Diffusion in aqueous solutions of sulfuric acid

1984 ◽  
Vol 62 (9) ◽  
pp. 1692-1697 ◽  
Author(s):  
Derek G. Leaist
Keyword(s):  
Aqueous Solution ◽  
Diffusion Coefficient ◽  
Sulfuric Acid ◽  
Aqueous Solutions ◽  
Diffusion Coefficients ◽  
Sharp Increase ◽  
Hydrogen Ions ◽  
Acid Component ◽  
Low Concentrations ◽  
Predicted Values

Diffusion of sulfuric acid in aqueous solution has been measured by a conductimetric technique at 25 °C over the concentration range from 0.00035 to 0.2 mol dm−3. At the lower end of this range, dissociation of bisulfate to sulfate and hydrogen ions produces a sharp increase in the rate of diffusion of the sulfuric acid component. Expressions are developed to predict the concentration dependence of the diffusion coefficient in terms of the mobilities of the diffusing ions and the degree of bisulfate dissociation. The treatment includes electrophoretic corrections that are derived from Onsager–Fuoss theory for the unsymmetrical, multi-ion electrolyte. At low concentrations where theory applies the observed diffusion coefficients are lower than the predicted values.

scholarly journals Temperature-dependent diffusion coefficient of H<sub>2</sub>SO<sub>4</sub> in air: laboratory measurements using laminar flow technique

2016 ◽  
Author(s):  
David Brus ◽  
Lenka Skrabalova ◽  
Erik Herrmann ◽  
Tinja Olenius ◽  
Tereza Travnickova ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Sulfuric Acid ◽  
Relative Humidity ◽  
Laminar Flow ◽  
Diffusion Coefficients ◽  
Loss Rate ◽  
Rate Coefficients ◽  
Flow Conditions ◽  
Flow Tube ◽  
Wall Loss

Abstract. We report measurements of the diffusion coefficient of sulfuric acid in humidified air at a range of relative humidities (from ~4 to 70 %), temperatures (278, 288 and 298 K) and initial H2SO4 concentration (from 1 × 10e6 to 1 × 10e8 molec. cm−3). The diffusion coefficients were estimated from the sulfuric acid wall loss rate coefficients under laminar flow conditions. The flow conditions were verified with additional fluid dynamics model CFD-FLUENT simulations which also reproduced the loss rate coefficients very well at all three temperatures with the maximum difference of 7 % between the measured and simulated values. The concentration of H2SO4 was measured continuously with chemical ionization mass spectrometer (CIMS) at seven different positions along the flow tube. The wall losses of H2SO4 were determined from the slopes of fits to measured H2SO4 concentrations as a function of the position along the flow tube. The observed wall loss rate coefficients, and hence the diffusion coefficients, were independent of different initial H2SO4 concentrations and different total flow rates. However, the determined diffusion coefficients decreased with increasing relative humidity, as also seen in previous experiments, and had a rather strong power dependence of the diffusion coefficient with respect to temperature, around ∝T5.4, which is in disagreement with the expected temperature dependency of ~T1.75 observed for other gases and not tested before for sulfuric acid. The effect of relative humidity on the diffusion coefficient is likely due to stronger hydration of H2SO4 molecules and likely also due to the presence of trace impurities such as amines, possibly brought to the system by humidification. Clustering kinetics simulations using quantum chemical data suggest that also the strong temperature dependence of the observed diffusion coefficient might be explained by increased diffusion volume of H2SO4 molecules due to stronger clustering with base-impurities like amines.

Modeling the Diffusion Mechanism and the Reaction Kinetics for the Photocatalytic Degradation of Acid Red 151 Aqueous Solutions by ZnO: Comparison of Linear and Non-Linear Methods

2007 ◽  
Vol 10 (2) ◽  
Author(s):  
K. Vasanth Kumar ◽  
K. Porkodi
Keyword(s):  
Aqueous Solution ◽  
Diffusion Coefficient ◽  
Aqueous Solutions ◽  
Photocatalytic Degradation ◽  
Reaction Kinetics ◽  
Diffusion Mechanism ◽  
Batch Processes ◽  
Average Diffusion Coefficient ◽  
Diffusion Controlled ◽  
Average Diffusion

