Mixture Of Phosphoric Acid Research Articles

Uranium extraction with modified sorbents

Hydrometallurgical processing of uranium-containing raw materials generates a significant amount of liquid industry-related waste, namely waste solutions that require disposal. Sorption is known as one of the most effective methods for purifying liquid matters contaminated with radionuclides. Various modification options are being developed for the purpose of using natural sorbents and increasing their sorption capacity. The authors proposed the methods for modifying natural aluminosilicate and coal-mineral raw materials. Zeolite found at the Kusmurun deposit and shungite from the Koksu deposit were selected for the research. The methods are based on obtaining solid-phase extractants. It was proposed to modify natural sorbents with a mixture of tributyl phosphate and di2-ethylhexyl phosphoric acid in kerosene, as well as a mixture of phosphoric acid and polyacrylamide. It was demonstrated that the first method is preferable for zeolite, and the second one for shungite. The research addressed the sorption properties of modified sorbents in static and dynamic modes. Uranium sorption isotherms were plotted. The maximum sorption capacity and the Langmuir constant were calculated. The research allowed synthesizing an organopolymer based on shungite, glycidyl methacrylate, orthophosphoric, and hydroxyethyl diphosphoric acids. Its sorption properties were studied under dynamic conditions. Its sorption capacity was assessed in comparison with modified natural sorbents.

Corrosion resistance of 5005 aluminum alloy by anodizing treatment in a mixture of phosphoric and boric acids

The corrosion resistance of 5005 aluminum alloy was improved by anodizing treatment in a mixture electrolyte of phosphoric acid and boric acid. The influence of anodizing parameters on the corrosion resistance of the studied alloy has been investigated. For example, the effect of the concentration of phosphoric acid, concentration of boric acid, voltage and time of anodization. In this work, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of the aluminum alloy. Scanning electron microscopy (SEM) method was used to study the surface of the aluminum alloy before and after anodization. The obtained results show that the anodizing treatment of 5005 aluminum alloy in phosphoric-boric acids provides better corrosion resistance in comparison with the anodizing treatment in phosphoric acid.

Percentage Analysis Mixed of CPO, Phosphic Acid and Sodium Hydroxide as a Replacement for Diesel Engine Oil Fuel Using a Calorize Test

One of the researches being developed is to produce methyl esters from CPO through transesterification reaction of vegetable oil (triglycerides) with methanol. Biodiesel from crude palm oil is a new hope for answering some of the energy needs. know the rate of combustion of the biodiesel produced. Biodiesel that is produced from a mixture of CPO, phosphoric acid and sodium hydroxide, with a percentage of I. 98% CPO, 1% Phosphoric Acid, 1% Sodium Hydroxide: II. 95% CPO, 2% Phosphoric Acid, 3% Sodium Hydroxide: III. 95% CPO, 3% Phosphoric Acid, 2% Sodium Hydroxide. The results showed that the most effective mixture was 95% CPO, 3% acid phosphate and 2% sodium hydroxide with a burning rate of 0.309 g / minute in 30.42 minutes with a final temperature of 57 (oC).

Mixed-acid intercalation for synthesis of a high conductivity electrochemically exfoliated graphene

Precise control of electrochemical intercalation and exfoliation conditions provides a method for tuning graphene properties. A systematic evaluation of the defects induced in graphene for varying intercalation times and intercalant composition is done using a sulphuric and phosphoric acid mixtures. Intercalation was performed in a concentrated mixture of sulphuric and phosphoric acid, followed by anodic exfoliation in aqueous ammonium sulphate solution. Multi-atom-doped graphene with primarily “boundary-type” defects is obtained, and the ratio of the defect-activated Raman modes showed a unique characteristics at 1600 s intercalation, irrespective of the intercalant composition. Careful selection of intercalation time is required to control the graphene defects. Phosphorus and nitrogen-doping increased with phosphoric acid content, influencing graphene properties. Interestingly, extending intercalation times beyond 1600 s deteriorated the electrical conductivity but enhanced the thermal stability with higher phosphoric acid content. We attribute this to loss of the sp2 graphitic structure at higher intercalation times which dominates over contributions from the dopants. The highest electrical conductivity of ∼14,000 S m−1 was two orders of magnitude higher than graphene obtained with pure sulphuric-acid intercalation. By adding phosphoric acid into the intercalant, the energy consumption and exfoliation time was reduced by 34% and by a factor of 3 respectively.

