCl Process Facilities and Hydrochloric Acid Regeneration Plants as promulgated on June 22, 1999.

A Method for Monitoring Organic Chlorides, Hydrochloric Acid and Chlorine in Air

NASA Technical Reports Server (NTRS)

Dennison, J. E.; Menichelli, R. P.

1971-01-01

While not commonly presented in nonurban atmospheres, organic chlorides, hydrochloric acid and chlorine are significant in industrial air pollution and industrial hygiene. Based on a microcoulometer, a much more sensitive method than has heretofore been available has been developed for monitoring these air impurities. The method has a response time (90%) of about twenty seconds, requires no calibration, is accurate to +/- 2.5%, and specific except for bromide and iodide interferences. The instrument is portable and has been operated unattended for 18 hours without difficulty.

Physical and chemical mechanism underlying ultrasonically enhanced hydrochloric acid leaching of non-oxidative roasting of bastnaesite.

PubMed

Zhang, Dongliang; Li, Mei; Gao, Kai; Li, Jianfei; Yan, Yujun; Liu, Xingyu

2017-11-01

In this study, we investigated an alternative to the conventional hydrochloric acid leaching of roasted bastnaesite. The studies suggested that the rare earth oxyfluorides in non-oxidatively roasted bastnaesite can be selectively leached only at elevated temperatures Further, the Ce(IV) in oxidatively roasted bastnaesite does not leach readily at low temperatures, and it is difficult to induce it to form a complex with F - ions in order to increase the leaching efficiency. Moreover, it is inevitably reduced to Ce(III) at elevated temperatures. Thus, the ultrasonically-assisted hydrochloric acid leaching of non-oxidatively roasted bastnaesite was studied in detail, including, the effects of several process factors and the, physical and chemical mechanisms underlying the leaching process. The results show that the leaching rate for the ultrasonically assisted process at 55°C (65% rare earth oxides) is almost the same as that for the conventional leaching process at 85°C. Based on the obtained results, it is concluded that ultrasonic cavitation plays a key role in the proposed process, resulting not only in a high shear stress, which damages the solid surface, but also in the formation of hydroxyl radicals (OH) and hydrogen peroxide (H 2 O 2 ). Standard electrode potential analysis and experimental results indicate that Ce(III) isoxidized by the hydroxyl radicals to Ce(IV), which can be leached with F - ions in the form of a complex, and that the Ce(IV) can subsequently be reduced to Ce(III) by the H 2 O 2. This prevents the Cl - ions in the solution from being oxidized to form chlorine. These results imply that the ultrasonically-assisted process can be used for the leaching of non-oxidatively roasted bastnaesite at low temperatures in the absence of a reductant. Copyright © 2017 Elsevier B.V. All rights reserved.

Cellulose acetate layer effect toward aluminium corrosion rate in hydrochloric acid media

NASA Astrophysics Data System (ADS)

Andarany, K. S.; Sagir, A.; Ahmad, A.; Deni, S. K.; Gunawan, W.

2017-09-01

Corrosion occurs due to the oxidation and reduction reactions between the material and its environment. The oxidation reaction defined as reactions that produce electrons and reduction is between two elements that bind the electrons. Corrosion cannot be inevitable in life both within the industry and household. Corrosion cannot eliminate but can be control. According to the voltaic table, Aluminum is a metal that easily corroded. This study attempts to characterize the type of corrosion by using a strong acid media (HCl). Experiment using a strong acid (HCl), at a low concentration that occurs is pitting corrosion, whereas at high concentrations that occurs is corrosion erosion. One of prevention method is by using a coating method. An efforts are made to slow the rate of corrosion is by coating the metal with “cellulose acetate” (CA). cellulose acetate consisted of cellulose powder dissolved in 99% acetic acid, and then applied to the aluminum metal. Soaking experiments using hydrochloric acid, cellulose acetate is able to slow down the corrosion rate of 47 479%.

Comparison of sulfuric and hydrochloric acids as catalysts in hydrolysis of Kappaphycus alvarezii (cottonii).

PubMed

Meinita, Maria Dyah Nur; Hong, Yong-Ki; Jeong, Gwi-Taek

2012-01-01

In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and by-products. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 (°)C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.

Reactivity of clay minerals with acids and alkalies

USGS Publications Warehouse

Carroll, Dorothy; Starkey, Harry C.

1971-01-01

One-g samples of a montmorillonite, a metabentonite, an illite, two kaolinites, and three halloysites were treated with 50 ml of hydrochloric acid (6⋅45 N, 1:1), acetic acid (4⋅5 N, 1:3), sodium hydroxide (2⋅8 N), sodium chloride solution (pH 6⋅10; Na = 35‰; Cl = 21⋅5‰), and natural sea water (pH 7⋅85; Na = 35⋅5‰; Cl = 21⋅ 5‰) for a 10-day period in stoppered plastic vials. The supernatant solutions were removed from the clay minerals and analyzed for SiO2, Al2O3, CaO, MgO, Na2O, and K2O. All the solutions removed some SiO2, Al2O3, and Fe2O3 from the samples, but the quantities were small. Sodium hydroxide attacked the kaolin group minerals more strongly than it did montmorillonite, metabentonite, or illite. Halloysite was more strongly attacked by hydrochloric acid than was any of the other experimental minerals. Hydrochloric acid removed iron oxide coatings from soil clay minerals, but acetic acid did not remove them completely. The samples most strongly attacked by HCl and NaOH were examined by X-ray diffraction. Acid treatment did not destroy the structure of the clays, but the halloysite structure was partially destroyed. Sodium hydroxide attacked the halloysite structure, as shown by chemical analysis and X-ray diffraction. These experiments show that treatment in dilute acids has no harmful effect in the preparation of clays for X-ray diffraction. Acetic acid is preferred to hydrochloric acid for this purpose. Hydrochloric acid cleans clay minerals by removing free iron oxide from the surface; acetic acid is less effective.

Rinsing with antacid suspension reduces hydrochloric acid-induced erosion.

PubMed

Alves, Maria do Socorro Coelho; Mantilla, Taís Fonseca; Bridi, Enrico Coser; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes; Amaral, Flávia Lucisano Botelho; Turssi, Cecilia Pedroso

2016-01-01

Mouthrinsing with antacids, following erosive episodes, have been suggested as a preventative strategy to minimize tooth surface loss due to their neutralizing effect. The purpose of this in situ study was to evaluate the effect of an antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate in controlling simulated erosion of enamel of intrinsic origin. The experimental units were 48 slabs (3×3×2mm) of bovine enamel, randomly divided among 12 volunteers who wore palatal appliances with two enamel slabs. One of them was exposed extra-orally twice a day to 25mL of a hydrochloric acid (HCl) solution (0.01M, pH 2) for 2min. There were two independent phases, lasting 5 days each. In the first phase, according to a random scheme, half of the participants rinsed with 10mL of antacid suspension (Gaviscon(®), Reckitt Benckiser Healthcare Ltd.), while the remainder was rinsed with deionized water, for 1min. For the second phase, new slabs were inserted and participants switched to the treatment not received in the first stage. Therefore, the groups were as follows: (a) erosive challenge with HCl+antacid suspension; (b) erosive challenge with HCl+deionized water (DIW); (c) no erosive challenge+antacid suspension; (d) no erosive challenge+DIW. Specimens were assessed in terms of surface loss using optical profilometry and Knoop microhardness. The data were analyzed using repeated measures two-way analysis of variance and Tukey's tests. Compared to DIW rinses, surface loss of enamel was significantly lower when using an antacid rinse following erosive challenges (p=0.015). The Knoop microhardness of the enamel was significantly higher when the antacid rinse was used (p=0.026). The antacid suspension containing sodium alginate, sodium bicarbonate and calcium carbonate, rinsed after erosive challenges of intrinsic origin, reduced enamel surface loss. Copyright © 2015 Elsevier Ltd. All rights reserved.

In vitro effects of hydrochloric acid and various concentrations of acetic, propionic, butyric, or valeric acids on bioelectric properties of equine gastric squamous mucosa.

PubMed

Andrews, Frank M; Buchanan, Benjamin R; Smith, Sionagh H; Elliott, Sarah B; Saxton, Arnold M

2006-11-01

To compare the effects of hydrochloric acid (HCl) and various concentrations of volatile fatty acids (VFAs) on tissue bioelectric properties of equine stomach nonglandular (NG) mucosa. Gastric tissues obtained from 48 adult horses. NG gastric mucosa was studied by use of Ussing chambers. Short-circuit current (Isc) and potential difference (PD) were measured and electrical resistance (R) and conductance calculated for tissues after addition of HCl and VFAs (5, 10, 20, and 40 mM) in normal Ringer's solution (NRS). Mucosa exposed to HCl in NRS (pH of 1.5 and, to a lesser extent, 4.0) had a significant decrease in Isc, PD, and R, whereas tissues exposed to acetic acid at a pH of < 4.0, propionic and butyric acids at a pH of acid at a pH of acid at a pH of acid, in the presence of HCl at a pH of

Double-stranded helical twisted beta-sheet channels in crystals of gramicidin S grown in the presence of trifluoroacetic and hydrochloric acids.

PubMed

Llamas-Saiz, Antonio L; Grotenbreg, Gijsbert M; Overhand, Mark; van Raaij, Mark J

2007-03-01

Gramicidin S is a nonribosomally synthesized cyclic decapeptide antibiotic with twofold symmetry (Val-Orn-Leu-D-Phe-Pro)(2); a natural source is Bacillus brevis. Gramicidin S is active against Gram-positive and some Gram-negative bacteria. However, its haemolytic toxicity in humans limits its use as an antibiotic to certain topical applications. Synthetically obtained gramicidin S was crystallized from a solution containing water, methanol, trifluoroacetic acid and hydrochloric acid. The structure was solved and refined at 0.95 A resolution. The asymmetric unit contains 1.5 molecules of gramicidin S, two trifluoroacetic acid molecules and ten water molecules located and refined in 14 positions. One gramicidin S molecule has an exact twofold-symmetrical conformation; the other deviates from the molecular twofold symmetry. The cyclic peptide adopts an antiparallel beta-sheet secondary structure with two type II' beta-turns. These turns have the residues D-Phe and Pro at positions i + 1 and i + 2, respectively. In the crystals, the gramicidin S molecules line up into double-stranded helical channels that differ from those observed previously. The implications of the supramolecular structure for several models of gramicidin S conformation and assembly in the membrane are discussed.

REMOVAL OF CHLORIDE FROM AQUEOUS SOLUTIONS

DOEpatents

Hyman, M.L.; Savolainen, J.E.

1960-01-01

A method is given for dissolving reactor fuel elements in which the uranium is associated with a relatively inert chromium-containing alloy such as stainless steel. An aqueous mixture of acids comprising 2 to 2.5 molar hydrochloric acid and 4 to 8 molar nitric acid is employed in dissolving the fuel element. In order io reduce corrosion in subsequent processing of the resulting solution, chloride values are removed from the solution by contacting it with concentrated nitric acid at an elevated temperature.

A two-stage pretreatment process using dilute hydrochloric acid followed by Fenton oxidation to improve sugar recovery from corn stover.

PubMed

Li, Wenzhi; Liu, Qiyu; Ma, Qiaozhi; Zhang, Tingwei; Ma, Longlong; Jameel, Hasan; Chang, Hou-Min

2016-11-01

A two-stage pretreatment process is proposed in this research in order to improve sugar recovery from corn stover. In the proposed process, corn stover is hydrolyzed by dilute hydrochloric acid to recover xylose, which is followed by a Fenton reagent oxidation to remove lignin. 0.7wt% dilute hydrochloric acid is applied in the first stage pretreatment at 120°C for 40min, resulting in 81.0% xylose removal. Fenton reagent oxidation (1g/L FeSO4·7H2O and 30g/L H2O2) is performed at room temperature (about 20°C) for 12 has a second stage which resulted in 32.9% lignin removal. The glucose yield in the subsequent enzymatic hydrolysis was 71.3% with a very low cellulase dosage (3FPU/g). This two-stage pretreatment is effective due to the hydrolysis of hemicelluloses in the first stage and the removal of lignin in the second stage, resulting in a very high sugar recovery with a low enzyme loading. Copyright © 2016 Elsevier Ltd. All rights reserved.

Solution of rocks and refractory minerals by acids at high temperatures and pressures. Determination of silica after decomposition with hydrofluoric acid

USGS Publications Warehouse

May, I.; Rowe, J.J.

1965-01-01

A modified Morey bomb was designed which contains a removable nichromecased 3.5-ml platinium crucible. This bomb is particularly useful for decompositions of refractory samples for micro- and semimicro-analysis. Temperatures of 400-450?? and pressures estimated as great as 6000 p.s.i. were maintained in the bomb for periods as long as 24 h. Complete decompositions of rocks, garnet, beryl, chrysoberyl, phenacite, sapphirine, and kyanite were obtained with hydrofluoric acid or a mixture of hydrofluoric and sulfuric acids; the decomposition of chrome refractory was made with hydrochloric acid. Aluminum-rich samples formed difficultly soluble aluminum fluoride precipitates. Because no volatilization losses occur, silica can be determined on sample solutions by a molybdenum-blue procedure using aluminum(III) to complex interfering fluoride. ?? 1965.

SOLVENT EXTRACTION OF THORIUM VALUES FROM AQUEOUS SOLUTIONS

DOEpatents

Warf, J.C.

1959-04-21

The separation of thorium values from rare earth metals contained ln aqueous solutions by means of extraction with a water immiscible alkyl phosphate diluted with a hydrocarbon such as hexane is described. While the extraction according to this invention may be carried out from any aqueous salt solution, it is preferred to use solutions containing free mineral acid. Hydrochloric acid and in particular nitric acid are sultable in a concentration ranging from 0.1 to 7 normal. The higher acid concentration results in higher extraction values.

Evaluation of White Bentonite Modified by Acid Attack

NASA Astrophysics Data System (ADS)

Andrade, C. G. Bastos; Fermino, D. M.; Fernandes, M. G.; Valenzuela-Diaz, F. R.

For industrial use, the smectite clays must be cleared of impurities, usually obtained by acid modification, using a high concentration solution of inorganic acid at temperatures under boiling point. In the present paper, a sample of white bentonite from Paraiba, Brazil, was modified by hydrochloric acid under moderate conditions (90°C, reaction times of 1, 6, 12, 18 and 24hours in close reactor, concentration of the aqueous solution of hydrochloric acid 1.5 M, acid solution/clay ratio of 1g/10mL). The purpose of these attacks is to reduce the concentration of impurities with minimal change in the clay minerals structure. The modified samples were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), Cation Exchange Capacity (CEC), Stereomicroscopy, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Detector (EDS). Thus, this modified bentonite tends to be a good economic and environmental alternative in manufacturing of products with high added value such as cosmetics and polymer/clay nanocomposites.

Preparation of Rutile from Ilmenite Concentrate Through Pressure Leaching with Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Xiang, Junyi; Liu, Songli; Lv, Xuewei; Bai, Chenguang

2017-04-01

Take into account the fact that the natural rutile utilized for the production of titanium dioxide pigment through chloride process is desperately lacking worldwide especially in China, an attempt was exploited for extracting synthetic rutile from Yunnan ilmenite concentrate with hydrochloric acid pressure leaching process. The leaching parameters for one step leaching process were investigated. The results shown that the optimum condition is leaching temperature of 413 K (140 °C), acid concentration of 20 pct HCl, leaching time of 4 hours and liquid/solid mass ratio of 8:1. A two steps leaching process was also suggested to reutilize the leaching liquor which with a high content of HCl. The results showed that the content of HCl decreased from 135 to 75 g/L, total iron increased from 44.5 g/L to about 87.6 g/L, and the liquid/solid mass ratio decreased to 5:1 with a two steps leaching process. The leaching product produced through a two steps leaching process shows a pure golden red with a high content of titanium (92.65 pct TiO2), a relatively low content of calcium (0.10 pct CaO) and magnesium (0.12 pct MgO), but high content of silicon (5.72 pct SiO2).

Insights into How Students Learn the Difference between a Weak Acid and a Strong Acid from Cartoon Tutorials Employing Visualizations

ERIC Educational Resources Information Center

Kelly, Resa M.; Akaygun, Sevil

2016-01-01

This article summarizes an investigation into how Flash-based cartoon video tutorials featuring molecular visualizations affect students' mental models of acetic acid and hydrochloric acid solutions and how the acids respond when tested for electrical conductance. Variation theory served as the theoretical framework for examining how students…

Acid effects on the measurement of mercury by cold vapor atomic absorption spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeloju, S.B.; Mann, T.F.

1987-07-01

The influence of nitric, hydrochloric and sulfuric acids on the measurement of mercury by cold vapor atomic absorption spectrometry has been investigated. Small pre-reduction peaks associated with the instability of mercury were observed in solutions containing less than or equal to 12.5, < 2 and less than or equal to 12.5% v/v of each acid, respectively. Mercury was found to be most stable in greater than or equal to 2% v/v hydrochloric acid and the measured absorbance was not greatly influenced by varying concentration of the acid. The mercury absorbance measurements were more sensitive in solutions containing less than ormore » equal to 6.3% v/v hydrochloric acid than in similar concentrations of nitric and sulfuric acids. The use of the three acids as a digestion mixture result in serious interference from nitrogen oxides. The interference was removed by use of expelling agents such as urea and sulfamic acid or overcome by use of excess stannous chloride, prior to the reduction of mercury(II) ions. The determination of mercury in NBS albacore tuna using both of these approaches to overcome the interference problem proved to be successful.« less

[The effect of bombesin and its analogs on the secretion of gastric juice and its content of pepsin and hydrochloric acid].

PubMed

Barashkova, G M; Klimov, P K; Kuranova, I L; Churkina, S I; Filonova, E B

1990-07-01

I.V. Infusion of bombesine after eating raw meat inhibited for 30-60 min the secretion of gastric juice and hydrochloric acid in dogs. Within 90-120 min of simultaneous infusion of pentagastrin and bombesine, the amount of secreted juice and its acidity decreased and then the secretion of gastric parietal cells increased. Simultaneous infusion of histamine and bombesine increased the response of gastric parietal cells during the whole experiment as compared with the histamine effect alone. Microapplication of bombesine into cerebral structures also decreased the secretory response of the parietal cells.

Sugar yields from dilute oxalic acid pretreatment of maple wood compared to those with other dilute acids and hot water.

PubMed

Zhang, Taiying; Kumar, Rajeev; Wyman, Charles E

2013-01-30

Dilute oxalic acid pretreatment was applied to maple wood to improve compatibility with downstream operations, and its performance in pretreatment and subsequent enzymatic hydrolysis was compared to results for hydrothermal and dilute hydrochloric and sulfuric acid pretreatments. The highest total xylose yield of ∼84% of the theoretical maximum was for both 0.5% oxalic and sulfuric acid pretreatment at 160 °C, compared to ∼81% yield for hydrothermal pretreatment at 200 °C and for 0.5% hydrochloric acid pretreatment at 140 °C. The xylooligomer fraction from dilute oxalic acid pretreatment was only 6.3% of the total xylose in solution, similar to results with dilute hydrochloric and sulfuric acids but much lower than the ∼70% value for hydrothermal pretreatment. Combining any of the four pretreatments with enzymatic hydrolysis with 60 FPU cellulase/g of glucan plus xylan in the pretreated maple wood resulted in virtually the same total glucose plus xylose yields of ∼85% of the maximum possible. Copyright © 2012 Elsevier Ltd. All rights reserved.

Establishment of hydrochloric acid/lipopolysaccharide-induced pelvic inflammatory disease model.

PubMed

Oh, Yeonsu; Lee, Jaehun; Kim, Hyeon-Cheol; Hahn, Tae-Wook; Yoon, Byung-Il; Han, Jeong-Hee; Kwon, Yong-Soo; Park, Joung Jun; Koo, Deog-Bon; Rhee, Ki-Jong; Jung, Bae Dong

2016-09-30

Pelvic inflammatory disease (PID), which is one of the most problematic complications experienced by women with sexually transmitted diseases, frequently causes secondary infections after reproductive abnormalities in veterinary animals. Although the uterus is self-protective, it becomes fragile during periods or pregnancy. To investigate PID, bacteria or lipopolysaccharide (LPS) extracted from gram negative bacteria has been used to induce the disease in several animal models. However, when LPS is applied to the peritoneum, it often causes systemic sepsis leading to death and the PID was not consistently demonstrated. Hydrochloric acid (HCl) has been used to induce inflammation in the lungs and stomach but not tested for reproductive organs. In this study, we developed a PID model in mice by HCl and LPS sequential intracervical (i.c.) administration. The proinflammatory cytokines, interleukin (IL)-1β, IL-6 and tumor necrosis factor-α, were detected in the mouse uterus by western blot analysis and cytokine enzyme-linked immunosorbent assay after HCl (25 mg/kg) administration i.c. followed by four LPS (50 mg/kg) treatments. Moreover, mice exhibited increased infiltration of neutrophils in the endometrium and epithelial layer. These results suggest that ic co-administration of HCl and LPS induces PID in mice. This new model may provide a consistent and reproducible PID model for future research.

A review on methods of recovery of acid(s) from spent pickle liquor of steel industry.

PubMed

Ghare, N Y; Wani, K S; Patil, V S

2013-04-01

Pickling is the process of removal of oxide layer and rust formed on metal surface. It also removes sand and corrosion products from the surface of metal. Acids such as sulfuric acid, hydrochloric acid are used for pickling. Hydrofluoric acid-Nitric acid mixture is used for stainless steel pickling. Pickling solutions are spent when acid concentration in pickling solutions decreases by 75-85%, which also has metal content up to 150-250 g/ dm3. Spent pickling liquor (SPL) should be dumped because the efficiency of pickling decreases with increasing content of dissolved metal in the bath. The SPL content depends on the plant of origin and the pickling method applied there. SPL from steel pickling in hot-dip galvanizing plants contains zinc(II), iron, traces of lead, chromium. and other heavy metals (max. 500 mg/dm3) and hydrochloric acid. Zinc(II) passes tothe spent solution after dissolution of this metal from zinc(II)-covered racks, chains and baskets used for transportation of galvanized elements. Unevenly covered zinc layers are usually removed in another pickling bath. Due to this, zinc(II) concentration increases even up to 110 g/dm3, while iron content may reach or exceed even 80 g/dm3 in the same solution. This review presents an overview on different aspects of generation and treatment of SPL with recourse to recovery of acid for recycling. Different processes are described in this review and higher weightage is given to membrane processes.

Effect of adding acid solution on setting time and compressive strength of high calcium fly ash based geopolymer

NASA Astrophysics Data System (ADS)

Antoni, Herianto, Jason Ghorman; Anastasia, Evelin; Hardjito, Djwantoro

2017-09-01

Fly ash with high calcium oxide content when used as the base material in geopolymer concrete could cause flash setting or rapid hardening. However, it might increase the compressive strength of geopolymer concrete. This rapid hardening could cause problems if the geopolymer concrete is used on a large scale casting that requires a long setting time. CaO content can be indicated by pH values of the fly ash, while higher pH is correlated with the rapid setting time of fly ash-based geopolymer. This study investigates the addition of acid solution to reduce the initial pH of the fly ash and to prolong the setting time of the mixture. The acids used in this study are hydrochloric acid (HCl), sulfuric acid (H2 SO4), nitric acid (HNO3) and acetic acid (CH3 COOH). It was found that the addition of acid solution in fly ash was able to decrease the initial pH of fly ash, however, the initial setting time of geopolymer was not reduced. It was even faster than that of the control mixture. The acid type causes various influence, depending on the fly ash properties. In addition, the use of acid solution in fly ash reduces the compressive strength of geopolymer mortar. It is concluded that the addition of acid solution cannot prolong the rapid hardening of high calcium fly ash geopolymer, and it causes adverse effect on the compressive strength.

Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media.

PubMed

Popov, L

2016-09-01

Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

A simple procedure for preparing chitin oligomers through acetone precipitation after hydrolysis in concentrated hydrochloric acid.

PubMed

Kazami, Nao; Sakaguchi, Masayoshi; Mizutani, Daisuke; Masuda, Tatsuhiko; Wakita, Satoshi; Oyama, Fumitaka; Kawakita, Masao; Sugahara, Yasusato

2015-11-05

Chitin oligomers are of interest because of their numerous biologically relevant properties. To prepare chitin oligomers containing 4-6 GlcNAc units [(GlcNAc)4-6], α- and β-chitin were hydrolyzed with concentrated hydrochloric acid at 40 °C. The reactant was mixed with acetone to recover the acetone-insoluble material, and (GlcNAc)4-6 was efficiently recovered after subsequent water extraction. Composition analysis using gel permeation chromatography and MALDI-TOF mass spectrometry indicated that (GlcNAc)4-6 could be isolated from the acetone-insoluble material with recoveries of approximately 17% and 21% from the starting α-chitin and β-chitin, respectively. The acetone precipitation method is highly useful for recovering chitin oligomers from the acid hydrolysate of chitin. The changes in the molecular size and higher-order structure of chitin during the course of hydrolysis were also analyzed, and a model that explains the process of oligomer accumulation is proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Establishment of hydrochloric acid/lipopolysaccharide-induced pelvic inflammatory disease model

PubMed Central

Oh, Yeonsu; Lee, Jaehun; Kim, Hyeon-Cheol; Hahn, Tae-Wook; Yoon, Byung-Il; Han, Jeong-Hee; Kwon, Yong-Soo; Park, Joung Jun; Koo, Deog-Bon; Rhee, Ki-Jong

2016-01-01

Pelvic inflammatory disease (PID), which is one of the most problematic complications experienced by women with sexually transmitted diseases, frequently causes secondary infections after reproductive abnormalities in veterinary animals. Although the uterus is self-protective, it becomes fragile during periods or pregnancy. To investigate PID, bacteria or lipopolysaccharide (LPS) extracted from gram negative bacteria has been used to induce the disease in several animal models. However, when LPS is applied to the peritoneum, it often causes systemic sepsis leading to death and the PID was not consistently demonstrated. Hydrochloric acid (HCl) has been used to induce inflammation in the lungs and stomach but not tested for reproductive organs. In this study, we developed a PID model in mice by HCl and LPS sequential intracervical (i.c.) administration. The proinflammatory cytokines, interleukin (IL)-1β, IL-6 and tumor necrosis factor-α, were detected in the mouse uterus by western blot analysis and cytokine enzyme-linked immunosorbent assay after HCl (25 mg/kg) administration i.c. followed by four LPS (50 mg/kg) treatments. Moreover, mice exhibited increased infiltration of neutrophils in the endometrium and epithelial layer. These results suggest that ic co-administration of HCl and LPS induces PID in mice. This new model may provide a consistent and reproducible PID model for future research. PMID:26726020

Increase in the permeability of tonoplast of garlic (Allium sativum) by monocarboxylic acids.

PubMed

Bai, Bing; Li, Lei; Hu, Xiaosong; Wang, Zhengfu; Zhao, Guanghua

2006-10-18

Immersion of intact aged garlic (Allium sativum) cloves in a series of 5% weak organic monocarboxylate solutions (pH 2.0) resulted in green color formation. No color was formed upon treatment with other weak organic acids, such as citric and malic acids, and the inorganic hydrochloric acid under the same conditions. To understand the significance of monocarboxylic acids and their differing function from that of other acids, acetic acid was compared with organic acids citric and malic and the inorganic hydrochloric acid. The effects of these acids on the permeability of plasma and intracellular membrane of garlic cells were measured by conductivity, light microscopy, and transmission electron microscopy. Except for hydrochloric acid, treatment of garlic with all three organic acids greatly increased the relative conductivity of their respective pickling solutions, indicating that all tested organic acids increased the permeability of plasma membrane. Moreover, a pickling solution containing acetic acid exhibited 1.5-fold higher relative conductivity (approximately 90%) as compared to those (approximately 60%) of both citric and malic acids, implying that exposure of garlic cloves to acetic acid not only changed the permeability of the plasma membrane but also increased the permeability of intracellular membrane. Exposure of garlic to acetic acid led to the production of precipitate along the tonoplast, but no precipitate was formed by citric and malic acids. This indicates that the structure of the tonoplast was damaged by this treatment. Further support for this conclusion comes from results showing that the concentration of thiosulfinates [which are produced only by catalytic conversion of S-alk(en)yl-l-cysteine sulfoxides in cytosol by alliinase located in the vacuole] in the acetic acid pickling solution is 1.3 mg/mL, but almost no thiosulfinates were detected in the pickling solution of citric and malic acids. Thus, all present results suggest that damage of

Pretreatment Solution for Water Recovery Systems

NASA Technical Reports Server (NTRS)

Muirhead, Dean (Inventor)

2018-01-01

Chemical pretreatments are used to produce usable water by treating a water source with a chemical pretreatment that contains a hexavalent chromium and an acid to generate a treated water source, wherein the concentration of sulfate compounds in the acid is negligible, and wherein the treated water source remains substantially free of precipitates after the addition of the chemical pretreatment. Other methods include reducing the pH in urine to be distilled for potable water extraction by pretreating the urine before distillation with a pretreatment solution comprising one or more acid sources selected from a group consisting of phosphoric acid, hydrochloric acid, and nitric acid, wherein the urine remains substantially precipitate free after the addition of the pretreatment solution. Another method described comprises a process for reducing precipitation in urine to be processed for water extraction by mixing the urine with a pretreatment solution comprising hexavalent chromium compound and phosphoric acid.

Benzaldehyde, 2-hydroxybenzoyl hydrazone derivatives as inhibitors of the corrosion of aluminium in hydrochloric acid.

PubMed

Fouda, A S; Gouda, M M; El-Rahman, S I

2000-05-01

The effect of benzaldehyde, 2-hydroxybenzoyl hydrazone derivatives on the corrosion of aluminium in hydrochloric acid has been investigated using thermometric and polarization techniques. The inhibitive efficiency ranking of these compounds from both techniques was found to be: 2>3>1>4. The inhibitors acted as mixed-type inhibitors but the cathode is more polarized. The relative inhibitive efficiency of these compounds has been explained on the basis of structure of the inhibitors and their mode of interaction at the surface. Results show that these additives are adsorbed on an aluminium surface according to the Langmuir isotherm. Polarization measurements indicated that the rate of corrosion of aluminium rapidly increases with temperature over the range 30-55 degrees C both in the absence and in the presence of inhibitors. Some thermodynamic data of the adsorption process are calculated and discussed.

Hydrochloric acid poisoning

MedlinePlus

... measure and monitor the person's vital signs, including temperature, pulse, breathing rate, and blood pressure. The person ... into the stomach to suction (aspirate) any remaining acid if the victim is seen shortly after ingesting ...

Characterization of the Unusual Product from the Reaction between Cobalt(II) Chloride, Ethane-1,2-diamine, and Hydrochloric Acid: An Undergraduate Project Involving an Unknown Metal Complex.

ERIC Educational Resources Information Center

Curtis, Neil F.; And Others

1986-01-01

Discusses the need for student research-type chemistry projects based upon "unknown" metal complexes. Describes an experiment involving the product from the reaction between cobalt(II) chloride, ethane-1,2-diamine (en) and concentrated hydrochloric acid. Outlines the preparation of the cobalt complex, along with procedure, results and…

Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

NASA Astrophysics Data System (ADS)

Lin, Hui-Wen; Cejudo-Marín, Rocío; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

2016-02-01

Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodically generated at a high Coulombic efficiency (i.e. ≥ 95%) with chlorine formation accounting for 3 ~ 5% of the charge supplied. HCl was anodically produced at moderate strengths at a CE of 65 ± 4% together with a CE of 89 ± 1% for cathodic caustic production. The reduction in CE for HCl generation was caused by proton cross-over from the anode to the middle compartment. Overall, this study showed the potential of simultaneous HCl and NaOH generation from NaCl and represents a major step forward for the water industry towards on-site production of HCl and NaOH. In this study, artificial brine was used as a source of sodium and chloride ions. In theory, artificial brine could be replaced by saline waste streams such as Reverse Osmosis Concentrate (ROC), turning ROC into a valuable resource.

Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

NASA Astrophysics Data System (ADS)

Puthirath, Anand B.; Methattel Raman, Shijeesh; Varma, Sreekanth J.; Jayalekshmi, S.

2016-04-01

Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puthirath, Anand B.; Varma, Sreekanth J.; Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in

2016-04-18

Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra canmore » be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.« less

Electrothermal vaporization of mineral acid solutions in inductively coupled plasma mass spectrometry: comparison with sample nebulization

NASA Astrophysics Data System (ADS)

Mora, Juan; Gras, Luis; van Veen, Eric H.; de Loos-Vollebregt, Margaretha T. C.

1999-06-01

The analytical behaviour of an electrothermal vaporization (ETV) device for the introduction of mineral acid solutions in inductively coupled plasma mass spectrometry (ICP-MS) was evaluated. Water, nitric acid, hydrochloric acid, perchloric acid and sulphuric acid in concentrations within the 0.05-1.0 mol l-1 range were studied. For all the acids tested, increasing the acid concentration increases the ion signal and deteriorates the precision. The magnitude of the signal enhancement depends on the analyte and on the acid considered. Acid solutions give rise to ion signals that are between 2 and 10 times higher than those with water. Among the acids tested, sulphuric acid provides the highest signals. The addition of palladium reduces matrix effects due to the acids and increases the signal in ETV ICP-MS. In comparison with conventional sample nebulization (CS), the ETV sample introduction system provides higher sensitivities (between 2 and 20 times higher) at the same acid concentration. The magnitude of this improvement is similar to that obtained with a microwave desolvation system (MWDS). The ETV sample introduction system gives rise to the lowest background signals from matrix-induced species. Due to this fact, the limits of detection (LODs) obtained for the isotopes affected by any interference are lower for ETV sample introduction than those obtained with the CS and the MWDS. For the isotopes that do not suffer from matrix-induced spectral interferences, the ETV gives rise to LODs higher than those obtained with the CS. For these isotopes the lowest LODs are obtained with MWDS.

Ultrastructural observation of the acid-base resistant zone of all-in-one adhesives using three different acid-base challenges.

PubMed

Tsujimoto, Miho; Nikaido, Toru; Inoue, Go; Sadr, Alireza; Tagami, Junji

2010-11-01

The aim of this study was to analyze the ultrastructure of the dentin-adhesive interface using two all-in-one adhesive systems (Clearfil Tri-S Bond, TB; Tokuyama Bond Force, BF) after different acid-base challenges. Three solutions were used as acidic solutions for the acid-base challenges: a demineralizing solution (DS), a phosphoric acid solution (PA), and a hydrochloric acid solution (HCl). After the acid-base challenges, the bonded interfaces were examined by scanning electron microscopy. Thickness of the acid-base resistant zone (ABRZ) created in PA and HCl was thinner than in DS for both adhesive systems. For BF adhesive, an eroded area was observed beneath the ABRZ after immersion in PA and HCl, but not in DS. Conversely for TB adhesive, the eroded area was observed only after immersion in PA. In conclusion, although the ABRZ was observed for both all-in-one adhesive systems, its morphological features were influenced by the ingredients of both the adhesive material and acidic solution.

Technical Compliance Guide for Clean Air Act Section 112(r) Risk Management Plan Program

DTIC Science & Technology

1996-06-01

hydrochloric acid , and nitric acid are expected to exist in reportable quantities at Army installations. Chlorine is expected to be the most widely...to form hypochlorous acid and hypochlorites... if excess chlorine is added to the process, the reaction will continue with ammonia or other... Hydrochloric Acid . Hydrochloric acid is commonly used in many industrial and laboratory type oI CAAA-90, Section 112(r), RMP Checklist applications. It is

Study and characterization of powder mackerel (Scomberomorus commerson) bone gelatin through hydrolysis of hydrochloric acid

NASA Astrophysics Data System (ADS)

Mardawati, E.; Sugandi, H.; Kayaputri, I. L.; Cahyana, Y.; Wira, D. W.; Pujianto, T.; Kastaman, R.

2018-02-01

Gelatin is one of the most common food additives in the food and beverage industry. Gelatin is generally made of leather or pig bones, causing concerns about the halal and safety of its product. Mackerel fish bone (Scomberomorus commerson) is a waste fish that has not been utilized well and it contains 18.6% of collagen so that it can be made into gelatin. The purpose of this research is to know the relation between HCl concentration with physical and chemical characteristics of gelatin and to know the best HCl concentration for gelatin production. Based on the physical and chemical analysis of gelatin, it is known that the concentration of hydrochloric acid influences the yield, viscosity, gel strength and pH produced. The higher HCl concentration there will be decrease in the pH value, gel strength, viscosity and protein. The yield will rise to the optimum point then decrease with respect to the high HCl concentration. Gelatin with 2% HCl concentration was the best treatment, with pH value 3.83, viscosity 3.65cP, gel strength 190.50 blooms which fulfilled British Standard, yield 10.16%, protein content 43.34%. It has functional group such as amino acids glycine, proline and hydroxyproline and 15 other amino acids, the gelatin group uptake in the region of amide wave numbers A, amides I, II and III, with a gelatin molecular weight of 290.35 g/mol.

Microtensile strength of spruce pine after exposure to acids and bases

Treesearch

Floyd G. Manwiller; Paul R. Godfrey

1972-01-01

Earlywood and latewood microtensile specimens from 12 trees of Pinus glabra Wal. were subjected to 10-percent solution of 5 acids and 3 bases at 90oC for up to 3 hours. Hydrochloric and sulfuric acids were the most damaging, lowering maximum tensile strength 27 and 17 percent in earlywood and 36 and 39 percent in latewood; they...

Dissolution mechanism of aluminum hydroxides in acid media

NASA Astrophysics Data System (ADS)

Lainer, Yu. A.; Gorichev, I. G.; Tuzhilin, A. S.; Gololobova, E. G.

2008-08-01

The effects of the concentration, temperature, and potential at the hydroxide/electrolyte interface on the aluminum hydroxide dissolution in sulfuric, hydrochloric, and perchloric acids are studied. The limiting stage of the aluminum hydroxide dissolution in the acids is found to be the transition of the complexes that form on the aluminum hydroxide surface from the solid phase into the solution. The results of the calculation of the acid-base equilibrium constants at the oxide (hydroxide)/solution interface using the experimental data on the potentiometric titration of Al2O3 and AlOOH suspensions are analyzed. A mechanism is proposed for the dissolution of aluminum hydroxides in acid media.

Response of citrus and other selected plant species to simulated HCL - acid rain

NASA Technical Reports Server (NTRS)

Knott, W. M.; Heagle, A. S.

1980-01-01

Mature valencia orange trees were sprayed with hydrochloric acid solutions (pH 7.8, 2.0, 1.0, and 0.5) in the field at the full bloom stage and at one month after fruit set. Potted valencia orange and dwarf citrus trees, four species of plants native to Merritt Island, and four agronomic species were exposed to various pH levels of simulated acid rain under controlled conditions. The acid rain was generated from dilutions of hydrochloric acid solutions or by passing water through an exhaust generated by burning solid rocket fuel. The plants were injured severely at pH levels below 1.0, but showed only slight injury at pH levels of 2.0 and above. Threshold injury levels were between 2.0 and 3.0 pH. The sensitivity of the different plant species to acid solutions was similar. Foliar injury symptoms were representative of acid rain including necrosis of young tissue, isolated necrotic spots or patches, and leaf abscission. Mature valencia orange trees sprayed with concentrations of 1.0 pH and 0.5 pH in the field had reduced fruit yields for two harvests after the treatment. All experimental trees were back to full productivity by the third harvest after treatment.

Tandem Lewis/Brønsted homogeneous acid catalysis: conversion of glucose to 5-hydoxymethylfurfural in an aqueous chromium(iii) chloride and hydrochloric acid solution

DOE PAGES

Swift, T. Dallas; Nguyen, Hannah; Anderko, Andrzej; ...

2015-07-25

Here, a kinetic model for the tandem conversion of glucose to 5-hydroxymethylfurfural (HMF) through fructose in aqueous CrCl 3–HCl solution was developed by analyzing experimental data. We show that the coupling of Lewis and Brønsted acids in a single pot overcomes equilibrium limitations of the glucose–fructose isomerization leading to high glucose conversions and identify conditions that maximize HMF yield. Adjusting the HCl/CrCl 3 concentration has a more pronounced effect on HMF yield at constant glucose conversion than that of temperature or CrCl 3 concentration. This is attributed to the interactions between HCl and CrCl 3 speciation in solution that leadsmore » to HMF yield being maximized at moderate HCl concentrations for each CrCl 3 concentration. This volcano-like behavior is accompanied with a change in the rate-limiting step from fructose dehydration to glucose isomerization as the concentration of the Brønsted acid increases. The maximum HMF yield in a single aqueous phase is only modest and appears independent of catalysts’ concentrations as long as they are appropriately balanced. However, it can be further maximized in a biphasic system. Our findings are consistent with recent studies in other tandem reactions catalyzed by different catalysts.« less

Tandem Lewis/Brønsted homogeneous acid catalysis: conversion of glucose to 5-hydoxymethylfurfural in an aqueous chromium(iii) chloride and hydrochloric acid solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swift, T. Dallas; Nguyen, Hannah; Anderko, Andrzej

Here, a kinetic model for the tandem conversion of glucose to 5-hydroxymethylfurfural (HMF) through fructose in aqueous CrCl 3–HCl solution was developed by analyzing experimental data. We show that the coupling of Lewis and Brønsted acids in a single pot overcomes equilibrium limitations of the glucose–fructose isomerization leading to high glucose conversions and identify conditions that maximize HMF yield. Adjusting the HCl/CrCl 3 concentration has a more pronounced effect on HMF yield at constant glucose conversion than that of temperature or CrCl 3 concentration. This is attributed to the interactions between HCl and CrCl 3 speciation in solution that leadsmore » to HMF yield being maximized at moderate HCl concentrations for each CrCl 3 concentration. This volcano-like behavior is accompanied with a change in the rate-limiting step from fructose dehydration to glucose isomerization as the concentration of the Brønsted acid increases. The maximum HMF yield in a single aqueous phase is only modest and appears independent of catalysts’ concentrations as long as they are appropriately balanced. However, it can be further maximized in a biphasic system. Our findings are consistent with recent studies in other tandem reactions catalyzed by different catalysts.« less

ANION EXCHANGE METHOD FOR SEPARATION OF METAL VALUES

DOEpatents

Hyde, E.K.; Raby, B.A.