AbstractBatch processes were carried out for the photocatalytic degradation of Acid Red 151 from its aqueous solution using ZnO catalyst at different initial dye concentrations. The process was found to be diffusion controlled for the first 15-20 minutes (before irradiation) with an average diffusion coefficient of 6.759 × 10

scholarly journals STUDY OF VISCOSITY OF AQUEOUS SOLUTIONS OF NATURAL POLYSACCHARIDES

2016 ◽  
pp. 11-19 ◽  
Author(s):  
Lyudmila Asyakina ◽  
Lyudmila Asyakina ◽  
Lyubov Dyshlyuk ◽  
Lyubov Dyshlyuk
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Biodegradable Polymers ◽  
Raw Materials ◽  
Hydroxypropyl Methylcellulose ◽  
Methyl Cellulose ◽  
Preparation Temperature ◽  
Low Concentrations ◽  
Wide Range ◽  
Solution Preparation

One of the steps of synthesis of biodegradable polymers is preparation of an aqueous solution of raw materials. Formulation of biodegradable films with optimum characteristics requires to undertake a separate rheological study of each aqueous solution. An essential parameter in this step is a uniform thickness, which is achieved by means of specified viscosity parameters. Viscosity of solutions depends on many parameters, among which are composition and concentration of components in a solution, solution preparation temperature, pH of the finished medium, and presence of free ions. This article describes studies and results on study of viscosity parameters of aqueous solutions of natural polysaccharides: agar-agar, hydroxypropyl methyl cellulose and carrageenan. For aqueous solutions of carrageenan and hydroxypropyl methylcellulose, viscosity was measured at 25°C. In addition, viscosity parameters were measured for 1.5% hhydroxypropyl methylcellulose solutions at 40°C and 60°C. Depending on the gel formation temperature, viscosity of agar-agar solutions was measured at 50°C or 70°C. According to the results of experiments, it was found that viscosity of 1.0-1.5% hydroxypropyl methylcellulose aqueous solutions is in the range of 8.0-80.0 cP. Heating to 100°C at pH 6 results in irreversible destruction of hydroxypropylmethylcellulose molecules. Aqueous solutions of agar-agar are similar to hydroxypropyl methylcellulose solutions but agar-agar is able to gelate at sufficiently low concentrations (from 0.5%). Viscosity of 3.0- 5.0% carrageenan aqueous solutions varies within a wide range: 1.5-1400.0 cP. Thus, rheological properties allow to adjust viscosity of the process mixture in the production of biodegradable polymers in the desired range and in different directions.

Diffusion coefficients of two anionic dyes in dilute aqueous electrolyte solution

1980 ◽  
Vol 33 (1) ◽  
pp. 83 ◽  
Author(s):  
B Craven ◽  
S Imamkhasani
Keyword(s):  
Diffusion Coefficient ◽  
Electrolyte Solution ◽  
Concentration Gradient ◽  
Diffusion Coefficients ◽  
Aqueous Electrolyte ◽  
Aqueous Electrolyte Solution ◽  
Anionic Dyes ◽  
Low Concentrations

Diaphragm cells were used to determine diffusion coefficients of two anionic dyes in dilute aqueous electrolyte solution. Allowance was made for disaggregation occurring as dye aggregates traverse the concentration gradient in the diaphragm, and an attempt was made to account for such effects semi-quantitatively. Diffusion coefficients of one of the dyes were measured polarographically, and the results compared with those obtained using diaphragm cells. Steps in the curves of diffusion coefficient against dye concentration suggest that at low concentrations both dyes form dimers; as the concentration is increased the dimers aggregate to form tetramers.

scholarly journals Cadmium Removal from Aqueous Solutions by Strain of Pantoea agglomerans UCP1320 Isolated from Laundry Effluent

2018 ◽  
Vol 12 (1) ◽  
pp. 297-307 ◽  
Author(s):  
Leonila. M. L. Acioly ◽  
Davi Cavalcanti ◽  
Marcos C. Luna ◽  
José C. V. Júnior ◽  
Rosileide F. S. Andrade ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Environmental Concern ◽  
Low Cost ◽  
Bacterial Biomass ◽  
Pantoea Agglomerans ◽  
Cadmium Removal ◽  
Work Related ◽  
Low Concentrations ◽  
Positive Effect