Synthesis of 4-(1-Adamantyl)-1-Naphthol and 4-(1-Adamantyl)-1-Methoxynaphthalene

Adamantylation of 1-napthol and 1-methoxynaphthol in the mixture of phosphoric and glacial acetic acids leads to the formation of 2- and 4-substituted products. Formed products are less involved into the further oxidative transformations in used conditions

Sustainable and Efficient Recovery of Tungsten from Wolframite in a Sulfuric Acid and Phosphoric Acid Mixed System

The innovative technology of coleaching scheelite concentrates by a mixture of sulfuric acid and phosphoric acid is an environmentally friendly and low-cost technology. Although the world’s first p...

New analytical method for chlorpyrifos determination in biobeds constructed in Brazil: Development and validation

A quick and efficient method was optimized and validated to determine chlorpyrifos in biobeds using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Chlorpyrifos was extracted from the matrix with 30 mL of a mixture of acetone, phosphoric acid and water 98:1:1 (v/v/v). After homogenization, centrifugation and filtration, 125 µL of the extract was evaporated and reconstituted in 5 mL of methanol acidified with 0.1% acetic acid. Validation was performed by studying analytical curve linearity (r2), estimated instrument and method limits of detection and limits of quantification (LODi, LODm, LOQi and LOQm, respectively), accuracy, precision (expressed as relative standard deviation, RSD), and matrix effect. Accuracy and precision were determined from the amount of pesticide recovered from biobed blank samples (i.e. without pesticide residue) spiked with chlorpyrifos at three different concentrations (2, 10 and 50 mg kg−1), with seven replicates at each concentration. For all three concentrations studied, the average recovery values obtained were between 96 and 115% with RSD values lower than 20%. The validated LOQ obtained was 2 mg kg−1 (from recovery studies) and the matrix effect observed was lower than ±20%, which demonstrated that there was neither considerable suppression nor enhancement of the analyte signal. The biobed system efficiently degraded chlorpyrifos in both 1) simulation of accidental spillage and 2) application of diluted pesticide solution. In the latter case, all the values obtained at the final sampling time (14 months) were below the validated LOQm.

Efecto de inoculantes y aditivos sobre fracciones de fermentación ruminal y degradación in vitro en ensilaje de sorgo (Sorghum sp)

La acción de inoculantes y aditivos sobre la composición química y degradación ruminal de la materia seca (MS) de ensilaje de sorgo ya ha sido reportada. Sin embargo, se desconoce el efecto que estos tienen sobre la actividad microbiana, y por lo tanto, sobre su potencial de asimilación a nivel ruminal. El objetivo de este estudio fue evaluar el efecto de la adición de inoculantes y aditivos en ensilaje de la planta completa de Sorghum sp. sobre las fracciones de fermentación ruminal y degradación in vitro. Se utilizó un diseño experimental completamente al azar, con 7 tratamientos (control, 3 inoculantes, 2 aditivos y una combinación de inoculante con aditivo) y 21 repeticiones por tratamiento. Se usaron diferentes tipos de inoculantes y aditivos en el proceso de ensilaje de sorgo: lactosuero, yogur, ácido fosfórico, Lactobacillus plantarum y mezcla mineral. Después de 60 d de fermentación, se cuantificaron MS, pH, proteína cruda (PC), degradación in vitro de la MS a 24 h (DIVMS), parámetros de la cinética de fermentación (Vmáx = volumen máximo, L = fase lag, S = tasa de fermentación) y volumen fraccional (fermentación rápida = 0 h a 8 h, media = 8 h a 24 h y lenta = 24 h a 72 h) por producción de gas in vitro. El análisis estadístico indicó que los inoculantes y aditivos modificaron la composición química, los parámetros L, Vmáx, DIVMS y las fracciones de fermentación rápida y media (P < 0.05). El uso de lactosuero y L. plantarum como inoculantes en ensilaje de sorgo redujo la pérdida de PC y, en general, los inoculantes y aditivos mejoraron el pH de los ensilajes; no obstante, disminuyeron el aprovechamiento de las fracciones de fermentación rápida y media, modificaron el potencial de fermentación y provocaron efecto negativo en la DIVMS.