1959-02-10

A method is described for selectively separating radium, bismuth, poloniums and lead values from a metallic mixture of thc same. The mixture is dissolved in aqueous hydrochloric acid and the acidity is adjusted to between 1 to 2M in hydrochloric acid to form the anionic polychloro complexes of polonium and bismuth. The solution is contacted with a first anion exchange resin such as strong base quaternary ammonia type to selectively absorb the polonium and bismuth leaving the radium and lead in the effluent. The effluent, after treatment in hydrochloric acid to increase the hydrochloric acid concentration to 6M is contacted with a second anion exchange iesin of the same type as the above to selectively adsorb the lead leaving the radium in the effluent. Radium is separately recovered from the effluent from the second exchange column. Lead is stripped from the loaded resin of the second column by treatment with 3M hydrochloric acid solution. The loaded resin of the first column is washed with 8M hydrochloric acid solution to recover bismuth and then treated with strong nitric acid solution to recover polonium.

Impact of laminar flow velocity of different acids on enamel calcium loss.

PubMed

Attin, T; Becker, K; Wiegand, A; Tauböck, T T; Wegehaupt, F J

2013-03-01

The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

THE INACTIVATION OF DILUTE SOLUTIONS OF CRYSTALLINE TRYPSIN BY X-RADIATION

PubMed Central

McDonald, Margaret R.

1955-01-01

The proteolytic activity of dilute solutions of clystalline trypsin is destroyed by x-rays, the amount of inactivation being an exponential function of the radiation dose. The reaction yield increases steadily with increasing concentration of trypsin, varying, as the concentration of enzyme is increased from 1 to 300 µM, from 0.068 to 0.958 micromole of trypsin per liter inactivated per 1000 r with 0.005 N hydrochloric acid as the solvent, from 0.273 to 0.866 with 0.005 N sulfuric acid as the solvent, and from 0.343 to 0.844 with 0.005 N nitric acid as the solvent. When the reaction yields are plotted as a function of the initial concentration of trypsin, they fall on a curve given by the expression Y α XK, in which Y is the reaction yield, X is the concentration of trypsin, and K is a constant equal to 0.46, 0.20, and 0.16, respectively, with 0.005 N hydrochloric, sulfuric, and nitric acids as solvents. The differences between the reaction yields found with chloride and sulfate ions in I to 10 µM trypsin solutions are significant only in the pH range from 2 to 4. The amount of inactivation obtained with a given dose of x-rays depends on the pH of the solution being irradiated and the nature of the solvent. The reaction yield-pH curve is a symmetrical one, with minimum yields at about pH 7. Buffers such as acetate, citrate, borate and barbiturate, and other organic molecules such as ethanol and glucose, in concentrations as low as 20 µM, inhibit the inactivation of trypsin by x-radiation. Sigmoid inactivation-dose curves instead of exponential ones are obtained in the presence of ethanol. The reaction yields for the inactivation of trypsin solutions by x-rays are approximately 1.5 times greater when the irradiation is done at 26°C. than when it is done at 5°C., when 0.005 N hydrochloric acid is the solvent. The dependence on temperature is less when 0.005 N sulfuric acid is used, and is negligible with 0.005 N nitric acid. The difficulties involved in

Preserving ground water samples with hydrochloric acid does not result in the formation of chloroform

USGS Publications Warehouse

Squillace, Paul J.; Pankow, James F.; Barbash, Jack E.; Price, Curtis V.; Zogorski, John S.

1999-01-01

Water samples collected for the determination of volatile organic compounds (VOCs) are often preserved with hydrochloric acid (HCl) to inhibit the biotransformation of the analytes of interest until the chemical analyses can he performed. However, it is theoretically possible that residual free chlorine in the HCl can react with dissolved organic carbon (DOC) to form chloroform via the haloform reaction. Analyses of 1501 ground water samples preserved with HCl from the U.S. Geological Survey's National Water-Quality Assessment Program indicate that chloroform was the most commonly detected VOC among 60 VOCs monitored. The DOC concentrations were not significantly larger in samples with detectable chloroform than in those with no delectable chloroform, nor was there any correlation between the concentrations of chloroform and DOC. Furthermore, chloroform was detected more frequently in shallow ground water in urban areas (28.5% of the wells sampled) than in agricultural areas (1.6% of the wells sampled), which indicates that its detection was more related to urban land-use activities than to sample acidification. These data provide strong evidence that acidification with HCl does not lead to the production of significant amounts of chloroform in ground water samples. To verify these results, an acidification study was designed to measure the concentrations of all trihalomethanes (THMs) that can form as a result of HCl preservation in ground water samples and to determine if ascorbic acid (C6H8O6) could inhibit this reaction if it did occur. This study showed that no THMs were formed as a result of HCl acidification, and that ascorbic acid had no discernible effect on the concentrations of THMs measured.

Computed phase diagrams for the system: Sodium hydroxide-uric acid-hydrochloric acid-water

NASA Astrophysics Data System (ADS)

Brown, W. E.; Gregory, T. M.; Füredi-Milhofer, H.

1987-07-01

Renal stone formation is made complex by the variety of solid phases that are formed, by the number of components in the aqueous phase, and by the multiplicity of ionic dissociation and association processes that are involved. In the present work we apply phase diagrams calculated by the use of equilibrium constants from the ternary system sodium hydroxide-uric acid-water to simplify and make more rigorous the understanding of the factors governing dissolution and precipitation of uric acid (anhydrous and dihydrate) and sodium urate monohydrate. The system is then examined in terms of four components. Finally, procedures are described for fluids containing more than four components. The isotherms, singular points, and fields of supersaturation and undersaturation are shown in various forms of phase diagrams. This system has two notable features: (1) in the coordinates -log[H 2U] versus -log[NaOH], the solubility isotherms for anhydrous uric acid and uric acid dihydrate approximate straight lines with slopes equal to +1 over a wide range of concentrations. As a result, substantial quantities of sodium acid urate monohydrate can precipitate from solution or dissolve without changing the degree of saturation of uric acid significantly. (2) The solubility isotherm for NaHU·H 2O has a deltoid shape with the low-pH branch having a slope of infinity. As a result of the vertical slope of this isotherm, substantial quantities of uric acid can dissolve or precipitate without changing the degree of saturation of sodium acid urate monohydrate significantly. The H 2U-NaOH singular point has a pH of 6.87 at 310 K in the ternary system.

METHOD OF RECOVERING THORIUM

DOEpatents

Fisher, R.W.

1957-12-10

A method is described for recovering thorium from impurities found in a slag containing thorium and said impurities, comprising leaching a composition containing thorium with water, removing the water solution, treating the residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting its acidity to 1 to 3 normal, adding oxalic acid, and thereafter separating the precipitated thorium oxalate digesting the residue from the hydrochloric acid treatment with a strong solution of sodium hydroxide at an elevated temperature, removing said solution and treating the insoluble residue with hydrochloric acid, separating the solution from the insoluble residue, adjusting the acidity of this solution to 1 to 3 normal, adding nitric acid to oxidize the iron present, adding oxalic acid and thereafter separating the thorium oxalate thus precipitated.

Microtensile strength of spruce pine after exposure to acids and bases

Treesearch

F.G. Manwiller; P.R. Godfrey

1973-01-01

Earlywood and latewood microtensile specimens from 12 trees of Pinus glabra Walt. were subjected to 10-percent solution of 5 acids and 3 bases at good for up to 3 hours. Hydrochloric and sulfuric acids were the most damaging, lowering maximum tensile strength 27 and 17 percent in earlywood and 36 and 39 percent in latewood; they reduced work to maximum load 40 percent...

Preservation of urine free catecholamines and their free O-methylated metabolites with citric acid as an alternative to hydrochloric acid for LC-MS/MS-based analyses.

PubMed

Peitzsch, Mirko; Pelzel, Daniela; Lattke, Peter; Siegert, Gabriele; Eisenhofer, Graeme

2016-01-01

Measurements of urinary fractionated metadrenalines provide a useful screening test to diagnose phaeochromocytoma. Stability of these compounds and their parent catecholamines during and after urine collection is crucial to ensure accuracy of the measurements. Stabilisation with hydrochloric acid (HCl) can promote deconjugation of sulphate-conjugated metadrenalines, indicating a need for alternative preservatives. Urine samples with an intrinsically acidic or alkaline pH (5.5-6.9 or 7.1-8.7, respectively) were used to assess stability of free catecholamines and their free O-methylated metabolites over 7 days of room temperature storage. Stabilisation with HCl was compared with ethylenediaminetetraacetic acid/metabisulphite and monobasic citric acid. Catecholamines and metabolites were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Free catecholamines and their O-methylated metabolites were stable in acidic urine samples over 7 days of room temperature storage, independent of the presence or absence of any stabilisation method. In contrast, free catecholamines, but not the free O-methylated metabolites, showed rapid degradation within 24 h and continuing degradation over 7 days in urine samples with an alkaline pH. Adjustment of alkaline urine samples to a pH of 3-5 with HCl or 4.8-5.4 with citric acid completely blocked degradation of catecholamines. Ethylenediaminetetraacetic acid/metabisulphite, although reducing the extent of degradation of catecholamines in alkaline urine, was largely ineffectual as a stabiliser. Citric acid is equally effective as HCl for stabilisation of urinary free catecholamines and minimises hazards associated with use of strong inorganic acids while avoiding deconjugation of sulphate-conjugated metabolites during simultaneous LC-MS/MS measurements of free catecholamines and their free O-methylated metabolites.

Manufacturing Chemical Equipment from Titanium - USSR

DTIC Science & Technology

1960-05-25

hydrochloric, sulfuric and orthophosphoric, oxalic, trichlor- and tri-flour- acetic acids , and of boiling solutions of formic and citric acids . Nor...sulfofrezon and oleinic acid . Titanium dust is explosive , therefore only wet grinding is being used. The cooling is done either by a ten percent solution of...pumping ore of various organic acids , solutions of chlorides, and of moderately concentrated hydrochloric acid.are made of titanium. Such apparatus

Reduction of mercury from mackerel fillet using combined solution of cysteine, EDTA, and sodium chloride.

PubMed

Hajeb, P; Jinap, S

2012-06-13

An acidic solution containing mercury chelating agents to eliminate mercury in raw fish (mackerel) fillet was developed. The solution contained hydrochloric acid, sodium hydroxide, cysteine, EDTA, and NaCl. The optimum conditions for mercury reduction were achieved using response surface methodology (RSM) at cysteine concentration of 1.25%, EDTA of 275 mg/L, NaCl of 0.5%, pH of 3.75, and exposure time of 18 min. The optimized conditions produced a solution which can remove up to 91% mercury from raw fish fillet. Cysteine and EDTA were identified as potential chelating agents with the greatest potential for use. The solution can be employed in fish industries to reduce mercury in highly contaminated fish.

SEPARATION OF POLONIUM, PROTACTINIUM OR MIXTURES THEREOF IN AQUEOUS SOLUTION FROM BISMUTH, LEAD, ZIRCONIUM AND/OR COLUMBIUM VALUES

DOEpatents

Van Winkle, Q.; Kraus, K.A.

1959-10-27

A process is presented for separating polonium, protactinium, or mixtures thereof in aqueous solution from bismuth, zirconium, lead, and niobium values contained in the solution. The method comprises providing hydrochloric acid in the solution in a concentration of at least 5N. contacting the aqueous solution with a substantially waterimmiscible organic solvent such as diisopropyl ketone, and separating the aqueous phase containing the bismuth, zirconium, lead, and niobium from the organic extract phase containing the polonium, protactinium, or mixture thereof.

Theoretical, thermodynamic and electrochemical analysis of biotin drug as an impending corrosion inhibitor for mild steel in 15% hydrochloric acid

PubMed Central

Xu, Xihua; Sun, Zhipeng; Ansari, K. R.; Lin, Yuanhua

2017-01-01

The corrosion mitigation efficiency of biotin drug for mild steel in 15% hydrochloric acid was thoroughly investigated by weight loss and electrochemical methods. The surface morphology was studied by the contact angle, scanning electrochemical microscopy, atomic force microscopy and scanning electron microscopy methods. Quantum chemical calculation and Fukui analysis were done to correlate the experimental and theoretical data. The influence of the concentration of inhibitor, immersion time, temperature, activation energy, enthalpy and entropy has been reported. The mitigation efficiency of biotin obtained by all methods was in good correlation with each other. Polarization studies revealed that biotin acted as a mixed inhibitor. The adsorption of biotin was found to obey the Langmuir adsorption isotherm. Surface studies showed the hydrophobic nature of the steel with inhibitor and vindicated the formation of a film on the metal surface that reduced the corrosion rate. PMID:29308235

Efficient removal of heavy metal ions from aqueous solution using salicylic acid type chelate adsorbent.

PubMed

An, Fuqiang; Gao, Baojiao; Dai, Xin; Wang, Min; Wang, Xiaohua

2011-09-15

In this study, 5-aminosalicylic acid was successfully grafted onto the poly(glycidyl methacrylate) (PGMA) macromolecular chains of PGMA/SiO(2) to obtain a novel adsorbent designated as ASA-PGMA/SiO(2). The adsorption properties of ASA-PGMA/SiO(2) for heavy metal ions were studied through batch and column methods. The experimental results showed that ASA-PGMA/SiO(2) possesses strong chelating adsorption ability for heavy metal ions, and its adsorption capacity for Cu(2+), Cd(2+), Zn(2+), and Pb(2+) reaches 0.42, 0.40, 0.35, and 0.31 mmol g(-1), respectively. In addition, pH has a great influence on the adsorption capacity in the studied pH range. The adsorption isotherm data greatly obey the Langmuir and Freundlich model. The desorption of metal ions from ASA-PGMA/SiO(2) is effective using 0.1 mol l(-1) of hydrochloric acid solution as eluent. Consecutive adsorption-desorption experiments showed that ASA-PGMA/SiO(2) could be reused almost without any loss in the adsorption capacity. Copyright © 2011 Elsevier B.V. All rights reserved.

Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin

PubMed Central

Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Hammed, Leiqaa A.; Al-Amiery, Ahmed A.; San, Ng Hooi; Musa, Ahmed Y.

2014-01-01

A new coumarin derivative, N,N′-((2E,2′E)-2,2′-(1,4-phenylenebis(methanylylidene))bis(hydrazinecarbonothioyl))bis(2-oxo-2H-chromene-3-carboxamide) PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear magnetic resonance, 1H-NMR and carbon-13 nuclear magnetic resonance 13C-NMR). The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential (ECORR), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM) was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH. PMID:28788680

Inhibition of Mild Steel Corrosion in Hydrochloric Acid Solution by New Coumarin.

PubMed

Kadhum, Abdul Amir H; Mohamad, Abu Bakar; Hammed, Leiqaa A; Al-Amiery, Ahmed A; San, Ng Hooi; Musa, Ahmed Y

2014-06-05

A new coumarin derivative, N , N '-((2E,2'E)-2,2'-(1,4-phenylenebis (methanylylidene))bis(hydrazinecarbonothioyl))bis(2-oxo-2H-chromene-3-carboxamide) PMBH, was synthesized and its chemical structure was elucidated and confirmed using spectroscopic techniques (Infrared spectroscopy IR, Proton nuclear magnetic resonance, 1 H-NMR and carbon-13 nuclear magnetic resonance 13 C-NMR). The corrosion inhibition effect of PMBH on mild steel in 1.0 M HCl was investigated using corrosion potential ( E CORR ), potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM) measurements. The obtained results indicated that PMBH has promising inhibitive effects on the corrosion of mild steel in 1.0 M HCl across all of the conditions examined. Scanning electron microscopy (SEM) was used to investigate the morphology of the mild steel before and after immersion in 1.0 M HCl solution containing 0.5 mM of PMBH. Surface analysis revealed improvement of corrosion resistance in presence of PMBH.

Effect of chloride ions on the corrosion behavior of low-alloy steel containing copper and antimony in sulfuric acid solution

NASA Astrophysics Data System (ADS)

Park, Sun-Ah; Kim, Seon-Hong; Yoo, Yun-Ha; Kim, Jung-Gu

2015-05-01

The influence of the addition of HCl on the corrosion behavior of low-alloy steel containing copper and antimony was investigated using electrochemical (potentiodynamic and potentiostatic polarization tests, and electrochemical impedance spectroscopy) and weight loss tests in a 1.6M H2SO4 solution with different concentrations of hydrochloric acid (0.00, 0.08, 0.15 and 0.20 M HCl) at 60 °C. The result showed that the corrosion rate decreased with increasing HCl by the formation of protective layers. SEM, EDS and XPS examinations of the corroded surfaces after the immersion test indicated that the corrosion production layer formed in the solution containing HCl was highly comprised of metallic Cu, Cu chloride and metallic (Fe, Cu, Sb) compounds. The corrosion resistance was improved by the Cu-enriched layer, in which chloride ions are an accelerator for cupric ion reduction during copper deposition. Furthermore, cuprous and antimonious chloride species are complex salts for cuprous ions adsorbed on the surface during copper deposition.

Removing hydrochloric acid exhaust products from high performance solid rocket propellant using aluminum-lithium alloy.

PubMed

Terry, Brandon C; Sippel, Travis R; Pfeil, Mark A; Gunduz, I Emre; Son, Steven F

2016-11-05

Hydrochloric acid (HCl) pollution from perchlorate based propellants is well known for both launch site contamination, as well as the possible ozone layer depletion effects. Past efforts in developing environmentally cleaner solid propellants by scavenging the chlorine ion have focused on replacing a portion of the chorine-containing oxidant (i.e., ammonium perchlorate) with an alkali metal nitrate. The alkali metal (e.g., Li or Na) in the nitrate reacts with the chlorine ion to form an alkali metal chloride (i.e., a salt instead of HCl). While this technique can potentially reduce HCl formation, it also results in reduced ideal specific impulse (ISP). Here, we show using thermochemical calculations that using aluminum-lithium (Al-Li) alloy can reduce HCl formation by more than 95% (with lithium contents ≥15 mass%) and increase the ideal ISP by ∼7s compared to neat aluminum (using 80/20 mass% Al-Li alloy). Two solid propellants were formulated using 80/20 Al-Li alloy or neat aluminum as fuel additives. The halide scavenging effect of Al-Li propellants was verified using wet bomb combustion experiments (75.5±4.8% reduction in pH, ∝ [HCl], when compared to neat aluminum). Additionally, no measurable HCl evolution was detected using differential scanning calorimetry coupled with thermogravimetric analysis, mass spectrometry, and Fourier transform infrared absorption. Copyright © 2016 Elsevier B.V. All rights reserved.

Hydrothermal synthesis of highly crystalline RuS{sub 2} nanoparticles as cathodic catalysts in the methanol fuel cell and hydrochloric acid electrolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yanjuan; College of Material Science and Engineering, Key Laboratory of Automobile Materials of Ministry of Education, Jilin University, 2699 Qianjin Street, Changchun 130012; Li, Nan, E-mail: lin@jlu.edu.cn

2015-05-15

Highlights: • Highly crystalline RuS{sub 2} nanoparticles have been first synthesized by a “one-step” hydrothermal method. • The product presents a pure cubic phase of stoichiometric ratio RuS{sub 2} with average particle size of 14.8 nm. • RuS{sub 2} nanoparticles were used as cathodic catalysts in methanol fuel cell and hydrochloric acid electrolysis. • The catalyst outperforms commercial Pt/C in methanol tolerance and stability towards Cl{sup −}. - Abstract: Highly crystalline ruthenium sulfide (RuS{sub 2}) nanoparticles have been first synthesized by a “one-step” hydrothermal method at 400 °C, using ruthenium chloride and thiourea as reactants. The products were characterized bymore » powder X-ray diffraction (XRD), scanning electron microscopy/energy disperse spectroscopy (SEM/EDS), thermo gravimetric-differential thermal analyze (TG-DTA), transmission electron microscopy equipped with selected area electron diffraction (TEM/SAED). Fourier transform infrared spectra (IR), and X-ray photoelectron spectroscopy (XPS). XRD result illustrates that the highly crystalline product presents a pure cubic phase of stoichiometric ratio RuS{sub 2} and the average particle size is 14.8 nm. SEM and TEM images display the products have irregular shape of 6–25 nm. XPS analyst indicates that the sulfur exists in the form of S{sub 2}{sup 2−}. Cyclic voltammetry (CV), rotating disk electrode (RDE), chronoamperometry (CA) and electrochemical impedance spectroscopy (EIS) measurements are conducted to evaluate the electrocatalytic activity and stability of the highly crystalline RuS{sub 2} nanoparticles in oxygen reduction reaction (ORR) for methanol fuel cell and hydrochloric acid electrolysis. The results illustrate that RuS{sub 2} is active towards oxygen reduction reaction. Although the activity of RuS{sub 2} is lower than that of Pt/C, the RuS{sub 2} catalyst outperforms commercial Pt/C in methanol tolerance and stability towards Cl{sup −}.« less

Effect of strong acids on red mud structural and fluoride adsorption properties.

PubMed

Liang, Wentao; Couperthwaite, Sara J; Kaur, Gurkiran; Yan, Cheng; Johnstone, Dean W; Millar, Graeme J

2014-06-01

The removal of fluoride using red mud has been improved by acidifying red mud with hydrochloric, nitric and sulphuric acid. The acidification of red mud causes sodalite and cancrinite phases to dissociate, confirmed by the release of sodium and aluminium into solution as well as the disappearance of sodalite bands and peaks in infrared and X-ray diffraction data. The dissolution of these mineral phases increases the amount of available iron and aluminium oxide/hydroxide sites that are accessible for the adsorption of fluoride. However, concentrated acids have a negative effect on adsorption due to the dissolution of these iron and aluminium oxide/hydroxide sites. The removal of fluoride is dependent on the charge of iron and aluminium oxide/hydroxides on the surface of red mud. Acidifying red mud with hydrochloric, nitric and sulphuric acid resulted in surface sites of the form ≡SOH2(+) and ≡SOH. Optimum removal is obtained when the majority of surface sites are in the form ≡SOH2(+) as the substitution of a fluoride ion does not cause a significant increase in pH. This investigation shows the importance of having a low and consistent pH for the removal of fluoride from aqueous solutions using red mud. Copyright © 2014 Elsevier Inc. All rights reserved.

Behavior of GaSb (100) and InSb (100) surfaces in the presence of H2O2 in acidic and basic cleaning solutions

NASA Astrophysics Data System (ADS)

Seo, Dongwan; Na, Jihoon; Lee, Seunghyo; Lim, Sangwoo

2017-03-01

Gallium antimonide (GaSb) and indium antimonide (InSb) have attracted strong attention as new channel materials for transistors due to their excellent electrical properties and lattice matches with various group III-V compound semiconductors. In this study, the surface behavior of GaSb (100) and InSb (100) was investigated and compared in hydrochloric acid/hydrogen peroxide mixture (HPM) and ammonium hydroxide/hydrogen peroxide mixture (APM) solutions. In the acidic HPM solution, surface oxidation was greater and the etching rates of the GaSb and InSb surfaces increased when the solution is concentrated, which indicates that H2O2 plays a key role in the surface oxidation of GaSb and InSb in acidic HPM solution. However, the GaSb and InSb surfaces were hardly oxidized in basic APM solution in the presence of H2O2 because gallium and indium are in the thermodynamically stable forms of H2GaO3- and InO2-, respectively. When the APM solution was diluted, however, the Ga on the GaSb surface was oxidized by H2O, increasing the etching rate. However, the effect of dilution of the APM solution on the oxidation of the InSb surface was minimal; thus, the InSb surface was less oxidized than the GaSb surface and the change in the etching rate of InSb with dilution of the APM solution was not significant. Additionally, the oxidation behavior of gallium and indium was more sensitive to the composition of the HPM and APM solutions than that of antimony. Therefore, the surface properties and etching characteristics of GaSb and InSb in HPM and APM solutions are mainly dependent on the behavior of the group III elements rather than the group V elements.

Adsorption and inhibitive properties of sildenafil (Viagra) for zinc in hydrochloric acid solution

NASA Astrophysics Data System (ADS)

Fouda, A. S.; Ibrahim, H.; Atef, M.

Sildenafil (Viagra) was investigated as corrosion inhibitor for Zn in 1 M HCl solution using chemical and electrochemical methods at 25 °C. Electrochemical results showed that this drug is efficient inhibitor for Zn in HCl and the inhibition efficiency (IE) reached to 91% at 300 ppm. The IE increases with the drug concentration and decreases with increasing temperature. The adsorption of this drug on Zn surface follows Langmuir adsorption isotherm. The polarization plots revealed that Sildenafil acts as a mixed-type inhibitor. The thermodynamic parameters of activation and adsorption were calculated and discussed. The surface morphology of the Zn specimens was evaluated using scanning electron microscope (SEM), energy dispersive X-ray (EDX), atomic force microscopy (AFM) and Fourier transform infrared spectroscopy (FTIR) techniques.

REDUCTION OF ACIDITY OF NITRIC ACID SOLUTIONS BY USE OF FORMALDEHYDE

DOEpatents

Healy, T.V.

1958-05-20

A continuous method is described of concentrating by evaporation and reducing the nitrate ion content of an aqueous solution of metallic salts containing nitric acid not in excess of 8N. It consists of heating the solution and then passing formaldehyde into the heated solution to bring about decomposition of the nitric acid. The evolved gases containing NO are contacted countercurrently with an aqueous metal salt solution containing nitric acid in excess of 8N so as to bring about decomposition of the nitric acid and lower the normality to at least 8N, whereupon it is passed into the body of heated solution.

The effect of hydrochloric acid addition to increase carbon nanotubes dispersibility as drug delivery system by covalent functionalization

NASA Astrophysics Data System (ADS)

Wulan, P. P. D. K.; Ulwani, S. H.; Wulandari, H.; Purwanto, W. W.; Mulia, K.

2018-03-01

This study is to obtain the effect of adding hydrochloric acid (HCl) to the mixture of sulfuric acid (H2SO4) and HNO3 in CNT covalent functionalization. HCl expected to increase the dispersibility of functionalized CNT by improving the dispersion time period done with H2SO4 or HNO3. Functionalization used mixture of H2SO4 and HNO3 with volume ratio of 3:1. Covalent functionalization used 0.5 grams of MWCNT ultra sonicated in 50mL HNO3 with and mixture of H2SO4 and HNO3. Additions of 200 mL HCl used variation of molarity from 1M, 2M, 3M, 4M, 5M to 6M. CNT were oxidized to form carboxylic and hydroxyl bonds on the surface that increase dispersibility of CNT. FTIR spectrums showed the existences of carboxyl and hydroxyl group on spectra of 2600-3700 cm-1 and 900-1400 cm-1. Dispersion tests, which showed functionalized CNT (f-CNT) dispersion capabilities, were done by dissolving f-CNT in water. The study resulted that 6M f-CNT (NSC6) gave the best dispersion with zeta potential value of -37.1mV. NSC6 gave the longest dispersion time which was 20 days until f-CNT settle again. SEM-EDS micrographs showed the surface structure of 6M f-CNT without significant damage and no longer contain impurities of Fe, Ni, and Cl.

40 CFR 420.91 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... from spent pickling acid solutions. (h) The term acid regeneration means those hydrochloric acid... regeneration processes. (j) The term spent acid solution (or spent pickle liquor) means those solutions of...

40 CFR 420.91 - Specialized definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... from spent pickling acid solutions. (h) The term acid regeneration means those hydrochloric acid... regeneration processes. (j) The term spent acid solution (or spent pickle liquor) means those solutions of...

ELECTROLYTIC REDUCTION OF NITRIC ACID SOLUTIONS

DOEpatents

Alter, H.W.; Barney, D.L.

1958-09-30

A process is presented for the treatment of radioactivc waste nitric acid solutions. The nitric acid solution is neutralized with an alkali metal hydroxide in an amount sufficient to precipitate insoluble hydroxides, and after separation of the precipitate the solution is electrolyzed to convert the alkali nitrate formed, to alkali hydroxide, gaseous ammonla and oxygen. The solution is then reusable after reducing the volume by evaporating the water and dissolved ammonia.

Recovery of nonwetting characteristics by surface modification of gallium-based liquid metal droplets using hydrochloric acid vapor.

PubMed

Kim, Daeyoung; Thissen, Peter; Viner, Gloria; Lee, Dong-Weon; Choi, Wonjae; Chabal, Yves J; Lee, Jeong-Bong J B

2013-01-01

The applicability of gallium-based liquid metal alloy has been limited by the oxidation problem. In this paper, we report a simple method to remove the oxide layer on the surface of such alloy to recover its nonwetting characteristics, using hydrochloric acid (HCl) vapor. Through the HCl vapor treatment, we successfully restored the nonwetting characteristics of the alloy and suppressed its viscoelasticity. We analyzed the change of surface chemistry before and after the HCl vapor treatment using X-ray photoelectron spectroscopy (XPS) and low-energy ion-scattering spectroscopy (LEIS). Results showed that the oxidized surface of the commercial gallium-based alloy Galinstan (Ga(2)O(3) and Ga(2)O) was replaced with InCl(3) and GaCl(3) after the treatment. Surface tension and static contact angle on a Teflon-coated glass of the HCl-vapor-treated Galinstan were measured to be 523.8 mN/m and 152.5°. A droplet bouncing test was successfully carried out to demonstrate the nonwetting characteristics of the HCl-vapor-treated Galinstan. Finally, the stability of the transformed surface of the HCl-vapor-treated Galinstan was investigated by measuring the contact angle and LEIS spectra after reoxidation in an ambient environment.

Novel nitrogen doped carbon dots for corrosion inhibition of carbon steel in 1 M HCl solution

NASA Astrophysics Data System (ADS)

Cui, Mingjun; Ren, Siming; Zhao, Haichao; Wang, Liping; Xue, Qunji

2018-06-01

Nitrogen doped carbon dots (NCDs) were synthesized and used for inhibiting the corrosion of Q235 carbon steel in hydrochloric acid (HCl) solution. Inhibition effectiveness in short- and long-term immersion was examined using electrochemical measurements, weight loss and surface analysis. Results revealed the inhibition efficiency was improved significantly after adding NCDs and strongly dependent on the concentration of NCDs. SVET results showed that the sample immersed in HCl solution with NCDs showed lower anodic current density mapping than that in blank HCl solution. According to the data extracted from the Langmuir adsorption, the absorption of NCDs involved both chemisorption and physisorption.

Decomposition mechanism of chromite in sulfuric acid-dichromic acid solution

NASA Astrophysics Data System (ADS)

Zhao, Qing; Liu, Cheng-jun; Li, Bao-kuan; Jiang, Mao-fa

2017-12-01

The sulfuric acid leaching process is regarded as a promising, cleaner method to prepare trivalent chromium products from chromite; however, the decomposition mechanism of the ore is poorly understood. In this work, binary spinels of Mg-Al, Mg-Fe, and Mg-Cr in the powdered and lump states were synthesized and used as raw materials to investigate the decomposition mechanism of chromite in sulfuric acid-dichromic acid solution. The leaching yields of metallic elements and the changes in morphology of the spinel were studied. The experimental results showed that the three spinels were stable in sulfuric acid solution and that dichromic acid had little influence on the decomposition behavior of the Mg-Al spinel and Mg-Fe spinel because Mg2+, Al3+, and Fe3+ in spinels cannot be oxidized by Cr6+. However, in the case of the Mg-Cr spinel, dichromic acid substantially promoted the decomposition efficiency and functioned as a catalyst. The decomposition mechanism of chromite in sulfuric acid-dichromic acid solution was illustrated on the basis of the findings of this study.

Nitric acid recovery from waste solutions

DOEpatents

Wilson, A. S.

1959-04-14

The recovery of nitric acid from aqueous nitrate solutions containing fission products as impurities is described. It is desirable to subject such solutions to concentration by evaporation since nitric acid is regenerated thereby. A difficulty, however, is that the highly radioactive fission product ruthenium is volatilized together with the nitric acid. It has been found that by adding nitrous acid, ruthenium volatilization is suppressed and reduced to a negligible degree so that the distillate obtained is practically free of ruthenium.

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2013 CFR

2013-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... prestandardized pH meter, 1.0 N hydrochloric acid, 0.1 N hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50...

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2012 CFR

2012-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... prestandardized pH meter, 1.0 N hydrochloric acid, 0.1 N hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50...

40 CFR Appendix A to Subpart Ddd... - Free Formaldehyde Analysis of Insulation Resins by the Hydroxylamine Hydrochloride Method

Code of Federal Regulations, 2014 CFR

2014-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... prestandardized pH meter, 1.0 N hydrochloric acid, 0.1 N hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50...

40 CFR 420.91 - Specialized definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... unreacted acid from spent pickling acid solutions. (h) The term acid regeneration means those hydrochloric... recovery or acid regeneration processes. (j) The term spent acid solution (or spent pickle liquor) means...

Solubility limits of dibutyl phosphoric acid in uranium-nitric acid solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.A.

2000-01-04

The Savannah River Site has enriched uranium (EU) solution that has been stored since being purified in its solvent extraction processes. The concentrations in solution are approximately 6 g/L U and 0.1 M nitric acid. Residual tributylphosphate in solution has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 30--50 mg/L. Dibutyl phosphoric acid, in turn, is in equilibrium with (HDBP){sub 2} and DBP{sup {minus}}. Uranium can form compounds with the dibutylphosphate ion (DBP{sup {minus}}) which have limited solubility, thereby creating a nuclear criticality safety issue. Literature reports and earlier SRTC tests have shown that it is feasiblemore » to precipitate U-DBP solid during the storage and processing of EU solutions. As a result, a series of solubility experiments were run at nitric acid concentrations from 0--4.0 M HNO{sub 3}, uranium at 0--90 g/L, and temperatures from 0--30 C. The data shows temperature and nitric acid concentration dependence consistent with what would be expected. With respect to uranium concentration, U-DBP solubility passes through a minimum between 6 and 12 g/L U at the acid concentrations and temperatures studied. However, the minimum shows a slight shift toward lower uranium concentrations at lower nitric acid concentrations. The shifts in solubility are strongly dependent upon the overall ionic strength of the solution. The data also reveal a shift to higher DBP solubility above 0.5 M HNO{sub 3} for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified distinct differences between precipitates from less than 0.5 M solutions and those from greater than 4 M acid. Analyses identified UO{sub 2}(DBP){sub 2} as the dominant compound present at low acid concentrations in accordance with literature reports. As the acid concentration increases, the crystalline UO{sub 2}(DBP){sub 2} shows molecular substitutions and an increase in amorphous content.« less

The effects of electrolysis on operational solutions in electromembrane extraction: The role of acceptor solution.

PubMed

Kubáň, Pavel; Boček, Petr

2015-06-12

Fundamental operational principle and instrumental set-up of electromembrane extraction (EME) suggest that electrolysis may play an important role in this recently developed micro-extraction technique. In the present study, the effect of electrolysis in EME is described comprehensively for the first time and it is demonstrated that electrolysis considerably influences EME performance. Micro-electromembrane extraction (μ-EME) across free liquid membrane formed by 1-pentanol was utilized for real-time monitoring of the electrolytically induced changes in composition of μ-EME solutions. These changes were visualized with a set of acid-base indicators. Changes in colours of their aqueous solutions revealed serious variations in their pH values, which occurred within seconds to minutes of the μ-EME process. Variations of up to eight pH units were observed for indicator solutions initially prepared in 1, 5 and 10mM hydrochloric acid. No or only negligible pH changes (less than 0.15 pH unit) were observed for indicator solutions prepared in 50 and 100mM acetic acid demonstrating that initial composition of the aqueous solutions was the crucial parameter. These results were also confirmed by theoretical calculations of maximum pH variations in the solutions, which were based on total electric charge transfers measured in the μ-EME systems, and by exact measurements of their pH values after μ-EMEs. Acceptor solutions that, in the current practice, consist predominantly of low concentrations of strong mineral acids or alkali hydroxides may thus not always ensure adequate EME performance, which was manifested by decrease in extraction recoveries of a basic drug papaverine. A suitable remedy to the observed effects is the application of acceptor solutions containing high concentrations of weak acids or bases. These solutions not only eliminate the decrease in recoveries but also serve well as matrices of extracted samples for subsequent analysis by capillary

Exploring the Capability of Evaluating Technical Solutions: A Collaborative Study into the Primary Technology Classroom

ERIC Educational Resources Information Center

Björkholm, Eva

2014-01-01

Within the field of technology education, evaluating technical solutions is considered as an important topic. Research indicates that pupils have difficulties in evaluating technical solutions in terms of fitness for purpose, i.e. how effective a technical solution supports its intended function. By using the learning study, which is an iterative…

High Energy Halogen Chemistry.

DTIC Science & Technology

1976-01-01

hydrochloric acid . The product was extracted with methylene chloride, dried over magnesium sulfate and distilled to give 65 5 (50$) of (3... hydrochloric acid and water was added to nake the solution turbid (l ml). After 30 rain, the product was distilled to give 1.5 g (£7$) of bis-(3...pressure. The residue was dissolved in 150 ml of absolute ethanol and 30 ml of 5$ hydrochloric acid was added slowly with cooling. The mixture was

Direct synthesis of zirconium powder by magnesium reduction

NASA Astrophysics Data System (ADS)

Lee, Dong-Won; Yun, Jung-Yeul; Yoon, Sung-Won; Wang, Jei-Pil

2013-05-01

The direct synthesis of zirconium powder has been conducted through an analysis of the chemical reaction between evaporated ZrCl4 and molten magnesium over a range of reduction temperatures, concentration of hydrochloric acid, and stirring time. The observed results indicated that the purity of zirconium powder increased with increased stirring time, and Mg and MgCl2 were removed by 10 wt% of hydrochloric acid solution. The pure zirconium powder was obtained by stirring again for 5 h using 5 wt% of hydrochloric acid solution. It was noted that the mean particle size increased when the reaction temperature was increased, and the size of the powder at 1,123 K and 1,173 K was found to be 10 μm and 15 μm, respectively. In addition, the purity of the powder was also improved with temperature, and its purity finally reached up to 99.5% at 1,250 K. Overall, pure zirconium powder was obtained after a stirring stage for 5 hours using 5 wt% of hydrochloric acid solution.

New uses for calcium chloride solution as a mounting medium.

PubMed

Herr, J M

1992-01-01

Fresh cross sections of stems (Psilotum nudum, Coleus blumei, and Pelargonium peltatum) and roots (Setcreasea purpurea) 120 microns thick were fixed in FPA50 (formalin: propionic acid: 50% ethanol, 5:5:90, v/v) for 24 hr and stored in 70% ethanol. The sections were transferred to water and then to 1% phloroglucin in 20% calcium chloride solution plus either hydrochloric, nitric, or lactic acid in the following ratios of phloroglucin-CaCl2 solution:acid: 25:4, 20:2, or 15:5. The sections were mounted on slides either in one of the three mixtures or in fresh 20% calcium chloride solution. A rapid reaction of the acid-phloroglucin with lignin produced a deep red color in tracheary elements and an orange-red color in sclerenchyma. Fixed and stored leaf pieces from Nymphaea odorata were autoclaved in lactic acid, washed in two changes of 95% ethanol, transferred to water, and treated with the three acid-phloroglucin-calcium chloride mixtures. The abundant astrosclereids stained an orange-red color similar to that of sclerenchyma in the sections. In addition, a new method is reported for specifically staining lignified tissues. When sections or leaf pieces are stained in aqueous 0.05% toluidine blue O, then placed in 20% calcium chloride solution, all tissues destain except those with lignified or partially lignified cell walls. Thus, toluidine blue O applied as described becomes a reliable specific test for lignin comparable to the acid-phloroglucin test.

Acid soldering flux poisoning

MedlinePlus

Acid soldering flux is a chemical used to clean and protect the area where two pieces of metal are ... The harmful substances in soldering fluxes are called hydrocarbons. They include: Ammonium chloride Rosin Hydrochloric acid Zinc chloride

Low Cost Technical Solutions to Jump Start an Insider Threat Program

DTIC Science & Technology

2016-05-11

Low Cost Technical Solutions to Jump Start an Insider Threat Program George J. Silowash Derrick L. Spooner Daniel L. Costa Michael J...Albrethsen May 2016 TECHNICAL NOTE CMU/SEI-2016-TN-004 CERT Division http://www.sei.cmu.edu Copyright 2016 Carnegie Mellon University This... technical note will explore tools that may be suitable for satisfying the basic technical needs of an insider threat program, giving organizations a

Simultaneous leaching of Pt, Pd and Rh from automotive catalytic converters in chloride-containing solutions

NASA Astrophysics Data System (ADS)

Hasani, M.; Khodadadi, A.; Koleini, S. M. J.; Saeedi, A. H.; Meléndez, A. M.

