Small Amount Of Phosphoric Acid Research Articles

Development of an analytical chip for colorimetric detection of medium-chain aldehydes by reaction with pararosaniline in porous glass

Medium-chain aldehydes are common human biogases that can be detected in the breath of patients with lung diseases. As such, the measurement of medium-chain aldehyde gases in human breath can provide significant, noninvasive, and diagnostic information related to the potential presence of such diseases. In this study, an analytical chip is developed for the detection of medium-chain aldehydes without interference from short-chain aldehydes. This analytical chip is composed of porous glass impregnated with pararosaniline and an acid (i.e., acetic acid with small amount of phosphoric acid). After exposure to medium-chain aldehydes, the red analytical chip became violet in color, and an absorption peak was observed at 620 nm. It was found that a non-reversible reaction occurred in the porous glass, therefore, the analytical chip functions in a cumulative manner. A linear relationship was determined between the absorbance change of the analytical chip at 620 nm and the nonanal exposure concentration. Importantly, the developed analytical chip successfully detected nonanal at concentrations of 8–270 ppb as calculated from the absorbance change at 620 nm after a 24 h exposure time. In addition, nonanal concentration was estimated using the change in the R value of the analytical chip photograph. This method is suitable for point-of-care breath analysis. Finally, the analytical chip was also found to be active toward octanal and decanal with a relative sensitivity of 0.7 compared to that of nonanal; it was not active toward short-chain aldehydes.

Highly Ordered Anodic Porous Alumina Prepared by Anodization of Al in Extremely Dilute H2SO4

Highly ordered anodic porous alumina with a period of ca. 90–160 nm was prepared by anodization using extremely dilute sulfuric acid. The hole period of anodic porous alumina was controllable in the range of 90–160 nm by changing the anodization voltage. The thickness of the oxide film obtained by the anodization of Al in extremely dilute sulfuric acid was nonuniform. However, we found that the addition of a small amount of phosphoric acid to the electrolyte improved the uniformity of the thickness of the oxide film obtained. The ordered anodic porous alumina obtained in this study is expected to be a starting material for fabricating various functional devices.

Performance and ageing behavior of water-processed LiNi0.5Mn0.3Co0.2O2/Graphite lithium-ion cells

In this study, water-processed LiNi0.5Mn0.3Co0.2O2 cathodes (NMC532) are investigated. Notably, corrosion of aluminum current collector occurring in aqueous processing owing to alkalinity of NMC slurry is avoided through addition of phosphoric acid which buffers the slurry pH, or by using a carbon-coated collector. The impact of small amounts of phosphoric acid on the electrochemical performance is evaluated in half-cells, and the best formulations are selected to perform further ageing tests in pouch cells. In particular, post mortem analyses such as electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy are conducted on the cathodes after long-term cycling in Li-ion cells to fully understand the enhanced cycling stability observed with H3PO4-containing water-based cathode. These analyses allow to conclude on the influence of the binder, the current collector, and the aqueous immersion of the NMC532 powder.

Effect of alcohol leachable chloride on strength of magnesium oxychloride cement

AbstractThe major crystalline phases in magnesium oxychloride cement (MOC) have been extensively studied, but the other phases have not been studied due to the difficulty in identifying them. In the current study, we focused on the effect of chlorine‐containing phases other than crystalline oxychlorides on the strength of cured MOC materials. The alcohol leachable chloride (ALC) was proposed to characterize the other phases containing chlorine, and the absolute ethanol leaching test was developed to determine ACL content in a cured MOC paste. The results showed that either decreasing MgO/MgCl2 molar ratio or increasing H2O/MgCl2 molar ratio led to an increase in ALC content in cured MOC slurry, but adding a small amount of phosphoric acid resulted in very little or almost no ALC in the modified MOC slurry. In addition, increasing ALC content has been shown to significantly reduce the compressive strength of hardened MOC pastes. Thus, the modified MOC pastes had high strength, compared with the corresponding common MOC pastes. According to the experimental results, the relationship between the ALC content and the compressive strength of cured MOC materials was established. Therefore, a low ALC content was proposed as a characteristic index of high‐quality MOC materials.