Advanced Energy-Saving Technology of Granular Nitrate-Containing NPK-Fertilizers

There was developed the technology of granular balanced nitrate-containing NPK-fertilizers 16-16-16 and 17-17-17. Key features of the proposed technology are: - Joint ammoniation of a mixture of nitric and phosphoric acids to a molar ratio of NH3:H3PO4 1.4÷1.5 and complete-ammoniation in Ammoniatior-Granulator drum to 1.65÷1.8. - Due to more efficient use of acid neutralization heat, the fluent slurry is obtained with low moisture content required for granulation. Ammoniation of a mixture of nitric and phosphoric acids at higher molar ratio makes it possible to exclude the possibility of acidification of ammonium nitrate, which causes the process of self-accelerating decomposition. The production of fertilizer grades with an increased molar ratio in the product have the following advantages: - higher degree of WPA neutralization to a molar ratio of NH3:H3PO4 of 1.65÷1.8 mol / mol allows to reduce the consumption of nitric acid and to exclude the stage of forced evaporation of nitrate slurry and the stage of ammonium nitrate melt preparation; - the cost of NPK-fertilizers with a lower content of ammonium nitrate is lower due to partial substitution of the nitrate nitrogen for ammonia nitrogen. - improvement of physical and chemical properties of the final product due to reduction of nitrate nitrogen content, - thermal stability of the obtained nitrate-containing NPK-fertilizers with an increased molar ratio in the product 1.65÷1.8; - flexibility to obtain a broad range of NPK-fertilizer grades.

Sapphire advanced mitigation process: wet etch to expose sub-surface damage and increase laser damage resistance and mechanical strength.

A novel, to the best of our knowledge, method of wet chemical etching of sapphire workpieces (such as optics, wafers, windows, and cones), called the sapphire advanced mitigation process (or sapphire AMP), has been developed that exposes sub-surface mechanical damage created during the optical fabrication process and significantly enhances the surface laser damage resistance ($ \gt {2{\times}}$>2×) and mechanical strength (up to $\sim{2.6{\times}}$∼2.6×). Sapphire AMP involves first treating the workpiece with a mixture of sulfuric and phosphoric acid $([{\rm H_{2}{\rm SO_{4}}}]:[{\rm H_{3}{\rm PO_{4}}}]=1:3)$([H2SO4]:[H3PO4]=1:3) at 220°C, followed with phosphoric acid at 160°C, then with sodium hydroxide base (NaOH) and surfactant at 40°C, and finally with a high-pressure deionized water spray rinse. Sapphire AMP has been demonstrated on both A- and C-plane sapphire workpieces. The mechanism of this etch process involves the reaction of the sapphire $({\rm Al_{2}}{\rm O_{3}})$(Al2O3) surface with sulfuric acid $({\rm H_{2}}{\rm SO_{4}})$(H2SO4) forming aluminum sulfate $[{{\rm Al}_2}{({{\rm SO}_4})_3}]$[Al2(SO4)3], which has low solubility. The high phosphoric acid content in the first and second steps of sapphire AMP results in the efficient conversion of ${{\rm Al}_2}{({{\rm SO}_4})_3}$Al2(SO4)3 to aluminum phosphate $({\rm AlPO_{4}})$(AlPO4), which is very soluble, greatly reducing reaction product redeposition on the workpiece surface. Sapphire AMP is shown to expose sub-surface mechanical damage on the sapphire surface created during the grinding and polishing processes, whose etched morphology has either isotropic or anisotropic evolution depending on the nature of the initial surface damage. Sapphire AMP was also designed to remove the key known surface, laser absorbing precursors (namely, foreign chemical impurities, the fracture surface layer of preexisting sub-surface damage, and reaction product or foreign species redeposition or precipitation). Static and sliding indention induced surface microfractures on sapphire are shown after sapphire AMP to have a significant decrease in the fast photoluminescence intensity (a known metric for measuring the degree of laser damaging absorbing precursors). In addition, the onset of laser damage (at 351 nm 3 ns) on sapphire AMP treated workpieces was shown to increase in fluence from $\sim{4}$∼4 to $ \gt {9}.{5}\;{{\rm J/cm}^2}$>9.5J/cm2. Finally, biaxial ball-on-ring mechanical tests on sapphire disks showed an increase in the failure stress from 340 MPa (with pre-existing 28 µm flaws) to $\sim{900}\;{\rm MPa}$∼900MPa after sapphire AMP, which is attributed to the blunting of the surface microfractures.