2017-01-01

Dissolution of platinum group metals (PGM; herein Pt, Pd and Rh) in different chloride-based leaching systems from spent auto catalysts was performed. Response surface methodology and a five-level-five-factor central composite design were used to evaluate the effects of 1) temperature, 2) liquid-to-solid ratio, 3) stirring speed, 4) acid concentration and 5) particle size on extraction yield of PGM by aqua regia. Analysis of variance was used to determine the optimum conditions and most significant factors affecting the overall metal extraction. In the optimum conditions, leaching of Pt, Pd and Rh was 91.58%, 93.49% and 60.15%, respectively. The effect of different oxidizing agents on the PGM dissolution in chloride medium was studied comparatively in the following leaching systems: a) aqua regia/sulfuric acid mixture, b) hydrogen peroxide in sulfuric acid (piranha solution), c) sodium hypochlorite and d) copper(II). Dissolution of Rh is increased in both aqua regia and hydrogen peroxide/hydrochloric acid solutions by adding sulfuric acid.

Technical solutions for mitigating security threats caused by health professionals in clinical settings.

PubMed

Fernandez-Aleman, Jose Luis; Belen Sanchez Garcia, Ana; Garcia-Mateos, Gines; Toval, Ambrosio

2015-08-01

The objective of this paper is to present a brief description of technical solutions for health information system security threats caused by inadequate security and privacy practices in healthcare professionals. A literature search was carried out in ScienceDirect, ACM Digital Library and IEEE Digital Library to find papers reporting technical solutions for certain security problems in information systems used in clinical settings. A total of 17 technical solutions were identified: measures for password security, the secure use of e-mail, the Internet, portable storage devices, printers and screens. Although technical safeguards are essential to the security of healthcare organization's information systems, good training, awareness programs and adopting a proper information security policy are particularly important to prevent insiders from causing security incidents.

Evaluation of sampling methods for measuring exposure to volatile inorganic acids in workplace air. Part 1: sampling hydrochloric acid (HCl) and nitric acid (HNO₃) from a test gas atmosphere.

PubMed

Howe, Alan; Musgrove, Darren; Breuer, Dietmar; Gusbeth, Krista; Moritz, Andreas; Demange, Martine; Oury, Véronique; Rousset, Davy; Dorotte, Michel

2011-08-01

Historically, workplace exposure to the volatile inorganic acids hydrochloric acid (HCl) and nitric acid (HNO(3)) has been determined mostly by collection on silica gel sorbent tubes and analysis of the corresponding anions by ion chromatography (IC). However, HCl and HNO(3) can be present in workplace air in the form of mist as well as vapor, so it is important to sample the inhalable fraction of airborne particles. As sorbent tubes exhibit a low sampling efficiency for inhalable particles, a more suitable method was required. This is the first of two articles on "Evaluation of Sampling Methods for Measuring Exposure to Volatile Inorganic Acids in Workplace Air" and describes collaborative sampling exercises carried out to evaluate an alternative method for sampling HCl and HNO(3) using sodium carbonate-impregnated filters. The second article describes sampling capacity and breakthrough tests. The method was found to perform well and a quartz fiber filter impregnated with 500 μL of 1 M Na(2)CO(3) (10% (m/v) Na(2)CO(3)) was found to have sufficient sampling capacity for use in workplace air measurement. A pre-filter is required to remove particulate chlorides and nitrates that when present would otherwise result in a positive interference. A GSP sampler fitted with a plastic cone, a closed face cassette, or a plastic IOM sampler were all found to be suitable for mounting the pre-filter and sampling filter(s), but care has to be taken with the IOM sampler to ensure that the sampler is tightly closed to avoid leaks. HCl and HNO(3) can react with co-sampled particulate matter on the pre-filter, e.g., zinc oxide, leading to low results, and stronger acids can react with particulate chlorides and nitrates removed by the pre-filter to liberate HCl and HNO(3), which are subsequently collected on the sampling filter, leading to high results. However, although there is this potential for both positive and negative interferences in the measurement, these are unavoidable

A New Green Ionic Liquid-Based Corrosion Inhibitor for Steel in Acidic Environments.

PubMed

Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdel Rahman O

2015-06-17

This work examines the use of new hydrophobic ionic liquid derivatives, namely octadecylammonium tosylate (ODA-TS) and oleylammonium tosylate (OA-TS) for corrosion protection of steel in 1 M hydrochloric acid solution. Their chemical structures were determined from NMR analyses. The surface activity characteristics of the prepared ODA-TS and OA-TS were evaluated from conductance, surface tension and contact angle measurements. The data indicate the presence of a double bond in the chemical structure of OA-TS modified its surface activity parameters. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements, scanning electron microscope (SEM), Energy dispersive X-rays (EDX) analysis and contact angle measurements were utilized to investigate the corrosion protection performance of ODA-TS and OA-TS on steel in acidic solution. The OA-TS and ODA-TS compounds showed good protection performance in acidic chloride solution due to formation of an inhibitive film on the steel surface.

Precipitation diagrams and solubility of uric acid dihydrate

NASA Astrophysics Data System (ADS)

Babić-Ivančić, V.; Füredi-Milhofer, H.; Brown, W. E.; Gregory, T. M.

1987-07-01

The solubility of uric acid dihydrate (UA·2H 2O) and the precipitation of UA·2H 2O and anhydrous uric acid (UA) from solutions containing sodium hydroxide and hydrochloric acid have been investigated. For the solubility studies, crystals of pure UA·2H 2O were prepared and equilibrated with water and with solutions of HCl or NaOH for 60 min or 20 h, respectively. The equilibrium pH (pH = 2-6.25) and uric acid concentration were determined. For the precipitation experiments, commercial UA was dissolved in NaOH in a 1:1.1 molar ratio and UA·2H 2O and/or UA were precipitated with hydrochloric acid. The precipitates and/or supernatants were examined 24 h after sample preparation. The results are represented in the form of tables, precipitation diagrams and "chemical potential" diagrams. Solubility measurements with 60 min equilibration times yielded the solubility products of UA·2H 2O, K sp(298 K) = (0.926 ± 0.025) × 10 -9mol2dm-6 and K sp(310 K) = (2.25 ± 0.05) × 10 -9mol2dm-6 and the first dissociation constants of uric acid, K 1(298 K) = (2.45 ± 0.07) × 10 -6moldm-3 and K 1(310 K) = (3.63 ± 0.08) × 10 -6moldm-3. Precipitation diagrams show that under the given experimental conditions, at 298 K, UA·2H 2O is stable for 24 h while at 310 K this was true only for precipitates formed from solutions of high supersaturations. At lower supersaturations, mixtures of UA·2H 2O and UA formed. Consequently, while the Ksp value determined from precipitation data obtained at 298 K (K sp = 1.04 × 10 -9mol2dm-6) was consistent with the respective solubility product, the 310 K precipitation boundary yielded an ion activity product, AP, the value of which fulfills the conditions Ksp(UA) < AP < Ksp (UA·2H 2O). Similar ion activity products were obtained from solubility measurements in pure water at 20 h equilibration time.

Nitric acid uptake by sulfuric acid solutions under stratospheric conditions - Determination of Henry's Law solubility

NASA Technical Reports Server (NTRS)

Reihs, Christa M.; Golden, David M.; Tolbert, Margaret A.

1990-01-01

The uptake of nitric acid by sulfuric acid solutions representative of stratospheric particulate at low temperatures was measured to determine the solubility of nitric acid in sulfuric acid solutions as a function of H2SO4 concentration and solution temperature. Solubilities are reported for sulfuric acid solutions ranging from 58 to 87 wt pct H2SO4 over a temperature range from 188 to 240 K, showing that, in general, the solubility of nitric acid increases with decreasing sulfuric acid concentration and with decreasing temperature. The measured solubilities indicate that nitric acid in the global stratosphere will be found predominantly in the gas phase.

Theoretical stusy of the reaction between 2,2',4' - trihydroxyazobenzene-5-sulfonic acid and zirconium

USGS Publications Warehouse

Fletcher, Mary H.

1960-01-01

Zirconium reacts with 2,2',4'-trihydroxyazobenzene-5-sulfonic acid in acid solutions to Form two complexes in which the ratios of dye to zirconium are 1 to 1 and 2 to 1. Both complexes are true chelates, with zirconium acting as a bridge between the two orthohydroxy dye groups. Apparent equilibrium constants for the reactions to form each of the complexes are determined. The reactions are used as a basis for the determination of the active component in the dye and a graphical method for the determination of reagent purity is described. Four absorption spectra covering the wave length region from 350 to 750 mu are given, which completely define the color system associated with the reactions in solutions where the hydrochloric acid concentration ranges from 0.0064N to about 7N.

Stability of cefozopran hydrochloride in aqueous solutions.

PubMed

Zalewski, Przemysław; Skibiński, Robert; Paczkowska, Magdalena; Garbacki, Piotr; Talaczyńska, Alicja; Cielecka-Piontek, Judyta; Jelińska, Anna

2016-01-01

The influence of pH on the stability of cefozopran hydrochloride (CZH) was investigated in the pH range of 0.44-13.00. Six degradation products were identified with a hybrid ESI-Q-TOF mass spectrometer. The degradation of CZH as a result of hydrolysis was a pseudo-first-order reaction. As general acid-base hydrolysis of CZH was not occurred in the solutions of hydrochloric acid, sodium hydroxide, acetate, borate and phosphate buffers, kobs = kpH because specific acid-base catalysis was observed. Specific acid-base catalysis of CZH consisted of the following reactions: hydrolysis of CZH catalyzed by hydrogen ions (kH+), hydrolysis of dications (k1H2O), monocations (k2H2O) and zwitter ions (k3H2O) and hydrolysis of zwitter ions (k1OH-) and monoanions (k2OH-) of CZH catalyzed by hydroxide ions. The total rate of the reaction was equal to the sum of partial reactions: [Formula: see text]. CZH similarly like other fourth generation cephalosporin was most stable at slightly acidic and neutral pH and less stable in alkaline pH. The cleavage of the β-lactam ring resulting from a nucleophilic attack on the carbonyl carbon in the β-lactam moiety is the preferred degradation pathway of β-lactam antibiotics in aqueous solutions.

Reference electrode for strong oxidizing acid solutions

DOEpatents

Rigdon, Lester P.; Harrar, Jackson E.; Bullock, Sr., Jack C.; McGuire, Raymond R.

1990-01-01

A reference electrode for the measurement of the oxidation-reduction potentials of solutions is especially suitable for oxidizing solutions such as highly concentrated and fuming nitric acids, the solutions of nitrogen oxides, N.sub.2 O.sub.4 and N.sub.2 O.sub.5, in nitric acids. The reference electrode is fabricated of entirely inert materials, has a half cell of Pt/Ce(IV)/Ce(III)/70 wt. % HNO.sub.3, and includes a double-junction design with an intermediate solution of 70 wt. % HNO.sub.3. The liquid junctions are made from Corning No. 7930 glass for low resistance and negligible solution leakage.

Respirable form of crystals of cromoglycic acid.

PubMed

Chan, H K; Gonda, I

1989-02-01

Respirable crystals of cromoglycic acid (CA) were prepared by precipitation of CA with hydrochloric acid from aqueous solutions of cromolyn sodium and subsequent recrystallization from hot water or mixtures of dimethyl sulphoxide and water. The properties of the materials were established by melting point measurements, UV, IR, and NMR spectroscopy, and X-ray diffraction. Aerosols of CA were generated by nebulization of dilute CA suspensions and drying. The aerodynamic size distribution of CA in the dried aerosols was found by cascade impaction, and could be characterized by a logarithmic normal function with a mass median aerodynamic diameter (MMAD) of 0.7 micron and geometric standard deviation (sigma g) of 1.9. The likely advantages and problems of CA aerosols in the prevention of asthma are discussed.

27 CFR 21.102 - Caustic soda, liquid.

Code of Federal Regulations, 2014 CFR

2014-04-01

... mark with distilled water at room temperature. Transfer a 25 ml aliquot of the solution to a titration..., and 50 ml of distilled water. Titrate with 0.25 N hydrochloric acid to the disappearance of the pink color. Not less than 25 ml of the hydrochloric acid shall be required to neutralize the sample of...

27 CFR 21.102 - Caustic soda, liquid.

Code of Federal Regulations, 2013 CFR

2013-04-01

... mark with distilled water at room temperature. Transfer a 25 ml aliquot of the solution to a titration..., and 50 ml of distilled water. Titrate with 0.25 N hydrochloric acid to the disappearance of the pink color. Not less than 25 ml of the hydrochloric acid shall be required to neutralize the sample of...

27 CFR 21.102 - Caustic soda, liquid.

Code of Federal Regulations, 2011 CFR

2011-04-01

... mark with distilled water at room temperature. Transfer a 25 ml aliquot of the solution to a titration..., and 50 ml of distilled water. Titrate with 0.25 N hydrochloric acid to the disappearance of the pink color. Not less than 25 ml of the hydrochloric acid shall be required to neutralize the sample of...

27 CFR 21.102 - Caustic soda, liquid.

Code of Federal Regulations, 2010 CFR

2010-04-01

... mark with distilled water at room temperature. Transfer a 25 ml aliquot of the solution to a titration..., and 50 ml of distilled water. Titrate with 0.25 N hydrochloric acid to the disappearance of the pink color. Not less than 25 ml of the hydrochloric acid shall be required to neutralize the sample of...

27 CFR 21.102 - Caustic soda, liquid.

Code of Federal Regulations, 2012 CFR

2012-04-01

... mark with distilled water at room temperature. Transfer a 25 ml aliquot of the solution to a titration..., and 50 ml of distilled water. Titrate with 0.25 N hydrochloric acid to the disappearance of the pink color. Not less than 25 ml of the hydrochloric acid shall be required to neutralize the sample of...

Process for the extraction of strontium from acidic solutions

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1994-01-01

The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

Process for the extraction of strontium from acidic solutions

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1993-01-01

The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid.

THE ACCURATE DETERMINATION OF MICROGRAM AMOUNTS OF BORON IN ALUMINUM AND ALUMINUM-URANIUM ALLOYS BY THE METHYL BORATE-CURCUMIN-OXALIC ACID METHOD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crocker, I.H.

1958-10-01

A method was developed for the deternninntion of boron in aluminum and aluminum--uranium alloys in which the boron concentration is 30 ppm or more. Boron is separated by distillation as methyl borate from a hydrochloric acid solution of the alloy and is determined spectrophotometrically by the boric acid-- curcumin-oxalic acid color reaction. A precision of plus or minus 2% is attain able when the determination is penformed with the utmost care. The accuracy is such that no bias need be given when a calibration curve is used. (auth)

Process for the extraction of strontium from acidic solutions

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1994-09-06

The invention is a process for selectively extracting strontium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant solution is a macrocyclic polyether in an aliphatic hydrocarbon diluent containing a phase modifier. The process will selectively extract strontium values from nitric acid solutions which are up to 6 molar in nitric acid. 4 figs.

Raman spectra of amino acids and their aqueous solutions

NASA Astrophysics Data System (ADS)

Zhu, Guangyong; Zhu, Xian; Fan, Qi; Wan, Xueliang

2011-03-01

Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids ( L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials.

Copper Corrosion Under Non-uniform Magnetic Field in 0.5 M Hydrochloric Acid

NASA Astrophysics Data System (ADS)

Garcia-Ochoa, E.; Corvo, F.; Genesca, J.; Sosa, V.; Estupiñán, P.

2017-05-01

The influence of a magnetic field on the electrochemical reactions taking place at the surface of a copper electrode immersed in a 0.5 M HCl solution at room temperature has been studied. The symmetry axis of the magnetic field was lined up in the same direction of the ion flow to minimize the Lorentz forces. Measurements of potentiodynamic polarization curves, electrochemical impedance spectroscopy and electrochemical noise allow concluding that the magnetic field significantly affects the cathodic reactions, with corrosion rates increasing under the presence of oxygen in acid media and decreasing when oxygen is eliminated.

40 CFR 420.96 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY Acid Pickling...) Sulfuric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire, coil. Subpart I Pollutant or... operations. (b) Hydrochloric acid pickling (spent acid solutions and rinse waters)—(1) Rod, wire, coil...

Effects of organic acids on thermal inactivation of acid and cold stressed Enterococcus faecium.

PubMed

Fernández, Ana; Alvarez-Ordóñez, Avelino; López, Mercedes; Bernardo, Ana

2009-08-01

In this study the adaptative response to heat (70 degrees C) of Enterococcus faecium using fresh and refrigerated (at 4 degrees C for up to 1 month) stationary phase cells grown in Brain Heart Infusion (BHI) buffered at pH 7.4 (non-acid-adapted cells) and acidified BHI at pH values of 6.4 and 5.4 with acetic, ascorbic, citric, lactic, malic and hydrochloric acids (acid-adapted cells) was evaluated. In all cases, the survival curves obtained were concave upward. A mathematical model based on the Weibull distribution accurately described the inactivation kinetic. The results indicate that previous adaptation to a low pH increased the bacterial heat resistance, whereas the subsequent cold storage of cells reduced E. faecium thermal tolerance. Fresh acid-adapted cells showed t(2.5)-values (time needed to obtain an inactivation level of 2.5 log10 cycles) ranging from 2.57 to 9.51 min, while non-acid-adapted cells showed t(2.5)-values of 1.92 min. The extent of increased heat tolerance varied with the acid examined, resulting in the following order: citric > or = acetic > malic > or = lactic > hydrochloric > or = ascorbic. In contrast, cold storage progressively decreased E. faecium thermal resistance. The t(2.5) values found at the end of the period studied were about 2-3-fold lower than those corresponding to non-refrigerated cells, although this decrease was more marked (about 5-fold) when cells were grown in buffered BHI and BHI acidified at pH 5.4 with hydrochloric acid. These findings highlight the need for a better understanding of microbial response to various preservation stresses in order to increase the efficiency of thermal processes and to indicate the convenience of counterbalancing the benefits of the hurdle concept.

White Paper on Potential Hazards Associated with Contaminated Cheesecloth Exposed to Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hypes, Philip A.

This white paper addresses the potential hazards associated with waste cheesecloth that has been exposed to nitric acid solutions. This issue was highlighted by the cleanup of a 100 ml leak of aqueous nitric acid solution containing Heat Source (HS) plutonium on 21 June 2016. Nitration of cellulosic material is a well-understood process due to industrial/military applications of the resulting material. Within the Department of Energy complex, nitric acids have been used extensively, as have cellulosic wipes. If cellulosic materials are nitrated, the cellulosic material can become ignitable and in extreme cases, reactive. We have chemistry knowledge and operating experiencemore » to support the conclusion that all current wastes are safe and compliant. There are technical questions worthy of further experimental evaluation. An extent of condition evaluation has been conducted back to 2004. During this time period there have been interruptions in the authorization to use cellulosic wipes in PF-4. Limited use has been authorized since 2007 (for purposes other than spill cleanup), so our extent of condition includes the entire current span of use. Our evaluation shows that there is no indication that process spills involving high molarity nitric acid were cleaned up with cheesecloth since 2007. The materials generated in the 21 June leak will be managed in a safe manner compliant with all applicable requirements.« less

Catalytic destruction of perchlorate in ferric chloride and hydrochloric acid solution with control of temperature, pressure and chemical reagents

DOEpatents

Gu, Baohua; Cole, David R.; Brown, Gilbert M.

2004-10-05

A method is described to decompose perchlorate in a FeCl.sub.3 /HCl aqueous solution such as would be used to regenerate an anion exchange resin used to remove perchlorate. The solution is mixed with a reducing agent, preferably an organic alcohol and/or ferrous chloride, and can be heated to accelerate the decomposition of perchlorate. Lower temperatures may be employed if a catalyst is added.

Acidities of Water and Methanol in Aqueous Solution and DMSO

ERIC Educational Resources Information Center

Gao, Daqing

2009-01-01

The relative acidities of water and methanol have been a nagging issue. In gas phase, methanol is more acidic than water by 36.0 kJ/mol; however, in aqueous solution, the acidities of methanol and water are almost identical. The acidity of an acid in solution is determined by both the intrinsic gas-phase ionization Gibbs energy and the solvent…

Synthesis, inhibition effects and quantum chemical studies of a novel coumarin derivative on the corrosion of mild steel in a hydrochloric acid solution.

PubMed

Al-Azawi, Khalida F; Al-Baghdadi, Shaimaa B; Mohamed, Ayad Z; Al-Amiery, Ahmed A; Abed, Talib K; Mohammed, Salam A; Kadhum, Abdul Amir H; Mohamad, Abu Bakar

2016-01-01

The acid corrosion inhibition process of mild steel in 1 M HCl by 4-[(2-amino-1, 3, 4-thiadiazol-5-yl)methoxy]coumarin (ATC), has been investigated using weight loss technique and scanning electron microscopy (SEM). ATC was synthesized, and its chemical structure was elucidated and confirmed using spectroscopic techniques (infrared and nuclear magnetic resonance spectroscopy). The results indicated that inhibition efficiencies were enhanced with an increase in concentration of inhibitor and decreased with a rise in temperature. The adsorption equilibrium constant (K) and standard free energy of adsorption (ΔGads) were calculated. Quantum chemical parameters such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively) and dipole moment (μ) were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in both the EHOMO and μ values but with a decrease in the ELUMO value. Our research show that the synthesized macromolecule represents an excellent inhibitor for materials in acidic solutions. The efficiency of this macromolecule had maximum inhibition efficiency up to 96 % at 0.5 mM and diminishes with a higher temperature degree, which is revealing of chemical adsorption. An inhibitor molecule were absorbed by metal surface and follow Langmuir isotherms low and establishes an efficient macromolecule inhibitor having excellent inhibitive properties due to entity of S (sulfur) atom, N (nitrogen) atom and O (oxygen) atom.

9 CFR 96.13 - Uncertified casings; disinfection with hydrochloric acid.

Code of Federal Regulations, 2014 CFR

2014-01-01

... solution, rinse them with water, and place them in a solution containing 81/2 pounds of sodium bicarbonate... from the sodium bicarbonate solution and wash them to remove the excess of bicarbonate. (Approved by...

9 CFR 96.13 - Uncertified casings; disinfection with hydrochloric acid.

Code of Federal Regulations, 2013 CFR

2013-01-01

... solution, rinse them with water, and place them in a solution containing 81/2 pounds of sodium bicarbonate... from the sodium bicarbonate solution and wash them to remove the excess of bicarbonate. (Approved by...

9 CFR 96.13 - Uncertified casings; disinfection with hydrochloric acid.

Code of Federal Regulations, 2012 CFR

2012-01-01

... solution, rinse them with water, and place them in a solution containing 81/2 pounds of sodium bicarbonate... from the sodium bicarbonate solution and wash them to remove the excess of bicarbonate. (Approved by...

9 CFR 96.13 - Uncertified casings; disinfection with hydrochloric acid.

Code of Federal Regulations, 2011 CFR

2011-01-01

... solution, rinse them with water, and place them in a solution containing 81/2 pounds of sodium bicarbonate... from the sodium bicarbonate solution and wash them to remove the excess of bicarbonate. (Approved by...

Population and size distribution of solute-rich mesospecies within mesostructured aqueous amino acid solutions.

PubMed

Jawor-Baczynska, Anna; Moore, Barry D; Lee, Han Seung; McCormick, Alon V; Sefcik, Jan

2013-01-01

Aqueous solutions of highly soluble substances such as small amino acids are usually assumed to be essentially homogenous systems with some degree of short range local structuring due to specific interactions on the sub-nanometre scale (e.g. molecular clusters, hydration shells), usually not exceeding several solute molecules. However, recent theoretical and experimental studies have indicated the presence of much larger supramolecular assemblies or mesospecies in solutions of small organic and inorganic molecules as well as proteins. We investigated both supersaturated and undersaturated aqueous solutions of two simple amino acids (glycine and DL-alanine) using Dynamic Light Scattering (DLS), Brownian Microscopy/Nanoparticles Tracking Analysis (NTA) and Cryogenic Transmission Electron Microscopy (Cryo-TEM). Colloidal scale mesospecies (nanodroplets) were previously reported in supersaturated solutions of these amino acids and were implicated as intermediate species on non-classical crystallization pathways. Surprisingly, we have found that the mesospecies are also present in significant numbers in undersaturated solutions even when the solute concentration is well below the solid-liquid equilibrium concentration (saturation limit). Thus, mesopecies can be observed with mean diameters ranging from 100 to 300 nm and a size distribution that broadens towards larger size with increasing solute concentration. We note that the mesospecies are not a separate phase and the system is better described as a thermodynamically stable mesostructured liquid containing solute-rich domains dispersed within bulk solute solution. At a given temperature, solute molecules in such a mesostructured liquid phase are subject to equilibrium distribution between solute-rich mesospecies and the surrounding bulk solution.

Effect of Ammonium- and Phosphonium-Based Ionic Liquids on the Separation of Lactic Acid by Supported Ionic Liquid Membranes (SILMs)

PubMed Central

Matsumoto, Michiaki; Panigrahi, Abhishek; Murakami, Yuuki; Kondo, Kazuo

2011-01-01

Biodegradable polymers have attracted much attention from an environmental point of view. Optically pure lactic acid that can be prepared by fermentation is one of the important raw materials for biodegradable polymer. The separation and purification of lactic acid from the fermentation broth are the major portions of the production costs. We proposed the application of supported ionic liquid membranes to recovering lactic acid. In this paper, the effect of ionic liquids, such as Aliquat 336, CYPHOS IL-101, CYPHOS IL-102, CYPHOS IL-104, CYPHOS IL-109 and CYPHOS IL-111 on the lactic acid permeation have been studied. Aliquat 336, CYPHOS IL-101 and CYPHOS IL-102 were found to be the best membrane solvents as far as membrane stability and permeation of lactic acid are concerned. CYPHOS IL-109 and CYPHOS IL-111 were found to be unsuitable, as they leak out from the pores of the supported liquid membrane (SLM), thereby allowing free transport of lactic acid as well as hydrochloric acid. CYPHOS IL-102 was found to be the most adequate (Permeation rate = 60.41%) among these ionic liquids as far as the separation of lactic acid is concerned. The permeation mechanisms, by which ionic liquid-water complexes act as the carrier of lactate and hydrochloric acid, were proposed. The experimental permeation results have been obtained as opposed to the expected values from the solution-diffusion mechanism. PMID:24957613

75 FR 37738 - 1-Naphthaleneacetic Acid; Time-Limited Tolerance, Technical Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-30

...-Naphthaleneacetic Acid; Time-Limited Tolerance, Technical Correction AGENCY: Environmental Protection Agency (EPA..., ethylene oxide, fenvalerate, et al.; tolerance actions. Today's rule restores the time-limited tolerance...-3) establishing a time-limited tolerance for residues of 1-naphthaleneacetic acid ethyl ester in or...

Compatible solute influence on nucleic acids: Many questions but few answers

PubMed Central

Kurz, Matthias

2008-01-01

Compatible solutes are small organic osmolytes including but not limited to sugars, polyols, amino acids, and their derivatives. They are compatible with cell metabolism even at molar concentrations. A variety of organisms synthesize or take up compatible solutes for adaptation to extreme environments. In addition to their protective action on whole cells, compatible solutes display significant effects on biomolecules in vitro. These include stabilization of native protein and nucleic acid structures. They are used as additives in polymerase chain reactions to increase product yield and specificity, but also in other nucleic acid and protein applications. Interactions of compatible solutes with nucleic acids and protein-nucleic acid complexes are much less understood than the corresponding interactions of compatible solutes with proteins. Although we may begin to understand solute/nucleic acid interactions there are only few answers to the many questions we have. I summarize here the current state of knowledge and discuss possible molecular mechanisms and thermodynamics. PMID:18522725

Condensation of anhydrides or dicarboxylic acids with compounds containing active methylene groups. Part 1: Condensation of phthalic anhydride with acetoacetic and malonic ester

NASA Technical Reports Server (NTRS)

Oshkaya, V. P.; Vanag, G. Y.

1985-01-01

Phthalic anhydride was condensed with acetoacetic ester in acetic anhydride and triethylamine solution, and when phthalyl chloride was reacted with sodium acetoacetic ester compounds were formed of the phthalide and indandione series: phthalylacetoacetic ester and a derivative of indan-1,3-dione which after boiling with hydrochloric acid yielded indan-1,3-dione. Phthalylmalonic ester was obtained from phthalic anhydride and malonic ester in the presence of triethylamine.

High Energy Halogen Chemistry.

DTIC Science & Technology

1978-01-01

underwent addition of triflic acid and of hydrochloric acid . The oxetane was polymerized ~zith phosphorous pentaflucride to ~lve a polymer stable to 2900...in aqueous dioxane . The oxetane was not affected by boron trifluoride etherate In chloroform, or by methanolic solutions of sulfuric or triflic acids ...concentrated hydrochloric acid to give 3-chloro-2-fluoro-2-nitro-l-propanol. NO • i 2 NO2OH CF I + CF SOH— 3 CF SO OCH CCH OH O OH ~ 3 3 2 2~ 2 F NO NO

Chemical treatment of low-grade uranium ores. Extraction of uranium from tricalcium phosphate; TRAITEMENT CHIMIQUE DES MINERAIS PAUVRES D'URANIUM. EXTRACTION DE L'URANIUM DU PHOSPHATE TRICALCIQUE (in French)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mechelynck, Ph.

1958-07-15

After an examination of the different processes for the treatment of uranium minerals, it is concluded that the extraction of uranium by ion exchange is not applicable to hydrochloric acid solutions of phosphates. A sulfuric or phosphoric solution can be used. For solvent extraction of uranium, sulfuric or phosphoric solutions are the best, but hydrochloric solutions can be used. The cost of the solvents used would determine the cost of the operation. It is necessary, in the case of liquid-liquid extraction, to filter or decant the solution before extraction. (tr-auth)

Process for the recovery of strontium from acid solutions

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1992-01-01

The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid.

Removal of chromium from aqueous solutions by diatomite treated with microemulsion.

PubMed

Dantas, T N; Dantas Neto, A A; Moura, M C

2001-06-01

In order to evaluate the sorption of heavy metals, a crude diatomite was impregnated with a microemulsion which showed remarkable increase in chromium sorption capacity as compared to untreated diatomite. Samples with two different granulometries were investigated, both yielding practically complete adsorption. The adsorption process is pH dependent and the best results for the initial Cr (III) concentration of 1.5 g/L were obtained at pH 2.95. The effect of the concentration of the chromium synthetic solution was also investigated. The adsorption isotherms were obtained (30. 40 and 50 degrees C) and the Freundlich and Langmuir models were used to determine the adsorption capacity of the adsorbent. Following the adsorption step, a desorption process was carried out using several eluant solutions. The best results were obtained using hydrochloric acid (100%) as eluant.

sym-Trisubstituted 1,3,5-Triazine Derivatives as Promising Organic Corrosion Inhibitors for Steel in Acidic Solution.

PubMed

El-Faham, Ayman; Dahlous, Kholood A; Al Othman, Zeid A; Al-Lohedan, Hamad A; El-Mahdy, Gamal A

2016-03-31

Triazine derivatives, namely, 2,4,6-tris(quinolin-8-yloxy)-1,3,5-triazine (T3Q), N²,N⁴,N⁶-tris(pyridin-2-ylmethyl)-1,3,5-triazine-2,4,6-triamine (T3AMPy) and 2,2',2''-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)] tris(ethan-1-ol) (T3EA) were synthesized and their inhibition of steel corrosion in hydrochloric acid solution was investigated using electrochemical techniques. The corrosion protection of the prepared compounds increased with increasing concentration and reached up to 98% at 250 ppm. The adsorption of T3Q, T3AMPy, and T3EA on the steel surface was in accordance with the Langmuir adsorption isotherm. The electrochemical results revealed that T3Q, T3AMPy and T3EA act as excellent organic inhibitors and can labeled as mixed type inhibitors. The efficiencies of the tested compounds were affected by the nature of the side chain present in the triazine ring, where T3EA gave the least inhibition while T3Q and T3AMPy gave higher and almost the same inhibition effects. The inhibition efficiencies obtained from the different electrochemical techniques were in good agreement.

Characteristic constants of 2,2',4'-trihydroxyazobenzene-5-sulfonic acid, a reagent for spectrophotometric analysis

USGS Publications Warehouse

Fletcher, Mary H.

1960-01-01

The dye 2,2',4'-trihydroxyazobenzene-5-sulfonic acid, has shown promise as a reagent for the determination of zirconium. As the literature contains very little information about this dye, basic data pertinent to its use as a reagent were determined. The sulfonic acid group and all three of the hydroxy groups show acidic characteristics. Apparent dissociation constants were determined for the three more labile protons and the approximate order of magnitude for the fourth constant was estimated. Absorption spectra for the different ionization species are given. A curve is also included which shows the fraction of dye in the different ionization forms at acidities from 10.35M hydrochloric acid to pH 11.9. A sixth dye species was found in 1.0 to 8.4M potassium hydroxide solutions, but its nature is unknown.

Process for the recovery of strontium from acid solutions

DOEpatents

Horwitz, E.P.; Dietz, M.L.

1992-03-31

The invention is a process for selectively extracting strontium and technetium values from aqueous nitric acid waste solutions containing these and other fission product values. The extractant is a macrocyclic polyether in a diluent which is insoluble in water, but which will itself dissolve a small amount of water. The process will extract strontium and technetium values from nitric acid solutions which are up to 6 molar in nitric acid. 5 figs.

Acid Rain

USGS Publications Warehouse

Bricker, Owen P.; Rice, Karen C.

1995-01-01

Although acid rain is fading as a political issue in the United States and funds for research in this area have largely disappeared, the acidity of rain in the Eastern United States has not changed significantly over the last decade, and it continues to be a serious environmental problem. Acid deposition (commonly called acid rain) is a term applied to all forms of atmospheric deposition of acidic substances - rain, snow, fog, acidic dry particulates, aerosols, and acid-forming gases. Water in the atmosphere reacts with certain atmospheric gases to become acidic. For example, water reacts with carbon dioxide in the atmosphere to produce a solution with a pH of about 5.6. Gases that produce acids in the presence of water in the atmosphere include carbon dioxide (which converts to carbonic acid), oxides of sulfur and nitrogen (which convert to sulfuric and nitric acids}, and hydrogen chloride (which converts to hydrochloric acid). These acid-producing gases are released to the atmosphere through natural processes, such as volcanic emissions, lightning, forest fires, and decay of organic matter. Accordingly, precipitation is slightly acidic, with a pH of 5.0 to 5.7 even in undeveloped areas. In industrialized areas, most of the acid-producing gases are released to the atmosphere from burning fossil fuels. Major emitters of acid-producing gases include power plants, industrial operations, and motor vehicles. Acid-producing gases can be transported through the atmosphere for hundreds of miles before being converted to acids and deposited as acid rain. Because acids tend to build up in the atmosphere between storms, the most acidic rain falls at the beginning of a storm, and as the rain continues, the acids "wash out" of the atmosphere.

Dibutyl Phosphoric Acid Solubility in High-Acid, Uranium-Bearing Solutions at SRS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pierce, R.A.

1998-10-02

The Savannah River Site has enriched uranium (EU) solution which has been stored for almost 10 years since being purified in the second uranium cycle of the H area solvent extraction process. The concentrations in solution are approximately 6 g/L U and about 0.1 M nitric acid. Residual tributylphosphate in the solutions has slowly hydrolyzed to form dibutyl phosphoric acid (HDBP) at concentrations averaging 50 mg/L. Uranium is known to form compounds with the dibutylphosphate ion (DBP) which have limited solubility. The potential to form uranium-DBP solids raises a nuclear criticality safety issue. Prior SRTC tests (WSRC-TR-98-00188) showed that U-DBPmore » solids precipitate at concentrations potentially attainable during the storage of enriched uranium solutions. Furthermore, evaporation of the existing EUS solution without additional acidification could result in the precipitation of U-DBP solids if the DBP concentration in the resulting solution exceeds 110 mg/L at ambient temperature. The same potential exists for evaporation of unwashed 1CU solutions. As a follow-up to the earlier studies, SRTC studied the solubility limits for solutions containing acid concentrations above 0.5M HNO3. The data obtained in these tests reveals a shift to higher levels of DBP solubility above 0.5M HNO3 for both 6 g/L and 12 g/L uranium solutions. Analysis of U-DBP solids from the tests identified a mixture of different molecular structures for the solids created. The analysis distinguished UO2(DBP)2 as the dominant compound present at low acid concentrations. As the acid concentration increases, the crystalline UO2(DBP)2 shows molecular substitutions and an increase in amorphous content. Further analysis by methods not available at SRS will be needed to better identify the specific compounds present. This data indicates that acidification prior to evaporation can be used to increase the margin of safety for the storage of the EUS solutions. Subsequent experimentation evaluated

Rare Earth Extraction from NdFeB Magnet Using a Closed-Loop Acid Process.

PubMed

Kitagawa, Jiro; Uemura, Ryohei

2017-08-14

There is considerable interest in extraction of rare earth elements from NdFeB magnets to enable recycling of these elements. In practical extraction methods using wet processes, the acid waste solution discharge is a problem that must be resolved to reduce the environmental impact of the process. Here, we present an encouraging demonstration of rare earth element extraction from a NdFeB magnet using a closed-loop hydrochloric acid (HCl)-based process. The extraction method is based on corrosion of the magnet in a pretreatment stage and a subsequent ionic liquid technique for Fe extraction from the HCl solution. The rare earth elements are then precipitated using oxalic acid. Triple extraction has been conducted and the recovery ratio of the rare earth elements from the solution is approximately 50% for each extraction process, as compared to almost 100% recovery when using a one-shot extraction process without the ionic liquid but with sufficient oxalic acid. Despite its reduced extraction efficiency, the proposed method with its small number of procedures at almost room temperature is still highly advantageous in terms of both cost and environmental friendliness. This study represents an initial step towards realization of a closed-loop acid process for recycling of rare earth elements.

Production of technical grade phosphoric acid from incinerator sewage sludge ash (ISSA).

PubMed

Donatello, S; Tong, D; Cheeseman, C R

2010-01-01

The recovery of phosphorus from sewage sludge ash samples obtained from 7 operating sludge incinerators in the UK using a sulfuric acid washing procedure to produce a technical grade phosphoric acid product has been investigated. The influences of reaction time, sulfuric acid concentration, liquid to solid ratio and source of ISSA on P recovery have been examined. The optimised conditions were the minimum stoichiometric acid requirement, a reaction time of 120 min and a liquid to solid ratio of 20. Under these conditions, average recoveries of between 72% and 91% of total phosphorus were obtained. Product filtrate was purified by passing through a cation exchange column, concentrated to 80% H(3)PO(4) and compared with technical grade H(3)PO(4) specifications. The economics of phosphate recovery by this method are briefly discussed. 2010 Elsevier Ltd. All rights reserved.

Studies of the structure of insulin fibrils by Fourier transform infrared (FTIR) spectroscopy and electron microscopy.

PubMed

Nielsen, L; Frokjaer, S; Carpenter, J F; Brange, J

2001-01-01

Fibril formation (aggregation) of insulin was investigated in acid media by visual inspection, transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. Insulin fibrillated faster in hydrochloric acid than in acetic acid at elevated temperatures, whereas the fibrillation tendencies were reversed at ambient temperatures. Electron micrographs showed that bovine insulin fibrils consisted of long fibers with a diameter of 5 to 10 nm and lengths of several microns. The fibrils appeared either as helical filaments (in hydrochloric acid) or arranged laterally in bundles (in acetic acid, NaCl). Freeze-thawing cycles broke the fibrils into shorter segments. FTIR spectroscopy showed that the native secondary structure of insulin was identical in hydrochloric acid and acetic acid, whereas the secondary structure of fibrils formed in hydrochloric acid was different from that formed in acetic acid. Fibrils of bovine insulin prepared by heating or agitating an acid solution of insulin showed an increased content of beta-sheet (mostly intermolecular) and a decrease in the intensity of the alpha-helix band. In hydrochloric acid, the frequencies of the beta-sheet bands depended on whether the fibrillation was induced by heating or agitation. This difference was not seen in acetic acid. Freeze-thawing cycles of the fibrils in hydrochloric acid caused an increase in the intensity of the band at 1635 cm(-1) concomitant with reduction of the band at 1622 cm(-1). The results showed that the structure of insulin fibrils is highly dependent on the composition of the acid media and on the treatment. Copyright 2001 Wiley-Liss Inc. and the American Pharmaceutical Association J Pharm Sci 90: 29-37, 2001

Process for the removal of radium from acidic solutions containing same

DOEpatents

Scheitlin, F.M.

The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of /sup 226/Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

Preparation and characterization of dialdehyde starch by one-step acid hydrolysis and oxidation.