Plasma Electrolytic Oxidation of Titanium in H2SO4–H3PO4 Mixtures

Oxide layers on titanium foils were produced by galvanostatically controlled plasma electrolytic oxidation in 12.9 M sulfuric acid with small amounts of phosphoric acid added up to a 3% mole fraction. In pure sulfuric acid, the oxide layer is distinctly modified by plasma discharges. As the time of the process increases, rough surfaces with typical circular pores evolve. The predominant crystal phase of the titanium dioxide material is rutile. With the addition of phosphoric acid, discharge effects become less pronounced, and the predominant crystal phase changes to anatase. Furthermore, the oxide layer thickness and mass gain both increase. Already small amounts of phosphoric acid induce these effects. Our findings suggest that anions of phosphoric acid preferentially adsorb to the anodic area and suppress plasma discharges, and conventional anodization is promoted. The process was systematically investigated at different stages, and voltage and oxide formation efficiency were determined. Oxide surfaces and their cross-sections were studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The phase composition was determined by X-ray diffraction and confocal Raman microscopy.

Preparation of phosphorus-doped porous carbon for high performance supercapacitors by one-step carbonization.

Biomass-derived porous carbon has received increasing attention as an energy storage device due to its cost-effectiveness, ease of manufacture, environmental friendliness, and sustainability. In this work, phosphorus-doped porous carbon was prepared from biomass sawdust (carbon source) and a small amount of phosphoric acid (P-doping source and gas expanding agent) by one-step carbonization. For comparison, parallel studies without phosphate treatment were performed under the same conditions. Benefiting from the addition of phosphoric acid, the prepared carbon material has higher carbon yield, higher specific area and micropore volume. Due to the heteroatom doping of P in the carbon material, the optimized PC-900 sample not only exhibits high specific capacitances of 292 F g−1 and 169.4 F g−1 at current densities of 0.1 A g−1 and 0.5 A g−1, respectively, but also excellent cycle longevity (98.3% capacitance retention after 5000 cycles) in 1 M H2SO4. In addition, the supercapacitor exhibits a high energy density of 10.6 W h kg−1 when the power density is 224.8 W kg−1 at a discharge current density of 0.5 A g−1. This work proposes a sustainable strategy to reuse waste biomass in high-performance and green supercapacitors for advanced energy storage equipment.

Effects of Small Amounts of Phosphoric Acid as Additive in the Preparation of Microporous Activated Carbons

The activated carbons with well-developed microporosity were prepared from fir wood (Cunninghamia lanceolata) impregnated with small amounts of phosphoric acid (impregnation ratios, 1.5 – 4.5 wt.%). For comparison purpose, a parallel study of fir wood without impregnation was carried out in the same conditions. The results showed that the addition of small amounts of H3PO4 could lower the thermal decomposition temperature of fir wood and significantly promote the adsorption capacity and the yield of activated carbon. The yield without phosphoric acid impregnation was 6.55 wt.%, which rose to 19.82 wt.% in the case of 3.0 wt.% H3PO4 impregnation. Using small amounts of phosphoric acid as additive was beneficial to improve specific surface area (SBET) and micropore volume (Vmic), and could produce activated carbons with well-developed microporous structure. With 3.0 wt.% H3PO4 impregnation, SBET and Vmic of the activated carbon reached as high as 1281.6 m2/g and 0.535 mL/g, the ratio of Vmic/Vtot (total pore volume) was higher than 80 %. DOI: http://dx.doi.org/10.5755/j01.ms.24.4.18999

Synthesis of Thermally Stable Nanocrystalline Phosphorus-modified Titanium(IV) Dioxides with Rutile Structure

Thermally stable nanocrystalline rutile TiO2 particles modified with small amounts of P were prepared via hydrothermal treatment from mixtures containing Ti-containing precursors, which were obtained by aging diluted HCl solutions of amorphous TiO2 at a low temperature, and small amounts of phosphoric acid. XRD results of the products and UV–vis spectra of the samples nitrified at a high temperature suggest the incorporation of P atoms in the TiO2 structure, which contributes to the enhanced thermal stability of the P-modified TiO2 samples.