Crystal structure, vibrational and spectroscopic study of single crystal (C6H15N4O2)H2PO4.H2O

A single crystal was selected from the reaction product of a stoichiometric mixture of phosphoric acid (H 3 PO 4 ) to which was added the L-arginine (C 6 H 14 N 4 O 2 ) and its crystal structure was determined from three dimensional X-ray diffraction data. The structure is monoclinic, space group P2 1 , a = 7.3450(14) A, b = 7.9176(15) A, c = 10.8796(22) A, β = 97.98(2)°, V = 626.57(186) A 3 and Z = 2, least squares refinement was converged to R 1 =0.0456, wR 2 =0.1433 for 3278 unique reflections. The structure consists of chains formed by edge sharing of PO 4 tetrahedra, water and arginine. The stacking along b axis consists of these chains bridged by layers formed by PO 4 water and arginine by hydrogen bonds. The Raman and infrared spectra of single crystal LAP were recorded to determine the symmetries of the vibrations of the various molecular groups such as NH 3 + , NH 2 , CH 2 , CH, COO - , H 2 O and H 2 PO 4 present in the crystal.

Development of Superhydrophilic 6061 Aluminum Alloy by Stepwise Anodization According to Pore-Widening Time

This study created alumina structures with the highest hydrophilic properties on 6061 aluminum alloy. The anodization process was applied to make various aluminum oxide structures. To create uniform alumina structures on top of a 6061 aluminum alloy surface, after conducting the first anodization in 0.3 M oxalic acid at 40 V at 0 <sup>o</sup>C, the alumina was removed using a mixture of chromic acid and phosphoric acid. Then, secondary and tertiary anodization was performed using the same electrolyte conditions as the primary anodization for 30 minutes at 40 V, respectively. Pore-widening (PW) of oxide film formed after the secondary anodic oxidation was performed for 20, 30, and 40 minutes in 0.1 M phosphoric acid solution. The PW time control allowed various oxide structures to be created, and reduced the area of the outermost surface in contact with water droplets. The smaller the initial area of water droplets, the better the hydrophilic phenomenon. The surface area can be represented as a solid fractional value. Surfaces with solid fraction values of less than or equal to 0.5 were superhydrophilic. This well-controlled anodization process with a pore-widening step can be used to create excellent superhydrophilicity on various metallic substrates, expanding their usefulness and efficacy.