PubMed

Zuo, Yingfeng; Liu, Wenjie; Xiao, Junhua; Zhao, Xing; Zhu, Ying; Wu, Yiqiang

2017-10-01

Dialdehyde starch was prepared by one-step synthesis of acid hydrolysis and oxidation, using corn starch as the raw material, sodium periodate (NaIO 4 ) as the oxidant, and hydrochloric acid (HCl) as the acid solution. The prepared dialdehyde starch was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC). The results confirmed that oxidation occurred between the starch and NaIO 4 . The acid hydrolysis reaction reduced the molecular weight of starch and effectively improved the aldehyde group contents (92.7%). Scanning electron microscope (SEM) analysis indicated that the average particle size decreased after acid hydrolysis and oxidation reaction. X-ray diffraction (XRD) and thermal gravimetric analyzer (TGA) analysis demonstrated that the crystallinity of the obtained dialdehyde starch showed a downward trend and a decelerated thermal decomposition rate. The starch after acid hydrolysis and oxidation exhibited lower hot paste viscosity and higher reactivity. Copyright © 2017. Published by Elsevier B.V.

Radiopharmaceutical composition containing tantalum-178 and process therefor

DOEpatents

Neirinckx, Rudi D.; Holman, B. Leonard; Davis, Michael A.; Harris, Gale I.

1989-05-16

A physiologically acceptable solution of tantalum-178 having an activity of 0.1 to 200 millicuries per milliliter of tantalum-178 solution is provided. The solution is obtained from tungsten-178 bound to a column of an anion exchange resin which forms tantalum-178 in situ by eluting the column with a hydrochloric acid solution containing hydrogen peroxide to form an acidic solution of tantalum-178. The acidic solution of tantalum-178 then is neutralized.

Uracil in formic acid hydrolysates of deoxyribonucleic acid

PubMed Central

Schein, Arnold H.

1966-01-01

1. When DNA is hydrolysed with formic acid for 30min. at 175° and the hydrolysate is chromatographed on paper with propan-2-ol–2n-hydrochloric acid, in addition to expected ultraviolet-absorbing spots corresponding to guanine, adenine, cytosine and thymine, an ultraviolet-absorbing region with RF similar to that of uracil can be detected. Uracil was separated from this region and identified by its spectra in acid and alkali, and by its RF in several solvent systems. 2. Cytosine, deoxyribocytidine and deoxyribocytidylic acid similarly treated with formic acid all yielded uracil, as did a mixture of deoxyribonucleotides. 3. Approx. 4% of deoxyribonucleotide cytosine was converted into uracil by the formic acid treatment. ImagesFig. 1. PMID:5949371

Spectrophotometric determination of molybdenum in rocks with thiocyanate

USGS Publications Warehouse

Lillie, E.G.; Greenland, L.P.

1974-01-01

A rapid procedure for the determination of microgram amounts of molybdenum in rocks is described. After acid decomposition, molybdenum is extracted from a hydrochloric acid solution into xylene with tributyl phosphate. After back-extraction with water, molybdenum is extracted as the ??-benzoinoximate into chloroform, stripped into hydrochloric acid extracted as the thiocyanate into amyl alcohol, and determined spectrophotometrically. The molybdenum thiocyanate color produced is stable, sensitive, and reproducible. Results of analyses of several of the U.S. Geological Survey standard rocks are given. ?? 1974.

In vitro thermal profile suitability assessment of acids and bases for thermochemical ablation: underlying principles.

PubMed

Freeman, Laura A; Anwer, Bilal; Brady, Ryan P; Smith, Benjamin C; Edelman, Theresa L; Misselt, Andrew J; Cressman, Erik N K

2010-03-01

To measure and compare temperature changes in a recently developed gel phantom for thermochemical ablation as a function of reagent strength and concentration with several acids and bases. Aliquots (0.5-1 mL) of hydrochloric acid or acetic acid and sodium hydroxide or aqueous ammonia were injected for 5 seconds into a hydrophobic gel phantom. Stepwise increments in concentration were used to survey the temperature changes caused by these reactions. Injections were performed in triplicate, measured with a thermocouple probe, and plotted as functions of concentration and time. Maximum temperatures were reached almost immediately in all cases, reaching 75 degrees C-110 degrees C at the higher concentrations. The highest temperatures were seen with hydrochloric acid and either base. More concentrated solutions of sodium hydroxide tended to mix incompletely, such that experiments at 9 M and higher were difficult to perform consistently. Higher concentrations for any reagent resulted in higher temperatures. Stronger acid and base combinations resulted in higher temperatures versus weak acid and base combinations at the same concentration. Maximum temperatures obtained are in a range known to cause tissue coagulation, and all combinations tested therefore appeared suitable for further investigation in thermochemical ablation. Because of the loss of the reaction chamber shape at higher concentrations of stronger agents, the phantom does not allow complete characterization under these circumstances. Adequate mixing of reagents to maximize heating potential and avoid systemic exposure to unreacted acid and base must be addressed if the method is to be safely employed in tissues. In addition, understanding factors that control lesion shape in a more realistic tissue model will be critical. Copyright 2010 SIR. Published by Elsevier Inc. All rights reserved.

Preparation of κ-carra-oligosaccharides with microwave assisted acid hydrolysis method

NASA Astrophysics Data System (ADS)

Li, Guangsheng; Zhao, Xia; Lv, Youjing; Li, Miaomiao; Yu, Guangli

2015-04-01

A rapid method of microwave assisted acid hydrolysis was established to prepare κ-carra-oligosaccharides. The optimal hydrolysis condition was determined by an orthogonal test. The degree of polymerization (DP) of oligosaccharides was detected by high performance thin layer chromatography (HPTLC) and polyacrylamide gel electrophoresis (PAGE). Considering the results of HPTLC and PAGE, the optimum condition of microwave assisted acid hydrolysis was determined. The concentration of κ-carrageenan was 5 mg mL-1; the reaction solution was adjusted to pH 3 with diluted hydrochloric acid; the solution was hydrolyzed under microwave irradiation at 100 for 15 °C min. Oligosaccharides were separated by a Superdex 30 column (2.6 cm × 90 cm) using AKTA Purifier UPC100 and detected with an online refractive index detector. Each fraction was characterized by electrospray ionization mass spectrometry (ESI-MS). The data showed that odd-numbered κ-carra-oligosaccharides with DP ranging from 3 to 21 could be obtained with this method, and the structures of the oligosaccharides were consistent with those obtained by traditional mild acid hydrolysis. The new method was more convenient, efficient and environment-friendly than traditional mild acid hydrolysis. Our results provided a useful reference for the preparation of oligosaccharides from other polysaccharides.

Vibrational studies in aqueous solutions. Part II. The acid oxalate ion and oxalic acid

NASA Astrophysics Data System (ADS)

Shippey, T. A.

1980-08-01

Assignments for oxalic acid in solution are re-examined. A detailed assignment of the IR and Raman spectra of the acid oxalate ion is presented for the first time. Raman spectroscopy is used to study the first ionization of oxalic acid.

Reduction of Plutonium in Acidic Solutions by Mesoporous Carbons

DOE PAGES

Parsons-Moss, Tashi; Jones, Stephen; Wang, Jinxiu; ...

2015-12-19

Batch contact experiments with several porous carbon materials showed that carbon solids spontaneously reduce the oxidation state of plutonium in 1-1.5 M acid solutions, without significant adsorption. The final oxidation state and rate of Pu reduction varies with the solution matrix, and also depends on the surface chemistry and surface area of the carbon. It was demonstrated that acidic Pu(VI) solutions can be reduced to Pu(III) by passing through a column of porous carbon particles, offering an easy alternative to electrolysis with a potentiostat.

9 CFR 96.13 - Uncertified casings; disinfection with hydrochloric acid.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) Disinfect the casings in a solution made as follows: Dissolve 90 pounds common salt in 100 gallons water and... solution shall be discarded unless means are provided for accurately determining the loss of strength. In event means for accurately determining loss of strength are provided it will be permissible to restore...

Etchant for incoloy-903 welds

NASA Technical Reports Server (NTRS)

Gerstmeyer, J. A.

1980-01-01

Special reagent consists of 1 part 90% lactic acid, 1 part 70% nitric acid, and 4 part, 37% hydrochloric acid. Solution etches parent and weld metals at same rate, without overetching. Underlying grain structure of both metals is revealed.

Removal of anionic dye Congo red from aqueous solution by raw pine and acid-treated pine cone powder as adsorbent: equilibrium, thermodynamic, kinetics, mechanism and process design.

PubMed

Dawood, Sara; Sen, Tushar Kanti

2012-04-15

Pine cone a natural, low-cost agricultural by-product in Australia has been studied for its potential application as an adsorbent in its raw and hydrochloric acid modified form. Surface study of pine cone and treated pine cone was investigated using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The modification process leads to increases in the specific surface area and decreases mean particle sizes of acid-treated pine cone when compared to raw pine cone biomass. Batch adsorption experiments were performed to remove anionic dye Congo red from aqueous solution. It was found that the extent of Congo red adsorption by both raw pine cone biomass and acid-treated biomass increased with initial dye concentration, contact time, temperature but decreased with increasing solution pH and amount of adsorbent of the system. Overall, kinetic studies showed that the dye adsorption process followed pseudo-second-order kinetics based on pseudo-first-order and intra-particle diffusion models. The different kinetic parameters including rate constant, half-adsorption time, and diffusion coefficient were determined at different physico-chemical conditions. Equilibrium data were best represented by Freundlich isotherm model among Langmuir and Freundlich adsorption isotherm models. It was observed that the adsorption was pH dependent and the maximum adsorption of 32.65 mg/g occurred at pH of 3.55 for an initial dye concentration of 20 ppm by raw pine cone, whereas for acid-treated pine cone the maximum adsorption of 40.19 mg/g for the same experimental conditions. Freundlich constant 'n' also indicated favourable adsorption. Thermodynamic parameters such as ∆G(0), ∆H(0), and ∆S(0) were calculated. A single-stage batch absorber design for the Congo red adsorption onto pine cone biomass also presented based on the Freundlich isotherm model equation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Solubility of xenon in amino-acid solutions. II. Nine less-soluble amino acids

NASA Astrophysics Data System (ADS)

Kennan, Richard P.; Himm, Jeffrey F.; Pollack, Gerald L.

1988-05-01

Ostwald solubility (L) of xenon gas, as the radioisotope 133Xe, has been measured as a function of solute concentration, at 25.0 °C, in aqueous solutions of nine amino acids. The amino-acid concentrations investigated covered much of their solubility ranges in water, viz., asparagine monohydrate (0-0.19 M), cysteine (0-1.16 M), glutamine (0-0.22 M), histidine (0-0.26 M), isoleucine (0-0.19 M), methionine (0-0.22 M), serine (0-0.38 M), threonine (0-1.4 M), and valine (0-0.34 M). We have previously reported solubility results for aqueous solutions of six other, generally more soluble, amino acids (alanine, arginine, glycine, hydroxyproline, lysine, and proline), of sucrose and sodium chloride. In general, L decreases approximately linearly with increasing solute concentration in these solutions. If we postulate that the observed decreases in gas solubility are due to hydration, the results under some assumptions can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each amino-acid solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 15.3±1.5 for asparagine, 6.8±0.3 for cysteine, 11.5±1.1 for glutamine, 7.3±0.7 for histidine, 5.9±0.4 for isoleucine, 10.6±0.8 for methionine, 11.2±1.3 for serine, 7.7± 1.0 for threonine, and 6.6±0.6 for valine. We have also measured the temperature dependence of solubility L(T) from 5-40 °C for arginine, glycine, and proline, and obtained hydration numbers H¯(T) in this range. Between 25-40 °C, arginine has an H¯ near zero. This may be evidence for an attractive interaction between xenon and arginine molecules in aqueous solution.

Raman spectroscopic study of the conformation of dicarboxylic acid salts in aqueous solutions

NASA Astrophysics Data System (ADS)

Fukushima, Kunio; Watanabe, Toshiaki; Umemura, Matome

1986-08-01

It is already known that the molecules of long chain monocarboxylic acid salts have a tendency to form micelles in aqueous solutions, the molecular chain taking the all- trans zigzag structure. However it is considered difficult for dicarboxylic acid salts to adopt the same structure as the monocarboxylic acid salts as they have two carboxyl groups, one on each end of the molecular chain. Therefore, a special structure is expected to exist for dicarboxylic acid salts in aqueous solution. In order to examine this, Raman spectra of suberic acid salt and azelaic acid salt in aqueous solution were measured and the normal vibrational calculation carried out, showing that dicarboxylic acid salts have a helical structure in aqueous solution.

Effectiveness of a Classroom Chemistry Demonstration Using the Cognitive Conflict Strategy

ERIC Educational Resources Information Center

Baddock, Maree; Bucat, Robert

2008-01-01

In an action research study, 66 students from Year 11 in an Australian school were shown the colour of methyl violet indicator in some hydrochloric acid solutions, and then in an acetic acid solution. The intent was to create a cognitive conflict, resolution of which would lead to an understanding of the concept "weak acid". Student…

Extraction equilibrium of indium(III) from nitric acid solutions by di(2-ethylhexyl)phosphoric acid dissolved in kerosene.

PubMed

Tsai, Hung-Sheng; Tsai, Teh-Hua

2012-01-04

The extraction equilibrium of indium(III) from a nitric acid solution using di(2-ethylhexyl) phosphoric acid (D2EHPA) as an acidic extractant of organophosphorus compounds dissolved in kerosene was studied. By graphical and numerical analysis, the compositions of indium-D2EHPA complexes in organic phase and stoichiometry of the extraction reaction were examined. Nitric acid solutions with various indium concentrations at 25 °C were used to obtain the equilibrium constant of InR₃ in the organic phase. The experimental results showed that the extraction distribution ratios of indium(III) between the organic phase and the aqueous solution increased when either the pH value of the aqueous solution and/or the concentration of the organic phase extractant increased. Finally, the recovery efficiency of indium(III) in nitric acid was measured.

Alginate biopolymer as green corrosion inhibitor for copper in 1 M hydrochloric acid: Experimental and theoretical approaches

NASA Astrophysics Data System (ADS)

Jmiai, A.; El Ibrahimi, B.; Tara, A.; El Issami, S.; Jbara, O.; Bazzi, L.

2018-04-01

The anti-corrosion behavior of sodium alginate (SA) on copper in the 1 M hydrochloric medium was carried out using weight loss and electrochemical measurements. The obtained results show that the inhibition increases with SA concentration and then reaches a maximum of 83% at a concentration of 0.1 mg L-1. The effect of temperature on the reactions of copper corrosion inhibition and analyzing the thermodynamic parameters revealed that the mode of adsorption has a physical nature and obeys the Langmuir isotherm. The surface morphology was performed by scanning electron microscopy coupled with energy dispersive X-ray spectrometry and atomic force microscopy. To better understand the adsorption mechanism, describing the relationship between inhibitory ability and the molecular structure of SA, quantum calculations using density functional theory were performed. Monte Carlo simulation approache was performed to know well of the relationship between the inhibition ability and molecular structure of alginate.

Efficiency of cardioplegic solutions containing L-arginine and L-aspartic acid.

PubMed

Pisarenko, O I; Shul'zhenko, V S; Studneva, I M

2006-04-01

In experiments on rats we studied the effects of cardioplegic solutions with L-aspartic acid or L-arginine on functional recovery and metabolism of isolated working heart after 40-min normothermal global ischemia and 30-min reperfusion. After reperfusion of the hearts preventively protected with cardioplegic solution containing L-aspartic acid or L-arginine, coronary flow decreased in comparison with the initial values. As a component of cardioplegic solution, L-arginine was less efficient in recovery of contractility and cardiac output of the hearts in comparison with L-aspartic acid. In hearts protected with L-aspartic acid, the postischemic levels of ATP and phosphocreatine were significantly higher, and the level of lactate was significantly lower than in hearts protected with L-arginine. In comparison with L-arginine, L-aspartic acid is a more efficient component of cardioplegic solution in protection of the heart from metabolic and functional damages caused by global ischemia and reperfusion.

Hydrogen peroxide generation in a model paediatric parenteral amino acid solution.

PubMed

Brawley, V; Bhatia, J; Karp, W B

1993-12-01

1. Parenteral amino acid solutions undergo photooxidation, which may be an important factor in total parenteral nutrition-associated hepatic dysfunction. Light-exposed parenteral solutions containing amino acids, in addition to vitamins and trace minerals, generate free radicals, which, in turn, may contribute to this type of injury. This study examined the characteristics of H2O2 production in a parenteral amino acid solution modelled on a commercially available paediatric parenteral amino acid solution. 2. The solution was exposed to light in the presence of riboflavin-5'-monophosphate (riboflavin), and peroxide formation in the presence and absence of catalase (H2O2 formation) was assayed using potassium iodide/molybdate. 3. Peak H2O2 production occurred at a light intensity of 8 microW cm-2 nm-1 in the 425-475 nm waveband and was linear to 2 h of light exposure. H2O2 production reached 500 mumol/l at 24 h. 4. H2O2 was directly related to a riboflavin concentration of up to 20 mumol/l and was maximal at 30 mumol/l. 5. H2O2 production was greatest in the amino acid/riboflavin solution at a pH of between 5 and 6. 6. Under the conditions of light exposure intensity, light exposure time, riboflavin concentration and pH found during the administration of parenteral nutrition in neonatal intensive care units, net H2O2 production occurs in solutions modelled on a paediatric parenteral amino acid preparation.

Effect of pH of spray solution on the electrical properties of cadmium oxide thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodlur, R. M.; Gunnagol, Raghu M.; Rabinal, M. K., E-mail: mkrabinal@yahoo.com

2015-06-24

Highly conducting transparent cadmium oxide thin films were prepared by conventional spray pyrolysis technique on glass at 375 °C substrate temperature. The pH of the spray solution was varied by adding ammonia/hydrochloric acid in the spray solution. The XRD pattern showed cubic phase. A lowest resistivity of 9.9 × 10{sup −4} Ω cm (with carrier concentration (n) = 5.1 × 10{sup 20} cm{sup −3}, mobility (µ)=12.4 cm{sup 2}/Vs) is observed for pH ∼12. The resistivity is tuned almost by three orders of magnitude by controlling the bath pH with optical transmittance more than 70 %. Thus, without any doping, the electricalmore » conductivity of CdO films could be easily tuned by simply varying the pH of spray solution without compromising the transparency and keeping the other deposition parameters fixed.« less

Optimization of a Nafion Membrane-Based System for Removal of Chloride and Fluoride from Lunar Regolith-Derived Water

NASA Technical Reports Server (NTRS)

Anthony, Stephen M.; Santiago-Maldonado, Edgardo; Captain, James G.; Pawate, Ashtamurthy S.; Kenis, Paul J. A.

2012-01-01

A long-term human presence in space will require self-sustaining systems capable of producing oxygen and potable water from extraterrestrial sources. Oxygen can be extracted from lunar regolith, and water contaminated with hydrochloric and hydrofluoric acids is produced as an intermediate in this process. We investigated the ability of Nafion proton exchange membranes to remove hydrochloric and hydrofluoric acids from water. The effect of membrane thickness, product stream flow rate, and acid solution temperature and concentration on water flux, acid rejection, and water and acid activity were studied. The conditions that maximized water transport and acid rejection while minimizing resource usage were determined by calculating a figure of merit. Water permeation is highest at high solution temperature and product stream flow rate across thin membranes, while chloride and fluoride permeation are lowest at low acid solution temperature and concentration across thin membranes. The figure of merit varies depending on the starting acid concentration; at low concentration, the figure of merit is highest across a thin membrane, while at high concentration, the figure of merit is highest at low solution temperature. In all cases, the figure of merit increases with increasing product stream flow rate.

Inhibition effects of a synthesized novel 4-aminoantipyrine derivative on the corrosion of mild steel in hydrochloric acid solution together with quantum chemical studies.

PubMed

Junaedi, Sutiana; Al-Amiery, Ahmed A; Kadihum, Abdulhadi; Kadhum, Abdul Amir H; Mohamad, Abu Bakar

2013-06-04

1,5-Dimethyl-4-((2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-one (DMPO) was synthesized to be evaluated as a corrosion inhibitor. The corrosion inhibitory effects of DMPO on mild steel in 1.0 M HCl were investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, open circuit potential (OCP) and electrochemical frequency modulation (EFM). The results showed that DMPO inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration. Changes in the impedance parameters suggested an adsorption of DMPO onto the mild steel surface, leading to the formation of protective films. The novel synthesized corrosion inhibitor was characterized using UV-Vis, FT-IR and NMR spectral analyses. Electronic properties such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively) and dipole moment (μ) were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in the EHOMO values but with a decrease in the ELUMO value.

Inhibition Effects of a Synthesized Novel 4-Aminoantipyrine Derivative on the Corrosion of Mild Steel in Hydrochloric Acid Solution together with Quantum Chemical Studies

PubMed Central

Junaedi, Sutiana; Al-Amiery, Ahmed A.; Kadihum, Abdulhadi; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar

2013-01-01

1,5-Dimethyl-4-((2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-one (DMPO) was synthesized to be evaluated as a corrosion inhibitor. The corrosion inhibitory effects of DMPO on mild steel in 1.0 M HCl were investigated using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, open circuit potential (OCP) and electrochemical frequency modulation (EFM). The results showed that DMPO inhibited mild steel corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration. Changes in the impedance parameters suggested an adsorption of DMPO onto the mild steel surface, leading to the formation of protective films. The novel synthesized corrosion inhibitor was characterized using UV-Vis, FT-IR and NMR spectral analyses. Electronic properties such as highest occupied molecular orbital energy, lowest unoccupied molecular orbital energy (EHOMO and ELUMO, respectively) and dipole moment (μ) were calculated and discussed. The results showed that the corrosion inhibition efficiency increased with an increase in the EHOMO values but with a decrease in the ELUMO value. PMID:23736696

Polymerization of beta-amino acids in aqueous solution

NASA Technical Reports Server (NTRS)

Liu, R.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

1998-01-01

We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged alpha- and beta-amino acids in homogeneous aqueous solution. alpha-Amino acids can be oligomerized efficiently using CDI, but not by EDAC. beta-Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an alpha- and beta-dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; comparison of a nitric acid in-bottle digestion procedure to other whole-water digestion procedures

USGS Publications Warehouse

Garbarino, John R.; Hoffman, Gerald L.

1999-01-01

A hydrochloric acid in-bottle digestion procedure is used to partially digest wholewater samples prior to determining recoverable elements by various analytical methods. The use of hydrochloric acid is problematic for some methods of analysis because of spectral interference. The inbottle digestion procedure has been modified to eliminate such interference by using nitric acid instead of hydrochloric acid in the digestion. Implications of this modification are evaluated by comparing results for a series of synthetic whole-water samples. Results are also compared with those obtained by using U.S. Environmental Protection Agency (1994) (USEPA) Method 200.2 total-recoverable digestion procedure. Percentage yields that use the nitric acid inbottle digestion procedure are within 10 percent of the hydrochloric acid in-bottle yields for 25 of the 26 elements determined in two of the three synthetic whole-water samples tested. Differences in percentage yields for the third synthetic whole-water sample were greater than 10 percent for 16 of the 26 elements determined. The USEPA method was the most rigorous for solubilizing elements from particulate matter in all three synthetic whole-water samples. Nevertheless, the variability in the percentage yield by using the USEPA digestion procedure was generally greater than the in-bottle digestion procedure, presumably because of the difficulty in controlling the digestion conditions accurately.

Molecular dynamics study on glycolic acid in the physiological salt solution

NASA Astrophysics Data System (ADS)

Matsunaga, S.

2018-05-01

Molecular dynamics (MD) study on glycolic acid in the physiological salt solution has been performed, which is a model of a biofuel cell. The structure and charge distribution of glycolic acid in aqueous solution used in MD is beforehand optimized by Gaussian09 utilizing the density functional theory. MD is performed in the NTV constant condition, i.e. the number of particles, temperature, and volume of MD cell are definite. The structure difference of the glycolic acid and oxalic acid is detected by the water distribution around the molecules using the pair distribution functions, gij(r), and the frequency dependent diffusion coefficients, Di(ν). The anomalous dielectric constant of the solution, i.e. about 12 times larger than that of water, has been obtained, which may be attributed to the ion pair formation in the solution.

Plutonium and americium separation from salts

DOEpatents

Hagan, Paul G.; Miner, Frend J.

1976-01-01

Salts or materials containing plutonium and americium are dissolved in hydrochloric acid, heated, and contacted with an alkali metal carbonate solution to precipitate plutonium and americium carbonates which are thereafter readily separable from the solution.

Mechanisms of neptunium redox reactions in nitric acid solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chatterjee, Sayandev; Bryan, Samuel A.; Casella, Amanda J.

First transuranium element neptunium (Np) exhibits complicated behavior in acidic solutions because it can adopt wide range of oxidation states typically from +3 to +6 and coordinate large variety of ligands. In particular, accurate determination of Np redox potentials in nitric acid solutions is challenging due to overlapping chemical and electrochemical reactions leading to significant experimental uncertainties. Furthermore, over past decades spectrophotometry has been extensively applied to identify and characterize Np solution species in different oxidation states. However, relevant spectral database of Np in nitric acid solutions that can serve for the reference purposes has yet to be established duemore » to the experimental difficulty to isolate and stabilize Np species in pure oxidation states without compromising solution optical properties. This work demonstrates that combination of voltammetry and controlled-potential in situ thin-layer spectropotentiometry overcomes these challenges so that Np species in pure +3, +4, +5, or +6 oxidation states were electrochemically generated in the systematically varied 0.1 – 5 M nitric acid solutions, and corresponding vis-NIR spectral signatures were obtained. In situ optical monitoring of the interconversion between adjacent Np oxidation states resulted in elucidation of the mechanisms of the involved redox reactions, in-depth understanding of the relative stability of the Np oxidation states, and allowed benchmarking of the redox potentials of the NpO22+/NpO2+, NpO2+/Np4+ and Np4+/Np3+ couples. Notably, the NpO2+/Np4+ couple was distinguished from the proximal Np4+/Np3+ process overcoming previous concerns and challenges encountered in accurate determination of the respective potentials.« less

Surface Hardening by Laser Skin Melting

DTIC Science & Technology

1979-07-01

typical cross-sectional view of a melt region. Various solutions includina Murakami’s reaqent, Vilella’s reagent and an oxalic acid solution were used...each type selectively revealinq different microstructu- ral features. A second etch in an oxalic acid/hydrochloric acid solution was used in the...genization due to vigorous hydrothermal mixing and liquid super- heating. Computations by Greenwald (13) from a heat flow model are graphically represented

Transcriptomic analysis of Escherichia coli O157:H7 and K-12 cultures exposed to inorganic and organic acids in stationary phase reveals acidulant- and strain-specific acid tolerance responses.

PubMed

King, Thea; Lucchini, Sacha; Hinton, Jay C D; Gobius, Kari

2010-10-01

The food-borne pathogen Escherichia coli O157:H7 is commonly exposed to organic acid in processed and preserved foods, allowing adaptation and the development of tolerance to pH levels otherwise lethal. Since little is known about the molecular basis of adaptation of E. coli to organic acids, we studied K-12 MG1655 and O157:H7 Sakai during exposure to acetic, lactic, and hydrochloric acid at pH 5.5. This is the first analysis of the pH-dependent transcriptomic response of stationary-phase E. coli. Thirty-four genes and three intergenic regions were upregulated by both strains during exposure to all acids. This universal acid response included genes involved in oxidative, envelope, and cold stress resistance and iron and manganese uptake, as well as 10 genes of unknown function. Acidulant- and strain-specific responses were also revealed. The acidulant-specific response reflects differences in the modes of microbial inactivation, even between weak organic acids. The two strains exhibited similar responses to lactic and hydrochloric acid, while the response to acetic acid was distinct. Acidulant-dependent differences between the strains involved induction of genes involved in the heat shock response, osmoregulation, inorganic ion and nucleotide transport and metabolism, translation, and energy production. E. coli O157:H7-specific acid-inducible genes were identified, suggesting that the enterohemorrhagic E. coli strain possesses additional molecular mechanisms contributing to acid resistance that are absent in K-12. While E. coli K-12 was most resistant to lactic and hydrochloric acid, O157:H7 may have a greater ability to survive in more complex acidic environments, such as those encountered in the host and during food processing.

Salicylic acid peels versus Jessner's solution for acne vulgaris: a comparative study.

PubMed

Bae, Byung Gi; Park, Chang Ook; Shin, Hyoseung; Lee, Soo Hyun; Lee, Yun Sun; Lee, Sang Ju; Chung, Kee Yang; Lee, Kwang Hoon; Lee, Ju Hee

2013-02-01

Salicylic acid was recently formulated in a hydroethanolic vehicle at a concentration of 20% to 30%. Salicylic acid has strong comedolytic effects because of its lipophilic nature. To compare the therapeutic efficacy and tolerability of salicylic acid peels with those of Jessner's solution peels in patients with acne vulgaris. Thirteen patients (13 men; mean age 22.6, range 20-28) with facial acne were enrolled. Jessner's solution was applied to one side of each patient's face and 30% salicylic acid to the other in three sessions at 2-week intervals. A blinded investigator counted noninflammatory and inflammatory lesions before treatment and 2 weeks after each treatment. Inflammatory and noninflammatory acne lesion counts decreased in proportion to the duration of treatment. Inflammatory acne lesion counts did not differ significantly between salicylic acid and Jessner's solution peels, although in terms of noninflammatory acne lesion counts, sites treated with salicylic acid showed significant improvement (p = .04), whereas those treated with Jessner's solution did not. We found that 30% salicylic acid peels were effective for inflammatory acne and more effective than Jessner's solution peels for treating noninflammatory acne. © 2012 by the American Society for Dermatologic Surgery, Inc. Published by Wiley Periodicals, Inc.

Rare earth element recycling from waste nickel-metal hydride batteries.

PubMed

Yang, Xiuli; Zhang, Junwei; Fang, Xihui

2014-08-30

With an increase in number of waste nickel-metal hydride batteries, and because of the importance of rare earth elements, the recycling of rare earth elements is becoming increasingly important. In this paper, we investigate the effects of temperature, hydrochloric acid concentration, and leaching time to optimize leaching conditions and determine leach kinetics. The results indicate that an increase in temperature, hydrochloric acid concentration, and leaching time enhance the leaching rate of rare earth elements. A maximum rare earth elements recovery of 95.16% was achieved at optimal leaching conditions of 70°C, solid/liquid ratio of 1:10, 20% hydrochloric acid concentration, -74μm particle size, and 100min leaching time. The experimental data were best fitted by a chemical reaction-controlled model. The activation energy was 43.98kJ/mol and the reaction order for hydrochloric acid concentration was 0.64. The kinetic equation for the leaching process was found to be: 1-(1-x)(1/3)=A/ρr0[HCl](0.64)exp-439,8008.314Tt. After leaching and filtration, by adding saturated oxalic solution to the filtrate, rare earth element oxalates were obtained. After removing impurities by adding ammonia, filtering, washing with dilute hydrochloric acid, and calcining at 810°C, a final product of 99% pure rare earth oxides was obtained. Copyright © 2014 Elsevier B.V. All rights reserved.

Surface tensions of solutions containing dicarboxylic acid mixtures

NASA Astrophysics Data System (ADS)

Lee, Jae Young; Hildemann, Lynn M.

2014-06-01

Organic solutes tend to lower the surface tension of cloud condensation nuclei, allowing them to more readily activate. The surface tension of various dicarboxylic acid aerosol mixtures was measured at 20 °C using the Wilhelmy plate method. At lower concentrations, the surface tension of a solution with equi-molar mixtures of dicarboxylic acids closely followed that of a solution with the most surface-active organic component alone. Measurements of surface tension for these mixtures were lower than predictions using Henning's model and the modified Szyszkowski equation, by ˜1-2%. The calculated maximum surface excess (Γmax) and inverse Langmuir adsorption coefficient (β) from the modified Szyszkowski equation were both larger than measured values for 6 of the 7 mixtures tested. Accounting for the reduction in surface tension in the Köhler equation reduced the critical saturation ratio for these multi-component mixtures - changes were negligible for dry diameters of 0.1 and 0.5 μm, but a reduction from 1.0068 to 1.0063 was seen for the 4-dicarboxylic acid mixture with a dry diameter of 0.05 μm.

Acid-base equilibrium in aqueous solutions of 1,3-dimethylbarbituric acid as studied by 13C NMR spectroscopy

NASA Astrophysics Data System (ADS)

Gryff-Keller, A.; Kraska-Dziadecka, A.

2011-12-01

13C NMR spectra of 1,3-dimethylbarbituric acid in aqueous solutions of various acidities and for various solute concentrations have been recorded and interpreted. The spectra recorded at pH = 2 and below contain the signals of the neutral solute molecule exclusively, while the ones recorded at pH = 7 and above only the signals of the appropriate anion, which has been confirmed by theoretical GIAO-DFT calculations. The signals in the spectra recorded for solutions of pH < 7 show dynamic broadenings. The lineshape analysis of these signals has provided information on the kinetics of the processes running in the dynamic acid-base equilibrium. The kinetic data determined this way have been used to clarify the mechanisms of these processes. The numerical analysis has shown that under the investigated conditions deprotonation of the neutral solute molecules undergoes not only via a simple transfer of the C-H proton to water molecules but also through a process with participation of the barbiturate anions. Moreover, the importance of tautomerism, or association, or both these phenomena for the kinetics of the acid-base transformations in the investigated system has been shown. Qualitatively similar changes of 13C NMR spectra with the solution pH variation have been observed for the parent barbituric acid.

Co-pyrolysis of microwave-assisted acid pretreated bamboo sawdust and soapstock.

PubMed

Wang, Yunpu; Wu, Qiuhao; Duan, Dengle; Zhang, Yayun; Ruan, Roger; Liu, Yuhuan; Fu, Guiming; Zhang, Shumei; Zhao, Yunfeng; Dai, Leilei; Fan, Liangliang

2018-05-30

Fast microwave-assisted co-pyrolysis of pretreated bamboo sawdust and soapstock was conducted. The pretreatment process was carried out under microwave irradiation. The effects of microwave irradiation temperature, irradiation time, and concentration of hydrochloric acid on product distribution from co-pyrolysis and the relative contents of the major components in bio-oil were investigated. A maximum bio-oil yield of 40.00 wt.% was obtained at 200 °C for 60 min with 0.5 M hydrochloric acid. As pretreatment temperature, reaction time and acid concentration increased, respectively, the relative contents of phenols, diesel fraction (C12 + aliphatics), and other oxygenates decreased. The gasoline fraction (including C5-C12 aliphatics and aromatics) ranged from 55.77% to 73.30% under various pretreatment conditions. Therefore, excessive reaction time and concentration of acid are not beneficial to upgrading bio-oil. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dissolving Carboxylic Acids and Primary Amines on the Overhead Projector

ERIC Educational Resources Information Center

Solomon, Sally D.; Rutkowsky, Susan A.

2010-01-01

Liquid carboxylic acids (or primary amines) with limited solubility in water are dissolved by addition of aqueous sodium hydroxide (or hydrochloric acid) on the stage of an overhead projector using simple glassware and very small quantities of chemicals. This effective and colorful demonstration can be used to accompany discussions of the…

Stability studies of lincomycin hydrochloride in aqueous solution and intravenous infusion fluids.

PubMed

Czarniak, Petra; Boddy, Michael; Sunderland, Bruce; Hughes, Jeff D

2016-01-01

The purpose of this study was to evaluate the chemical stability of Lincocin(®) (lincomycin hydrochloride) in commonly used intravenous fluids at room temperature (25°C), at accelerated-degradation temperatures and in selected buffer solutions. The stability of Lincocin(®) injection (containing lincomycin 600 mg/2 mL as the hydrochloride) stored at 25°C±0.1°C in sodium lactate (Hartmann's), 0.9% sodium chloride, 5% glucose, and 10% glucose solutions was investigated over 31 days. Forced degradation of Lincocin(®) in hydrochloric acid, sodium hydroxide, and hydrogen peroxide was performed at 60°C. The effect of pH on the degradation rate of lincomycin hydrochloride stored at 80°C was determined. Lincomycin hydrochloride w as found to maintain its shelf life at 25°C in sodium lactate (Hartmann's) solution, 0.9% sodium chloride solution, 5% glucose solution, and 10% glucose solution, with less than 5% lincomycin degradation occurring in all intravenous solutions over a 31-day period. Lincomycin hydrochloride showed less rapid degradation at 60°C in acid than in basic solution, but degraded rapidly in hydrogen peroxide. At all pH values tested, lincomycin followed first-order kinetics. It had the greatest stability near pH 4 when stored at 80°C (calculated shelf life of 4.59 days), and was least stable at pH 2 (calculated shelf life of 0.38 days). Lincocin(®) injection was chemically found to have a shelf life of at least 31 days at 25°C when added to sodium lactate (Hartmann's) solution, 0.9% sodium chloride solution, 5% glucose solution, and 10% glucose solution. Solutions prepared at approximately pH 4 are likely to have optimum stability.

Ex Vivo Liver Experiment of Hydrochloric Acid-Infused and Saline-Infused Monopolar Radiofrequency Ablation: Better Outcomes in Temperature, Energy, and Coagulation.

PubMed

Jiang, Xiong-ying; Gu, Yang-kui; Huang, Jin-hua; Gao, Fei; Zou, Ru-hai; Zhang, Tian-qi

2016-04-01

To compare temperature, energy, and coagulation between hydrochloric acid-infused radiofrequency ablation (HAIRFA) and normal saline-infused radiofrequency ablation (NSIRFA) in ex vivo porcine liver model. 30 fresh porcine livers were excised in 60 lesions, 30 with HAIRFA and the other 30 with NSIRFA. Both modalities used monopolar perfusion electrode connected to a RF generator set at 103 °C and 30 W. In each group, ablation time was set at 10, 20, or 30 min (10 lesions from each group at each time). We compared tissue temperatures (at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 cm away from the electrode tip), average power, deposited energy, deposited energy per coagulation volume (DEV), coagulation diameters, coagulative volume, and spherical ratio between the two groups. Temperature-time curves showed that HAIRFA provided progressively greater heating than that of NSIRFA. At 30 min, mean average power, deposited energy, coagulation volumes (113.67 vs. 12.28 cm(3)) and diameters, and increasing in tissue temperature were much greater with HAIRFA (P < 0.001 for all), except DEV was lower (456 vs. 1396 J/cm(3), P < 0.001). The spherical ratio was closer to 1 with HAIRFA (1.23 vs. 1.46). Coagulation diameters, volume, and average power of HAIRFA increased significantly with longer ablation times. While with NSIRFA, these characteristics were stable till later 20 min, except the power decreased with longer ablation times. HAIRFA creates much larger and more spherical lesions by increasing overall energy deposition, modulating thermal conductivity, and transferring heat during ablation.

SEPARATION OF THORIUM FROM RARE EARTHS WITH TANNIN (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vlodavets, N.I.

1959-03-01

Thorium is quantitatively precipitated with tannin in a 0.005 N solution of nitric or hydrochloric acid. This permits its separation from trivalent rare earths, which are not precipitated with tannin in such relatively weak acid solutions. The accuracy of the determinations is as usual at the gravimetric determinations of macroquantities of elements. (auth)

Method for incorporating radioactive phosphoric acid solutions in concrete

DOEpatents

Wolf, G.A.; Smith, J.W.; Ihle, N.C.

1982-07-08

A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH)/sub 2/ to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with Portland cement to form concrete.

Method for incorporating radioactive phosphoric acid solutions in concrete

DOEpatents

Wolf, Gary A [Kennewick, WA; Smith, Jeffrey W [Lancaster, OH; Ihle, Nathan C [Walla Walla, WA

1984-01-01

A method for incorporating radioactive phosphoric acid solutions in concrete is described wherein the phosphoric acid is reacted with Ca(OH).sub.2 to form a precipitate of hydroxyapatite and the hydroxyapatite is mixed with portland cement to form concrete.

High School Forum: "Invitations to Enquiry": The Calcite/Acid Reaction.

ERIC Educational Resources Information Center

Herron, J. Dudley, Ed.; Driscoll, D. R.

1979-01-01

Describes a high school chemistry experiment which involves the reaction between calcite and hydrochloric and sulfuric acids. This reaction can be carried out as a projected demonstration and on an individual basis. (HM)

Methanol Uptake by Low Temperature Aqueous Sulfuric Acid Solutions

NASA Technical Reports Server (NTRS)

Iraci, L. T.; Essin, A. M.; Golden, D. M.; Hipskind, R. Stephen (Technical Monitor)

2001-01-01

The global methanol budget is currently unbalanced, with source terms significantly larger than the sinks terms. To evaluate possible losses of gaseous methanol to sulfate aerosols, the solubility and reactivity of methanol in aqueous sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosols is under investigation. Methanol will partition into sulfate aerosols according to its Henry's law solubility. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H*, for cold (196 - 220 K) solutions ranging between 45 and 70 wt % H2SO4. We have found that methanol solubility ranges from approx. 10(exp 5) - 10(exp 7) M/atm for UT/LS conditions. Solubility increases with decreasing temperature and with increasing sulfuric acid content. Although methanol is slightly more soluble than are acetone and formaldehyde, current data indicate that uptake by clean aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These solubility measurements include uptake due to physical solvation and any rapid equilibria which are established in solution. Reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H is not significant over our experimental time scale for solutions below 80 wt % H2SO4. To confirm this directly, results obtained using a complementary equilibrium measurement technique will also be presented.

Methods of increasing the harshness of texture of old concrete pavements--acid etching.

