Molecular Diffusivity of Phenol in Sub- and Supercritical Water: Application of the Split-Flow Taylor Dispersion Technique

2011 ◽  
Vol 115 (11) ◽  
pp. 2555-2562 ◽  
Author(s):  
Andriy Plugatyr ◽  
Igor M. Svishchev
Keyword(s):  
Supercritical Water ◽  
Taylor Dispersion ◽  
Water Application ◽  
Molecular Diffusivity ◽  
Split Flow ◽  
Taylor Dispersion Technique ◽  
Dispersion Technique

Split-flow Taylor dispersion technique for diffusivity and concentration measurements of hydrazine in aqueous solution

2014 ◽  
Vol 92 (4) ◽  
pp. 279-283
Author(s):  
Kashif I. Choudhry ◽  
Igor M. Svishchev ◽  
Andriy Plugatyr
Keyword(s):  
Aqueous Solution ◽  
Diffusion Coefficient ◽  
Taylor Dispersion ◽  
Alkaline Media ◽  
Monitoring Method ◽  
Flow Monitoring ◽  
Split Flow ◽  
Taylor Dispersion Technique ◽  
Dispersion Technique

A sensitive continuous-flow monitoring method is developed for the determination of the diffusion coefficient and concentration of hydrazine in an aqueous solution. The effect of pH on the diffusion coefficient of hydrazine in water was studied at room temperature using the developed split-flow Taylor dispersion technique. The hydrazine calibration curve was linear in the range of 10−1000 ppb and the limit of quantification was 10 ppb. The results showed that the diffusion coefficient of hydrazine does not change significantly over the pH range of 4.01−8.27 but increases in alkaline media of pH greater than 8.27. This method can be used for accurate determination of hydrazine concentration in aqueous flow systems.

Diffusion Coefficients of Aqueous Solutions of Carbohydrates as Seen by Taylor Dispersion Technique at Physiological Temperature (37 °C)

2006 ◽  
Vol 258-260 ◽  
pp. 305-309 ◽  
Author(s):  
Ana C.F. Ribeiro ◽  
Cecilia Isabel A.V Santos ◽  
Victor M.M. Lobo ◽  
Artur J.M. Valente ◽  
Pedro M.R.A. Prazeres ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Concentration Dependence ◽  
Diffusion Coefficients ◽  
Taylor Dispersion ◽  
Mutual Diffusion ◽  
Physiological Temperature ◽  
Taylor Dispersion Technique ◽  
Dispersion Technique

Binary mutual diffusion coefficients have been measured for aqueous solutions of some carbohydrates (glucose, fructose, lactose, sucrose, α-cyclodextrin and β- cyclodextrin) at concentrations from 0.002 mol dm-3 to 0.010 mol dm-3. The concentration dependence of the diffusion coefficients at physiological temperature, 37 °C, is discussed on the basis of their structures.

Optimization of Taylor Dispersion Technique for Measurement of Mutual Diffusion in Benchmark Mixtures

2016 ◽  
Vol 28 (4) ◽  
pp. 459-465 ◽  
Author(s):  
C. I. A. V. Santos ◽  
V. Shevtsova ◽  
H. D. Burrows ◽  
A. C. F. Ribeiro
Keyword(s):  
Taylor Dispersion ◽  
Mutual Diffusion ◽  
Taylor Dispersion Technique ◽  
Dispersion Technique

scholarly journals Diffusion of Quinine with Ethanol as a Co-Solvent in Supercritical CO2

Molecules ◽  
2020 ◽  
Vol 25 (22) ◽  
pp. 5372
Author(s):  
Yury Gaponenko ◽  
Aliaksandr Mialdun ◽  
Valentina Shevtsova
Keyword(s):  
Diffusion Coefficients ◽  
Supercritical Co2 ◽  
Critical Value ◽  
Taylor Dispersion ◽  
Small Range ◽  
Subsequent Increase ◽  
Pure Ethanol ◽  
Taylor Dispersion Technique ◽  
Dispersion Technique ◽  
Relative Change

This study aims at contributing to quinine extraction using supercritical CO2 and ethanol as a co-solvent. The diffusion coefficients of quinine in supercritical CO2 are measured using the Taylor dispersion technique when quinine is pre-dissolved in ethanol. First, the diffusion coefficients of pure ethanol in the supercritical state of CO2 were investigated in order to get a basis for seeing a relative change in the diffusion coefficient with the addition of quinine. We report measurements of the diffusion coefficients of ethanol in scCO2 in the temperature range from 304.3 to 343 K and pressures of 9.5, 10 and 12 MPa. Next, the diffusion coefficients of different amounts of quinine dissolved in ethanol and injected into supercritical CO2 were measured in the same range of temperatures at p = 12 Mpa. At the pressure p = 9.5 MPa, which is close to the critical pressure, the diffusion coefficients were measured at the temperature, T = 343 K, far from the critical value. It was found that the diffusion coefficients are significantly dependent on the amount of quinine in a small range of its content, less than 0.1%. It is quite likely that this behavior is associated with a change in the spatial structure, that is, the formation of clusters or compounds, and a subsequent increase in the molecular weight of the diffusive substance.

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