Corrosion Resistant Alloys for Phosphoric Acid Production and Storage

This paper addresses the topic of material selection for several parts of the phosphoric acid production chain, focusing essentially on corrosion resistant alloys and life cycle cost. During the phosphate attack by sulfuric acid, the vessel can be susceptible to corrosion due to the presence of an aggressive slurry which consists of a mixture of phosphoric acid, sulfuric acid, chlorides and hydrofluoric acid. This study reports the results of corrosion tests performed on various stainless steels in this kind of mixture at 80°C and 110°C, corresponding to the temperature of the di-hydrate and hemi-hydrate processes, respectively. From this study, it is highlighted that the super-duplex stainless steel 2507Cu / UNS S32550 (25% chromium, 7% nickel) can be recommended for phosphoric acid production provided that the temperature does not exceed 80°C. This alloy also offers a good resistance to abrasion and may allow the design engineer to decrease the wall thickness thanks to its high mechanical properties. If the temperature is higher than 110°C, materials containing more alloying elements must be selected, like alloy 31 / UNS N08031 or alloy 28 / UNS N08028. For phosphoric acid transportation and storage, the behavior of various stainless steels is also investigated. The influence of several levels of chloride contamination on the corrosion rates is considered. The results reveal that the duplex steel 2202 / UNS S32202 (22% chromium, 2% nickel) is a cost-efficient alternative to conventional austenitic stainless steels, offering better mechanical properties and corrosion resistance in the presence of chlorides.

One-step method for obtaining bifunctional charcoal and study of its properties

Single-stage process of obtaining active carbon by thermal processing of plant raw materials (mixture of different types of wood sawdust) impregnated with the mixture of phosphoric acid, urea and nitric acid salts has been developed. Active influence of impregnates on the process of carbonization and formation of carbon residue has been demonstrated. It is established that carbon residue obtained in the interval of heating 20–700 °С possesses high sorption activity to the vapors of organic compounds and has ion-exchange capacity. It has been shown that the value of carbon residue depending on the impregnate used in the wood increases by 3,1 times at 600 °С and by 4,2 times – at 700 °С as compared to the yield of non-treated initial raw materials.

Dissolution behavior of the associated rare-earth elements in scheelite using a mixture of sulfuric and phosphoric acids

In scheelite, the associated rare-earth elements (REEs) can exist in the form of isomorphous RE2(WO4)3 or monazite (REPO4). To extract REEs from scheelite using the mixture of H2SO4 and H3PO4 acids, the dissolution behavior of isomorphic REEs and monazite was investigated in this study. The results show that the isomorphic REEs were easily decomposed using mixed acid, that is, H2SO4–H3PO4. Owing to the eutectic and sorption of gypsum, a part of the leached REE enters gypsum residue in the form of RE phosphate with increasing reaction temperature and volume ratios of H2SO4–H3PO4. After washing with a diluted acid solution, the precipitated REE was completely leached again into the washing liquor until 100% digestion of REE was obtained. However, only 1.3% leaching of the REE was attained for the monazite REE due to inefficient dissolution from using the mixed acid (H2SO4–H3PO4). However, considering mechanical activation of the associated REE in scheelite, the REE leaching could be improved to 35% in the presence of mixed acid.

Selective etching of fs-laser inscribed high aspect ratio microstructures in YAG

We report on a systematic investigation of selective etching of fs-laser inscribed microstructures in Y3Al5O12 (YAG). The resulting microchannels are up to 8.9 mm long and exhibit cross sections from below 10 µm to more than 100 µm. Aspect ratios of up to 593 were achieved. Investigations with different structuring and etching parameters revealed that the etching process is mainly diffusion determined. The etching depth depends on the square root of time, similar to the well-known Brownian motion. In addition, we could enhance the etching diffusion constant by a factor of two, reducing the time to etch the longest channel by an order of magnitude, using a 1:1 mixture of sulfuric and phosphoric acid instead of pure phosphoric acid. The observed fundamental time dependence in conjunction with diffusion coefficients up to 160 µm/h1/2 makes the etching behavior highly predictable and paves the way toward arbitrary three-dimensional micro- and nanostructuring over long distances in crystalline materials.