DOT National Transportation Integrated Search

1975-01-01

Of the four acids tested in the laboratory, the nitric and hydrochloric types were selected for field experiments. These two acids performed about equally well, the choice as to which to use is dictated by price and availability. In the field experim...

40 CFR 420.91 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... STANDARDS IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY Acid Pickling Subcategory § 420.91 Specialized definitions. (a) The term sulfuric acid pickling means those operations in which steel products are immersed... steel products are immersed in hydrochloric acid solutions to chemically remove oxides and scale, and...

Phosphorylation of Glyceric Acid in Aqueous Solution Using Trimetaphosphate

NASA Technical Reports Server (NTRS)

Kolb, Vera; Orgel, Leslie E.

1996-01-01

The phosphorylation of glyceric acid is an interesting prebiotic reaction because it converts a simple, potentially prebiotic organic molecule into phosphate derivatives that are central to carbohydrate metabolism. We find that 0.05 M glyceric acid in the presence of 0.5 M trimetaphosphate in alkaline solution gives a mixture of 2- and 3-phosphoglyceric acids in combined yields of up to 40%.

Regeneration of strong-base anion-exchange resins by sequential chemical displacement

DOEpatents

Brown, Gilbert M.; Gu, Baohua; Moyer, Bruce A.; Bonnesen, Peter V.

2002-01-01

A method for regenerating strong-base anion exchange resins utilizing a sequential chemical displacement technique with new regenerant formulation. The new first regenerant solution is composed of a mixture of ferric chloride, a water-miscible organic solvent, hydrochloric acid, and water in which tetrachloroferrate anion is formed and used to displace the target anions on the resin. The second regenerant is composed of a dilute hydrochloric acid and is used to decompose tetrachloroferrate and elute ferric ions, thereby regenerating the resin. Alternative chemical displacement methods include: (1) displacement of target anions with fluoroborate followed by nitrate or salicylate and (2) displacement of target anions with salicylate followed by dilute hydrochloric acid. The methodology offers an improved regeneration efficiency, recovery, and waste minimization over the conventional displacement technique using sodium chloride (or a brine) or alkali metal hydroxide.

Signal enhancement for gradient reverse-phase high-performance liquid chromatography-electrospray ionization mass spectrometry analysis with trifluoroacetic and other strong acid modifiers by postcolumn addition of propionic acid and isopropanol.

PubMed

Kuhlmann, F E; Apffel, A; Fischer, S M; Goldberg, G; Goodley, P C

1995-12-01

Trifluoroacetic acid (TFA) and other volatile strong acids, used as modifiers in reverse-phase high-performance liquid chromatography, cause signal suppression for basic compounds when analyzed by electrospray ionization mass spectrometry (ESI-MS). Evidence is presented that signal suppression is caused by strong ion pairing between the TFA anion and the protonated sample cation of basic sample molecules. The ion-pairing process "masks" the protonated sample cations from the ESI-MS electric fields by rendering them "neutral. " Weakly basic molecules are not suppressed by this process. The TFA signal suppression effect is independent from the well-known spray problem that electrospray has with highly aqueous solutions that contain TFA. This previously reported spray problem is caused by the high conductivity and surface tension of aqueous TFA solutions. A practical method to enhance the signal for most basic analytes in the presence of signal-suppressing volatile strong acids has been developed. The method employs postcolumn addition of a solution of 75% propionic acid and 25% isopropanol in a ratio 1:2 to the column flow. Signal enhancement is typically 10-50 times for peptides and other small basic molecules. Thus, peptide maps that use ESI-MS for detection can be performed at lower levels, with conventional columns, without the need to use capillary chromatography or reduced mass spectral resolution to achieve satisfactory sensitivity. The method may be used with similar results for heptafluorobutyric acid and hydrochloric acid. A mechanism for TFA signal suppression and signal enhancement by the foregoing method, is proposed.

Automated protein hydrolysis delivering sample to a solid acid catalyst for amino acid analysis.

PubMed

Masuda, Akiko; Dohmae, Naoshi

2010-11-01

In this study, we developed an automatic protein hydrolysis system using strong cation-exchange resins as solid acid catalysts. Examining several kinds of inorganic solid acids and cation-exchange resins, we found that a few cation-exchange resins worked as acid catalysts for protein hydrolysis when heated in the presence of water. The most efficient resin yielded amounts of amino acids that were over 70% of those recovered after conventional hydrolysis with hydrochloric acid and resulted in amino acid compositions matching the theoretical values. The solid-acid hydrolysis was automated by packing the resin into columns, combining the columns with a high-performance liquid chromatography system, and heating them. The amino acids that constitute a protein can thereby be determined, minimizing contamination from the environment.

Ionizing radiation induced degradation of salicylic acid in aqueous solution

NASA Astrophysics Data System (ADS)

Albarrán, Guadalupe; Mendoza, Edith

2018-06-01

The radiation-induced degradation of salicylic acid (SA-) in aqueous solutions (1.0 and 0.1 mmol dm-3) saturated with N2O or air or without oxygen were studied. Irradiation was carried out using a cobalt-60 source. With a 1 mmol dm-3 solution saturated with N2O a seemingly total degradation occurred at about 18 kGy, although small quantities of 2,3-dihydroxybenzoic acid, catechol and 2,5-dihydroxybenzoic acid were present at that dose at concentrations of 67, 22 and 6 μmol dm-3 respectively. Under air and when free oxygen, the three radiolytic products were present at 18.54 kGy while SA- was destroyed only to 90% and 62%, respectively. In the case of 0.1 mmol dm-3 SA- solutions, the acid was degraded at 3.5 kGy if the solution contained N2O, at 5.8 kGy in air and at 7 kGy without oxygen. The concentration of the radiolytic products increased with increasing dose and after a maximum they decreased. The oxidation was followed by measuring the chemical oxygen demand; the slopes were 0.48 and 0.11, 0.21 and 0.07, 0.15 and 0.03 mmol dm-3 kGy-1 for 1.0 and 0.10 mmol dm-3 solutions saturated with N2O or air or without oxygen, respectively.

RECOVERY OF ACTINIDES FROM AQUEOUS NITRIC ACID SOLUTIONS

DOEpatents

Ader, M.

1963-11-19

A process of recovering actinides is presented. Tetravalent actinides are extracted from rare earths in an aqueous nitric acid solution with a ketone and back-extracted from the ketone into an aqueous medium. The aqueous actinide solution thus obtained, prior to concentration by boiling, is sparged with steam to reduce its ketone to a maximum content of 3 grams per liter. (AEC)

Interaction between Al3+ and acrylic acid and polyacrylic acid in acidic aqueous solution: a model experiment for the behavior of Al3+ in acidified soil solution.

PubMed

Etou, Mayumi; Masaki, Yuka; Tsuji, Yutaka; Saito, Tomoyuki; Bai, Shuqin; Nishida, Ikuko; Okaue, Yoshihiro; Yokoyama, Takushi

2011-01-01

From the viewpoint of the phytotoxicity and mobility of Al(3+) released from soil minerals due to soil acidification, the interaction between Al(3+) and acrylic acid (AA) and polyacrylic acid (PAA) as a model compound of fulvic acid was investigated. The interaction was examined at pH 3 so as to avoid the hydrolysis of Al(3+). The interaction between Al(3+) and AA was weak. However, the interaction between Al(3+) and PAA was strong and depended on the initial (COOH in PAA)/Al molar ratio (R(P)) of the solution. For the range of 1/R(P), the interaction between Al(3+) and PAA can be divided into three categories: (1) 1:1 Al-PAA-complex (an Al(3+) combines to a carboxyl group), (2) intermolecular Al-PAA-complex (an Al(3+) combines to more than 2 carboxyl groups of other Al-PAA-complexes) in addition to the 1:1 Al-PAA-complex and (3) precipitation of intermolecular complexes. In conclusion, R(P) is an important factor affecting the behavior of Al(3+) in acidic soil solution.

IN VITRO INTERACTIONS BETWEEN LACTIC ACID SOLUTION AND ART GLASS-IONOMER CEMENTS

PubMed Central

Wang, Linda; Cefaly, Daniela Francisca Gigo; dos Santos, Janaína Lima; dos Santos, Jean Rodrigo; Lauris, José Roberto Pereira; Mondelli, Rafael Francisco Lia; Atta, Maria Teresa

2009-01-01

Objectives: Production of acids such as lactic acid contributes to establish a cariogenic environment that leads to dental substrate demineralization. Fluoride plays an important role in this case and, as fluoride-releasing materials, glass-ionomer cements are expected to contribute to minimize deleterious reactions. This study evaluated interactions of glass-ionomer cements used in atraumatic restorative treatment (ART-GICs) with an aqueous lactic acid solution, testing the null hypotheses that no changes occur in the pH of the solution or on the surface roughness and mass of the ART-GICs when exposed to lactic acid solution over a 6-week period. Material and Methods: Ketac Molar, Fuji IX, Vitro Molar and Magic Glass were tested, and compared to Filtek Z250 and Ketac Fil Plus as control groups. Six specimens of each material were made according to manufacturers' instructions. The pH of the solution and roughness and mass changes of each specimen were determined over 6 weeks. Each specimen was individually stored in 2 mL of 0.02 M lactic acid solution for 1 week, renewing the solution every week. pH of solution and mass of the specimens were monitored weekly, and surface roughness of the specimens was assessed before and at the end of the 6-week acid challenge. pH and mass data were analyzed statistically by repeated measures using one-way ANOVA and Tukey's post-hoc tests for each material. Paired t-tests were used for roughness analysis. Tukey's post-hoc tests were applied to verify differences of final roughness among the materials. Significance level was set at 5%. Results: The null hypotheses were partially rejected. All materials were able to increase the pH of the lactic acid solution and presented rougher surfaces after immersion, while mass change was minimal and generally not statistically significant. Conclusions: These findings can be helpful to predict the performance of these materials under clinical conditions. A protective action against the carious

Acid precipitation and its influence upon aquatic ecosystems--an overview

Treesearch

Eville Gorham

1976-01-01

The impact of acid precipitation reflects a usually deleterious balance between good and bad effects which may lead to serious and sometimes extreme degradation of aquatic as well as terrestrial ecosystems, particularly around metal smelters. Addition of hydrogen ions as sulfuric, nitric, and hydrochloric acid can alter and impoverish the species composition of biotic...

Treatment of infectious skin defects or ulcers with electrolyzed strong acid aqueous solution.

PubMed

Sekiya, S; Ohmori, K; Harii, K

1997-01-01

A chronic ulcer with an infection such as methicillin-resistant Staphylococcus aureus is hard to heal. Plastic and reconstructive surgeons often encounter such chronic ulcers that are resistant to surgical or various conservative treatments. We applied conservative treatment using an electrolyzed strong acid aqueous solution and obtained satisfactory results. The lesion was washed with the solution or soaked in a bowl of the solution for approximately 20 min twice a day. Fresh electrolyzed strong acid aqueous solution is unstable and should be stored in a cool, dark site in a sealed bottle. It should be used within a week after it has been produced. Here we report on 15 cases of infectious ulcers that were treated by electrolyzed strong acid aqueous solution. Of these cases, 7 patients were healed, 3 were granulated, and in 5, infection subsided. In most cases the lesion became less reddish and less edematous. Discharge or foul odor from the lesion was decreased. Electrolyzed strong acid aqueous solution was especially effective for treating a chronic refractory ulcer combined with diabetes melitus or peripheral circulatory insufficiency. This clinically applied therapy of electrolyzed strong acid aqueous solution was found to be effective so that this new therapeutic technique for ulcer treatment can now be conveniently utilized.

Growth behavior of anodic porous alumina formed in malic acid solution

NASA Astrophysics Data System (ADS)

Kikuchi, Tatsuya; Yamamoto, Tsuyoshi; Suzuki, Ryosuke O.

2013-11-01

The growth behavior of anodic porous alumina formed on aluminum by anodizing in malic acid solutions was investigated. High-purity aluminum plates were electropolished in CH3COOH/HClO4 solutions and then anodized in 0.5 M malic acid solutions at 293 K and constant cell voltages of 200-350 V. The anodic porous alumina grew on the aluminum substrate at voltages of 200-250 V, and a black, burned oxide film was formed at higher voltages. The nanopores of the anodic oxide were only formed at grain boundaries of the aluminum substrate during the initial stage of anodizing, and then the growth region extended to the entire aluminum surface as the anodizing time increased. The anodic porous alumina with several defects was formed by anodizing in malic acid solution at 250 V, and oxide cells were approximately 300-800 nm in diameter.

Technical and legal considerations and solutions in the area of battery charging for electric vehicles

NASA Astrophysics Data System (ADS)

Juda, Z.

2016-09-01

The issue of protecting health of residents of urbanized areas from the effect of excessive particulate matter and toxic components of car exhaust gases imposes the need of introduction of clean electric vehicles to the market. The increasing market availability of electric vehicles, especially in the segment of short-range (neighborhood) vehicles is followed by development of new and advanced infrastructure solutions. This also applies to the increasingly popular hybrid vehicles PHEV (Plug-in Hybrid Electric Vehicles). However, problems with the existing designs are primarily associated with limited driving range on a single battery charge, the density of charging stations in urban and suburban area, energy system efficiency due to increased electricity demand and the unification of solutions for charging stations, on-board chargers and the necessary accessories. Technical solutions are dependent on many factors, including the type and size of battery in the vehicle and access to power grid with increased load capacity. The article discusses the legal and technical actions outlined in the above directions. It shows the available and planned solutions in this area.

Investigation of Gas-Sensing Property of Acid-Deposited Polyaniline Thin-Film Sensors for Detecting H2S and SO2

PubMed Central

Dong, Xingchen; Zhang, Xiaoxing; Wu, Xiaoqing; Cui, Hao; Chen, Dachang

2016-01-01

Latent insulation defects introduced in manufacturing process of gas-insulated switchgears can lead to partial discharge during long-time operation, even to insulation fault if partial discharge develops further. Monitoring of decomposed components of SF6, insulating medium of gas-insulated switchgear, is a feasible method of early-warning to avoid the occurrence of sudden fault. Polyaniline thin-film with protonic acid deposited possesses wide application prospects in the gas-sensing field. Polyaniline thin-film sensors with only sulfosalicylic acid deposited and with both hydrochloric acid and sulfosalicylic acid deposited were prepared by chemical oxidative polymerization method. Gas-sensing experiment was carried out to test properties of new sensors when exposed to H2S and SO2, two decomposed products of SF6 under discharge. The gas-sensing properties of these two sensors were compared with that of a hydrochloric acid deposited sensor. Results show that the hydrochloric acid and sulfosalicylic acid deposited polyaniline thin-film sensor shows the most outstanding sensitivity and selectivity to H2S and SO2 when concentration of gases range from 10 to 100 μL/L, with sensitivity changing linearly with concentration of gases. The sensor also possesses excellent long-time and thermal stability. This research lays the foundation for preparing practical gas-sensing devices to detect H2S and SO2 in gas-insulated switchgears at room temperature. PMID:27834895

10 CFR Appendix E to Part 110 - Illustrative List of Chemical Exchange or Ion Exchange Enrichment Plant Equipment and Components...

Code of Federal Regulations, 2010 CFR

2010-01-01

... designed or prepared electrochemical reduction cells to reduce uranium from one valence state to another for uranium enrichment using the chemical exchange process. The cell materials in contact with process solutions must be corrosion resistant to concentrated hydrochloric acid solutions. The cell cathodic...

SURFACE TREATMENT OF MOLYBDENUM METAL

DOEpatents

Coffer, C.O.

1961-12-01

A process of descaling molybdenum articles comprises first immersing them in an aqueous sodium hydroxide-potassium permanganate solution of between 60 and 85 deg C, rinsing, and then immersing them in an aqueous solution containing a mixture of sulfuric, hydrochloric, and chromic acids.

Recovery of fission product palladium from acidic high level waste solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rizvi, G.H.; Mathur, J.N.; Murali, M.S.

1996-07-01

The recovery of palladium from a synthetic pressurized heavy water reactor high level waste (PHWR-HLW) solution has been carried out, and the best reagents to use for the actual HLW solutions are discussed. The extraction of palladium from nitric acid solutions has been carried out using Cyanex-471X (triisobutylphosphine sulfide, TIPS) as the extractant. The metal ion could be quantitatively extracted from solutions with nitric acid concentrations between 2.0 and 6.0 M. The species extracted into the organic phase was found to be Pd(NO{sub 3}){sub 2}{center_dot}TIPS. Nitric acid in the range of 2.0 to 5.0 M had no effect on TIPSmore » for at least 71 hours. A systematic study of gamma irradiation on loading and stripping of palladium from loaded organic phases using several potential extractants, TIPS, alpha benzoin oxime, dioctylsulfide, and dioctylsulfoxide has been made. A flow sheet for the recovery of palladium from actual HLW solutions using TIPS is proposed.« less

The ototoxic effect of boric acid solutions applied into the middle ear of guinea pigs.

PubMed

Oztürkcan, Sedat; Dündar, Riza; Katilmis, Hüseyin; Ilknur, Ali Ekber; Aktaş, Sinem; Haciömeroğlu, Senem

2009-05-01

This study analyzed the ototoxic effects of boric acid solutions. Boric acid solutions have been used as otologic preparations for many years. Boric acid is commonly found in solutions prepared with alcohol or distilled water but can also be found in a powder form. These preparations are used for both their antiseptic and acidic qualities in external and middle ear infections. We investigated the ototoxic effect of boric acid solutions on guinea pigs. We are unaware of any similar, previously published study of this subject in English. The study was conducted on 28 young albino guinea pigs. Prior to application of the boric acid solution under general anesthesia, an Auditory Brainstem Response (ABRs) test was applied to the right ear of the guinea pigs. Following the test, a perforation was created on the tympanic membrane of the right ear of each guinea pig and small gelfoam pieces were inserted into the perforated area. Test solutions were administered to the middle ear for 10 days by means of a transcanal route. Fifteen days after inserting the gelfoams in all of the guinea pigs, we anasthesized the guinea pigs and removed the gelfoams from the perforated region of the ear and then performed an ABRs on each guinea pig. The ABRs were within the normal range before the applications. After the application, no significant changes were detected in the ABRs thresholds in neither the saline group nor the group administered boric acid and distilled water solution; however, significant changes were detected in the ABRs thresholds of the Gentamicine and boric acid and alcohol solution groups. We believe that a 4% boric acid solution prepared with distilled water can be a more reliable preparation than a 4% boric acid solution prepared with alcohol.

Removal of radium from acidic solutions containing same by adsorption on coal fly ash

DOEpatents

Scheitlin, Frank M.

1984-01-01

The invention is a process for the removal of radium from acidic aqueous solutions. In one aspect, the invention is a process for removing radium from an inorganic-acid solution. The process comprises contacting the solution with coal fly ash to effect adsorption of the radium on the ash. The radium-containing ash then is separated from the solution. The process is simple, comparatively inexpensive, and efficient. High radium-distribution coefficients are obtained even at room temperature. Coal fly ash is an inexpensive, acid-resistant, high-surface-area material which is available in large quantities throughout the United States. The invention is applicable, for example, to the recovery of .sup.226 Ra from nitric acid solutions which have been used to leach radium from uranium-mill tailings.

Hazardous Waste Cleanup: Veolia ES Technical Solutions, L.L.C. in Middlesex, New Jersey

EPA Pesticide Factsheets

Veolia ES Technical Solutions is located at 125 Factory Lane in Middlesex, New Jersey. Veolia owns and operates a solvent-reprocessing facility that is located on a four-acre site in an industrial area of Middlesex Borough.

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

NASA Technical Reports Server (NTRS)

Muirhead, Dean

2011-01-01

Two batches of nominally pretreated and augmented urine were prepared with the baseline pretreatment formulation of sulfuric acid and chromium trioxide. The urine was augmented with inorganic salts and organic compounds in order to simulate a urinary ionic concentrations representing the upper 95 percentile on orbit. Three strong mineral acids: phosphoric, hydrochloric, and nitric acid, were substituted for the sulfuric acid for comparison to the baseline sulfuric acid pretreatment formulation. Three concentrations of oxidizer in the pretreatment formulation were also tested. Pretreated urine was distilled to 85% water recovery to determine the effect of each acid and its conjugate base on the precipitation of minerals during distillation. The brines were analyzed for calcium and sulfate ion, total, volatile, and fixed suspended solids. Test results verified that substitution of phosphoric, hydrochloric, or nitric acids for sulfuric acid would prevent the precipitation of gypsum up to 85% recovery from pretreated urine representing the upper 95 percentile calcium concentration on orbit.

Generator for gallium-68 and compositions obtained therefrom

DOEpatents

Neirinckx, Rudi D.; Davis, Michael A.

1981-01-01

A generator for obtaining radioactive gallium-68 from germanium-68 bound in a resin containing unsubstituted phenolic hydroxyl groups. The germanium-68 is loaded into the resin from an aqueous solution of the germanium-68. A physiologically acceptable solution of gallium-68 having an activity of 0.1 to 50 millicuries per milliliter of gallium-68 solution is obtained. The solution is obtained from the bound germanium-68 which forms gallium-68 in situ by eluting the column with a hydrochloric acid solution to form an acidic solution of gallium-68. The acidic solution of gallium-68 can be neutralized.

Molecular gated-AlGaN/GaN high electron mobility transistor for pH detection.

PubMed

Ding, Xiangzhen; Yang, Shuai; Miao, Bin; Gu, Le; Gu, Zhiqi; Zhang, Jian; Wu, Baojun; Wang, Hong; Wu, Dongmin; Li, Jiadong

2018-04-18

A molecular gated-AlGaN/GaN high electron mobility transistor has been developed for pH detection. The sensing surface of the sensor was modified with 3-aminopropyltriethoxysilane to provide amphoteric amine groups, which would play the role of receptors for pH detection. On modification with 3-aminopropyltriethoxysilane, the transistor exhibits good chemical stability in hydrochloric acid solution and is sensitive for pH detection. Thus, our molecular gated-AlGaN/GaN high electron mobility transistor acheived good electrical performances such as chemical stability (remained stable in hydrochloric acid solution), good sensitivity (37.17 μA/pH) and low hysteresis. The results indicate a promising future for high-quality sensors for pH detection.

Solution Preserves Nucleic Acids in Body-Fluid Specimens

NASA Technical Reports Server (NTRS)

Pierson, Duane L.; Stowe, Raymond P.

2004-01-01

A solution has been formulated to preserve deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in specimens of blood, saliva, and other bodily fluids. Specimens of this type are collected for diagnostic molecular pathology, which is becoming the method of choice for diagnosis of many diseases. The solution makes it possible to store such specimens at room temperature, without risk of decomposition, for subsequent analysis in a laboratory that could be remote from the sampling location. Thus, the solution could be a means to bring the benefits of diagnostic molecular pathology to geographic regions where refrigeration equipment and diagnostic laboratories are not available. The table lists the ingredients of the solution. The functions of the ingredients are the following: EDTA chelates divalent cations that are necessary cofactors for nuclease activity. In so doing, it functionally removes these cations and thereby retards the action of nucleases. EDTA also stabilizes the DNA helix. Tris serves as a buffering agent, which is needed because minor contaminants in an unbuffered solution can exert pronounced effects on pH and thereby cause spontaneous degradation of DNA. SDS is an ionic detergent that inhibits ribonuclease activity. SDS has been used in some lysis buffers and as a storage buffer for RNA after purification. The use of the solution is straightforward. For example, a sample of saliva is collected by placing a cotton roll around in the subject's mouth until it becomes saturated, then the cotton is placed in a collection tube. Next, 1.5 mL of the solution are injected directly into the cotton and the tube is capped for storage at room temperature. The effectiveness of the solution has been demonstrated in tests on specimens of saliva containing herpes simplex virus. In the tests, the viral DNA, as amplified by polymerase chain reaction, was detected even after storage for 120 days.

Hydrophobic interactions between polymethacrylic acid and sodium laureth sulfate in aqueous solutions

NASA Astrophysics Data System (ADS)

Yaremko, Z. M.; Fedushinskaya, L. B.; Burka, O. A.; Soltys, M. N.

2014-09-01

The role of hydrophobic interaction in the development of associative processes is demonstrated, based on the concentration dependences of the viscosity and pH of binary solutions of polymethacrylic acid as an anionic polyelectrolyte and sodium laureth sulfate as an anionic surfactant. It is found that the inflection point on the dependence of the difference between the pH values of binary solutions of polymethacrylic acid and sodium laureth sulfate on the polyelectrolyte concentration is a criterion for determining the predominant contribution from hydrophobic interaction, as is the inflection point on the dependence of pH of individual solutions of polymethacrylic acid on the polyelectrolyte concentration.

Impact of fluorescent lighting on the browning potential of model wine solutions containing organic acids and iron.

PubMed

Grant-Preece, Paris; Barril, Celia; Schmidtke, Leigh M; Clark, Andrew C

2018-03-15

Model wine solutions containing organic acids, individually or combined, and iron(III), were exposed to light from fluorescent lamps or stored in darkness for four hours. (-)-Epicatechin was then added, and the solutions incubated in darkness for 10days. Browning was monitored by UV-visible absorption spectrophotometry and UHPLC-DAD. The pre-irradiated solutions containing tartaric acid exhibited increased yellow/brown coloration compared to the dark controls mainly due to reaction of the tartaric acid photodegradation product glyoxylic acid with (-)-epicatechin to form xanthylium cation pigments. In these solutions, browning decreased as the concentrations of organic acids other than tartaric acid increased. Xanthylium cations were also detected in the pre-irradiated malic acid solution. However, in the malic acid, succinic acid, citric acid and lactic acid solutions, any coloration was mainly due to the production of dehydrodiepicatechin A, which was largely independent of prior light exposure, but strongly affected by the organic acid present. Copyright © 2017 Elsevier Ltd. All rights reserved.

Micro-organization of humic acids in aqueous solutions

NASA Astrophysics Data System (ADS)

Klučáková, Martina; Věžníková, Kateřina

2017-09-01

The methods of dynamic light scattering and micro-rheology were used to investigate the molecular organization of humic acids in solutions. The obtained results were supplemented by ultraviolet/visible spectrometry and measurement of the zeta potential. Particle tracking micro-rheology was used for the first time as a novel method in humic research. Solutions of humic acids were prepared in three different mediums: NaOH, NaCl, and NaOH neutralized by HCl after dissolution of the humic sample. The molecular organization of humic acids was studied over a wide concentration range (0.01-10 g dm-3). Two breaks were detected in the obtained concentration dependencies. The rearrangements were observed at concentrations around 0.02 g dm-3 and 1 g dm-3. Changes in the measured values observed at around 0.02 g dm-3 were less noticeable and were related to the formation of particles between 100 and 1000 nm in size and the strong bimodal character of humic systems diluted by NaCl. The ;switch-over point; at around 1 g dm-3 indicated changes in the secondary structure of humic acids connected with the increase in colloidal stability (decrease of zeta potential), the decrease in polydispersity, and minimal values of viscosity.

An SNMP-based solution to enable remote ISO/IEEE 11073 technical management.

PubMed

Lasierra, Nelia; Alesanco, Alvaro; García, José

2012-07-01

This paper presents the design and implementation of an architecture based on the integration of simple network management protocol version 3 (SNMPv3) and the standard ISO/IEEE 11073 (X73) to manage technical information in home-based telemonitoring scenarios. This architecture includes the development of an SNMPv3-proxyX73 agent which comprises a management information base (MIB) module adapted to X73. In the proposed scenario, medical devices (MDs) send information to a concentrator device [designated as compute engine (CE)] using the X73 standard. This information together with extra information collected in the CE is stored in the developed MIB. Finally, the information collected is available for remote access via SNMP connection. Moreover, alarms and events can be configured by an external manager in order to provide warnings of irregularities in the MDs' technical performance evaluation. This proposed SNMPv3 agent provides a solution to integrate and unify technical device management in home-based telemonitoring scenarios fully adapted to X73.

21 CFR 173.300 - Chlorine dioxide.

Code of Federal Regulations, 2014 CFR

2014-04-01

... hypochlorite and hydrochloric acid. (ii) Treating an aqueous solution of sodium chlorate with hydrogen peroxide... electrolysis. (2) The generator effluent contains at least 90 percent (by weight) of chlorine dioxide with...

Method for liquid chromatographic extraction of strontium from acid solutions

DOEpatents

Horwitz, E. Philip; Dietz, Mark L.

1992-01-01

A method and apparatus for extracting strontium and technetium values from biological, industrial and environmental sample solutions using a chromatographic column is described. An extractant medium for the column is prepared by generating a solution of a diluent containing a Crown ether and dispersing the solution on a resin substrate material. The sample solution is highly acidic and is introduced directed to the chromatographic column and strontium or technetium is eluted using deionized water.

The Effect of Various Acids to the Gelation Process to the Silica Gel Characteristic Using Organic Silica

NASA Astrophysics Data System (ADS)

Rahman, NA; Widiyastuti, W.; Sigit, D.; Ajiza, M.; Sujana, W.

2018-01-01

Bagasse ash is solid waste of cane sugar industry which contain of silica more than 51%. Some previous study of silica gel from bagasse ash have been conducted often and been applied. This study concerns about the effect of various acid used in the process of gelation to the characteristic of silica gel produced. Then, this silica gel will be used as adsorbent. As that, the silica gel must fulfill the requirements of adsorbent, as have good pores characteristics, fit in mesoporous size so that adsorbent diffusion process is not disturbed. A fitted pores size of silica gel can be prepared by managing acid concentration used. The effect of acid, organic acid (tartaric acid) and inorganic acid (hydrochloric acid), is investigated in detail. The acid is added into sodium silicate solution in that the gel is formed, the pores structures can be investigated with BET, the crystal form is analyzed with XRD and the pore structure is analyzed visually with SEM. By managing the acid concentration added, it gets the effect of acid to the pore structure of silica gel. The bigger concentration is, the bigger the pore’s size of silica gel produced.

49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Chloric acid solution or chlorine dioxide hydrate... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When the.... Fiberboard boxes must be reinforced and insulated and sufficient dry ice must be used to maintain the hydrate...

49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Chloric acid solution or chlorine dioxide hydrate... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When the.... Fiberboard boxes must be reinforced and insulated and sufficient dry ice must be used to maintain the hydrate...

49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Chloric acid solution or chlorine dioxide hydrate... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When the.... Fiberboard boxes must be reinforced and insulated and sufficient dry ice must be used to maintain the hydrate...

49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Chloric acid solution or chlorine dioxide hydrate... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When the.... Fiberboard boxes must be reinforced and insulated and sufficient dry ice must be used to maintain the hydrate...

49 CFR 173.229 - Chloric acid solution or chlorine dioxide hydrate, frozen.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Chloric acid solution or chlorine dioxide hydrate... Than Class 1 and Class 7 § 173.229 Chloric acid solution or chlorine dioxide hydrate, frozen. When the.... Fiberboard boxes must be reinforced and insulated and sufficient dry ice must be used to maintain the hydrate...

An in vitro study on the effect of TiF(4) treatment against erosion by hydrochloric acid on pellicle-covered enamel.

PubMed

Hove, L H; Young, A; Tveit, A B

2007-01-01

The aim of this in vitro study was to examine the effect of fluoride treatment on pellicle-covered enamel exposed to an acidic challenge simulating gastric reflux. Sixteen bovine and 16 human teeth were sectioned into four pieces, divided into four groups: (1) control, (2) 2-hour pellicle, (3) TiF(4), and (4) 2-hour pellicle + TiF(4), and subsequently subjected to 3 ml 0.01 M HCl stepwise for 4 + 4 + 4 min. The acid was analysed for calcium by atomic absorption spectroscopy. TiF(4) reduced Ca release from enamel by 76, 57 and 56% following the 4 + 4 + 4-min acid exposures, respectively, in bovine and 44, 54 and 54% in human enamel. These results suggest that treatment of enamel with a TiF(4) solution, with or without pellicle removal, may provide protection for the enamel against acid attack.

Bipolar membrane electrodialysis for generation of hydrochloric acid and ammonia from simulated ammonium chloride wastewater.

PubMed

Li, Ya; Shi, Shaoyuan; Cao, Hongbin; Wu, Xinmin; Zhao, Zhijuan; Wang, Liying

2016-02-01

Simulated ammonium chloride wastewater was treated by a lab-scale bipolar membrane electrodialysis for the generation of HCl and NH3·H2O and desalination. The influence of initial concentration of NH4Cl, current density, salt solution volume, initial concentration of acid and base and membrane stack structure on the yields of HCl and NH3·H2O was investigated. The current efficiency and energy consumption were also examined under different conditions. The results showed that, at the current density of 48 mA/cm(2), the highest concentration of HCl and NH3·H2O with initial concentration of 110 g/L NH4Cl was 57.67 g/L and 45.85 g/L, respectively. Higher initial concentration of NH4Cl was favor to reduce unit energy consumption and increase current efficiency of the BMED system. The membrane stack voltage of BMED increased quickly under constant current when the concentration of NH4Cl contained in the solution of salt compartment was depleted below the "inflection point concentration" about 8000 mg/L. It means that the concentration of NH4Cl below 8000 mg/L was no longer suitable for BMED because of higher energy consumption. The HCl and NH3·H2O concentration increased more quickly following the increase of current density. When increasing the volume of NH4Cl, the concentration of HCl and NH3·H2O also increased. The high initial concentration of acid and base could improve the final concentration of them, while the growth rate was decreased. Compared with the BMED system with three compartments, the growth rate of HCl concentration with the two compartments was higher and its unit energy consumption was lower. It meant that the performance of the BMED system could be improved by optimizing operation conditions. The application feasibility of the generation of HCl and NH3·H2O and desalination of ammonium chloride wastewater by BMED was proved. Copyright © 2015 Elsevier Ltd. All rights reserved.

THE GRAVIMETRIC DETERMINATION OF MOLYBDENUM IN URANIUM-MOLYBDENUM ALLOYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1959-03-01

The sample is dissolved in nitric and hydrochloric acids. After heating the solution with sulfuric acid, molybodenum is precipitated as the benzoin-oxime complex which is ignited to molybdic oxide. This is dissolved in ammonia, and the molybdenum is precipitated and weighed as lead molybdate. (auth)

The Use of Ascorbic Acid as a Food Additive: Technical-Legal Issues

PubMed Central

Varvara, Michele; Bozzo, Giancarlo; Celano, Giuseppe; Disanto, Chiara; Pagliarone, Cosimo Nicola

2016-01-01

Ascorbic acid (C6H8O6) is an organic compound belonging to the family of monosaccharide. It is highly soluble in water, and is often called one of the secrets of the Mediterranean diet. Its use is widespread in the food industry is also important, having always been exploited for its antioxidant and stabilising ability. Many indeed are the additive formulations that take advantage of these properties. The purpose of this paper is to explain the characteristics that make ascorbic acid an important food additive and to emphasise the technical and legal issues related to its use in food productions. In particular, in the course of this employment, laws and scientific studies have been applied to the resolution of a lawsuit, having as its object the use of ascorbic acid in preparations of ground beef sold at a butcher shop. The views expressed in court by the technical consultant have led to the acquittal of the accused, in the light of the demonstrated and proven non-toxicity of the molecule and the use of a mixture of additives for the production of sausage. The European and national legislations, supported by numerous scientific studies, define the possible use of ascorbic acid according to the principle of quantum satis, and it can be used in foods for children. Our work aims to represent further evidence of the safety of use of ascorbic acid as a food additive, and – as confirmed by the legal decision reported – it wants to bring out the prospects for use of ascorbic acid for technological purposes even by registered establishments. PMID:27800425

Polarization studies on zinc in hydrochloric acid solution containing some organic solvents

NASA Astrophysics Data System (ADS)

Mohamed, A. K.

1999-05-01

The corrosion behaviour of zinc metal in some organic solvents was tested electrochemically using galvanometric polarization measurements. The results showed that the studied organic solvents act as mixed type inhibitors. The inhibition was assumed to occur via physical adsorption of the inhibitor molecules fitting a Temkin's isotherm. The inhibition eficiency of the solvents increase in the order: glycerol>ethylene glycol>DMSO>dioxane. This order is not affected by the variation in temperature in the range 35-55 circC. The increase in temperature was found to increase the corrosion in absence and in presence of inhibitors. Some thermodynamic parameters for adsorption were also computed and discussed. Le comportement de corrosion du zinc métallique dans certains solvants organiques a été testé électrochimiquement en utilisant les mesures de polarisation galvanométrique. Les résultats ont montré que les solvants organiques étudiés agissent comme des inhibiteurs de type mixte. L'inhibition semble se produire par l'adsorption physique des molécules inhibitrices selon une isotherme de Temkin. L'efficacité d'inhibition des solvants augmente dans l'ordre suivant : glycérol>éthylène glycol>DMSO>dioxane. Cet ordre n'est pas affecté par une variation de température dans l'intervalle compris entre 35 et 55 circC. La corrosion augmente avec la température, en absence ou en présence d'inhibiteurs. Certains paramètres thermodynamiques d'adsorption ont été calculés et discutés.

Induction of an oxalate decarboxylase in the filamentous fungus Trametes versicolor by addition of inorganic acids.

PubMed

Zhu, Cui Xia; Hong, Feng

2010-01-01

In order to improve yields and to reduce the cost of oxalate decarboxylase (OxDC, EC 4.1.1.2), the induction of OxDC in the white-rot fungus Trametes versicolor was studied in this work. OxDC was induced by addition of inorganic acids including hydrochloric acid, sulfuric acid, and phosphoric acid to culture media. The results showed that all the acids could enhance OxDC expression. The activity of the acid-induced OxDC rose continuously. All of the OxDC volumetric activities induced by the inorganic acids were higher than 20.0 U/L and were two times higher than that obtained with oxalic acid. OxDC productivity was around 4.0 U*L(-1)*day(-1). The highest specific activity against total protein was 3.2 U/mg protein at day 8 after induction of sulfuric acid, and the specific activity against mycelial dry weight was 10.6 U/g at day 9 after induction of hydrochloric acid. The growth of mycelia was inhibited slightly when the pH values in culture media was around 2.5-3.0, while the growth was inhibited heavily when the pH was lower than 2.5.

Effect of citric acid on the acidification of artificial pepsin solution for metacercariae isolation from fish.

PubMed

Kim, Min-Ki; Pyo, Kyoung-Ho; Hwang, Young-Sang; Chun, Hyang Sook; Park, Ki Hwan; Ko, Seong-Hee; Chai, Jong-Yil; Shin, Eun-Hee

2013-11-15

Artificial digestive solution based on pepsin is essential for collecting metacercariae from fish. To promote the enzymatic reactivity of pepsin, the pH of the solution has to be adjusted to pH 1.0-2.0. Hydrochloride (HCl) is usually used for this purpose, but the use of HCl raises safety concerns. The aim of this work was to address the usefulness of citric acid as an alternative for HCl for the acidification of pepsin solution, and to examine its potential to damage metacercariae during in vitro digestion as compared with HCl. Changes in pH after adding 1-9% of citric acid (m/v) to pepsin solution were compared to a 1% HCl (v/v) addition. Digestion of fish muscle was evaluated by measuring released protein concentrations by spectrophotometry. In addition, survival rates of metacercariae in pepsin solution were determined at different citric acid concentrations and were compared that of with 1% HCl. The present study shows that addition of citric acid reduced the pH of pepsin solutions to the required level. Addition of more than 5% of citric acid resulted in the effective digestion of fish muscle over 3h in vitro, and 5% citric acid was less lethal to metacercariae than 1% HCl in pepsin solution. Pepsin solution containing 5% citric acid had digestive capacity superior to pepsin solution containing 1% HCl after 3h incubation with released protein concentrations of 12.0 ng/ml for 5% citric acid and 9.6 ng/ml for 1% HCl. Accordingly, the present study suggests that the addition of 5% citric acid to pepsin solution is a good alternative to 1% HCl in infection studies because citric acid is a stable at room temperature and has a good safety profile. In addition, we suggest that the use of citric acid enables the preparation of commercial digestive solutions for the detection of microorganisms in fish and other vertebrate muscle tissue. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

IRON COATED URANIUM AND ITS PRODUCTION

DOEpatents

Gray, A.G.

1960-03-15

A method of applying a protective coating to a metallic uranium article is given. The method comprises etching the surface of the article with an etchant solution containlng chloride ions, such as a solution of phosphoric acid and hydrochloric acid, cleaning the etched surface, electroplating iron thereon from a ferrous ammonium sulfate electroplating bath, and soldering an aluminum sheath to the resultant iron layer.

PROCESS OF SECURING PLUTONIUM IN NITRIC ACID SOLUTIONS IN ITS TRIVALENT OXIDATION STATE

DOEpatents

Thomas, J.R.

1958-08-26

>Various processes for the recovery of plutonium require that the plutonium be obtalned and maintained in the reduced or trivalent state in solution. Ferrous ions are commonly used as the reducing agent for this purpose, but it is difficult to maintain the plutonium in a reduced state in nitric acid solutions due to the oxidizing effects of the acid. It has been found that the addition of a stabilizing or holding reductant to such solution prevents reoxidation of the plutonium. Sulfamate ions have been found to be ideally suitable as such a stabilizer even in the presence of nitric acid.

Fatty acid and carotenoid production by Sporobolomyces ruberrimus when using technical glycerol and ammonium sulfate.