Activity inhibition and its mitigation in high temperature proton exchange membrane fuel cells: The role of phosphoric acid, ammonium trifluoromethanesulfonate, and polyvinylidene difluoride

In the presented work we systematically study the influence of phosphoric acid, ammonium trifluoromethanesulfonate (ATFMS), and polyvinylidene difluoride (PVDF) on the oxygen reduction reaction (ORR) activity of carbon supported, Pt based catalysts. The influence of phosphoric acid is investigated in a mixed solution of perchloric acid with small amounts of phosphoric acid added. Thin-film rotating disk electrode (TF-RDE) measurements show that such a mixed electrolyte is advantageous as the oxygen reduction reaction (ORR) is inhibited without influencing the oxygen solubility in the electrolyte. In contrast to previous reports it is seen when investigating additives that ATFMS acts as a catalyst poison; whereas the results provide evidence of a better performance in case of the PVDF incorporated catalysts as compared to reference samples without PVDF. The technological relevance of the PVDF improvements and its stability over prolonged time was validated by membrane electrode assembly (MEA) tests.

Evaluating Perfluorinated Acid Electrolytes for High-Temperature Proton Exchange Membrane Fuel Cell

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) based on phosphoric acid doped polybenzimidazole (H3PO4/PBI) membrane operate at elevated temperatures between 150 ºC and 180 ºC. The HT-PEMFC stacks have much simpler water and thermal management than lower-temperature PEM fuel cells and can operate on reformat gas. These advantages make this type of fuel cells an interesting candidate for auxiliary and stationary power units. At this moment, however, no commercial HT-PEMFCs have been developed to meet the reliability and cost requirements.One of the main reasons that limit the wide application of HT-PEMFCs is the sluggish oxygen reduction reaction (ORR) rate in concentrated phosphoric acid. Despite good physical and chemical properties, phosphoric acid is a rather poor fuel cell electrolyte. The slow ORR kinetics in concentrated phosphoric acid is still not completely understood, and it is believed to be related to strong adsorption of phosphoric acid species on the surface of the platinum catalyst.Fluorinated acids as alternative electrolytes might hold the key to overcoming this obstacle. They seem to adsorb less strongly on platinum compared with phosphoric acid, which may increase the ORR rate and lead to high-performance fuel cells. In addition, these novel acids are ideal model systems to study the influence of adsorbates on ORR.Appleby and Baker [1] were among the first who proposed trifluoromethane sulfonic acid (CF3SO3H) as an alternative electrolyte for phosphoric acid fuel cells. Later, Yeager and his co-workers adopted the idea and conducted a more extensive research on fluorinated acids such as monofluorophosphoric acid [FPO(OH)2] and trifluoromethane sulfonic acid. The quest for novel electrolyte compounds that have the physical and chemical properties to meet the HT-PEMFC requirements remains challenging. An ideal candidate material should be both electrochemically and thermally stable, and it should have a very low vapour pressure over the operating temperature range of HT-PEMFCs. Recently, a number of perfluoroalkyl- phosphonic and phosphinic acids with different chain length have been successfully synthesized. These compounds might have the desired properties to serve as electrolytes for HT-PEMFCs. Besides their higher O2solubility they show significant advantages over phosphoric acid, such as a high protonic conductivity under unhydrous conditions [2]. Furthermore, these strong acids tend not to have specific adsorption on the platinum surface.Here, we report cyclic voltammetry (CV) and rotating disc electrode (RDE) experiments with small amounts of phosphoric acid and novel perfluorinated electrolyte candidates added into the perchloric acid electrolyte. Noticeable differences in the voltammograms (Fig. 1) and significant impact on the RDE kinetic current (Fig. 2) were observed. For a more thorough analysis of the adsorption mechanism, electrochemical impedance spectroscopy (EIS) measurements were carried out. Evaluation of the charge transfer resistance for the ORR on platinum was found to be in good agreement with the RDE measurements.Additionally, preliminary experiments were performed to assess the effectiveness of such alternative electrolytes for practical fuel cell applications. Perfluorinated acids were added into the catalyst layer of a HT-PEMFC. First results on the influence on membrane electrode assembly (MEA) performance will be presented.

