Extraction Kinetics of Cerium(III) from Chloride Medium by Di-(2-Ethylhexyl)phosphoric Acid in the Presence of Acetic Acid Using a Constant Interfacial Area Cell with Laminar flow

2012 ◽  
Vol 482-484 ◽  
pp. 2204-2209 ◽  
Author(s):  
Hong Tao Chang ◽  
Mei Li ◽  
Zhao Gang Liu ◽  
Yan Hong Hu ◽  
Fu Shun Zhang
Keyword(s):  
Acetic Acid ◽  
Laminar Flow ◽  
Phosphoric Acid ◽  
Interfacial Area ◽  
Extraction Process ◽  
Effect Of Temperature ◽  
Complexing Agent ◽  
Extraction Kinetics ◽  
Specific Interfacial Area ◽  
Diffusion Controlled

The Ce(III) extraction kinetics with di-(2-ethylhexyl)phosphoric acid (D2EHPA) in the presence of a complexing agent acetic acid(HAc) has been investigated using constant interfacial cell with laminar flow. The kinetics mechanism and extraction rate equation were achieved by the studies on the effect of stirring rate, temperature and specific interfacial area on the rate of extraction. The effect of temperature on the kinetics was analyzed, the value of the apparent activation energy was calculated as 11.96 kJ/mol, and it was found that the extraction process was a diffusion-controlled kinetics regime.

Study on Mass-Transfer Kinetics of Nd by 2-Ethylhexylphosphonic Acid Mono-(2-Ehylhexyl) Ester in the Presence of a Complexing Agent

2012 ◽  
Vol 461 ◽  
pp. 647-651
Author(s):  
Hong Tao Chang ◽  
Mei Li ◽  
Zhao Gang Liu ◽  
Yan Hong Hu ◽  
Fu Shun Zhang
Keyword(s):  
Interfacial Area ◽  
Extraction Process ◽  
Effect Of Temperature ◽  
Complexing Agent ◽  
Extraction Kinetics ◽  
Specific Interfacial Area ◽  
Diffusion Controlled ◽  
Mass Transfer Kinetics ◽  
Kinetics Of ◽  
Rate Of Extraction

The Nd(III) extraction kinetics by 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (HEH/EHP) in the presence of a complexing agent acetic acid(HAc) has been investigated using constant interfacial cell. The kinetics mechanism and extraction rate equation were achieved by the studies on the effect of stirring rate, temperature and specific interfacial area on the rate of extraction. The effect of temperature on the kinetics was analyzed, the value of the apparent activation energy was calculated as 9.24 kJ/mol, and it was found that the extraction process was a diffusion-controlled kinetics process.

scholarly journals Kinetics analysis of the forward extraction of cerium(III) by D2EHPA from chloride medium in the presence of two complexing agents using a constant interfacial area cell with laminar flow

2018 ◽  
Vol 7 (4) ◽  
pp. 380-386 ◽  
Author(s):  
Jiannan Pei ◽  
Junwen Zhou ◽  
Feng Jiang ◽  
Kaihua Chen ◽  
Shaohua Yin ◽  
...  
Keyword(s):  
Laminar Flow ◽  
Interfacial Reaction ◽  
Rate Equation ◽  
Ph Value ◽  
Kinetic Studies ◽  
Interfacial Area ◽  
Extraction Process ◽  
Extraction Rate ◽  
Complexing Agents ◽  
Specific Interfacial Area

Abstract The kinetic studies performed on the forward extract of cerium(III) from chloride solution with the complex agents, citric acid (H3Cit) and lactic acid (HLac) in the presence of di-(2-ethylhexyl)phosphoric acid (D2EHPA, H2A2) have been investigated using a constant interfacial area cell with laminar flow. The effects of stirring speed, temperature, and specific interfacial area on the extraction rate are discussed separately, and the results show that the extraction process is a diffusion-controlled kinetics process with an interfacial reaction. Studies on the effect of pH value and H2A2 concentration on the extraction rate are used to obtain the rate equation. The rate-controlling step is also suggested by the predictions derived from the interfacial reaction models, and the rate equation obtained by the kinetic model is consistent with that obtained by the experimental results. The information on the extraction kinetics in this extraction system will provide some knowledge of its application.