PubMed

Razani, Seyed Hadi; Mousavi, Seyed Mohammad; Yeganeh, Hassan Mehrabani Mehrabanii; Marc, Ivan

2007-10-01

The production of carotenoids, lipid content, and fatty acid composition were all studied in a strain of Sporobolomyces ruberrimus when using different concentrations of technical glycerol as the carbon source and ammonium sulfate as the nitrogen source. The total lipids represented an average of 13% of the dry weight, and the maximum lipids were obtained when using 65.5 g/l technical glycerol (133.63 mg/ g). The optimal conditions for fatty acid production were at 27 degrees C using 20 g of ammonium sulfate and a pH range from 6 to 7, which produced a fatty acid yield of 32.5+/-1 mg/g, including 1.27+/- 0.15 mg of linolenic acid (LNA), 7.50+/-0.45 mg of linoleic acid (LLA), 5.50+/-0.35 mg of palmitic acid (PA), 0.60+/-0.03 mg of palmitoleic acid (PAL), 1.28+/-0.11 mg of stearic acid (SA), 9.09+/-0.22 mg of oleic acid, 2.50+/-0.10 mg of erucic acid (EA), and 4.25+/-0.20 mg of lignoceric acid (LCA), where the palmitic, oleic, and linoleic acids combined formed about 37% of the total fatty acids. The concentration of total carotenoids was 2.80 mg/g when using 20 g of ammonium sulfate, and consisted of torularhodin (2.70 mg/g) and beta-carotene (0.10 mg/ g), at 23 degrees C and pH 6. However, the highest amount with the maximum specific growth rate was obtained (micromax=0.096 h(-1)) with an ammonium sulfate concentration of 30 g/l.

Ex Vivo Liver Experiment of Hydrochloric Acid-Infused and Saline-Infused Monopolar Radiofrequency Ablation: Better Outcomes in Temperature, Energy, and Coagulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Xiong-ying; Gu, Yang-kui; Huang, Jin-hua, E-mail: huangjh@sysucc.org.cn

ObjectiveTo compare temperature, energy, and coagulation between hydrochloric acid-infused radiofrequency ablation (HAIRFA) and normal saline-infused radiofrequency ablation (NSIRFA) in ex vivo porcine liver model.Materials and Methods30 fresh porcine livers were excised in 60 lesions, 30 with HAIRFA and the other 30 with NSIRFA. Both modalities used monopolar perfusion electrode connected to a RF generator set at 103 °C and 30 W. In each group, ablation time was set at 10, 20, or 30 min (10 lesions from each group at each time). We compared tissue temperatures (at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 cm away from the electrode tip), average power, deposited energy,more » deposited energy per coagulation volume (DEV), coagulation diameters, coagulative volume, and spherical ratio between the two groups.ResultsTemperature–time curves showed that HAIRFA provided progressively greater heating than that of NSIRFA. At 30 min, mean average power, deposited energy, coagulation volumes (113.67 vs. 12.28 cm{sup 3}) and diameters, and increasing in tissue temperature were much greater with HAIRFA (P < 0.001 for all), except DEV was lower (456 vs. 1396 J/cm{sup 3}, P < 0.001). The spherical ratio was closer to 1 with HAIRFA (1.23 vs. 1.46). Coagulation diameters, volume, and average power of HAIRFA increased significantly with longer ablation times. While with NSIRFA, these characteristics were stable till later 20 min, except the power decreased with longer ablation times.ConclusionsHAIRFA creates much larger and more spherical lesions by increasing overall energy deposition, modulating thermal conductivity, and transferring heat during ablation.« less

Domestic Aluminum Resources: Dilemmas of Development. Volume II. Appendixes II-VII. Detailed Agency Comments and GAO Response.

DTIC Science & Technology

1980-07-17

31 Clay/hydrochloric acid, gas - induced crystallization 32 Clay/nitric acid evaporative crystallization 32 Clay/hydrochloric acid, evapora- tive...ALUMINA AND ALUMINUM TECHNOLOGIES 53 Evaluation of nonbauxitic alumina production processes 54 Clay/carbo-chlorination 54 Clay/hydrochloric acid, gas ...reports that the miniplant program is centered on a single process-- clay/hydrochloric acid- gas precipitation. The Bureau of Mines has not retreated

New Technical Solution for Vertical Shaft Equipping Using Steel Headframe of Multifunction Purpose

NASA Astrophysics Data System (ADS)

Kassikhina, Elena; Pershin, Vladimir; Glazkov, Yurij

2017-11-01

The article reviews a novel approach to the design of steel angle headframe for vertical shafts of coal and ore mines on the basis of rational design solutions. Practice of construction of coal and ore mines provides application of various designs for steel angle headframes which are divided into separate large assembly blocks and constructive elements during assembling operations. Design of these blocks and elements, their weight and dimensions effect the chose of the method of assembling on which economic and technological indicators, as well as duration of down-time, depend on during performance of construction operations in shaft. The technical solution on equipment provision for mine vertical shaft using headframe of multifunctional purpose will allow changing the management construction of vertical shaft. The constructive design of the headgear allows application of the effective method of assembly and thus to provide improvement of the technical and economic indexes, and high calendar time rate of the shaft construction due to reduction of duration of works on equipment provision for the shaft and to refurbishment of the shaft in order to carry out horizontal mining.

Structure of polyacrylic acid and polymethacrylic acid solutions : a small angle neutron scattering study

NASA Astrophysics Data System (ADS)

Moussaid, A.; Schosseler, F.; Munch, J. P.; Candau, S. J.

1993-04-01

The intensity scattered from polyacrylic acid and polymethacrylic acid solutions has been measured by small angle neutron scattering experiemnts. The influence of polymer concentration, ionization degree, temperature and salt content has been investigated. Results are in qualitative agreement with a model which predicts the existence of microphases in the unstable region of the phase diagram. Quantitative comparison with the theory is performed by fitting the theoretical structure factor to the experimental data. For a narrow range of ionizaiton degrees nearly quantitative agreement with the theory is found for the polyacrylic acide system.

Biomass Potential of Virgin and Calcined Tapioca (Cassava Starch) for the Removal of Sr(II) and Cs(I) from Aqueous Solutions.

PubMed

Ogata, Fumihiko; Nagai, Noriaki; Ueta, Erimi; Nakamura, Takehiro; Kawasaki, Naohito

2018-01-01

In this study, we prepared novel adsorbents containing virgin and calcined tapioca products for removing strontium (Sr(II)) and cesium (Cs(I)) from aqueous solutions. The characteristics of tapioca, along with its capacity to adsorb Sr(II) and Cs(I), were evaluated. Multiple tapioca products were prepared and tested. The adsorbent prepared by boiling the tapioca followed by calcination at 300°C (BTP300) was the most effective. In addition, adsorption was affected by the adsorbent's surface properties. The Sr(II) and Cs(I) adsorbed onto BTP300 could be recovered through desorption by hydrochloric acid at different concentrations, which indicates that BTP300 can be used several times for adsorption/desorption. The results of this study suggest that BTP300, which was produced from tapioca biomass, can remove Sr(II) and Cs(I) from aqueous solutions.

Metal etching composition

NASA Technical Reports Server (NTRS)

Otousa, Joseph E. (Inventor); Thomas, Clark S. (Inventor); Foster, Robert E. (Inventor)

1991-01-01

The present invention is directed to a chemical etching composition for etching metals or metallic alloys. The composition includes a solution of hydrochloric acid, phosphoric acid, ethylene glycol, and an oxidizing agent. The etching composition is particularly useful for etching metal surfaces in preparation for subsequent fluorescent penetrant inspection.

Experimental study of Pb (II) solution sorption behavior onto Coffee Husk Bioactivated Carbon

NASA Astrophysics Data System (ADS)

Fona, Z.; Habibah, U.

2018-04-01

Coffee husk which is abundantly produced in the coffee plantations is potential to be a challenging adsorbent. The fate of Pb (II) solution in the sorption mechanism onto the adsorbent has been investigated. This paper aimed to study the efficiency of Pb (II) aqueous solution removal using activated carbon from coffee husk (CAC). The sorption characteristics were using two isotherm models, Langmuir and Freundlich, were also reported. The coffee husk from local plantations in Middle Aceh was carbonized and sieved to 120/140 mesh. The charcoal was activated using hydrochloric acid before contacted with the different initial concentrations of Pb (II) solution. The remaining concentrations of the metal in the specified contact times were determined using Atomic Adsorption Spectrophotometer at 283.3 wavelength. The result showed that the equilibrium concentrations were obtained in about 30 minutes which depended on the initial concentration. The sorption mechanism followed Freundlich isotherm model where the adsorption constant and capacity were accordingly 1.353 and 1.195 mgg‑1. The iodine sorption was up to 1,053 mgg‑1. Based on the ash and moisture content, as well as iodine sorption, the activated carbon met the national standard.

Synthesis, characterization and corrosion inhibition properties of benzamide-2-chloro-4-nitrobenzoic acid and anthranilic acid-2-chloro-4-nitrobenzoic acid for mild steel corrosion in acidic medium

NASA Astrophysics Data System (ADS)

Pandey, Archana; Verma, Chandrabhan; Singh, B.; Ebenso, Eno E.

2018-03-01

The present study deals with the synthesis of two new compounds namely, benzamide - 2-chloro-4-nitrobenzoic acid (BENCNBA) and anthranilic acid-2-chloro-4-nitrobenzoic acid (AACNBA) using solid phase reactions. The phase diagram studies revealed that formation of the investigated compounds occurs in 1:1 molar ratio. The synthesized compounds were characterized using several spectral techniques such as FT-IR, 1H and 13C NMR, UV-Vis, powder X-ray diffraction (PXRD). Single crystal XRD (SCXRD) study showed that both BENCNBA and AACNBA compounds crystallize in triclinic crystal system with P-1 space group. Further, the presence of intermolecular hydrogen bonding between the constituent components was also supported by single crystal X-ray diffraction (SCXRD) method. Heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions have also been computed using the enthalpy of fusion values derived from differential scanning calorimeter (DSC) study. The inhibition effect of BENCNBA and AACNBA on the mild steel corrosion in hydrochloric acid solution was tested using electrochemical methods. Electrochemical impedance spectroscopy (EIS) study revealed that both BENCNBA and AACNBA behaved as interface corrosion inhibitors and showed maximum inhibition efficiencies of 95.71% and 96.42%, respectively at 400 ppm (1.23 × 10-3 M) concentration. Potentiodynamic polarization (PDP) measurements suggested that BENCNBA and AACNBA acted as mixed type corrosion inhibitors. EIS and PDP results showed that BENCNBA and AACNBA act as efficient corrosion inhibitors for mild steel and their inhibition efficiencies enhances on increasing their concentrations.

Effects of the pH and Concentration on the Stability of Standard Solutions of Proteinogenic Amino Acid Mixtures.

PubMed

Kato, Megumi; Yamazaki, Taichi; Kato, Hisashi; Yamanaka, Noriko; Takatsu, Akiko; Ihara, Toshihide

2017-01-01

To prepare metrologically traceable amino acid mixed standard solutions, it is necessary to determine the stability of each amino acid present in the mixed solutions. In the present study, we prepared amino acid mixed solutions using certified reference standards of 17 proteinogenic amino acids, and examined the stability of each of these amino acids in 0.1 N HCl. We found that the concentration of glutamic acid decreased significantly during storage. LC/MS analysis indicated that the instability of glutamic acid was due to the partial degradation of glutamic acid to pyroglutamic acid in 0.1 N HCl. Using accelerated degradation tests, we investigated several solvent compositions to improve the stability of glutamic acid in amino acid mixed solution, and determined that the change of the pH by diluting the mixed solution improved the stability of glutamic acid.

Computational model for simulation small testing launcher, technical solution

NASA Astrophysics Data System (ADS)

Chelaru, Teodor-Viorel; Cristian, Barbu; Chelaru, Adrian

2014-12-01

The purpose of this paper is to present some aspects regarding the computational model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The computational model consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, by recycling military rocket motors. From technical point of view, the paper is focused on national project "Suborbital Launcher for Testing" (SLT), which is based on hybrid propulsion and control systems, obtained through an original design. Therefore, while classical suborbital sounding rockets are unguided and they use as propulsion solid fuel motor having an uncontrolled ballistic flight, SLT project is introducing a different approach, by proposing the creation of a guided suborbital launcher, which is basically a satellite launcher at a smaller scale, containing its main subsystems. This is why the project itself can be considered an intermediary step in the development of a wider range of launching systems based on hybrid propulsion technology, which may have a major impact in the future European launchers programs. SLT project, as it is shown in the title, has two major objectives: first, a short term objective, which consists in obtaining a suborbital launching system which will be able to go into service in a predictable period of time, and a long term objective that consists in the development and testing of some unconventional sub-systems which will be integrated later in the satellite launcher as a part of the European space program. This is why the technical content of the project must be carried out beyond the range of the existing suborbital vehicle

Computational model for simulation small testing launcher, technical solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chelaru, Teodor-Viorel, E-mail: teodor.chelaru@upb.ro; Cristian, Barbu, E-mail: barbucr@mta.ro; Chelaru, Adrian, E-mail: achelaru@incas.ro

The purpose of this paper is to present some aspects regarding the computational model and technical solutions for multistage suborbital launcher for testing (SLT) used to test spatial equipment and scientific measurements. The computational model consists in numerical simulation of SLT evolution for different start conditions. The launcher model presented will be with six degrees of freedom (6DOF) and variable mass. The results analysed will be the flight parameters and ballistic performances. The discussions area will focus around the technical possibility to realize a small multi-stage launcher, by recycling military rocket motors. From technical point of view, the paper ismore » focused on national project 'Suborbital Launcher for Testing' (SLT), which is based on hybrid propulsion and control systems, obtained through an original design. Therefore, while classical suborbital sounding rockets are unguided and they use as propulsion solid fuel motor having an uncontrolled ballistic flight, SLT project is introducing a different approach, by proposing the creation of a guided suborbital launcher, which is basically a satellite launcher at a smaller scale, containing its main subsystems. This is why the project itself can be considered an intermediary step in the development of a wider range of launching systems based on hybrid propulsion technology, which may have a major impact in the future European launchers programs. SLT project, as it is shown in the title, has two major objectives: first, a short term objective, which consists in obtaining a suborbital launching system which will be able to go into service in a predictable period of time, and a long term objective that consists in the development and testing of some unconventional sub-systems which will be integrated later in the satellite launcher as a part of the European space program. This is why the technical content of the project must be carried out beyond the range of the existing suborbital

Effect of neodymium:yttrium-aluminum-garnet laser and fluoride on the acid demineralization of enamel.

PubMed

Braga, Sheila Regina Maia; de Oliveira, Elisabeth; Sobral, Maria Angela Pita

2017-02-01

The aim of the present study was to evaluate the protective effect of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser and acidic phosphate fluoride (APF) on enamel erosion caused by hydrochloric acid. Fifty human enamel specimens were distributed according to the following treatments (n = 10): untreated (control), APF (1.23%) 4 min, Nd:YAG laser (100 mJ, 1 W, 10 Hz, 141.5 J/cm 2 ), APF + Nd:YAG laser, and Nd:YAG laser + APF. For 14 days the specimens were submitted to erosive challenge: 5 min in 3 mL hydrochloric acid (0.01 M, pH 2.2), rinsed with distilled water, and stored in artificial saliva for 3 h. This cycle was repeated four times per day. The calcium (Ca) loss was determined in demineralizing solution by atomic emission spectroscopy, and superficial roughness (Ra) was measured before and after the erosive challenge. The mean Ca loss was (mg/L, ± standard deviation): control 12.74 ± 3.33, APF 1.71 ± 0.11, laser 1.64 ± 0.08, APF + laser 1.38 ± 0.08, and laser + APF 1.48 ± 0.07. Kruskal-Wallis test showed a significant difference between the control and other groups. APF + laser showed minor loss of Ca. After the erosive challenge, the APF + laser group showed Ra alteration. A significant reduction in tooth dissolution was observed after fluoride application combined with Nd:YAG irradiation. © 2015 Wiley Publishing Asia Pty Ltd.

INTERACTION OF AQUEOUS SOLUTIONS OF CHLORINE WITH MALIC ACID, TARTARIC ACID, AND VARIOUS FRUIT JUICES, A SOURCE OF MUTAGENS

EPA Science Inventory

The interactions of aqueous solutions of chlorine with some fruit acids (citric acid, DL-malic acid, and L-tartaric acid) at different pH values were studied. iethyl ether extraction followed by GC/MS analysis indicated that a number of mutagens (certain chlorinated propanones an...

Determination of carboxyl groups in wood fibers by headspace gas chromatography

Treesearch

X.-S. Chai; Q.X. Hou; J.Y. Zhu; S.-L. Chen; S.F. Wang; L. Lucia

2003-01-01

The phase reaction conversion (PRC) headspace gas chromatographic (HSGC) technique was employed to develop a method for the determination of the content of carboxyl groups in wood fibers. Acid treatment of the wood fibers using hydrochloric was applied to convert carboxyl groups to carboxyl acids. Bicarbonate solution is then used to react with carboxyl acids on the...

Biocompatibility of a bicarbonate-buffered amino-acid-based solution for peritoneal dialysis.

PubMed

Bender, Thorsten O; Witowski, Janusz; Aufricht, Christoph; Endemann, Michaela; Frei, Ulrich; Passlick-Deetjen, Jutta; Jörres, Achim

2008-09-01

Amino-acid-based peritoneal dialysis (PD) fluids have been developed to improve the nutritional status of PD patients. As they may potentially exacerbate acidosis, an amino-acid-containing solution buffered with bicarbonate (Aminobic) has been proposed to effectively maintain acid-base balance. The aim of this study was to evaluate the mesothelial biocompatibility profile of this solution in comparison with a conventional low-glucose-based fluid. Omentum-derived human peritoneal mesothelial cells (HPMC) were preexposed to test PD solutions for up to 120 min, then allowed to recover in control medium for 24 h, and assessed for heat-shock response, viability, and basal and stimulated cytokine [interleukin (IL)-6] and prostaglandin (PGE(2)) release. Acute exposure of HPMC to conventional low-glucose-based PD solution resulted in a time-dependent increase in heat-shock protein (HSP-72) expression, impaired viability, and reduced ability to release IL-6 in response to stimulation. In contrast, in cells treated with Aminobic, the expression of HSP-72 was significantly lower, and viability and cytokine-producing capacity were preserved and did not differ from those seen in control cells. In addition, exposure to Aminobic increased basal release of IL-6 and PGE(2). These data point to a favorable biocompatibility profile of the amino-acid-based bicarbonate-buffered PD solution toward HPMC.

Tested Demonstrations: Buffer Capacity of Various Acetic Acid-Sodium Acetate Systems: A Lecture Experiment.

ERIC Educational Resources Information Center

Donahue, Craig J.; Panek, Mary G.

1985-01-01

Background information and procedures are provided for a lecture experiment which uses indicators to illustrate the concept of differing buffer capacities by titrating acetic acid/sodium acetate buffers with 1.0 molar hydrochloric acid and 1.0 molar sodium hydroxide. A table with data used to plot the titration curve is included. (JN)

Convenient UV-spectrophotometric determination of citrates in aqueous solutions with applications in the pharmaceutical analysis of oral electrolyte formulations.

PubMed

Krukowski, Sylwester; Karasiewicz, Mateusz; Kolodziejski, Waclaw

2017-07-01

Herein, we present a convenient method for quantitative spectrophotometric determination of citrate ions in aqueous solutions in the middle-UV range. It involves measuring the absorbance of citric acid at 209 nm under suppressed dissociation at pH < 1.0 in the presence of hydrochloric acid. Validation of the method was performed according to the guidelines of the International Conference on Harmonization. A very good linear dependence of the absorbance on concentration (r 2  = 0.9999) was obtained in a citrate concentration range of 0.5-5.0 mmol/L. This method is characterized by excellent precision and accuracy; the coefficient of variation in each case is below the maximal permissible value (%RSD < 2). The proposed analytical procedure has been successfully applied to the determination of citrates in oral electrolyte formulations. Copyright © 2017. Published by Elsevier B.V.

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2013 CFR

2013-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50 mL of the hydroxylamine hydrochloride solution...

40 CFR Appendix B to Subpart Nnn... - Free Formaldehyde Analysis of Insulation Resins by Hydroxylamine Hydrochloride

Code of Federal Regulations, 2014 CFR

2014-07-01

... buffer. 3.350-mL burette for 1.0 N sodium hydroxide. 3.4Magnetic stirrer and stir bars. 3.5250-mL beaker... N sodium hydroxide solution. 4.2Hydroxylamine hydrochloride solution, 100 grams per liter, pH... hydrochloric acid, and 0.1 N sodium hydroxide. 5.5Add 50 mL of the hydroxylamine hydrochloride solution...

A new approach to study cadmium complexes with oxalic acid in soil solution.

PubMed

Dytrtová, Jana Jaklová; Jakl, Michal; Sestáková, Ivana; Zins, Emilie-Laure; Schröder, Detlef; Navrátil, Tomáš

2011-05-05

This study presents a new analytical approach for the determination of heavy metals complexed to low-molecular-weight-organic acids in soil solutions, which combines the sensitivity of differential pulse anodic stripping voltammetry (DPASV) with the molecular insight gained by electrospray ionization mass spectrometry (ESI-MS). The combination of these analytical methods allows the investigation of such complexes in complex matrixes. On the voltammograms of the soil solutions, in addition to the expected complexes of oxalic acid with cadmium and lead, respectively, also peaks belonging to mixed complexes of cadmium, lead, and oxalic acid (OAH(2)) were observed. In order to verify the possible formation of complexes with OAH(2), aqueous solutions of OAH(2) with traces of Cd(II) were investigated as model systems. Signals corresponding to several distinct molecular complexes between cadmium and oxalic acid were detected in the model solutions using negative-ion ESI-MS, which follow the general formula [Cd(n)(X,Y)((2n+1))](-), where n is the number of cadmium atoms, X=Cl(-), and Y=OAH(-). Some of these complexes were also identified in the ESI mass spectra taken from the soil solutions. Copyright © 2011 Elsevier B.V. All rights reserved.

Separation and preconcentration of the rare-earth elements and yttrium from geological materials by ion-exchange and sequential acid elution

USGS Publications Warehouse

Crock, J.G.; Lichte, F.E.; Riddle, G.O.; Beech, C.L.

1986-01-01

The abundance of rare-earth elements (REE) and yttrium in geological materials is generally low, and most samples contain elements that interfere in the determination of the REE and Y, so a separation and/or preconcentration step is often necessary. This is often achieved by ion-exchange chromatography with either nitric or hydrochloric acid. It is advantageous, however, to use both acids sequentially. The final solution thus obtained contains only the REE and Y, with minor amounts of Al, Ba, Ca, Sc, Sr and Ti. Elements that potentially interfere, such as Be, Co, Cr, Fe, Mn, Th, U, V and Zr, are virtually eliminated. Inductively-coupled argon plasma atomic-emission spectroscopy can then be used for a final precise and accurate measurement. The method can also be used with other instrumental methods of analysis. ?? 1986.

Dissolution of Simulated and Radioactive Savannah River Site High-Level Waste Sludges with Oxalic Acid & Citric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

STALLINGS, MARY

This report presents findings from tests investigating the dissolution of simulated and radioactive Savannah River Site sludges with 4 per cent oxalic acid and mixtures of oxalic and citric acid previously recommended by a Russian team from the Khlopin Radium Institute and the Mining and Chemical Combine (MCC). Testing also included characterization of the simulated and radioactive waste sludges. Testing results showed the following: Dissolution of simulated HM and PUREX sludges with oxalic and citric acid mixtures at SRTC confirmed general trends reported previously by Russian testing. Unlike the previous Russian testing six sequential contacts of a mixture of oxalicmore » acid citric acids at a 2:1 ratio (v/w) of acid to sludge did not produce complete dissolution of simulated HM and PUREX sludges. We observed that increased sludge dissolution occurred at a higher acid to sludge ratio, 50:1 (v/w), compared to the recommended ratio of 2:1 (v/w). We observed much lower dissolution of aluminum in a simulated HM sludge by sodium hydroxide leaching. We attribute the low aluminum dissolution in caustic to the high fraction of boehmite present in the simulated sludge. Dissolution of HLW sludges with 4 per cent oxalic acid and oxalic/citric acid followed general trends observed with simulated sludges. The limited testing suggests that a mixture of oxalic and citric acids is more efficient for dissolving HM and PUREX sludges and provides a more homogeneous dissolution of HM sludge than oxalic acid alone. Dissolution of HLW sludges in oxalic and oxalic/citric acid mixtures produced residual sludge solids that measured at higher neutron poison to equivalent 235U weight ratios than that in the untreated sludge solids. This finding suggests that residual solids do not present an increased nuclear criticality safety risk. Generally the neutron poison to equivalent 235U weight ratios of the acid solutions containing dissolved sludge components are lower than those in the

Investigation on solubility of hydroxy dibasic acids in alkanolamine solutions

NASA Astrophysics Data System (ADS)

Du, M.

2017-12-01

Solubilities of three hydroxy dibasic (adipic, suberic, and sebacic) acids in alkanolamine solutions were measured within the 30-90℃ temperature range. It is found that solubility of these acids sharply grows with temperature and concentration of alkanolamine solvent. In addition, the study substantiates the adjustment of pH to optimize the CO2 absorption and desorption processes. The precipitation of added acids from alkanolamine solvents by cooling is found to be quite problematic, which makes the recovery of residual acids from lean alkanolamine solvents non-feasible and requires the application of alternative methods.

Incorporation of stratospheric acids into water ice

NASA Technical Reports Server (NTRS)

Elliott, Scott; Turco, Richard P.; Toon, Owen B.; Hamill, Patrick

1990-01-01

Hydrochloric and hydrofluoric acids are absorbed within the water ice lattice at mole fractions maximizing below 0.00001 and 0.0001 in a variety of solid impurity studies. The absorption mechanism may be substitutional or interstitial, leading in either case to a weak permeation of stratospheric ices by the acids at equilibrium. Impurities could also inhabit grain boundaries, and the acid content of atmospheric ice crystals will then depend on details of their surface and internal microstructures. Limited evidence indicates similar properties for the absorption of HNO3. Water ice lattices saturated with acid cannot be a significant local reservoir for HCl in the polar stratosphere.

Improved method for extracting lanthanides and actinides from acid solutions

DOEpatents

Horwitz, E.P.; Kalina, D.G.; Kaplan, L.; Mason, G.W.

1983-07-26

A process for the recovery of actinide and lanthanide values from aqueous acidic solutions uses a new series of neutral bi-functional extractants, the alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxides. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high-level nuclear reprocessing waste solutions.

Speciation of platinum(IV) in nitric acid solutions.

PubMed

Vasilchenko, Danila; Tkachev, Sergey; Baidina, Iraida; Korenev, Sergey

2013-09-16

The speciation of platinum(IV) ions in nitric acid (6-15.8 M) solutions of H2[Pt(OH)6] has been studied by (195)Pt NMR and Raman spectroscopy. Series of aqua-hydroxo-nitrato complexes [Pt(L)(x)(NO3)(6-x)] (L = H2O or OH(-); x = 0, ..., 6) were found to exist in such solutions. The pair additivity model of chemical shifts and statistical theory were used to assign signals in NMR spectra to particular [Pt(L)(x)(NO3)(6-x)] species. Mononuclear hexanitratoplatinates(IV) have been isolated in solid state in substantial yield as pyridinium salt (PyH)2[Pt(NO3)6] and characterized by single-crystal X-ray diffraction. Aging of the platinum nitric acid solutions for more than 5-6 h results in oligomerization of [Pt(L)(x)(NO3)(6-x)] species and the formation of oligonuclear aqua-hydroxo-nitrato complexes with OH(-) and NO3(-) bridging ligands. Oligomeric platinum(IV) complexes with two and four nuclei were unambiguously detected by NMR on (195)Pt -enriched samples. Oligomers with even higher nuclearity were also detected. Dimeric anions [Pt2(μ-OH)2(NO3)8](2-) have been isolated as single crystals of tetramethylammonium salt and characterized by X-ray diffraction.

Ethanol and xylitol production by fermentation of acid hydrolysate from olive pruning with Candida tropicalis NBRC 0618.

PubMed

Mateo, Soledad; Puentes, Juan G; Moya, Alberto J; Sánchez, Sebastián

2015-08-01

Olive tree pruning biomass has been pretreated with pressurized steam, hydrolysed with hydrochloric acid, conditioned and afterwards fermented using the non-traditional yeast Candida tropicalis NBRC 0618. The main aim of this study was to analyse the influence of acid concentration on the hydrolysis process and its effect on the subsequent fermentation to produce ethanol and xylitol. From the results, it could be deduced that both total sugars and d-glucose recovery were enhanced by increasing the acid concentration tested; almost the whole hemicellulose fraction was hydrolysed when 3.77% was used. It has been observed a sequential production first of ethanol, from d-glucose, and then xylitol from d-xylose. The overall ethanol and xylitol yields ranged from 0.27 to 0.38kgkg(-1), and 0.12 to 0.23kgkg(-1) respectively, reaching the highest values in the fermentation of the hydrolysates obtained with hydrochloric acid 2.61% and 1.11%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

The dissolution of quartz in dilute aqueous solutions of organic acids at 25°C

USGS Publications Warehouse

Bennett, P.C.; Melcer, M.E.; Siegel, D.I.; Hassett, J.P.

1988-01-01

The dissolution of quartz in dilute aqueous solutions of organic acids at 25° and standard pressure was investigated by the batch dissolution method. The bulk dissolution rate of quartz in 20 mmole/Kg citrate solutions at pH 7 was 8 to 10 times faster than that in pure water. After 1750 hours the concentration of dissolved silica in the citrate solution was 167 μmole/Kg compared to 50 μmole/Kg in water and a 20 mmole/Kg solution of acetate at pH 7. Solutions of salicylic, oxalic, and humic acids also accelerated the dissolution of quartz in aqueous solution at pH 7. The rate of dissolution in organic acids decreased sharply with decreasing pH.The possibility of a silica-organic acid complex was investigated using UV-difference spectroscopy. Results suggest that dissolved silica is complexed by citrate, oxalate and pyruvate at pH 7 by an electron-donor acceptor complex, whereas no complexation occurs between silica and acetate, lactate, malonate, or succinate. Three models are proposed for the solution and surface complexation of silica by organic acid anions which result in the accelerated dissolution and increased solubility of quartz in organic rich water.

SEPARATION OF THORIUM FROM URANIUM

DOEpatents

Bane, R.W.

1959-09-01

A description is given for the separation of thorium from uranium by forming an aqueous acidic solution containing ionic species of thorium, uranyl uranium, and hydroxylamine, flowing the solution through a column containing the phenol-formaldehyde type cation exchange resin to selectively adsorb substantially all the thorium values and a portion of the uranium values, flowing a dilute solution of hydrochloric acid through the column to desorb the uranium values, and then flowing a dilute aqueous acidic solution containing an ion, such as bisulfate, which has a complexing effect upon thortum through the column to desorb substantially all of the thorium.

Crude oil polycyclic aromatic hydrocarbons removal via clay-microbe-oil interactions: Effect of acid activated clay minerals.

PubMed

Ugochukwu, Uzochukwu C; Fialips, Claire I

2017-07-01

Acid treatment of clay minerals is known to modify their properties such as increase their surface area and surface acidity, making them suitable as catalysts in many chemical processes. However, the role of these surface properties during biodegradation processes of polycyclic aromatic hydrocarbons (PAHs) is only known for mild acid (0.5 M Hydrochloric acid) treated clays. Four different clay minerals were used for this study: a montmorillonite, a saponite, a palygorskite and a kaolinite. They were treated with 3 M hydrochloric acid to produce acid activated clay minerals. The role of the acid activated montmorillonite, saponite, palygorskite and kaolinite in comparison with the unmodified clay minerals in the removal of PAHs during biodegradation was investigated in microcosm experiments. The microcosm experiments contained micro-organisms, oil, and clays in aqueous medium with a hydrocarbon degrading microorganism community predominantly composed of Alcanivorax spp. Obtained results indicated that acid activated clays and unmodified kaolinite did not enhance the biodegradation of the PAHs whereas unmodified montmorillonite, palygorskite and saponite enhanced their biodegradation. In addition, unmodified palygorskite adsorbed the PAHs significantly due to its unique channel structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extraction of steroidal glucosiduronic acids from aqueous solutions by anionic liquid ion-exchangers

PubMed Central

Mattox, Vernon R.; Litwiller, Robert D.; Goodrich, June E.

1972-01-01

A pilot study on the extraction of three steroidal glucosiduronic acids from water into organic solutions of liquid ion-exchangers is reported. A single extraction of a 0.5mm aqueous solution of either 11-deoxycorticosterone 21-glucosiduronic acid or cortisone 21-glucosiduronic acid with 0.1m-tetraheptylammonium chloride in chloroform took more than 99% of the conjugate into the organic phase; under the same conditions, the very polar conjugate, β-cortol 3-glucosiduronic acid, was extracted to the extent of 43%. The presence of a small amount of chloride, acetate, or sulphate ion in the aqueous phase inhibited extraction, but making the aqueous phase 4.0m with ammonium sulphate promoted extraction strongly. An increase in the concentration of ion-exchanger in the organic phase also promoted extraction. The amount of cortisone 21-glucosiduronic acid extracted by tetraheptylammonium chloride over the pH range of 3.9 to 10.7 was essentially constant. Chloroform solutions of a tertiary, a secondary, or a primary amine hydrochloride also will extract cortisone 21-glucosiduronic acid from water. The various liquid ion exchangers will extract steroidal glucosiduronic acid methyl esters from water into chloroform, although less completely than the corresponding free acids. The extraction of the glucosiduronic acids from water by tetraheptylammonium chloride occurs by an ion-exchange process; extraction of the esters does not involve ion exchange. PMID:5075264

DYNAMIC CONDUCTIVITY MEASUREMENTS IN HUMIC AND FULVIC ACID SOLUTIONS. (R828158)

EPA Science Inventory

Conductivity changes of dilute aqueous humic and fulvic acids solutions were monitored after the addition of small quantities of Cu, Cd, Pb, and Zn. The solutions were stirred at a constant and reproducible rate, and measurements proceeded until stable conductivities were atta...

Alkaline earth cation extraction from acid solution

DOEpatents

Dietz, Mark; Horwitz, E. Philip

2003-01-01

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

[Effects of choledochal perfusion with biliary acid solutions on activity of the sphincter of Oddi (author's transl)].

PubMed

Bevilacqua, R G; Margarido, N F; Soares, L A; Mansur, R; Koch, V; Gonçalves, E L

1979-06-01

The changes of sphincter of Oddi's resistance, induced by choledochal perfusion of conjugated (taurocolic) and non-conjugated (colic) biliary acid solutions, in anesthetized dogs, were studied. The perfusions were made at a constant flow and intracholedochal pressures were registered. The mean number of contractions per minute, the mean maximal pressures and the mean minimal pressures in each study periods were analysed. The choledochal perfusion with the biliary acids solutions induced a slight but significative increase in sphincteric resistance. After 15 minutes, the perfusion with colic acid solution induced maximal pressures significantly more elevated than the ones observed with taurocolic acid solution. The non-conjugated solution induced a pressure tracing significantly distinct from the tracing observed with the conjugated acid solution. No changes in resistance were observed with a 2% NaCl solution. This implies that the observed changes in resistance were not related to osmotic stimulation of the sphincter of Oddi.

Extraction of pectin from passion fruit rind (Passiflora edulis var. flavicarpa Degener) for edible coating

NASA Astrophysics Data System (ADS)

Inayati, Puspita, Rifka Intan; Fajrin, Vika Latifiana

2018-02-01

One of fruit preservation method is by applying the edible coating. Rind of passion fruit (Passiflora edulis var. flavicarpa Degener), which is kind of waste, can be utilized as edible coating through pectin extraction process. The purposes of this work were to determine the suitable solvent for the pectin extraction and techniques for applying the produced edible coating on strawberry, to produce edible coating from the pectin, and the test the performance of the edible coating which was applied to strawberries. Pectin from passion fruit rind was collected through conventional extraction method using two types of solvent, i.e. acetic acid solution and hydrochloric acid solution with concentration of 0.01 N, 0.015 N, 0.02 N, 0.025 N, and 0.03 N. The results showed that chloric acid solution was more suitable for the pectin extraction from passion fruit. Maximum yield of 30.78% was obtained at hydrochloric acid concentration of 0.02 N. Obtained pectin from the extraction was then processed into the edible coating by adding plasticizers and calcium chloride dihydrate. Storability of the coated strawberry was observed to measure the performance of the edible coating

Rapid spot tests for detecting the presence of adulterants in urine specimens submitted for drug testing.

PubMed

Dasgupta, Amitava; Wahed, Amer; Wells, Alice

2002-02-01

Several adulterants are used to mask tests for abused drugs in urine. Adulterants such as "Klear" and "Whizzies" contain potassium nitrite, and "Urine Luck" contains pyridinium chlorochromate (PCC). The presence of these adulterants cannot be detected by routine specimen integrity checks (pH, specific gravity, and temperature). We developed rapid spot tests for detecting these adulterants in urine. Addition of 3% hydrogen peroxide in urine adulterated with PCC caused rapid formation of a dark brown color. In contrast, unadulterated urine turned colorless when hydrogen peroxide was added. When urine contaminated with nitrite and 2 to 3 drops of 2N hydrochloric acid were added to 2% aqueous potassium permanganate solution, the dark pink permanganate solution turned colorless immediately with effervescence. Urine contaminated with nitrite liberated iodine from potassium iodide solution in the presence of 2N hydrochloric acid. Urine adulterated with PCC also liberated iodine from potassium iodide in acid medium but did not turn potassium permanganate solution colorless. Urine specimens from volunteers and random urine samples that tested negative for drugs did not cause false-positive results. These rapid spot tests are useful for detecting adulterated urine to avoid false-negative drug tests.

Research for amino acids in lunar samples.

NASA Technical Reports Server (NTRS)

Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Rash, J. J.; Aue , W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

1972-01-01

The study was primarily directed toward the examination of Apollo 14 lunar fines for indigenous amino acids or materials which could be converted to amino acids on hydrolysis with 6 N hydrochloric acid. Initial experiments were conducted to confirm the integrity of the derivatization reactions and reagents, and to optimize the gas-liquid chromatographic (GLC) instrumental and chromatographic system for the separation and flame ionization detection of the amino acid derivatives. In studies on the recovery of amino acids added to lunar fines, low recoveries were obtained when 10 ng of each amino acid were added to 50 mg of virgin fines, but the subsequent addition of 50 ng of each to the previously extracted sample resulted in much higher recoveries.

Comparative study of buffered 50% glycolic acid (pH 3.0) + 0.5% salicylic acid solution vs Jessner's solution in patients with acne vulgaris.

PubMed

In Jae, Jeong; Dong Ju, Hyun; Dong Hyun, Kim; Yoon, Moon Soo; Lee, Hee Jung

2017-11-21

Superficial chemical peels are frequently used in acne vulgaris treatment. Although glycolic acid (GA) has been widely used in clinical practice, its pH ranges from 0.08-2.75 and thus should be neutralized after application to avoid burns. To evaluate treatment efficacy and safety of chemical peeling using buffered 50% GA (pH 3.0) + 0.5% salicylic acid (SA) solution that does not need to be neutralized in the treatment of acne vulgaris compared to the conventional peeling using Jessner's solution. We performed a prospective, randomized, evaluator-blind, split-face clinical trial. Twenty patients were randomized by assigning one side of each patient's face to receive a 50% GA (pH 3.0) + 0.5% SA peel (GA side) and the other side to receive the Jessner's solution (Jessner's solution side). All patients underwent 2 sessions of treatment spaced 2 weeks apart. Lesion count, acne severity, subjective efficacy assessment, and side effects were evaluated. The total lesion count was significantly reduced for the GA and Jessner's solution sides (P < .001). However, there was no significant difference in the total lesion count, acne severity, or subjective efficacy assessment between the 2 sides (P > .05). The GA side had fewer side effects than the Jessner's solution side. The results of this study suggest that chemical peeling using the 50% GA (pH 3.0) + 0.5% SA solution can be as effective and convenient as the conventional peeling using Jessner's solution in the treatment of acne vulgaris and may show fewer adverse events than the conventional peeling. © 2017 Wiley Periodicals, Inc.

Compositional data for Bengal delta sediment collected from boreholes at Srirampur, Kachua, Bangladesh

USGS Publications Warehouse

Breit, George N.; Yount, James C.; Uddin, Md. Nehal; Muneem, Ad. Atual; Lowers, Heather; Driscoll, Rhonda L.; Whitney, John W.