Etching, micro hardness and laser damage threshold studies of a nonlinear optical material L-valine

A nonlinear optical crystal of L-valine was grown from an aqueous solution containing a small amount of phosphoric acid by the slow evaporation method. The grown crystal was characterized by a single crystal X-ray diffraction to determine the unit cell parameters. The powder X-ray diffraction analysis also confirmed the lattice parameters to be a = 9.6687(7) A, b = 5.2709(4) A, c = 12.0371(10) A and β = 90.805(4)°. The results of the Inductively Coupled Plasma Optical Emission Spectrometry (ICPOES) indicate the presence of a small amount of phosphorus in the grown crystal. The Vickers micro hardness test was performed to study the mechanical strength of the crystals. Chemical etching studies were carried out to analyze the dislocation structure. The laser damaged threshold of the grown crystal was measured to be 11.11 GW/cm2 for 10 ns pulse at 1064 nm, which is higher than that of the standard nonlinear optical crystals like KDP. Second harmonic generation of the grown crystals was also 1.44 times that of KDP.

Organized Mesoporous TiO2 Films Stabilized by Phosphorus: Application for Dye-Sensitized Solar Cells

A synthetic protocol was developed for the preparation of thin mesoporous films with enhanced thermal stability. This objective was achieved by a modification of the procedure of supramolecular templating by a Pluronic P-123 copolymer by an addition of a small amount of phosphoric acid to the precursor solution. Thin mesoporous films up to thick were prepared via layer-by-layer deposition. The roughness factor exceeding 1300 was achieved on these films. After annealing at , well-developed 5–6 nm anatase nanocrystals were present in the pore walls of a still perfect mesoporous structure. The pore coalescence and structure collapse during heat-treatment were effectively hindered by the presence of phosphorus. Our P-modified mesoporous films were sensitized with the N-945 dye and used as photoanodes of the dye-sensitized solar cells. They reached the conversion efficiency of 5.03 or 5.05% for the film thickness of 1.8 or , respectively. Whereas the roughness factor scaled linearly with the number of layers, the solar conversion efficiency reached a constant value for films consisting of eight or more layers.

Low-temperature Fracture in Reactive-ethylene-terpolymer-modified Asphalt Binders

This paper reports on the low-temperature fracture and yield properties of a number of Strategic Highway Research Program asphalt binders that were modified with 5% by weight of a reactive terpolymer of ethylene, butyl acrylate and glycidyl methacrylate. Selected binders were also tested with the addition of small amounts of phosphoric acid. Fracture toughness and energy were determined at temperatures close to where the stiffness reached 300 MPa while the 2% offset yield stress was determined at somewhat lower strain rates in compression. Significant differences were found in the fracture properties ( K Ic and G Ic ) of these binders depending on the compatibility of the polymer with the base asphalt. It is suggested that the fracture energy and yield stress at low temperatures may be able to more accurately grade binders for their performance with respect to thermal stress cracking in the pavement compared to the currently used SHRP specification properties.

Potential utilization of phosphogypsum

The waste phosphogypsum produced by Paradeep Phosphate Limited (PPL) at Paradeep (Cuttack, Orissa, India) consists primarily of calcium sulfate with small amounts of phosphoric acid, calcium fluoride and other harmful components. Presently these are dumped as waste. In this work, laboratory trials have been made to utilize the calcium sulfate present in the phosphogypsum to prepare usable products like ammonium sulfate, calcium carbonate and magnesium sulfate.

