Study of Vibrational Spectra of Polyaniline Doped with Sulfuric Acid and Phosphoric Acid

2001 ◽  
Vol 96 (1-3) ◽  
pp. 173-182 ◽  
Author(s):  
Manju Arora ◽  
Vandna Luthra ◽  
Ramadhar Singh ◽  
S K Gupta
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Vibrational Spectra

scholarly journals Study of the regularity of the process of decomposition of apatite with sulfuricacid at the boilingpoint of the solution

2019 ◽  
Vol 58 (4) ◽  
pp. 119-122
Author(s):  
Rauf F. Sabirov ◽  
◽  
Alexey F. Makhotkin ◽  
Yury N. Sakharov ◽  
Igor A. Makhotkin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Boiling Point ◽  
Batch Reactor ◽  
Material Balance ◽  
Mercury Thermometer ◽  
Experimental Values ◽  
Kinetics Of ◽  
Liquid And Solid Phases ◽  
Phosphoric Acids

Experimental research of the kinetics of the decomposition process of Kovdorsky apatite with a size = 0.16 mm with sulfuric acid in a 1 dm3 batch reactor. Phosphoric acid with the concentration of 68.6 % wt and the sulfuric acid with the concentration of 12.3% wt in stoichiometric amount was introduces at the beginning of the process. The process was carried out at a ratio of liquid and solid phases 2.5:1 respectively at the boiling point of the mixture equal to 136 °C. The observing the progress was carried out according to the method of joint designation of sulfuric and phosphoric acids by titrimetric analysis. With methyl orange and then phenolphthalein 2 titration jumps were recorded, the first of which corresponded to the neutralization of sulfuric acid to Na2SO4 and phosphoric acid to NaH2PO4, the second to the neutralization of NaH2PO4 to Na2HPO4. The change in temperature of the reaction mixture was fixed during the process using a mercury thermometer. In the analysis of the derived experimental values of specified parameters that the boiling point decreases from 136 to 133.1 оС within 50 minutes during the process. A comparison of the reported values with the concentration values of sulfuric and phosphoric acids measured during the process shows that the change in boiling point of the reaction mixture is proportional to the change in the concentrations of sulfuric and phosphoric acids. This model is a closed system that provides thermal insulation and no loss of material balance. Thus, the kinetics of the decomposition of apatite with sulfuric acid at the boiling point can be monitored by the temperature change under specified conditions.

scholarly journals Plasma Electrolytic Oxidation of Titanium in H2SO4–H3PO4 Mixtures

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 116 ◽  
Author(s):  
Bernd Engelkamp ◽  
Björn Fischer ◽  
Klaus Schierbaum
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Oxide Layer ◽  
Plasma Electrolytic Oxidation ◽  
Phase Changes ◽  
Crystal Phase ◽  
Plasma Discharges ◽  
X Ray ◽  
Electrolytic Oxidation ◽  
Plasma Electrolytic

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.

Electropolishing of 316L Stainless Steel Using Sulfuric Acid-Free Electrolyte

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Wei Han ◽  
Fengzhou Fang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Photoelectron Spectroscopy ◽  
316L Stainless Steel ◽  
Electrochemical Analysis ◽  
Limiting Current ◽  
Plateau Region ◽  
X Ray

Abstract The study is to investigate the electropolishing characteristics of 316L stainless steel in a sulfuric acid-free electrolyte of phosphoric acid and glycerol and to explore the possibility of using this eco-friendly electrolyte instead of the widely used sulfuric acid-based electrolyte. The influences of process parameters on polishing effects and the corrosion resistance of electropolished samples are investigated. The experimental results show that the electropolishing temperature and acid concentration are directly related to the mass transport mechanism in the limiting current plateau region. The grain boundaries of workpiece were electrochemically dissolved faster than the grain themselves at the beginning of the electropolishing process because they are more reactive than grains. Moreover, the conventional sulfuric—phosphoric acid electrolyte was also used to electropolish the 316L stainless steel, and the electropolished surfaces were compared with the sulfuric acid-free electrolyte proposed in this study. When the sulfuric acid-free electrolyte was used to electropolish the 316L stainless steel, the X-ray photoelectron spectroscopy (XPS) analysis shows that atomic Cr/Fe ratio of 316L stainless steel was increased from 0.802 to 1.909 after electropolishing process in the sulfuric acid-free electrolyte of phosphoric acid and glycerol. The corrosion resistance of the electropolished 316L stainless steel is studied using electrochemical analysis, and the results are verified experimentally.