2006-01-01

Processes active within sediment of the Bengal delta have attracted world concern because of the locally high content of arsenic dissolved in ground water drawn from that sediment. Sediment samples were collected from two boreholes in Srirampur village, Kachua upazila, Chandphur district, Bangladesh, to investigate the processes contributing to arsenic contamination. The samples were mineralogically and chemically analyzed to determine compositional variations related to the arsenic content of the sediment. Mineralogy of the sediments was determined using powder X-ray diffraction. Bulk chemical composition was measured by Combustion, Inductively Coupled Plasma Atomic Emission Spectroscopy, Energy Dispersive X-ray Fluorescence, and Hydride Generation Atomic Absorption Spectrophotometry. Solutions produced by four chemical extractions-0.1 molar strontium chloride, 0.5 normal hydrochloric acid, titanium(III)-EDTA, and a solution of hydrogen peroxide and hydrochloric acid-were analyzed to evaluate the chemical reactivity of the sediment with an emphasis on arsenic residence. Acid-volatile sulfide, acid-soluble sulfate, and reducible sulfide were also measured. Sediment sampled at Srirampur is typically unlithified, gray, micaceous, feldspathic, arenaceous silt and sand. Arsenic content of the sediment ranges from <1 to 210 ppm, with the highest contents measured in sediment collected at a depth of 320 meters. Samples with high arsenic contents typically contain high concentrations of sulfur. The greatest amount of arsenic was extracted using the oxidative hydrogen peroxide and hydrochloric acid extraction solution. The extraction results are consistent with the apparent association of arsenic in sulfur in the bulk chemical analyses. Pyrite is typically the most abundant form of sulfur in the sediment and is dissolved by the oxidative extraction.

An improved method for the determination of trace levels of arsenic and antimony in geological materials by automated hydride generation-atomic absorption spectroscopy

USGS Publications Warehouse

Crock, J.G.; Lichte, F.E.

1982-01-01

An improved, automated method for the determination of arsenic and antimony in geological materials is described. After digestion of the material in sulfuric, nitric, hydrofluoric and perchloric acids, a hydrochloric acid solution of the sample is automatically mixed with reducing agents, acidified with additional hydrochloric acid, and treated with a sodium tetrahydroborate solution to form arsine and stibine. The hydrides are decomposed in a heated quartz tube in the optical path of an atomic absorption spectrometer. The absorbance peak height for arsenic or antimony is measured. Interferences that exist are minimized to the point where most geological materials including coals, soils, coal ashes, rocks and sediments can be analyzed directly without use of standard additions. The relative standard deviation of the digestion and the instrumental procedure is less than 2% at the 50 ??g l-1 As or Sb level. The reagent-blank detection limit is 0.2 ??g l-1 As or Sb. ?? 1982.

A Full Automatic Device for Sampling Small Solution Volumes in Photometric Titration Procedure Based on Multicommuted Flow System

PubMed Central

Borges, Sivanildo S.; Vieira, Gláucia P.; Reis, Boaventura F.

2007-01-01

In this work, an automatic device to deliver titrant solution into a titration chamber with the ability to determine the dispensed volume of solution, with good precision independent of both elapsed time and flow rate, is proposed. A glass tube maintained at the vertical position was employed as a container for the titrant solution. Electronic devices were coupled to the glass tube in order to control its filling with titrant solution, as well as the stepwise solution delivering into the titration chamber. The detection of the titration end point was performed employing a photometer designed using a green LED (λ=545 nm) and a phototransistor. The titration flow system comprised three-way solenoid valves, which were assembled to allow that the steps comprising the solution container loading and the titration run were carried out automatically. The device for the solution volume determination was designed employing an infrared LED (λ=930 nm) and a photodiode. When solution volume delivered from proposed device was within the range of 5 to 105 μl, a linear relationship (R = 0.999) between the delivered volumes and the generated potential difference was achieved. The usefulness of the proposed device was proved performing photometric titration of hydrochloric acid solution with a standardized sodium hydroxide solution and using phenolphthalein as an external indicator. The achieved results presented relative standard deviation of 1.5%. PMID:18317510

Reactive solute transport in acidic streams

USGS Publications Warehouse

Broshears, R.E.

1996-01-01

Spatial and temporal profiles of Ph and concentrations of toxic metals in streams affected by acid mine drainage are the result of the interplay of physical and biogeochemical processes. This paper describes a reactive solute transport model that provides a physically and thermodynamically quantitative interpretation of these profiles. The model combines a transport module that includes advection-dispersion and transient storage with a geochemical speciation module based on MINTEQA2. Input to the model includes stream hydrologic properties derived from tracer-dilution experiments, headwater and lateral inflow concentrations analyzed in field samples, and a thermodynamic database. Simulations reproduced the general features of steady-state patterns of observed pH and concentrations of aluminum and sulfate in St. Kevin Gulch, an acid mine drainage stream near Leadville, Colorado. These patterns were altered temporarily by injection of sodium carbonate into the stream. A transient simulation reproduced the observed effects of the base injection.

Nonclinical safety evaluation of boric acid and a novel borate-buffered contact lens multi-purpose solution, Biotrue™ multi-purpose solution.

PubMed

Lehmann, David M; Cavet, Megan E; Richardson, Mary E

2010-12-01

Multipurpose solutions (MPS) often contain low concentrations of boric acid as a buffering agent. Limited published literature has suggested that boric acid and borate-buffered MPS may alter the corneal epithelium; an effect attributed to cytotoxicity induced by boric acid. However, this claim has not been substantiated. We investigated the effect of treating cells with relevant concentrations of boric acid using two cytotoxicity assays, and also assessed the impact of boric acid on corneal epithelial barrier function by measuring TEER and immunostaining for tight junction protein ZO-1 in human corneal epithelial cells. Boric acid was also assessed in an in vivo ocular model when administered for 28 days. Additionally, we evaluated Biotrue multi-purpose solution, a novel borate-buffered MPS, alone and with contact lenses for ocular compatibility in vitro and in vivo. Boric acid passed both cytotoxicity assays and did not alter ZO-1 distribution or corneal TEER. Furthermore, boric acid was well-tolerated on-eye following repeated administration in a rabbit model. Finally, Biotrue multi-purpose solution demonstrated good ocular biocompatibility both in vitro and in vivo. This MPS was not cytotoxic and was compatible with the eye when administered alone and when evaluated with contact lenses. We demonstrate that boric acid and a borate-buffered MPS is compatible with the ocular environment. Our findings provide evidence that ocular effects reported for some borate-buffered MPS may be incorrectly attributed to boric acid and are more likely a function of the unique combination of ingredients in the MPS formulation tested. Copyright © 2010 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

Solution properties and taste behavior of lactose monohydrate in aqueous ascorbic acid solutions at different temperatures: Volumetric and rheological approach.

PubMed

Sarkar, Abhijit; Sinha, Biswajit

2016-11-15

The densities and viscosities of lactose monohydrate in aqueous ascorbic acid solutions with several molal concentrations m=(0.00-0.08)molkg(-1) of ascorbic acid were determined at T=(298.15-318.15)K and pressure p=101kPa. Using experimental data apparent molar volume (ϕV), standard partial molar volume (ϕV(0)), the slope (SV(∗)), apparent specific volumes (ϕVsp), standard isobaric partial molar expansibility (ϕE(0)) and its temperature dependence [Formula: see text] the viscosity B-coefficient and solvation number (Sn) were determined. Viscosity B-coefficients were further employed to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ1(0≠)) and of the solute (Δμ2(0≠)). Effects of molality, solute structure and temperature and taste behavior were analyzed in terms of solute-solute and solute-solvent interactions; results revealed that the solutions are characterized predominantly by solute-solvent interactions and lactose monohydrate behaves as a long-range structure maker. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydroxamic acids as weak base indicators: protonation in strong acid media.

PubMed

García, B; Ibeas, S; Hoyuelos, F J; Leal, J M; Secco, F; Venturini, M

2001-11-30

The protonation equilibria of N-phenylbenzohydroxamic, benzohydroxamic, salicylhydroxamic, and N-p-tolylcinnamohydroxamic acids have been studied at 25 degrees C in concentrated sulfuric, hydrochloric, and perchloric acid media; the UV-vis spectral measurements were analyzed using the Hammett equation and the Bunnett-Olsen and excess acidity methods. The medium effects observed in the UV spectral curves were corrected with the Cox-Yates and vector analysis methods. The H(A) acidity function based on benzamides provided the best results. The range of variation of the solvation coefficient m is similar to that of amides, this indicating similar solvation requirements for amides and hydroxamic acids. For the same substrate, the observed variations of pK(BH)(+) with the mineral acid used was justified by formation of solvent-separated ion pairs; for the same mineral acid, the observed changes in pK(BH)(+) can be explained by the solvation of BH(+). The change of the pK(BH)(+) values was in reasonably good agreement with the sequence of the catalytic efficiency of the mineral acids used, HCl > H(2)SO(4) > HClO(4).

Interaction of Ethyl Alcohol Vapor with Sulfuric Acid Solutions

NASA Technical Reports Server (NTRS)

Leu, Ming-Taun

2006-01-01

We investigated the uptake of ethyl alcohol (ethanol) vapor by sulfuric acid solutions over the range approx.40 to approx.80 wt % H2SO4 and temperatures of 193-273 K. Laboratory studies used a fast flow-tube reactor coupled to an electron-impact ionization mass spectrometer for detection of ethanol and reaction products. The uptake coefficients ((gamma)) were measured and found to vary from 0.019 to 0.072, depending upon the acid composition and temperature. At concentrations greater than approx.70 wt % and in dilute solutions colder than 220 K, the values approached approx.0.07. We also determined the effective solubility constant of ethanol in approx.40 wt % H2SO4 in the temperature range 203-223 K. The potential implications to the budget of ethanol in the global troposphere are briefly discussed.

Comparison of Four Strong Acids on the Precipitation Potential of Gypsum in Brines During Distillation of Pretreated, Augmented Urine

NASA Technical Reports Server (NTRS)

Muirhead, Dean; Carrier, Christopher

2012-01-01

In this study, three different mineral acids were substituted for sulfuric acid (H2SO4) in the urine stabilizer solution to eliminate the excess of sulfate ions in pretreated urine and assess the impact on maximum water recovery to avoid precipitation of minerals during distillation. The study evaluated replacing 98% sulfuric acid with 85% phosphoric acid (H3PO4), 37% hydrochloric acid (HCl), or 70% nitric acid (HNO3). The effect of lowering the oxidizer concentration in the pretreatment formulation also was studied. This paper summarizes the test results, defines candidate formulations for further study, and specifies the injection masses required to stabilize urine and minimize the risk of mineral precipitation during distillation. In the first test with a brine ersatz acidified with different acids, the solubility of calcium in gypsum saturated solutions was measured. The solubility of gypsum was doubled in the brines acidified with the alternative acids compared to sulfuric acid. In a second series of tests, the alternative acid pretreatment concentrations were effective at preventing precipitation of gypsum and other minerals up to 85% water recovery from 95th-percentile pretreated, augmented urine. Based on test results, phosphoric acid is recommended as the safest alternative to sulfuric acid. It also is recommended that the injected mass concentration of chromium trioxide solution be reduced by 75% to minimize liquid resupply mass by about 50%, reduce toxicity of brines, and reduce the concentration of organic acids in distillate. The new stabilizer solution formulations and required doses to stabilize urine and prevent precipitation of minerals up to 85% water recovery are given. The formulations in this study were tested on a limited number of artificially augmented urine batches collected from employees at the Johnson Space Center (JSC). This study successfully demonstrated that the desired physical and chemical stability of pretreated urine and brines

Trapping proton transfer intermediates in the disordered hydrogen-bonded network of cryogenic hydrofluoric acid solutions.

PubMed

Ayotte, Patrick; Plessis, Sylvain; Marchand, Patrick

2008-08-28

A molecular-level description of the structural and dynamical aspects that are responsible for the weak acid behaviour of dilute hydrofluoric acid solutions and their unusual increased acidity at near equimolar concentrations continues to elude us. We address this problem by reporting reflection-absorption infrared spectra (RAIRS) of cryogenic HF-H(2)O binary mixtures at various compositions prepared as nanoscopic films using molecular beam techniques. Optical constants for these cryogenic solutions [n(omega) and k(omega)] are obtained by iteratively solving Fresnel equations for stratified media. Modeling of the experimental RAIRS spectra allow for a quantitative interpretation of the complex interplay between multiple reflections, optical interference and absorption effects. The evolution of the strong absorption features in the intermediate 1000-3000 cm(-1) range with increasing HF concentration reveals the presence of various ionic dissociation intermediates that are trapped in the disordered H-bonded network of cryogenic hydrofluoric acid solutions. Our findings are discussed in light of the conventional interpretation of why hydrofluoric acid is a weak acid revealing molecular-level details of the mechanism for HF ionization that may be relevant to analogous elementary processes involved in the ionization of weak acids in aqueous solutions.

Influence of D-Penicillamine on the Viscosity of Hyaluronic Acid Solutions

NASA Astrophysics Data System (ADS)

Liang, Jing; Krause, Wendy E.; Colby, Ralph H.

2006-03-01

Polyelectrolyte hyaluronic acid (HA, hyaluronan) is an important component in synovial fluid. Its presence results in highly viscoelastic solutions with excellent lubricating and shock-absorbing properties. In comparison to healthy synovial fluid, diseased fluid has a reduced viscosity. In osteoarthritis this reduction in viscosity results from a decline in both the molecular weight and concentration of hyaluronic acid HA. Initial results indicate that D-penicillamine affects the rheology of bovine synovial fluid, a model synovial fluid solution, and its components, including HA. In order to understand how D-penicillamine modifies the viscosity of these solutions, the rheological properties of sodium hyaluronate (NaHA) in phosphate-buffered saline (PBS) with D-penicillamine were studied as function of time, D-penicillamine concentration (0 -- 0.01 M), and storage conditions. Penicillamine has a complex, time dependent effect on the viscosity of NaHA solutions---reducing the zero shear rate viscosity of a 3 mg/mL NaHA in PBS by ca. 40% after 44 days.

Isotherm-Based Thermodynamic Models for Solute Activities of Organic Acids with Consideration of Partial Dissociation.

PubMed

Nandy, Lucy; Ohm, Peter B; Dutcher, Cari S

2016-06-23

Organic acids make up a significant fraction of the organic mass in atmospheric aerosol particles. The calculation of gas-liquid-solid equilibrium partitioning of the organic acid is therefore critical for accurate determination of atmospheric aerosol physicochemical properties and processes such as new particle formation and activation to cloud condensation nuclei. Previously, an adsorption isotherm-based statistical thermodynamic model was developed for capturing solute concentration-activity relationships for multicomponent aqueous solutions over the entire concentration range (Dutcher et al. J. Phys. Chem. C/A 2011, 2012, 2013), with model parameters for energies of adsorption successfully related to dipole-dipole electrostatic forces in solute-solvent and solvent-solvent interactions for both electrolytes and organics (Ohm et al. J. Phys. Chem. A 2015). However, careful attention is needed for weakly dissociating semivolatile organic acids. Dicarboxylic acids, such as malonic acid and glutaric acid are treated here as a mixture of nondissociated organic solute (HA) and dissociated solute (H(+) + A(-)). It was found that the apparent dissociation was greater than that predicted by known dissociation constants alone, emphasizing the effect of dissociation on osmotic and activity coefficient predictions. To avoid additional parametrization from the mixture approach, an expression was used to relate the Debye-Hückel hard-core collision diameter to the adjustable solute-solvent intermolecular distance. An improved reference state treatment for electrolyte-organic aqueous mixtures, such as that observed here with partial dissociation, has also been proposed. This work results in predictive correlations for estimation of organic acid and water activities for which there is little or no activity data.

77 FR 24700 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-25

... Process Facilities and Hydrochloric Acid Regeneration Plants (Renewal) AGENCY: Environmental Protection...: NESHAP for Steel Pickling, HCl Process Facilities and Hydrochloric Acid Regeneration Plants (Renewal...: Steel pickling, HCl process facilities and hydrochloric acid regeneration plants. Estimated Number of...

Effect of sodium metabisulfite on hydrogen peroxide production in light-exposed pediatric parenteral amino acid solutions.

PubMed

Brawley, V; Bhatia, J; Karp, W B

1998-06-15

The effect of sodium metabisulfite (MBS) on hydrogen peroxide (HP) production in model and commercial amino acid solutions exposed to phototherapy light was studied. Model and commercial pediatric amino acid solutions were prepared such that the amino acid concentration was 1%. MBS concentration, riboflavin concentration, and duration of exposure to phototherapy light were varied to determine the effect on HP production. Control solutions were kept in the dark. HP production was assayed in the model amino acid solutions by using potassium iodide in the presence of ammonium molybdate. In all experiments, HP production was measured at 360 nm in the presence and absence of catalase. In light-exposed solutions, HP production increased linearly for several hours and reached a plateau by eight hours. A mean maximum of 940 microM was produced (data pooled for all solutions). No detectable HP was generated in the solutions kept in the dark. After two hours of light exposure, it was necessary to add at least 10 times more MBS than is typically found in commercial total parenteral nutrient solutions to scavenge all the HP produced. An average of up to 940 microM of HP was produced in model and commercial pediatric parenteral 1% amino acid solutions in the presence of phototherapy light and clinically relevant concentrations of riboflavin and MBS. Light exposure decreased the antioxidant effect of MBS.

Production of high specific activity silicon-32

DOEpatents

Phillips, Dennis R.; Brzezinski, Mark A.

1994-01-01

A process for preparation of silicon-32 is provide and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidization state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

High specific activity silicon-32

DOEpatents

Phillips, Dennis R.; Brzezinski, Mark A.

1996-01-01

A process for preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution to from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidization state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

High specific activity silicon-32

DOEpatents

Phillips, D.R.; Brzezinski, M.A.

1996-06-11

A process for preparation of silicon-32 is provided and includes contacting an irradiated potassium chloride target, including spallation products from a prior irradiation, with sufficient water, hydrochloric acid or potassium hydroxide to form a solution, filtering the solution, adjusting pH of the solution from about 5.5 to about 7.5, admixing sufficient molybdate-reagent to the solution to adjust the pH of the solution to about 1.5 and to form a silicon-molybdate complex, contacting the solution including the silicon-molybdate complex with a dextran-based material, washing the dextran-based material to remove residual contaminants such as sodium-22, separating the silicon-molybdate complex from the dextran-based material as another solution, adding sufficient hydrochloric acid and hydrogen peroxide to the solution to prevent reformation of the silicon-molybdate complex and to yield an oxidation state of the molybdate adapted for subsequent separation by an anion exchange material, contacting the solution with an anion exchange material whereby the molybdate is retained by the anion exchange material and the silicon remains in solution, and optionally adding sufficient alkali metal hydroxide to adjust the pH of the solution to about 12 to 13. Additionally, a high specific activity silicon-32 product having a high purity is provided.

Ultrasound assisted cocrystallization from solution (USSC) containing a non-congruently soluble cocrystal component pair: Caffeine/maleic acid.

PubMed

Aher, Suyog; Dhumal, Ravindra; Mahadik, Kakasaheb; Paradkar, Anant; York, Peter

2010-12-23

Ultrasound assisted solution cocrystallization (USSC) has been studied using a non-congruently soluble pair of caffeine and maleic acid in methanol. USSC was compared with solvent cooling and slurry sonication using different molar ratios of caffeine:maleic acid (1:0.5, 1:1, 1:2, 1:3 and 1:3.5) in solution/slurry. Products were characterized by PXRD and Raman spectroscopy techniques. In USSC trials, the content of cocrystal in the product was observed to increase with increase in amount of maleic acid in solution. Only USSC offered pure caffeine/maleic acid 2:1 cocrystal product when caffeine:maleic acid; 1:3.5 molar ratio was taken in solution. Caffeine/maleic acid 1:1 cocrystal and maleic acid were not obtained in neither of the techniques. Products of solvent cooling and slurry sonication experiments were mixtures of caffeine and caffeine/maleic acid 2:1 cocrystal in varying amounts. In USSC, ultrasound application must have attained simultaneous supersaturation of cocrystal components in solution due to altered supersaturation conditions resulting in cocrystal formation. For this simultaneous attainment of supersaturation, molar ratio of cocrystal components in solution was identified as an important parameter while designing experiments for a non-congruently soluble pair having large solubility difference. Copyright © 2010 Elsevier B.V. All rights reserved.

An extraction process to recover vanadium from low-grade vanadium-bearing titanomagnetite.

PubMed

Chen, Desheng; Zhao, Hongxin; Hu, Guoping; Qi, Tao; Yu, Hongdong; Zhang, Guozhi; Wang, Lina; Wang, Weijing

2015-08-30

An extraction process to recover vanadium from low-grade vanadium-bearing titanomagnetite was developed. In this study, a mixed solvent system of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) diluted with kerosene was used for the selective extraction of vanadium from a hydrochloric acid leaching solution that contained low vanadium concentration with high concentrations of iron and impurities of Ca, Mg, and Al. In the extraction process, the initial solution pH and the phase ratio had considerable functions in the extraction of vanadium from the hydrochloric acid leaching solution. Under optimal extraction conditions (i.e., 30-40°C for 10min, 1:3 phase ratio (O/A), 20% D2EHPA concentration (v/v), and 0-0.8 initial solution pH), 99.4% vanadium and only 4.2% iron were extracted by the three-stage counter-current extraction process. In the stripping process with H2SO4 as the stripping agent and under optimal stripping conditions (i.e., 20% H2SO4 concentration, 5:1 phase ratio (O/A), 20min stripping time, and 40°C stripping temperature), 99.6% vanadium and only 5.4% iron were stripped by the three-stage counter-current stripping process. The stripping solution contained 40.16g/LV2O5,0.691g/L Fe, 0.007g/L TiO2, 0.006g/L SiO2 and 0.247g/L CaO. A V2O5 product with a purity of 99.12% V2O5 and only 0.026% Fe was obtained after the oxidation, precipitation, and calcination processes. The total vanadium recovered from the hydrochloric acid leaching solution was 85.5%. Copyright © 2015 Elsevier B.V. All rights reserved.

Glycolic acid physical properties and impurities assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambert, D. P.; Pickenheim, B. R.; Bibler, N. E.

This document has been revised due to recent information that the glycolic acid used in Savannah River National Laboratory (SRNL) experiments contains both formaldehyde and methoxyacetic acid. These impurities were in the glycolic acid used in the testing included in this report and in subsequent testing using DuPont (now called Chemours) supplied Technical Grade 70 wt% glycolic acid. However, these impurities were not reported in earlier revisions. Additional data concerning the properties of glycolic acid have also been added to this report. The Defense Waste Processing Facility (DWPF) is planning to implement a nitric-glycolic acid flowsheets to increase attainment tomore » meet closure commitment dates during Sludge Batch 9. In fiscal year 2009, SRNL was requested to determine the physical properties of formic and glycolic acid blends. Blends of formic acid in glycolic acid were prepared and their physical properties tested. Increasing amounts of glycolic acid led to increases in blend density, viscosity and surface tension as compared to the 90 wt% formic acid that is currently used at DWPF. These increases are small, however, and are not expected to present any difficulties in terms of processing. The effect of sulfur impurities in Technical Grade glycolic acid was studied for its impact on DWPF glass quality. While the glycolic acid specification allows for more sulfate than the current formic acid specification, the ultimate impact is expected to be on the order of 0.033 wt% sulfur in glass. Note that lower sulfur content glycolic acid could likely be procured at some increased cost if deemed necessary. A paper study on the effects of radiation on glycolic acid was performed. The analysis indicates that substitution of glycolic acid for formic acid would not increase the radiolytic production rate of H2 and cause an adverse effect in the Slurry Receipt and Adjustment Tank (SRAT) or Slurry Mix Evaporator (SME) process. It has been cited that glycolic acid

Solution influence on biomolecular equilibria - Nucleic acid base associations

NASA Technical Reports Server (NTRS)

Pohorille, A.; Pratt, L. R.; Burt, S. K.; Macelroy, R. D.

1984-01-01

Various attempts to construct an understanding of the influence of solution environment on biomolecular equilibria at the molecular level using computer simulation are discussed. First, the application of the formal statistical thermodynamic program for investigating biomolecular equilibria in solution is presented, addressing modeling and conceptual simplications such as perturbative methods, long-range interaction approximations, surface thermodynamics, and hydration shell. Then, Monte Carlo calculations on the associations of nucleic acid bases in both polar and nonpolar solvents such as water and carbon tetrachloride are carried out. The solvent contribution to the enthalpy of base association is positive (destabilizing) in both polar and nonpolar solvents while negative enthalpies for stacked complexes are obtained only when the solute-solute in vacuo energy is added to the total energy. The release upon association of solvent molecules from the first hydration layer around a solute to the bulk is accompanied by an increase in solute-solvent energy and decrease in solvent-solvent energy. The techniques presented are expectd to displace less molecular and more heuristic modeling of biomolecular equilibria in solution.

Improving clarity and stability of skim milk powder dispersions by dissociation of casein micelles at pH 11.0 and acidification with citric acid.

PubMed

Pan, Kang; Zhong, Qixin

2013-09-25

Casein micelles in milk cause turbidity and have poor stability at acidic conditions. In this study, skim milk powder dispersions were alkalized to pH 10.0 or 11.0, corresponding to reduced particle mass. In the following acidification with hydrochloric or citric acid, the re-formation of casein particles was observed. The combination of treatment at pH 11.0 and acidification with citric acid resulted in dispersions with the lowest turbidity and smallest particles, which enabled translucent dispersions at pH 5.5-7.0, corresponding to discrete nanoparticles. The concentration of ionic calcium was lower when acidified with citric acid than hydrochloric acid, corresponding to smaller particles with less negative zeta potential. The pH 11.0 treatment followed by acidification with citric acid also resulted in smaller particles than the simple chelating effects (directly implementing sodium citrate). The produced casein nanoparticles with reduced dimensions can be used for beverage and other novel applications.

Enhanced conductivity of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) film by acid treatment for indium tin oxide-free organic solar cells

NASA Astrophysics Data System (ADS)

Lin, Chun-Chiao; Huang, Chih-Kuo; Hung, Yu-Chieh; Chang, Mei-Ying

2016-08-01

An acid treatment is used in the enhancement of the conductivity of the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) thin film, which is often used as the anode in organic solar cells. There are three types of acid treatment for PEDOT:PSS thin film: hydrochloric, sulfuric, and phosphoric acid treatments. In this study, we examine and compare these three ways with each other for differences in conductivity. Hydrochloric acid results in the highest conductivity enhancement, from 0.3 to 1109 S/cm. We also discuss the optical transmittance, conductivity, surface roughness, surface morphology, and stability, as well as the factors that can influence device efficiency. The devices are fabricated using an acid-treated PEDOT:PSS thin film as the anode. The highest power conversion efficiency was 1.32%, which is a large improvement over that of the unmodified organic solar cell (0.21%). It is comparable to that obtained when using indium tin oxide (ITO) as an electrode, ca. 1.46%.

Science Notes.

ERIC Educational Resources Information Center

School Science Review, 1989

1989-01-01

Contains articles on digestive enzymes in grasshoppers; bird and badger observation; reactions between hydrochloric acid and sodium carbonate solutions; observing the migration of ions; pupil's heating skills (Bunsen burners); photolysis experimentation; capillary kinetics; experience with trireme; connection circuits; special relativity; a…

Inhibition effect of Arabic gum and cellulose acetate coatings on aluminium in acid/base media

NASA Astrophysics Data System (ADS)

Alva, S.; Sundari, R.; Rahmatullah, A.; Wahyudi, H.

2018-03-01

Nowadays aluminium is broadly used for battery purpose due to its conductivity, non toxic and economic reasons. Arabic gum and cellulose acetate are used as potential inhibitors to hinder corrosion effect on aluminium plate immersed in a solution of hydrochloric acid or sodium hydroxide. This investigation has studied the corrosion rate in terms of different concentrations of acid or base media. The average inhibition efficiency in the interested concentration range of both HCl and NaOH (0.1 M – 3.0 M) for 1 × 1 cm2 aluminium (Al) plate coated by 20% Arabic gum (AG) and 5% cellulose acetate (CA) with each thickness of 0.5 mm is found to be higher than 90%. The electrochemical behavior of corrosion effect is examined by cyclic voltammetric performance with respect to HCl or NaOH media. This investigation is useful especially for the study of Arabic gum and cellulose acetate utilized as polymer inhibitor in strong corrosive media.

Determination of sub-microgram amounts of selenium in geological materials by atomic-absorption spectrophotometry with electrothermal atomisation after solvent extraction

USGS Publications Warehouse

Sanzolone, R.F.; Chao, T.T.

1981-01-01

An atomic-absorption spectrophotometric method with electrothermal atomisation has been developed for the determination of selenium in geological materials. The sample is decomposed with a mixture of nitric, perchloric and hydrofluoric acids and heated with hydrochloric acid to reduce selenium to selenium (IV). Selenium is then extracted into toluene from a hydrochloric acid - hydrobromic acid medium containing iron. A few microlitres of the toluene extract are injected into a carbon rod atomiser, using a nickel solution as a matrix modifier. The limits of determination are 0.2-200 p.p.m. of selenium in a geological sample. For concentrations between 0.05 and 0.2 p.p.m., back-extraction of the selenium into dilute hydrochloric acid is employed before atomisation. Selenium values for reference samples obtained by replicate analysis are in general agreement with those reported by other workers, with relative standard deviations ranging from 4.1 to 8.8%. Recoveries of selenium spiked at two levels were 98-108%. Major and trace elements commonly encountered in geological materials do not interfere. Arsenic has a suppressing effect on the selenium signals, but only when its concentration is greater than 1000 p.p.m. Nitric acid interferes seriously with the extraction of selenium and must be removed by evaporation in the sample-digestion step.

An investigation into the stability and sterility of citric acid solutions used for cough reflex testing.

PubMed

Falconer, James R; Wu, Zimei; Lau, Hugo; Suen, Joanna; Wang, Lucy; Pottinger, Sarah; Lee, Elaine; Alazawi, Nawar; Kallesen, Molly; Gargiulo, Derryn A; Swift, Simon; Svirskis, Darren

2014-10-01

Citric acid is used in cough reflex testing in clinical and research settings to assess reflexive cough in patients at risk of swallowing disorders. To address a lack of knowledge in this area, this study investigated the stability and sterility of citric acid solutions. Triplicate solutions of citric acid (0.8 M) in isotonic saline were stored at 4 ± 2 °C for up to 28 days and analysed by high-performance liquid chromatography. Microbiological sterility of freshly prepared samples and bulk samples previously used for 2 weeks within the hospital was determined using a pour plate technique. Microbial survival in citric acid was determined by inoculating Staphylococcus aureus, Escherichia coli, or Candida albicans into citric acid solution and monitoring the number of colony-forming units/mL over 40 min. Citric acid solutions remained stable at 4 °C for 28 days (98.4 ± 1.8 % remained). The freshly prepared and clinical samples tested were sterile. However, viability studies revealed that citric acid solution allows for the survival of C. albicans but not for S. aureus or E. coli. The microbial survival study showed that citric acid kills S. aureus and E. coli but has no marked effect on C. albicans after 40 min. Citric acid samples at 0.8 M remained stable over the 4-week testing period, with viable microbial cells absent from samples tested. However, C. albicans has the ability to survive in citric acid solution if inadvertently introduced in practice. For this reason, in clinical and research practice it is suggested to use single-use aliquots prepared aseptically which can be stored for up to 28 days at 4 °C.

Understanding the dissolution of α-zein in aqueous ethanol and acetic acid solutions.

PubMed

Li, Yunqi; Li, Ji; Xia, Qiuyang; Zhang, Boce; Wang, Qin; Huang, Qingrong

2012-10-04

Zein is a corn prolamin that has broad industrial applications because of its unique physical properties. Currently, the high cost of extraction and purification, which is directly related to the dispersion of zein in different solvents, is the major bottleneck of the zein industry. Solution behaviors of zein have been studied for a long time. However, the physical nature of zein in different solvents remains unclear. In this study, small-angle X-ray scattering (SAXS), static light scattering (SLS), and rheology were combined to study the structure and protein-solvent interaction of α-zein in both acetic acid and aqueous ethanol solutions. We found that the like-dissolve-like rule, the partial unfolding, and the protonation of zein are all critical to understanding the solution behaviors. Zein holds an elongated conformation (i.e., prolate ellipsoid) in all solutions, as revealed from SAXS data. There is an "aging effect" for zein in aqueous ethanol solutions, as evidenced by the transition of Newtonian rheological profiles for fresh zein solutions to the non-Newtonian shear thinning behavior for zein solutions after storage at room temperature for 24 h. Such shear thinning behavior becomes more pronounced for zein solutions at higher concentrations. The SLS results clearly show that acetic acid is a better solvent to dissolve zein than aqueous ethanol solution, as supported by a more negative second virial coefficient. This is majorly caused by the protonation of the protein, which was further verified by the dissolution of zein in water (a nonsolvent for zein) with the addition of acids.

The kinetics of oxidation of bilirubin and ascorbic acid in solution

NASA Astrophysics Data System (ADS)

Solomonov, A. V.; Rumyantsev, E. V.; Kochergin, B. A.; Antina, E. V.

2012-07-01

The results of a comparative study of the oxidation of bilirubin, ascorbic acid, and their mixture in aqueous solutions under the action of air oxygen and hydrogen peroxide are presented. The observed and true rate constants for the oxidation reactions were determined. It was shown that the oxidation of tetrapyrrole pigment occurred under these conditions bypassing the stage of biliverdin formation to monopyrrole products. Simultaneous oxidation of bilirubin and ascorbic acid was shown to be accompanied by the inhibition of ascorbic acid oxidation by bilirubin, whereas ascorbic acid itself activated the oxidation of bilirubin.

Method for extracting lanthanides and actinides from acid solutions

DOEpatents

Horwitz, E. Philip; Kalina, Dale G.; Kaplan, Louis; Mason, George W.

1985-01-01

A process for the recovery of actinide and lanthanide values from aqueous acidic solutions with an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high level nuclear reprocessing waste solutions.

40 CFR 63.1161 - Performance testing and test methods.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Facilities and Hydrochloric Acid Regeneration Plants § 63.1161 Performance testing and test methods. (a...) Establishment of hydrochloric acid regeneration plant operating parameters. (1) During the performance test for hydrochloric acid regeneration plants, the owner or operator shall establish site-specific operating parameter...

40 CFR 63.1161 - Performance testing and test methods.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Facilities and Hydrochloric Acid Regeneration Plants § 63.1161 Performance testing and test methods. (a...) Establishment of hydrochloric acid regeneration plant operating parameters. (1) During the performance test for hydrochloric acid regeneration plants, the owner or operator shall establish site-specific operating parameter...

Gamma-irradiation of malic acid in aqueous solutions. [prebiotic significance

NASA Technical Reports Server (NTRS)

Negron-Mendoza, A.; Graff, R. L.; Ponnamperuma, C.

1980-01-01

The gamma-irradiation of malic acid in aqueous solutions was studied under initially oxygenated and oxygen-free conditions in an attempt to determine the possible interconversion of malic acid into other carboxylic acids, specifically those associated with Krebs cycle. The effect of dose on product formation of the system was investigated. Gas-liquid chromatography combined with mass spectrometry was used as the principal means of identification of the nonvolatile products. Thin layer chromatography and direct probe mass spectroscopy were also employed. The findings show that a variety of carboxylic acids are formed, with malonic and succinic acids in greatest abundance. These products have all been identified as being formed in the gamma-irradiation of acetic acid, suggesting a common intermediary. Since these molecules fit into a metabolic cycle, it is strongly suggestive that prebiotic pathways provided the basis for biological systems.

Determination of the mode of occurrence of As, Cr, and Hg in three Chinese coal samples by sequential acid leaching

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, B.; Li, W.; Wang, G.

2007-07-01

Sequential acid leaching was used to leach minerals and the trace elements they contain. One-step leaching uses concentrated nitric acid as solvent, while three-step leaching uses 5M hydrochloric acid, concentrated hydrofluoric acid, and concentrated hydrochloric acid as solvents. The sequential acid leaching by three-and one-step leach was also examined. The results showed that one-step leaching could leach over 80% of arsenic from coal samples, and also could leach mercury to a certain degree. During one-step leaching, little chromium is removed, but it is available to leach by three-step leaching; and during the sequential acid leaching by three and one-step leaching,more » almost 98% ash is leached. The result of acid leaching could also give detailed information on mode of occurrence of As, Cr, and Hg, which could be classified into: silicate association, pyrite association, organic association, and carbonates and sulfates association. Over half of chromium in the three coals is associated with organic matters and the rest is associated with silicates. The mode of occurrence of arsenic and mercury is mainly associated with different mineral matters depending on the coal samples studied.« less

CATION EXCHANGE METHOD FOR THE RECOVERY OF PROTACTINIUM

DOEpatents

Studier, M.H.; Sullivan, J.C.

1959-07-14

A cation exchange prccess is described for separating protactinium values from thorium values whereby they are initially adsorbed together from an aqueous 0.1 to 2 N hydrochloric acid on a cation exchange resin in a column. Then selectively eluting the thorium by an ammonium sulfate solution and subsequently eluting the protactinium by an oxalate solution.

Methanol Uptake By Low Temperature Aqueous Sulfuric Acid Solutions

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Essin, Andrew M.; Golden, David M.; Hipskind, R. Stephen (Technical Monitor)

2001-01-01

To evaluate the role of upper tropospheric and lower stratospheric aerosols in the global budget of methanol, the solubility and reactivity of CH3OH in aqueous sulfuric acid solutions are under investigation. Using standard uptake techniques in a Knudsen cell reactor, we have measured the effective Henry's law coefficient, H(*), for methanol dissolution into 45 to 70 percent by weight H2SO4. We find that methanol solubility ranges from 10(exp 5) to 10(exp 8) M/atm and increases with decreasing temperature and with increasing sulfuric acid content. These solubility measurements include uptake due to physical solvation and all rapid equilibria which are established in solution. Our data indicate that simple uptake by aqueous sulfuric acid particles will not be a significant sink for methanol in the UT/LS. These results differ from those recently reported in the literature, and an explanation of this disparity will be presented. In addition to solvation, reaction between primary alcohols and sulfuric acid does occur, leading to the production of alkyl sulfates. Literature values for the rate of this reaction suggest that formation of CH3OSO3H may proceed in the atmosphere but is not significant under our experimental conditions. Results obtained using a complementary equilibrium measurement technique confirm this directly. In addition, the extent of methanol sequestration via formation of mono- and dimethylsulfate will be evaluated under several atmospheric conditions.

A Volumetric Method for Titrimetric Analysis of Hydrogen Peroxide

DTIC Science & Technology

1985-05-06

fairly satisfactory indicator. Sulfuric acid solutions of cerium are stable over long periods of time, unlike the less stable nitric and hydrochloric acid ...Fisher number D141-5. 5. Sulfuric acid , concentrated (95-98 percent). For example, Fisher number A 300-212. 6. O-Phosphoric acid , 85 percent:. For example...Fisher number A 242-500. 7. 5 N sulfuric acid (Reference 11): Slowly pour 75 mL of concentrated sulfuric acid (95-98 percent) into approximately 200

Non-catalytic hydrogenation of VO2 in acid solution.

PubMed

Chen, Yuliang; Wang, Zhaowu; Chen, Shi; Ren, Hui; Wang, Liangxin; Zhang, Guobin; Lu, Yalin; Jiang, Jun; Zou, Chongwen; Luo, Yi

2018-02-26

Hydrogenation is an effective way to tune the property of metal oxides. It can conventionally be performed by doping hydrogen into solid materials with noble-metal catalysis, high-temperature/pressure annealing treatment, or high-energy proton implantation in vacuum condition. Acid solution naturally provides a rich proton source, but it should cause corrosion rather than hydrogenation to metal oxides. Here we report a facile approach to hydrogenate monoclinic vanadium dioxide (VO 2 ) in acid solution at ambient condition by placing a small piece of low workfunction metal (Al, Cu, Ag, Zn, or Fe) on VO 2 surface. It is found that the attachment of a tiny metal particle (~1.0 mm) can lead to the complete hydrogenation of an entire wafer-size VO 2 (>2 inch). Moreover, with the right choice of the metal a two-step insulator-metal-insulator phase modulation can even be achieved. An electron-proton co-doping mechanism has been proposed and verified by the first-principles calculations.

Toluene nitration in irradiated nitric acid and nitrite solutions

NASA Astrophysics Data System (ADS)

Elias, Gracy; Mincher, Bruce J.; Mezyk, Stephen P.; Muller, Jim; Martin, Leigh R.

2011-04-01

The kinetics, mechanisms, and stable products produced for the nitration of aryl alkyl mild ortho-para director toluene in irradiated nitric acid and neutral nitrite solutions were investigated using γ and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection, GC-MS and LC-MS, were used to assess the stable reaction products. Free-radical based nitration reaction products were found in irradiated acidic and neutral media. In 6.0 M HNO3, ring substitution, side chain substitution, and oxidation, produced different nitrated toluene products. For ring substitution, nitrogen oxide radicals were added mainly to cyclohexadienyl radicals, whereas for side chain substitution, these radicals were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite solutions, radiolytically-induced ring nitration products approached a statistically random distribution, suggesting a direct free-radical reaction involving addition of the rad NO2 radical.

Removal of iron interferences by solvent extraction for geochemical analysis by atomic-absorption spectrophotometry

USGS Publications Warehouse

Zhou, L.; Chao, T.T.; Sanzolone, R.F.

1985-01-01

Iron is a common interferent in the determination of many elements in geochemical samples. Two approaches for its removal have been taken. The first involves removal of iron by extraction with methyl isobutyl ketone (MIBK) from hydrochloric acid medium, leaving the analytes in the aqueous phase. The second consists of reduction of iron(III) to iron(II) by ascorbic acid to minimize its extraction into MIBK, so that the analytes may be isolated by extraction. Elements of interest can then be determined using the aqueous solution or the organic extract, as appropriate. Operating factors such as the concentration of hydrochloric acid, amounts of iron present, number of extractions, the presence or absence of a salting-out agent, and the optimum ratio of ascorbic acid to iron have been determined. These factors have general applications in geochemical analysis by atomic-absorption spectrophotometry. ?? 1985.