Effects of phosphoric acid additions on the behaviour of the lead—acid cell: A review

The electrochemical behaviour of a lead—acid cell changes significantly after the addition of small amounts of phosphoric acid (H 3PO 4). The o

Rapid Simultaneous Analysis of Nicotinic Acid and Nicotinamide in Foods, and Their Behavior during Storage

A simple and sensitive method was developed for determination of nicotinic acid (NA) and nicotinamide (NAA) in foods. NA and NAA were extracted with methanol from meat after addition of a small amount of phosphoric acid. After filtration, NA and NAA in the extract were determined by high performance liquid chromatography (HPLC) with a UV detector at 261nm. Standard solutions of NA and NAA were prepared with a mixture of 0.2% sodium chloride-1% ammonium acetate solution: methanol (1:4). The HPLC system adopted was ion-pair chromatography in the reverse-phase mode on a 5cm short column (C18) with sodium dodecyl sulfate as a counter ion. Recoveries of NA and NAA added to beef, pork and tuna were more than 97%, and the detection limit was about 0.1mg% in samples.During storage, NAA in meat and fish appeared to be changed to NA concomitantly with growth of bacteria, and the change was confirmed to be caused by bacteria rather than by any enzyme in the meat. NA was detected in most commercial meat and fish samples tested.

Effect of a small amount of phosphoric acid in inductively coupled plasma atomic spectroscopy

Small amount of phosphoric acid even down to 0.1% in a sample solution will reduce appreciably the line intensities of analytes in the ICP-AES when employing aerosol desolvation. The phenomenon was chiefly due to insufficient desolvation of the aerosols, and therefore can be overcome by elevating the desolvation temperature or eliminating the desolvation step.

CHANGES IN NONVOLATILE ACIDS AND OTHER CHEMICAL CONSTITUENTS OF NEW YORK STATE GRAPES AND WINES DURING MATURATION AND FERMENTATION

ABSTRACTThe changes in chemical components during maturation and fermentation of four native American and one French hybrid grape cultivar obtained from a commercial vineyard and winery were examined. In all cultivars, titratable acidity, tartrate, and malate content decreased during the maturation period. Titratable acidity values ranged from 0.99% for ‘Niagara’ to 1.82% for ‘Catawba’ at maturity. Soluble solids and color content remained constant until veraison after which they increased steadily. Small amounts of phosphoric acid were detected during maturation. In nearly all cases, fermentation of the musts was completed within one week. Reductions in total acidity, tartrate, malate, phosphoric acid, and reducing sugar content were seen. Increases in the amounts of ethanol and succinic acid were also observed. During the course of the fermentation, pH values varied among cultivars.

Rhodium Complex Catalyzed Methanol Carbonylation. Effects of Medium and Various Additives

Kinetic experiments in an isothermal batch reactor demonstrated the influence of water concentration (0-27 m), the addition of strong acids (phosphoric, sulfuric, and hydrochloric acid), solvents (acetic acid, benzene, methyl ethyl ketone, and dioxane) and promoters (methyl iodide and hydrogen iodide) on the carbonylation reaction previously studied. The best medium for the reaction was acetic acid. When a 57% aqueous hydrogen iodide solution was used as promoter, the water content was adequate, but when methyl iodide was used, an equivalent amount of water had to be added to reach the same reaction rate. The reaction was zero order with respect to methanol over a broad concentration range when a small amount of phosphoric acid was added. When dioxane was the solvent, the polarity of the medium was adjusted to the optimal value by adding water. The same set of standard conditions was used as reference for all the experiments: 40 atm carbon monoxide pressure (25/sup 0/C); 182.6/sup 0/C 3 M methanol; 0.0046 M rhodium as RhCl/sub 3//4.2H/sub 2/O; 0.5 M iodine as 57% aqueous hydrogen iodide solution; and acetic acid as solvent. Tables and graphs.

The characterization of phosphoric acid‐treated peat as a cation exchanger

Abstract Peat, obtained from Glenamoy, County Mayo, Ireland, is shown to have enhanced cation exchange capacities after treatment with small amounts of phosphoric acid. It is also shown that the use of both sulfuric and phosphoric acid yields higher capacities which are analogous to those observed previously for the sulfuric acid treatment alone. Even though the phosphoric acid treatment did not show the highest capacities, it has excellent physical properties: Greatly reduced leaching and swelling in comparison to the other forms of peat which have been studied. Also, high recoveries of Cu from dilute solutions (l.33ppm) is seen. Thus, the data indicate the feasibility of utilizing phosphoric acid‐treated peat as an inexpensive cation exchanger in large scale water treatment flow systems.