Extraction Kinetics and Mechanism of La(III) by P204-Kerosine from Phosphoric Acid

2014 ◽  
Vol 881-883 ◽  
pp. 677-682 ◽  
Author(s):  
Yun Shan Xiao ◽  
Ya Gu Dang ◽  
De Jun Fei ◽  
Ying Zhang
Keyword(s):  
Phosphoric Acid ◽  
Interfacial Area ◽  
Extraction Process ◽  
Kinetics And Mechanism ◽  
Extraction Rate ◽  
Extraction Kinetics ◽  
Interface Area ◽  
Plateau Region ◽  
Specific Interface Area ◽  
Mixed Mechanism

The extraction kinetics and mechanism of La (III) by P204-kerosine from phosphoric acid were investigated by constant interfacial cell with laminar flow. The effects of stirring speed, temperature, specific interface area on extraction rate were studied. The results indicated that a plateau region is appeared at the stirring speed of over 115r/min. The extraction apparent activation energy was calculated to be-13.40kJ/mol and the extraction process is controlled by a mixed mechanism of diffusion and chemical reaction. The rate equation of extraction was deduced. Under conditions of 25°C and interfacial area 19.64cm2, the extraction rate constant was 2.08×10-6 m·s-1·. Through the derivation of the reaction mechanism the reaction zone is at the liquid-liquid interface.

The kinetics and mechanism of solvent extraction of Pr(iii) from chloride medium in the presence of two complexing agents with di-(2-ethylhexyl) phosphoric acid

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48659-48664 ◽  
Author(s):  
Shao-Hua Yin ◽  
Shi-Wei Li ◽  
Jin-Hui Peng ◽  
Li-Bo Zhang
Keyword(s):  
Lactic Acid ◽  
Citric Acid ◽  
Solvent Extraction ◽  
Phosphoric Acid ◽  
Interfacial Area ◽  
Kinetics And Mechanism ◽  
Complexing Agents ◽  
Extraction Kinetics ◽  
Chloride Medium ◽  
Kinetics Of

The extraction kinetics of Pr(iii) from chloride medium containing two complexing agents lactic acid (HLac) and citric acid (H3cit) with di-(2-ethylhexyl)phosphoric acid (D2EHPA, H2A2) have been investigated by constant interfacial area cell with lamina flow.

The Effect of Temperature on Sodium Movements in Rat Uteri and a Model for Control of their Ion Content

1971 ◽  
Vol 49 (3) ◽  
pp. 240-262 ◽  
Author(s):  
E. E. Daniel ◽  
Kathleen Robinson
Keyword(s):  
Atp Depletion ◽  
Rate Coefficients ◽  
Effect Of Temperature ◽  
Ion Content ◽  
Substantial Fraction ◽  
Cellular Fraction ◽  
Diffusion Controlled ◽  
Na Efflux ◽  
Pinocytotic Vesicles ◽  
Na Uptake

The uptake and efflux of 22Na was studied in isolated rat uterine horns (both fresh and Na-rich) at 5, 15, 25, and 37 °C. Reduction of temperature from 37 °C to 25 or to 15 °C reduced 22Na uptake into, and efflux from, both the extracellular space and cells to the degree expected of a diffusion-controlled process (Q10 < 2). Reduction of the temperature to 5 °C during uptake into Na-rich horns revealed that a substantial fraction of cellular sodium became less exchangeable. At 5 °C, 22Na efflux was also markedly reduced, more than from ouabain or ATP depletion. Analysis of this change by curve-peeling and by reducing the temperature at various stages of efflux suggested that the main cause was a shift of 22Na from the larger, faster cellular fraction (No. 2) to the slower cellular fraction (No. 3). Bound 22Na was also markedly increased. The rate coefficients from curve-peeling for both cellular fractions were decreased. Radioactivity still in fraction 2 at 5 °C emerged at a rate of about half that at 15 °C. However, an overall coefficient for efflux of 22Na which would have emerged in fraction 2 at 15 or 25 °C showed that the Q10 for 22Na efflux between 5 and 15 °C was about 15. Tissues did not swell when they gained sodium at 5 °C. The effects of ouabain to increase 22Na influx and 42K efflux were eliminated at 5 °C. The effects of ATP depletion by iodoacetate and dinitrophenol to decrease 22Na efflux and to increase 22Na uptake, K loss, and swelling were reduced at 5 °C. Prior ATP depletion altered but did not prevent the marked reduction of efflux by cooling to 5 °C. Efflux of lithium, but not of potassium, was markedly slowed at 5 °C. K-free solutions still increased 22Na uptake at 5 °C. A model involving pinocytotic vesicles to explain these and earlier results was postulated.