40 CFR 63.1161 - Performance testing and test methods.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Facilities and Hydrochloric Acid Regeneration Plants § 63.1161 Performance testing and test methods. (a...) or measure the concentration of HCl (and Cl2 for hydrochloric acid regeneration plants) in gases... to the initial test or tests. (c) Establishment of hydrochloric acid regeneration plant operating...

40 CFR 63.1161 - Performance testing and test methods.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Facilities and Hydrochloric Acid Regeneration Plants § 63.1161 Performance testing and test methods. (a...) or measure the concentration of HCl (and Cl2 for hydrochloric acid regeneration plants) in gases... to the initial test or tests. (c) Establishment of hydrochloric acid regeneration plant operating...

40 CFR 63.1161 - Performance testing and test methods.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Facilities and Hydrochloric Acid Regeneration Plants § 63.1161 Performance testing and test methods. (a...) or measure the concentration of HCl (and Cl2 for hydrochloric acid regeneration plants) in gases... to the initial test or tests. (c) Establishment of hydrochloric acid regeneration plant operating...

Corrosion property of 9Cr-ODS steel in nitric acid solution for spent nuclear fuel reprocessing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeuchi, M.; Koizumi, T.; Inoue, M.

2013-07-01

Corrosion tests of oxide dispersion strengthened with 9% Cr (9Cr-ODS) steel, which is one of the desirable materials for cladding tube of sodium-cooled fast reactors, in pure nitric acid solution, spent FBR fuel solution, and its simulated solution were performed to understand the corrosion behavior in a spent nuclear fuel reprocessing. In this study, the 9Cr-ODS steel with lower effective chromium content was evaluated to understand the corrosion behavior conservatively. As results, the tube-type specimens of the 9Cr-ODS steels suffered severe weight loss owing to active dissolution at the beginning of the immersion test in pure nitric acid solution inmore » the range from 1 to 3.5 M. In contrast, the weight loss was decreased and they showed a stable corrosion in the higher nitric acid concentration, the dissolved FBR fuel solution, and its simulated solution by passivation. The corrosion rates of the 9Cr-ODS steel in the dissolved FBR fuel solution and its simulated solution were 1-2 mm/y and showed good agreement with each other. The passivation was caused by the shift of corrosion potential to noble side owing to increase in nitric acid concentration or oxidative ions in the dissolved FBR fuel solution and the simulated spent fuel solution. (authors)« less

REDUCTION OF PLUTONIUM VALUES IN AN ACIDIC AQUEOUS SOLUTION WITH FORMALDEHYDE

DOEpatents

Olson, C.M.

1959-06-01

A method is given for reducing Pu to the tetravalent state and lowering the high acidity of dissolver solutions containing U and Pu. Formaldehyde is added to the HNO/sub 3/ solution of U and Pu to effect a formaldehyde to HNO/sub 3/ molar ratio of 0.375:1 to 1.5:1. The Pu can then be removed from the solution by carrier precipitation using BiPO/sub 4/ or by ion exchange. (T.R.H.)

Aquatic photolysis: photolytic redox reactions between goethite and adsorbed organic acids in aqueous solutions

USGS Publications Warehouse

Goldberg, M.C.; Cunningham, K.M.; Weiner, Eugene R.

1993-01-01

Photolysis of mono and di-carboxylic acids that are adsorbed onto the surface of the iron oxyhydroxide (goethite) results in an oxidation of the organic material and a reduction from Fe(III) to Fe(II) in the iron complex. There is a subsequent release of Fe2+ ions into solution. At constant light flux and constant solution light absorption, the factors responsible for the degree of photolytic reaction include: the number of lattice sites that are bonded by the organic acid; the rate of acid readsorption to the surface during photolysis; the conformation and structure of the organic acid; the degree of oxidation of the organic acid; the presence or absence of an ??-hydroxy group on the acid, the number of carbons in the di-acid chain and the conformation of the di-acid. The ability to liberate Fe(III) at pH 6.5 from the geothite lattice is described by the lyotropic series: tartrate>citrate> oxalate > glycolate > maleate > succinate > formate > fumarate > malonate > glutarate > benzoate = butanoate = control. Although a larger amount of iron is liberated, the series is almost the same at pH 5.5 except that oxalate > citrate and succinate > maleate. A set of rate equations are given that describe the release of iron from the goethite lattice. It was observed that the pH of the solution increases during photolysis if the solutions are not buffered. There is evidence to suggest the primary mechanism for all these reactions is an electron transfer from the organic ligand to the Fe(III) in the complex. Of all the iron-oxyhydroxide materials, crystalline goethite is the least soluble in water; yet, this study indicates that in an aqueous suspension, iron can be liberated from the goethite lattice. Further, it has been shown that photolysis can occur in a multiphase system at the sediment- water interface which results in an oxidation of the organic species and release of Fe2+ to solution where it becomes available for further reaction. ?? 1993.

THE KINETICS OF SAPONIFICATION OF IODOACETIC ACID BY SODIUM HYDROXIDE AND BY CERTAIN ALKALINE BUFFER SOLUTIONS.

PubMed

Brdicka, R

1936-07-20

1. The rate of the saponification of iodoacetic acid in sodium hydroxide and alkaline buffer solutions yielding glycollic acid was measured by means of Heyrovský's polarographic method. 2. From the bimolecular velocity constants, increasing with the ionic strength of the solution, the Brönsted factor, F, which characterizes the primary salt effect, was calculated. 3. In the borate buffer solutions the monomolecular constants of the saponification were determined which, at values above the pH of neutralization of boric acid, show a proportionality to the concentration of hydroxyl anions. Below the pH of neutralization of boric acid, they are proportional to the concentration of borate anions.

Acid precipitation: compositional changes during throughfall; soil water. Technical completion report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, R.

1984-12-01

Lysimeters were installed at two soil depths within each of the three major ecosystems on Camels Hump Mountain. Collections were made weekly during the frost-free season of 1982 and 1983. Samples were analyzed for pH, conductivity, and a broad range of metals, anionic and cationic constituents, and for other physical properties. The findings included: soil solutions obtained from the upper-elevations in a northern coniferous forest zone are significantly more acidic than those from the lower elevation hardwood forest zone; soil solutions for all ecological zones are more acidic in the spring during and shortly after snowmelt than they are latermore » in the frost free-season; aluminum in soil solutions from the upper elevations is present in concentrations known to be phytotoxic to seedlings of forest trees and to groundcover plants; cadmium, Pb, and Zn are, in the spring, present in concentrations that are close to being phytotoxic; there are changes in the ratios of divalent cations to specific metals during the season and as functions of altitude and forest zones; nitrate concentration in soil water are also elevation- and time dependent.« less

Quenching characteristics of bathocuproinedisulfonic acid, disodium salt in aqueous solution and copper sulfate plating solution

NASA Astrophysics Data System (ADS)

Koga, Toshiaki; Hirakawa, Chieko; Takeshita, Michinori; Terasaki, Nao

2018-04-01

Bathocuproinedisulfonic acid, disodium salt (BCS) is generally used to detect Cu(I) through a color reaction. We newly found BCS fluorescence in the visible blue region in an aqueous solution. However, the fluorescence mechanism of BCS is not well known, so we should investigate its fundamental information. We confirmed that the characteristics of fluorescence are highly dependent on the molecular concentration and solvent properties. In particular, owing to the presence of the copper compound, the fluorescence intensity extremely decreases. By fluorescence quenching, we observed that a copper compound concentration of 10-6 mol/L or less could easily be measured in an aqueous solution. We also observed BCS fluorescence in copper sulfate plating solution and the possibility of detecting monovalent copper by fluorescence reabsorption.

Technical solutions to nonproliferation challenges

NASA Astrophysics Data System (ADS)

Satkowiak, Lawrence

2014-05-01

The threat of nuclear terrorism is real and poses a significant challenge to both U.S. and global security. For terrorists, the challenge is not so much the actual design of an improvised nuclear device (IND) but more the acquisition of the special nuclear material (SNM), either highly enriched uranium (HEU) or plutonium, to make the fission weapon. This paper provides two examples of technical solutions that were developed in support of the nonproliferation objective of reducing the opportunity for acquisition of HEU. The first example reviews technologies used to monitor centrifuge enrichment plants to determine if there is any diversion of uranium materials or misuse of facilities to produce undeclared product. The discussion begins with a brief overview of the basics of uranium processing and enrichment. The role of the International Atomic Energy Agency (IAEA), its safeguard objectives and how the technology evolved to meet those objectives will be described. The second example focuses on technologies developed and deployed to monitor the blend down of 500 metric tons of HEU from Russia's dismantled nuclear weapons to reactor fuel or low enriched uranium (LEU) under the U.S.-Russia HEU Purchase Agreement. This reactor fuel was then purchased by U.S. fuel fabricators and provided about half the fuel for the domestic power reactors. The Department of Energy established the HEU Transparency Program to provide confidence that weapons usable HEU was being blended down and thus removed from any potential theft scenario. Two measurement technologies, an enrichment meter and a flow monitor, were combined into an automated blend down monitoring system (BDMS) and were deployed to four sites in Russia to provide 24/7 monitoring of the blend down. Data was downloaded and analyzed periodically by inspectors to provide the assurances required.

Technical solutions to nonproliferation challenges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Satkowiak, Lawrence

2014-05-09

The threat of nuclear terrorism is real and poses a significant challenge to both U.S. and global security. For terrorists, the challenge is not so much the actual design of an improvised nuclear device (IND) but more the acquisition of the special nuclear material (SNM), either highly enriched uranium (HEU) or plutonium, to make the fission weapon. This paper provides two examples of technical solutions that were developed in support of the nonproliferation objective of reducing the opportunity for acquisition of HEU. The first example reviews technologies used to monitor centrifuge enrichment plants to determine if there is any diversionmore » of uranium materials or misuse of facilities to produce undeclared product. The discussion begins with a brief overview of the basics of uranium processing and enrichment. The role of the International Atomic Energy Agency (IAEA), its safeguard objectives and how the technology evolved to meet those objectives will be described. The second example focuses on technologies developed and deployed to monitor the blend down of 500 metric tons of HEU from Russia's dismantled nuclear weapons to reactor fuel or low enriched uranium (LEU) under the U.S.-Russia HEU Purchase Agreement. This reactor fuel was then purchased by U.S. fuel fabricators and provided about half the fuel for the domestic power reactors. The Department of Energy established the HEU Transparency Program to provide confidence that weapons usable HEU was being blended down and thus removed from any potential theft scenario. Two measurement technologies, an enrichment meter and a flow monitor, were combined into an automated blend down monitoring system (BDMS) and were deployed to four sites in Russia to provide 24/7 monitoring of the blend down. Data was downloaded and analyzed periodically by inspectors to provide the assurances required.« less

Time dependent inhibition of xanthine oxidase in irradiated solutions of folic acid, aminopterin and methotrexate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robinson, K.; Pilot, T.F.; Meany, J.E.

1990-01-01

The xanthine oxidase catalyzed oxidation of hypoxanthine was followed by monitoring the formation of uric acid at 290 nm. Inhibition of xanthine oxidase occurs in aqueous solutions of folic acid methotrexate and aminopterin. These compounds are known to dissociate upon exposure to ultraviolet light resulting in the formation of their respective 6-formylpteridine derivatives. The relative rates of dissociation were monitored spectrophotometrically by determining the absorbance of their 2,4-dinitrophenylhydrazine derivatives at 500 nm. When aqueous solutions of folic acid, aminopterin and methotrexate were exposed to uv light, a direct correlation was observed between the concentrations of the 6-formylpteridine derivatives existing inmore » solution and the ability of these solutions to inhibit xanthine oxidase. The relative potency of the respective photolysis products were estimated.« less

Direct sensing of fluoride in aqueous solutions using a boronic acid based sensor.

PubMed

Wu, Xin; Chen, Xuan-Xuan; Song, Bing-Nan; Huang, Yan-Jun; Ouyang, Wen-Juan; Li, Zhao; James, Tony D; Jiang, Yun-Bao

2014-11-21

Binding of the fluoride ion triggers aggregation of a pyreneboronic acid-catechol ensemble in acidic aqueous solutions, giving rise to intense excimer emission, allowing for sensitive fluoride ion sensing at ppm levels, with an apparent fluoride binding constant higher than 10(3) M(-1) which is unprecedented for boronic acid sensors in water.

40 CFR 63.1205 - What are the standards for hazardous waste burning lightweight aggregate kilns that are effective...

Code of Federal Regulations, 2012 CFR

2012-07-01

... rolling average, dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid... hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen; and (7) Particulate matter in... average, dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid and...

40 CFR 63.1205 - What are the standards for hazardous waste burning lightweight aggregate kilns that are effective...

Code of Federal Regulations, 2010 CFR

2010-07-01

... rolling average, dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid... hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen; and (7) Particulate matter in... average, dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid and...

40 CFR 63.1203 - What are the standards for hazardous waste incinerators that are effective until compliance with...

Code of Federal Regulations, 2013 CFR

2013-07-01

... as propane; (6) Hydrochloric acid and chlorine gas in excess of 77 parts per million by volume, combined emissions, expressed as hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen... basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid and chlorine gas in...

40 CFR 63.1205 - What are the standards for hazardous waste burning lightweight aggregate kilns that are effective...

Code of Federal Regulations, 2011 CFR

2011-07-01

... rolling average, dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid... hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen; and (7) Particulate matter in... average, dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid and...

40 CFR 63.1205 - What are the standards for hazardous waste burning lightweight aggregate kilns that are effective...

Code of Federal Regulations, 2013 CFR

2013-07-01

... as propane; (6) Hydrochloric acid and chlorine gas in excess of 600 parts per million by volume, combined emissions, expressed as hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen...) Hydrochloric acid and chlorine gas in excess of 600 parts per million by volume, combined emissions, expressed...

40 CFR 63.1203 - What are the standards for hazardous waste incinerators that are effective until compliance with...

Code of Federal Regulations, 2014 CFR

2014-07-01

... as propane; (6) Hydrochloric acid and chlorine gas in excess of 77 parts per million by volume, combined emissions, expressed as hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen... basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid and chlorine gas in...

40 CFR 63.1205 - What are the standards for hazardous waste burning lightweight aggregate kilns that are effective...

Code of Federal Regulations, 2014 CFR

2014-07-01

... as propane; (6) Hydrochloric acid and chlorine gas in excess of 600 parts per million by volume, combined emissions, expressed as hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen...) Hydrochloric acid and chlorine gas in excess of 600 parts per million by volume, combined emissions, expressed...

THE KINETICS OF SAPONIFICATION OF IODOACETIC ACID BY SODIUM HYDROXIDE AND BY CERTAIN ALKALINE BUFFER SOLUTIONS

PubMed Central

Brdička, R.

1936-01-01

1. The rate of the saponification of iodoacetic acid in sodium hydroxide and alkaline buffer solutions yielding glycollic acid was measured by means of Heyrovský's polarographic method. 2. From the bimolecular velocity constants, increasing with the ionic strength of the solution, the Brönsted factor, F, which characterizes the primary salt effect, was calculated. 3. In the borate buffer solutions the monomolecular constants of the saponification were determined which, at values above the pH of neutralization of boric acid, show a proportionality to the concentration of hydroxyl anions. Below the pH of neutralization of boric acid, they are proportional to the concentration of borate anions. PMID:19872968

SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION

DOEpatents

Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

1963-02-12

This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

Degradation of hydroxycinnamic acid mixtures in aqueous sucrose solutions by the Fenton process.

PubMed

Nguyen, Danny M T; Zhang, Zhanying; Doherty, William O S

2015-02-11

The degradation efficiencies and behaviors of caffeic acid (CaA), p-coumaric acid (pCoA), and ferulic acid (FeA) in aqueous sucrose solutions containing the mixture of these hydroxycinnamic acids (HCAs) were studied by the Fenton oxidation process. Central composite design and multiresponse surface methodology were used to evaluate and optimize the interactive effects of process parameters. Four quadratic polynomial models were developed for the degradation of each individual acid in the mixture and the total HCAs degraded. Sucrose was the most influential parameter that significantly affected the total amount of HCA degraded. Under the conditions studied there was a <0.01% loss of sucrose in all reactions. The optimal values of the process parameters for a 200 mg/L HCA mixture in water (pH 4.73, 25.15 °C) and sucrose solution (13 mass %, pH 5.39, 35.98 °C) were 77% and 57%, respectively. Regression analysis showed goodness of fit between the experimental results and the predicted values. The degradation behavior of CaA differed from those of pCoA and FeA, where further CaA degradation is observed at increasing sucrose and decreasing solution pH. The differences (established using UV/vis and ATR-FTIR spectroscopy) were because, unlike the other acids, CaA formed a complex with Fe(III) or with Fe(III) hydrogen-bonded to sucrose and coprecipitated with lepidocrocite, an iron oxyhydroxide.

40 CFR 63.1203 - What are the standards for hazardous waste incinerators that are effective until compliance with...

Code of Federal Regulations, 2010 CFR

2010-07-01

... monitoring system), dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid... hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen; and (7) Particulate matter in... oxygen, and reported as propane; (6) Hydrochloric acid and chlorine gas in excess of 21 parts per million...

40 CFR 63.1203 - What are the standards for hazardous waste incinerators that are effective until compliance with...

Code of Federal Regulations, 2011 CFR

2011-07-01

... monitoring system), dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid... hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen; and (7) Particulate matter in... oxygen, and reported as propane; (6) Hydrochloric acid and chlorine gas in excess of 21 parts per million...

40 CFR 63.1203 - What are the standards for hazardous waste incinerators that are effective until compliance with...

Code of Federal Regulations, 2012 CFR

2012-07-01

... monitoring system), dry basis, corrected to 7 percent oxygen, and reported as propane; (6) Hydrochloric acid... hydrochloric acid equivalents, dry basis and corrected to 7 percent oxygen; and (7) Particulate matter in... oxygen, and reported as propane; (6) Hydrochloric acid and chlorine gas in excess of 21 parts per million...

Changes in properties of polyacid-modified composite resins (compomers) following storage in acidic solutions.

PubMed

Nicholson, J W; Gjorgievska, E; Bajraktarova, B; McKenzie, M A

2003-06-01

The interaction of three polyacid-modified composite resins (compomers) with various acidic storage solutions, and also water, over periods of time up to 6 months has been studied and compared with those of a glass-ionomer and a composite resin. This interaction has been shown to vary in a complex way with length of storage and nature of the acid, and citric acid was found to be the most aggressive storage medium for glass-ionomer cement, and also for the compomers. The pure composite resin, by contrast, was relatively unaffected by all of the acid solutions examined. In all acids, the compomers showed a distinct buffering effect, i.e. they increased the pH towards neutral, as did the glass-ionomer. The extent of this also varied with duration of storage and nature of the acid. The biaxial flexure strength was determined and found to be essentially unaffected by the complex chemical interactions with acidic storage solutions. Values obtained for the compomers were lower than those of the composite resin, but above those of the glass-ionomer. Fourier-transform infrared (FT-IR) spectroscopy was employed to study the changes in the compomers following storage in the aqueous media, but bands were broad and no detailed assignments could be made. There were changes in the region of the spectra associated with metal carboxylates however, and this indicates that the secondary acid-base reaction had occurred following water uptake.

The thermochemical characteristics of solution of phenol and benzoic acid in water-dimethylsulfoxide and water-acetonitrile mixtures

NASA Astrophysics Data System (ADS)

Zakharov, A. G.; Voronova, M. I.; Batov, D. V.; Smirnova, K. V.

2011-03-01

The solution of phenol and benzoic acid in water-dimethylsulfoxide (DMSO) and water-acetonitrile (AN) mixtures was studied. As distinct from benzoic acid, the thermodynamic characteristics of solution of phenol sharply change at concentrations corresponding to a change in the character of cluster formation in water-DMSO and water-AN mixtures. Differences in the solvation of phenol and benzoic acid are explained by different mechanisms of the interaction of the solutes with clusters existing in binary mixtures.

Formation of amino acids by cobalt-60 irradiation of hydrogen cyanide solutions

NASA Technical Reports Server (NTRS)

Sweeney, M. A.; Toste, A. P.; Ponnamperuma, C.

1976-01-01

Experiments were conducted to study the pathway for the prebiotic origin of amino acids from hydrogen cyanide (HCN) under the action of ionizing radiation considered as an effective source of energy on the primitive earth. The irradiations were performed in a cobalt-60 source with a dose rate of 200,000 rad/hr. Seven naturally occurring amino acids are identified among the products formed by the hydrolysis of gamma-irradiated solutions of HCN: glycine, alanine, valine, serine, threonine, aspartic acid, and glutamic acid. The identity of these amino acids is established by gas chromatography and mass spectrometry. Control experiments provided evidence that the amino acids are not the result of contamination.

Study of stability of methotrexate in acidic solution spectrofluorimetric determination of methotrexate in pharmaceutical preparations through acid-catalyzed degradation reaction.

PubMed

Sabry, Suzy M; Abdel-Hady, M; Elsayed, M; Fahmy, Osama T; Maher, Hadir M

2003-07-14

Study of the degradation reaction of methotrexate (MTX) in acidic solution was carried out. Optimization of the experimental parameters of MTX acid hydrolysis was investigated. Spectrofluorimetric method for determination of MTX through measurement of its acid-degradation product, 4-amino-4-deoxy-10-methylpteroic acid (AMP), was developed. Stability of the standard solution of MTX prepared in sulfuric acid was discussed in the view of accelerated stability analysis. Two other comparative spectroflourimetric methods based on measuring the fluorescence intensities from either a condensation reaction with acetylacetone-formaldehyde (Hantzsch reaction) or a reaction with fluorescamine were also described. Beer's law validation, accuracy, precision, limits of detection, limits of quantification, and other aspects of analytical merit are presented in the text. The proposed methods were successfully applied for the analysis of MTX in pure drug and tablets dosage form. The sensitivity of the developed methods was favorable, so it was possible to be adopted for determination of MTX in plasma samples for routine use in high-dose MTX therapy.

Spectroscopic studies and thermal analysis of mononuclear metal complexes with moxifloxacin and 2,2‧-bipyridine and their effects on acute lung injury induced by hydrochloric acid in rats

NASA Astrophysics Data System (ADS)

El-Hamid, S. M. Abd; El-Demerdash, R. S.; Arafat, H. F. H.; Sadeek, S. A.

2017-12-01

The article describes the interaction of Y(III), Zr(IV), La(III), Ce(IV) and U(VI) with moxifloxacin hydrochloride and 2,2‧-bipyridine. Characterization of complexes was made by elemental analyses, molar conductivity, magnetic moment measurements and spectral measurements e.g. IR, UV-Vis., 1H NMR and mass as well as thermal analyses (TG and DTG). The molar conductivity shows that the complexes are electrolytes nature. Spectroscopic investigation of the solid complexes studied here indicate that moxifloxacin hydrochloride and 2,2‧-bipyridine are coordinated to the metal ions in a neutral bidentate manner. After complete characterization, the chemical formulae of the complexes were established. The calculated bond length and force constant, F(Udbnd O), in the uranyl complex are 1.756 Å and 637.90 Nm-1, respectively. Kinetic and thermodynamic parameters were determined using Coats-Redfern and Horowitz-Metzger equations. Establishment of hydrochloric acid that induce acute lung injury (ALI) in rats by intratracheal administration through damaging the alveolar epithelium and activation of the neutrophil and subsequent oxidative stress by increasing malondialdehyde (MDA), tumor necrosis factor (TNF-α) and neutrophil, which were confirmed by histopathological investigation while decreasing in antioxidant enzymes and lymphocytes. Whereas treatment with mixed-ligand metal complexes significantly decrease MDA, TNF-α and neutrophils and increase antioxidant and lymphocytes.

NOTES: a review of the technical problems encountered and their solutions.

PubMed

Mintz, Yoav; Horgan, Santiago; Cullen, John; Stuart, David; Falor, Eric; Talamini, Mark A

2008-08-01

Natural orifice translumenal endoscopic surgery (NOTES) is currently investigated and developed worldwide. In the past few years, multiple groups have confronted this challenge. Many technical problems are encountered in this technique due to the currently available tools for this approach. Some of the unique technical problems in NOTES include: blindly performed primary incisions; uncontrolled pneumoperitoneal pressure; no support for the endoscope in the abdominal cavity; inadequate vision; insufficient illumination; limited retraction and exposure; and the complexity of suturing and performing a safe anastomosis. In this paper, we review the problems encountered in NOTES and provide possible temporary solutions. Acute and survival studies were performed on 15 farm pigs. The hybrid technique approach (i.e., endoscopic surgery with the aid of laparoscopic vision) was performed in all cases. Procedures performed included liver biopsies, bilateral tubal ligation, oophprectomy, cholecystectomy, splenectomy and small bowel resection, and anastomosis. All attempted procedures were successfully performed. New methods and techniques were developed to overcome the technical problems. Closure of the gastrotomy was achieved by T-bar sutures and by stapler closure of the stomach incision. Small bowel anastomosis was achieved by the dual-lumen NOTES technique. The hybrid technique serves as a temporary approach to aid in developing the NOTES technique. A rectal or vaginal port of entry enables and facilitates gastrointestinal NOTES by using available laparoscopic instruments. The common operations performed today in the laparoscopic fashion could be probably performed in the NOTES approach. The safety of these procedures, however, is yet to be determined.

Method for extracting lanthanides and actinides from acid solutions by modification of Purex solvent

DOEpatents

Horwitz, E.P.; Kalina, D.G.

1984-05-21

A process has been developed for the extraction of multivalent lanthanide and actinide values from acidic waste solutions, and for the separation of these values from fission product and other values, which utilizes a new series of neutral bi-functional extractants, the alkyl(phenyl)-N, N-dialkylcarbamoylmethylphosphine oxides, in combination with a phase modifier to form an extraction solution. The addition of the extractant to the Purex process extractant, tri-n-butylphosphate in normal paraffin hydrocarbon diluent, will permit the extraction of multivalent lanthanide and actinide values from 0.1 to 12.0 molar acid solutions.

Extraction of Li and Co from Li-ion Batteries by Chemical Methods

NASA Astrophysics Data System (ADS)

Guzolu, Jafar Sharrivar; Gharabaghi, Mahdi; Mobin, Mohammad; Alilo, Hojat

2017-04-01

In this work a process involving ultrasonic washing and leaching and precipitation was used to recover Li and Co from spent Li-ion batteries. Ultrasonic washing was used to reduce energy consumption and pollution whereas hydrochloric acid was used as leaching reagent. 98 % of Li and nearly 99 % of Co were obtained under optimum condition of 5 M hydrochloric acid solution, temperature of 95 °C, reaction time of 70 min, and solid-liquid ratio of 10 g/L. In this process at first nickel, copper, iron, aluminum, cobalt, and manganese were precipitated from leaching solution using sodium hydroxide at pH f 12.5 and reaction time of 1 h and temperature was 55 °C and all metal recoveries were more than 99 %. In the precipitation experiments, lithium loss was only 18.34 %. In the next stage, white lithium carbonate was precipitated by addition of saturated sodium carbonate solution to the left filtrate from first precipitation step. The purity of the recovered powder of lithium was 95 %.

Radiation-induced degradation of cyclohexanebutyric acid in aqueous solutions by gamma ray irradiation

NASA Astrophysics Data System (ADS)

Jia, Wenbao; He, Yanquan; Ling, Yongsheng; Hei, Daqian; Shan, Qing; Zhang, Yan; Li, Jiatong

2015-04-01

The radiation-induced degradation of cyclohexanebutyric acid under gamma ray irradiation was investigated. Degradation experiments were performed with 100 mL sealed Pyrex glass vessels loaded with 80 mL of cyclohexanebutyric acid solutions at various initial concentrations of 10, 20, and 40 mg L-1. The absorbed doses were controlled at 0, 0.65, 1.95, 3.25, 6.5, 9.75, and 13 kGy. The results showed that gamma ray irradiation could effectively degrade cyclohexanebutyric acid in aqueous solutions. The removal rate of cyclohexanebutyric acid increased significantly with the increase of absorbed dose and the decrease of its initial concentration. At the same time, the removal of chemical oxygen demand (COD) was as effective as that of cyclohexanebutyric acid. The kinetic studies showed that the degradation of cyclohexanebutyric acid followed pseudo first-order reaction. Above all, the proposed mechanism obtained when NaNO2, NaNO3 and tert-butanol were added showed that the •OH radical played a major role in the gamma degradation process of cyclohexanebutyric acid, while •H and eaq- played a minor role in the gamma degradation process. The degradation products were identified by Fourier transform infrared spectroscopy (FTIR) and gas chromatography/mass spectrometry (GC/MS) during cyclohexanebutyric acid degradation.

Stability of antimicrobial activity of peracetic acid solutions used in the final disinfection process.

PubMed

Costa, Solange Alves da Silva; Paula, Olívia Ferreira Pereira de; Silva, Célia Regina Gonçalves E; Leão, Mariella Vieira Pereira; Santos, Silvana Soléo Ferreira dos

2015-01-01

The instruments and materials used in health establishments are frequently exposed to microorganism contamination, and chemical products are used before sterilization to reduce occupational infection. We evaluated the antimicrobial effectiveness, physical stability, and corrosiveness of two commercial formulations of peracetic acid on experimentally contaminated specimens. Stainless steel specimens were contaminated with Staphylococcus aureus, Escherichia coli, Candida albicans, blood, and saliva and then immersed in a ready peracetic acid solution: 2% Sekusept Aktiv (SA) or 0.25% Proxitane Alpha (PA), for different times. Then, washes of these instruments were plated in culture medium and colony-forming units counted. This procedure was repeated six times per day over 24 non-consecutive days. The corrosion capacity was assessed with the mass loss test, and the concentration of peracetic acid and pH of the solutions were measured with indicator tapes. Both SA and PA significantly eliminated microorganisms; however, the SA solution was stable for only 4 days, whereas PA remained stable throughout the experiment. The concentration of peracetic acid in the SA solutions decreased over time until the chemical was undetectable, although the pH remained at 5. The PA solution had a concentration of 500-400 mg/L and a pH of 2-3. Neither formulation induced corrosion and both reduced the number of microorganisms (p = 0.0001). However, the differences observed in the performance of each product highlight the necessity of establishing a protocol for optimizing the use of each one.

Industrial ecotoxicology "acid rain".

PubMed

Astolfi, E; Gotelli, C; Higa, J

1986-01-01

The acid rain phenomenon was studied in the province of Cordoba, Argentina. This study, based on a previously outlined framework, determined the anthropogenic origin of the low pH due to the presence of industrial hydrochloric acid wastage. This industrial ecotoxicological phenomenon seriously affected the forest wealth, causing a great defoliation of trees and shrubs, with a lower effect on crops. A survey on its effects on human beings has not been carried out, but considering the corrosion caused to different metals and its denouncing biocide effect on plants and animals, we should expect to find some kind of harm to the health of the workers involved or others engaged in farming, and even to those who are far away from the polluting agent.

A 25% tannic acid solution as a root canal irrigant cleanser: a scanning electron microscope study.

PubMed

Bitter, N C

1989-03-01

A scanning electron microscope was used to evaluate the cleansing properties of a 25% tannic acid solution on the dentinal surface in the pulp chamber of endodontically prepared teeth. This was compared with the amorphous smear layer of the canal with the use of hydrogen peroxide and sodium hypochlorite solution as an irrigant. The tannic acid solution removed the smear layer more effectively than the regular cleansing agent.

Determination of acid ionization constants for weak acids by osmometry and the instrumental analysis self-evaluation feedback approach to student preparation of solutions

NASA Astrophysics Data System (ADS)

Kakolesha, Nyanguila

One focus of this work was to develop of an alternative method to conductivity for determining the acid ionization constants. Computer-controlled osmometry is one of the emerging analytical tools in industrial research and clinical laboratories. It is slowly finding its way into chemistry laboratories. The instrument's microprocessor control ensures shortened data collection time, repeatability, accuracy, and automatic calibration. The equilibrium constants of acetic acid, chloroacetic acid, bromoacetic acid, cyanoacetic acid, and iodoacetic acid have been measured using osmometry and their values compared with the existing literature values obtained, usually, from conductometric measurements. Ionization constant determined by osmometry for the moderately strong weak acids were in reasonably good agreement with literature values. The results showed that two factors, the ionic strength and the osmotic coefficient, exert opposite effects in solutions of such weak acids. Another focus of the work was analytical chemistry students solution preparation skills. The prevailing teacher-structured experiments leave little room for students' ingenuity in quantitative volumetric analysis. The purpose of this part of the study was to improve students' skills in making solutions using instrument feedback in a constructivist-learning model. After making some solutions by weighing and dissolving solutes or by serial dilution, students used the spectrophotometer and the osmometer to compare their solutions with standard solutions. Students perceived the instrument feedback as a nonthreatening approach to monitoring the development of their skill levels and liked to clarify their understanding through interacting with an instructor-observer. An assessment of the instrument feedback and the constructivist model indicated that students would assume responsibility for their own learning if given the opportunity. This study involved 167 students enrolled in Quantitative Chemical

Agent Regeneration and Hazardous Waste Minimization and Teaching Note. IBM Case Study. Doc #93-1.

ERIC Educational Resources Information Center

Oliker, L. Richard; And Others

The manufacturing process used to produce printbands for International Business Machines, Inc. involves a photolithographic process in which the stainless steel panels are chemically machined using strong ferric chloride etching solution containing hydrochloric acid. The waste material that results from this chemical reaction is a solution…

Novel technical solutions for wireless ECG transmission & analysis in the age of the internet cloud.

PubMed

Al-Zaiti, Salah S; Shusterman, Vladimir; Carey, Mary G

2013-01-01

Current guidelines recommend early reperfusion therapy for ST-elevation myocardial infarction (STEMI) within 90 min of first medical encounter. Telecardiology entails the use of advanced communication technologies to transmit the prehospital 12-lead electrocardiogram (ECG) to offsite cardiologists for early triage to the cath lab; which has been shown to dramatically reduce door-to-balloon time and total mortality. However, hospitals often find adopting ECG transmission technologies very challenging. The current review identifies seven major technical challenges of prehospital ECG transmission, including: paramedics inconvenience and transport delay; signal noise and interpretation errors; equipment malfunction and transmission failure; reliability of mobile phone networks; lack of compliance with the standards of digital ECG formats; poor integration with electronic medical records; and costly hardware and software pre-requisite installation. Current and potential solutions to address each of these technical challenges are discussed in details and include: automated ECG transmission protocols; annotatable waveform-based ECGs; optimal routing solutions; and the use of cloud computing systems rather than vendor-specific processing stations. Nevertheless, strategies to monitor transmission effectiveness and patient outcomes are essential to sustain initial gains of implementing ECG transmission technologies. © 2013.

Effects of topical oxiconazole and boric acid in alcohol solutions to rat inner ears.

PubMed

Özdemir, Süleyman; Tuncer, Ülkü; Tarkan, Özgür; Akar, Funda; Sürmelioğlu, Özgür

2013-06-01

The aim of this study is to evaluate the ototoxicity of topical oxiconazole and boric acid in alcohol solutions. Prospective controlled animal study. Research laboratory. Fifty adult Wistar albino rats were divided into 5 groups consisting of 10 animals each. The right tympanic membranes were perforated, and baseline and posttreatment distortion product otoacoustic emission (DPOAE) measurements were performed. The solutions were applied through the external ear canal to the middle ear twice a day for 14 days. The rats in group I and group II received 0.1 mL of oxiconazole-containing solution drops and 4% boric acid in alcohol solution drops, respectively. Group III received gentamicin solution (40 mg/mL) (ototoxic control), group IV received saline solution, and group V was followed without any medication. The baseline DPOAE results of the right ears of all animals tested were normal. Animals in groups I, II, IV, and V showed no statistically significant change in the DPOAE amplitudes. The rats in the gentamicin group showed a significant decrease. This study demonstrates that topically used oxiconazole and boric acid in alcohol solutions to the middle ear appear to be safe on the inner ear of rats. The safety of these drugs has not yet been confirmed in humans. Caution should be taken when prescribing these drugs, especially to patients who had tympanic membrane perforation. Ear drops should be chosen more carefully in an external ear infection for patients with tympanic membrane perforation to avoid ototoxicity.

Coatings from blends of Eudragit® RL and L55: a novel approach in pH-controlled drug release.

PubMed

Wulff, R; Leopold, C S

2014-12-10

The aim of the present study was to investigate the drug release from theophylline pellets coated with blends of quaternary polymethacrylate and methacrylic acid-ethyl acrylate copolymers. Pellets were coated with blends of Eudragit(®) RL PO (RL) and Eudragit(®) L 100-55 (L55) in either organic solution or aqueous dispersion at various copolymer ratios. Generally, the coatings were less permeable for theophylline in phosphate buffer pH 6.8 than they were in hydrochloric acid pH 1.2. Further dissolution experiments revealed that the differences in drug release are caused by the different pH values. A design of experiments for historical data was performed on drug release data of pellets with different coating levels and blend ratios of RL and L55. Drug release in hydrochloric acid was predominantly affected by the coating level, whereas for drug release in phosphate buffer pH 6.8 the blend ratio was the determining factor. As expected, dissolution experiments at different pH values showed that drug release depends on the ratio of dissociated L55 to RL because ionization is a requirement for the functional groups to interact. With the dissolution test for delayed-release solid dosage forms (Ph. Eur.) it was demonstrated that the unique release behavior in neutral media is preserved after the exposition to hydrochloric acid. These findings indicate that the combination of RL and L55 in coatings prepared from solutions is a promising approach for controlled drug release. Copyright © 2014 Elsevier B.V. All rights reserved.

Uptake of Hypobromous Acid (HOBr) by Aqueous Sulfuric Acid Solutions: Low-Temperature Solubility and Reaction

NASA Technical Reports Server (NTRS)

Iraci, Laura T.; Michelsen, Rebecca R.; Ashbourn, Samatha F. M.; Rammer, Thomas A.; Golden, David M.

2005-01-01

Hypobromous acid (HOBr) is a key species linking inorganic bromine to the chlorine and odd hydrogen chemical families. We have measured the solubility of HOBr in 45 - 70 wt% sulfuric acid solutions representative of upper tropospheric and lower stratospheric aerosol composition. Over the temperature range 201 - 252 K, HOBr is quite soluble in sulfuric acid, with an effective Henry's law coefficient, H* = 10(exp 4) - 10(exp 7) mol/L/atm. H* is inversely dependent on temperature, with Delta H = -46.2 kJ/mol and Delta S = -106.2 J/mol/K for 55 - 70 wt% H2SO4 solutions. Our study includes temperatures which overlap both previous measurements of HOBr solubility. For uptake into aqueous 45 wt% H2SO4, the solubility can be described by log H* = 3665/T - 10.63. For 55 - 70 wt% H2SO4, log H* = 2412/T - 5.55. At temperatures colder than approx. 213 K, the solubility of HOBr in 45 wt% H2SO4 is noticeably larger than in 70 wt% H2SO4. The solubility of HOBr is comparable to that of HBr, indicating that upper tropospheric and lower stratospheric aerosols should contain equilibrium concentrations of HOBr which equal or exceed those of HBr. Our measurements indicate chemical reaction of HOBr upon uptake into aqueous sulfuric acid in the presence of other brominated gases followed by evolution of gaseous products including Br2O and Br2, particularly at 70 wt% H2SO4.

Microdroplet fusion mass spectrometry: accelerated kinetics of acid-induced chlorophyll demetallation

PubMed Central

Lee, Jae Kyoo; Nam, Hong Gil; Zare, Richard N.

2017-01-01

Kinetics of acid-induced chlorophyll demetallation was recorded in microdroplets by fusing a stream of microdroplets containing 40 μM chlorophyll a or b dissolved in methanol with a stream of aqueous microdroplets containing 35 mM hydrochloric acid (pH = 1·46). The kinetics of the demetallation of chlorophyll in the fused microdroplets (14 ± 6 μm diameter; 84 ± 18 m s−1 velocity) was recorded by controlling the traveling distance of the fused microdroplets between the fusion region and the inlet of a mass spectrometer. The rate of acid-induced chlorophyll demetallation was about 960 ± 120 times faster in the charged microdroplets compared with that reported in bulk solution. If no voltage was applied to the sprayed microdroplets, then the acceleration factor was about 580 ± 90, suggesting that the applied voltage is not a major factor determining the acceleration. Chlorophyll a was more rapidly demetallated than chlorophyll b by a factor of ~26 in bulk solution and ~5 in charged microdroplets. The demetallation kinetics was second order in the H+ concentration, but the acceleration factor of microdroplets compared with bulk solution appeared to be unchanged in going from pH = 1·3 to 7·0. The water:methanol ratio of the fused microdroplets was varied from 7:3 to 3:7 causing an increase in the reaction rate of chlorophyll a demetallation by 20%. This observation demonstrates that the solvent composition, which has different evaporation rates, does not significantly affect the acceleration. We believe that a major portion of the acceleration can be attributed to confinement effects involving surface reactions rather than either to evaporation of solvents or to the introduction of charges to the microdroplets. PMID:29233214

Microdroplet fusion mass spectrometry: accelerated kinetics of acid-induced chlorophyll demetallation.