Background: Cadmium (Cd), which is a deadly heavy metal of work-related and environmental concern, has been recognized as a substance that is teratogenic and carcinogenic for humans. Therefore, the need to develop low-cost adsorbents to remove heavy metals from aqueous solution has greatly increased. Adsorbents such as Pantoea agglomerans biomass have been used. Aims: We investigated the biotechnological potential of Pantoea agglomerans for the biosorption of cadmium from aqueous solution. Patients and Methods: Pantoea agglomerans UCP1320 isolated from the effluent of a laundry industry was used to remove cadmium from aqueous solutions. Two approaches were compared using active or thermally inactivated biomass. Three different cadmium concentrations of 1, 10 and 100 ppm were used under constant stirring at temperatures of 25°C and 35°C as was pH of 3.0, 5.0 and 7.0. Variable incubation times of 1, 6, and 24h were also studied. Results: The results showed that the temperature did not influence the uptake of metal by living cells nor by inactive bacterial biomass. However, increasing the pH had a positive effect on removing intermediate concentrations of cadmium. Low concentrations of cadmium were completely removed by both live and inactive biomass. Conclusion: Pantoea agglomerans biomass was shown to have a promising performance for the biotechnological removal of cadmium which had been dissolved in aqueous solution.

Investigations of corrosion behaviour of SnSb12Cu6Pb alloy in 0.1M H2SO4 and 0.5M NaCl solution

2020 ◽  
Vol 1 (101) ◽  
pp. 5-14
Author(s):  
J. Hrabia-Wiśnios ◽  
B. Leszczyńska-Madej ◽  
R. Kowalik
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Sodium Chloride ◽  
Aqueous Solutions ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Working Environment ◽  
Nacl Solution ◽  
Selective Corrosion

Purpose: The results presented the microstructure and corrosive behavior of SnSb12Cu6Pb alloy (B82) in H2SO4 aqueous solution and NaCl aqueous solution. Design/methodology/approach: The electrochemical corrosion has been investigated in two different aqueous solutions: 0.1M sulfuric acid (H2SO4) and 0.5M sodium chloride (NaCl) solution measuring of potential changes relative to immersion time and conducting mass loss test. Microscopic investigations before and after corrosion tests were made using scanning electron microscopy. Findings: The obtained results indicate very good corrosion resistance of the alloy tested in NaCl solution. Corrosion progresses faster in a sulfuric acid aqueous solution compared to sodium chloride aqueous solution. Also, it was found that the dominant mechanism of corrosion degradation in both solutions is selective corrosion which is a particularly undesirable type of corrosion because it involves the loss of one alloying component and the formation of porous structure on the alloy surface. Research limitations/implications: The aqueous solutions used in this study are not a natural working environment of the bearing. However, a comparison of acidic and neutral solutions allows explaining the corrosion behavior of tin babbitts due to contaminants of oil lubricants. Further research should be conducted in more aggressive environments characteristic of industrial conditions. Practical implications: One of the important properties of bearing alloys are corrosion resistance. Corrosion properties are extremely important for the transport and storage of metallic components before they are used. Also, the working environment can have a destructive effect on the properties of the materials used. Industry environment, aging stagnant oil, and some acids may lead to selective corrosion of the tin, copper, lead, or antimony components and leaving a rough and weakened the babbitt surface. Electrochemical corrosion can contribute to the acceleration of bearing wear and consequent to bearing damage. Originality/value: Studies of the corrosion of tin-babbitt bearings are not extensive in the literature due to rare tin corrosion. This study could be an important complement to knowledge about the corrosion behavior of tin-based bearing alloys.

Effect of thermal history of aqueous solutions of KCl on the metastable zone width

1984 ◽  
Vol 49 (3) ◽  
pp. 559-569 ◽  
Author(s):  
Jaroslav Nývlt
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Thermal History ◽  
Equilibrium Solubility ◽  
Metastable Zone Width ◽  
Zone Width ◽  
Preceding Experiment ◽  
History Of ◽  
Metastable Zone ◽  
The Given

The metastable zone width of an aqueous solution of KCI was measured as a function of the time and temperature of overheating above the equilibrium solubility temperature. It has been found that when the experiments follow close upon one another, the parameters of the preceding experiment affect the results of the experiment to follow.The results are interpreted in terms of hypotheses advanced in the literature to account for the effect of thermal history of solution. The plausibility and applicability of these hypotheses are assessed for the given cause of aqueous solution of a well soluble electrolyte.

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