Modeling Two-Phase Flow in Porous Media Including Fluid-Fluid Interfacial Area

2008 ◽  
Author(s):  
Jennifer Niessner ◽  
S. Majid Hassanizadeh ◽  
Dustin Crandall
Keyword(s):  
Porous Media ◽  
Capillary Pressure ◽  
Two Phase Flow ◽  
Interfacial Area ◽  
Flow In Porous Media ◽  
Extended Model ◽  
Phase Flow ◽  
Two Phase ◽  
Specific Interfacial Area ◽  
Macro Scale

We present a new numerical model for macro-scale two-phase flow in porous media which is based on a physically consistent theory of multi-phase flow. The standard approach for modeling the flow of two fluid phases in a porous medium consists of a continuity equation for each phase, an extended form of Darcy’s law as well as constitutive relationships for relative permeability and capillary pressure. This approach is known to have a number of important shortcomings and, in particular, it does not account for the presence and role of fluid–fluid interfaces. An alternative is to use an extended model which is founded on thermodynamic principles and is physically consistent. In addition to the standard equations, the model uses a balance equation for specific interfacial area. The constitutive relationship for capillary pressure involves not only saturation, but also specific interfacial area. We show how parameters can be obtained for the alternative model using experimental data from a new kind of flow cell and present results of a numerical modeling study.

scholarly journals Probing the Catalytic Efficiency of Supported Heteropoly Acids for Esterification: Effect of Weak Catalyst Support Interactions

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Alsalme ◽  
Aliyah A. Alsharif ◽  
Hamda Al-Enizi ◽  
Mujeeb Khan ◽  
Saad G. Alshammari ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Active Sites ◽  
Catalyst Support ◽  
Supported Catalyst ◽  
Catalytic Efficiency ◽  
Biodiesel Production ◽  
Effect Of Temperature ◽  
Heteropoly Acids ◽  
Catalyst Loading ◽  
Esterification Activity

Supported heteropoly acids are an interesting class of solid acid catalysts which possess flexible structure and super acidic properties essentially required for the oil-based biodiesel production. In this study, a series of catalysts containing 25 wt.% of heteropolytungstate (HPW) supported on various clays or SiO2 were prepared, and their catalytic efficiency was evaluated for esterification of acetic acid with heptanol. The as-prepared catalysts were characterized by various techniques including FT-IR spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, and BET. The catalytic efficiency of both bulk and supported HPW catalysts for the esterification activity strongly depends on the type of support and amount of catalyst; the bulk HPW catalyst and the catalyst supported by kaolinite with 25 wt.% of HPW exhibited highest activity. In order to study the effect of temperature on conversion, all the catalysts were subjected to different reaction temperatures. It was revealed that esterification activity of both bulk and supported HPW catalysts strongly depends upon the temperature variations of the reaction. Besides, the effect of leaching of active sites on the catalysts performance for biodiesel production was also evaluated by inductively coupled plasma studies (ICP). The kaolinite-supported catalyst (25% HPW/kaolinite) demonstrated higher amount of leaching which is also confirmed by the significant decrease in its catalytic activity when it is used for the second time. However, the higher activity demonstrated by HPW/kaolinite maybe because of some homogeneous reaction indicating a weak catalyst support interaction (WCSI) resulting in the leaching of the catalyst during the test. Furthermore, the effects of other reaction variables such as catalyst loading and reaction time on the conversion of acetic acid were also studied.

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