scholarly journals Rare Earth Occurrences in Streams of Processing a Phosphate Ore

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 262 ◽  
Author(s):  
Xiaosheng Yang ◽  
Hannu Tapani Makkonen ◽  
Lassi Pakkanen
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Rare Earth Elements ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Phosphate Ore ◽  
Mineral Liberation ◽  
Efficient Recovery ◽  
Liberation Analysis

Rare earth elements (REEs) are defined as lanthanides with Y and Sc. Rare earth occurrences including the REE-bearing phases and their distributions, measured by rare earth oxides (REOs), in the streams of processing a phosphate ore were determined by using MLA, the mineral liberation analysis and EPMA, the electron probe microanalysis. The process includes an apatite ore beneficiation by flotation and further processing of the beneficiation concentrate with sulfuric acid. Twenty-six, sixty-two and twelve percent of the total REOs (TREO) contents from the ore end up in the products of beneficiation tailings, phosphogypsum (PG) and phosphoric acid, respectively. Apatite, allanite, monazite and pyrochlore are identified as REE-bearing minerals in the beneficiation process. In the beneficiation tailings, the REEs are mainly distributed in monazite (10.3% TREO), apatite (5.9% TREO), allanite (5.4% TREO) and pyrochlore (4.3% TREO). Gypsum, monazite, apatite and other REE-bearing phases were found to host REEs in the PG and the REEs distributions are 44.9% TREO in gypsum, 15.8% TREO in monazite, 0.6% TREO in apatite and 0.6% TREO in other REE-bearing phases. Perspectives on the efficient recovery of REEs from the beneficiation tailings and the PG are discussed.

scholarly journals Effect of Soil Washing Solutions on Simultaneous Removal of Heavy Metals and Arsenic from Contaminated Soil

2020 ◽  
Vol 17 (9) ◽  
pp. 3133 ◽  
Author(s):  
Kanghee Cho ◽  
Eunji Myung ◽  
Hyunsoo Kim ◽  
Cheonyoung Park ◽  
Nagchoul Choi ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Soil Washing ◽  
Metal Extraction ◽  
Simultaneous Removal ◽  
Removal Of Heavy Metals ◽  
Removal Efficiencies

In this study, we investigated the feasibility of using a solution of sulfuric acid and phosphoric acid as an extraction method for soil-washing to remove Cu, Pb, Zn, and As from contaminated soil. We treated various soil particles, including seven fraction sizes, using sulfuric acid. In addition, to improve Cu, Pb, Zn, and As removal efficiencies, washing agents were compared through batch experiments. The results showed that each agent behaved differently when reacting with heavy metals (Cu, Pb, and Zn) and As. Sulfuric acid was more effective in extracting heavy metals than in extracting As. However, phosphoric acid was not effective in extracting heavy metals. Compared with each inorganic acid, As removal from soil by washing agents increased in the order of sulfuric acid (35.81%) < phosphoric acid (62.96%). Therefore, an enhanced mixture solution using sulfuric acid and phosphoric acid to simultaneously remove heavy metals and As from contaminated soils was investigated. Sulfuric acid at 0.6 M was adopted to combine with 0.6 M phosphoric acid to obtain the mixture solution (1:1) that was used to determine the effect for the simultaneous removal of both heavy metals and As from the contaminated soil. The removal efficiencies of As, Cu, Pb, and Zn were 70.5%, 79.6%, 80.1%, and 71.2%, respectively. The combination of sulfuric acid with phosphoric acid increased the overall As and heavy metal extraction efficiencies from the contaminated soil samples. With the combined effect of dissolving oxides and ion exchange under combined washings, the removal efficiencies of heavy metals and As were higher than those of single washings.

Study on the Determination of Manganese in Alloy Steel Materials by Spectrophotometry

2013 ◽  
Vol 803 ◽  
pp. 196-199
Author(s):  
Mei Mei Li ◽  
Nai Jun Li
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Alloy Steel ◽  
Acid System ◽  
Mixed Acid ◽  
Relative Standard ◽  
Beer's Law ◽  
Beer’S Law ◽  
Standard Deviations

With samples decomposed by mixed acid of sulfuric acid-phosphoric acid, manganese in alloy steel was determined by periodate spectrophotometry. The acid system for dissolving samples was established, and 525 nm as the optimal measuring wavelength was selected. The results showed that Beer's law was obeyed in range of 0 to 36μg/mL for manganese (II). The relative standard deviations were between 0.6% to 2.0%(n=6). The recoveries of samples were between 95.1to 101.4%.

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