Enantioselective Synthesis of 1-Substituted 1,2,3,4-Tetrahydroisoquinolines through 1,3-Dipolar Cycloaddition by a Chiral Phosphoric Acid

A new approach is described for the asymmetric synthesis of 1-substituted 1,2,3,4-tetrahydroisoquinolines that is based on the enantioselective 1,3-dipolar cycloaddition reaction of a nitrone and a vinyl ether in the presence of a chiral phosphoric acid that gives the chiral tetrahydroisoquinolines in high yields and with high enantioselectivities. 1H and 31P NMR analyses of the mixture of nitrone and chiral phosphoric acid suggest the formation of a 1:1 complex.

Determination of ceftriaxone concentration in human cerebrospinal fluid by high-performance liquid chromatography with UV detection

Determination of ceftriaxone (CTRX) concentration in human cerebrospinal fluid (CSF) is required to clarify whether a high concentration of CTRX in CSF is associated with CTRX-induced encephalopathy (CIE). In our study, in order to perform an accurate analysis of CSF sample from CIE patient, we proposed HPLC with UV detection (HPLC-UV) using an octadecylsilica (ODS) column, a methanol and 10 mM phosphoric acid (25:75, v/v) mixture solution as a mobile phase, and a detection wavelength at 280 nm. The linear range was from 0.1 to 100 μg/mL (r = 0.999) in the present HPLC-UV. In the recovery tests using blank samples of human CSF and control serum spiked with CTRX, the recoveries of CTRX were >95.3%, and the RSD (n = 3) was <5.8%. We applied the proposed HPLC-UV system to determine CTRX in the CSF and serum samples obtained from a patient diagnosed as having CIE, and it was revealed that the CTRX concentrations in the CSF sample and the serum were 2.61 and 37.35 μg/mL, respectively. To the best of our knowledge, this is the first report describing the determination of CTRX concentration in a CSF sample obtained from a peritoneal dialysis patient diagnosed as having CIE.

Excitation of plasmons in self-ordered arrays of aluminum and silver nanoconcaves within UV–IR spectral range

Large-scale hexagonally aluminum nanoconcave arrays were synthesized by electrochemical anodization of aluminum using oxalic acid and mixtures of phosphoric acid and citric acid; which, in turn, were used as nanostructured substrates to control the plasmonic resonances of silver. Plasmonic properties of both systems were investigated based on specular reflectivity in the ultraviolet–visible–infrared range. We found that their optical reflectance was dramatically reduced as compared with unstructured films deposited by thermal evaporation that were used as references. At the same time pronounced reflectance dips were detectable in the 262–1077 nm wavelength range, which were ascribed to plasmonic resonances of first and higher orders. We propose that the use of nanostructured aluminum as a substrate can be extended for the control of plasmonic properties of other metals.

Hydrothermally cladded crystalline fibers for laser applications [Invited

Various rare earth doped single crystal YAG and sesquioxide fibers have been drawn using the laser heated pedestal growth (LHPG) method. Crystalline core/clad fibers have been successfully fabricated using a two-step hydrothermal growth method applied to core fibers. The development of a two-step process is essential to the growth of reasonable cladding layers. Various shapes of the cladding layer were observed, i.e., octagon, hexagon, square and intermediate shapes. EDX study shows a stoichiometry of YAG composition of the clad and there is no significant diffusion of the rare earth ion across the core/clad interface. No birefringence was observed under cross-polarized light indicating that a negligible stress between core/clad crystals was formed during hydrothermal process. Acid etching is an effective method to obtain faceted YAG fibers with a reduced diameter in a controlled manner. An etch rate of ∼0.15 µm/min was measured using 50:50 mixtures of phosphoric acid and sulfuric acid at elevated temperature. Scattering loss of 0.05 dB/cm and a net peak gain of 19 dB was measured from 10% Yb:YAG core/YAG clad fiber. The hydrothermal technique is a versatile epitaxial method to growth undoped YAG cladding of various thicknesses onto doped YAG core fibers and has a great potential to pave the way forward for improving laser performance.