Isotope Exchange Kinetics in Clay-Water System

10.26686/wgtn.17003164.v1 ◽

2021 ◽

Author(s):

◽

Roderick John Furkert

Keyword(s):

Specific Activity ◽

Water System ◽

Geiger Counter ◽

Radioactive Material ◽

Sensitive Volume ◽

Activity Count ◽

Adsorbed Molecules ◽

Free Gas ◽

Solid Liquid ◽

Adsorption Phenomena

<p>Knowledge of reactions at solid/liquid and solid/gas interfaces is of great importance in the study of all adsorption phenomena. Techniques that enable a study of molecules (liquid or gaseous) adsorbed onto a surface may be divided into two categories: (a) those that upset the equilibrium between molecules in the gaseous (or liquid) phase above the solid surface and molecules actually adsorbed onto it, and (b) those that do not. Those techniques that do not disturb this equilibrium will give results that would be expected to have greater reliability than those obtained from techniques that upset this equilibrium (for example by heating or by affecting one component of the equilibrium by titration, precipitation etc.) In an endeavour to study the properties of water adsorbed onto various substances such as clay, wool and textile fibres without affecting the equilibrium the technique of isotopic exchange has been developed. Essentially the procedure is to take a closed adsorber system in equilibrium with a gas (or liquid), part of which is in the sensitive region of a geiger counter, and to add a very small amount of radioactively labelled gas (or liquid) to the system. The adsorber is placed in the bottom of a geiger counter out of the sensitive volume and a known fraction of gas (or liquid) is in the sensitive volume. As the system is at equilibrium there is continuous exchange between the adsorbed molecules on the sample and the molecules in the gaseous (or liquid) state. Thus, when a very small amount, by weight, of the radioactively labelled gas (or liquid) is added to the system, exchange will take place with the non-radioactive molecules adsorbed on the surface of the material under study. Thus radioactivity will be removed from the sensitive volume of the geiger counter and adsorbed onto the surface of the material, and so the specific activity (count rate), as measured with the geiger counter, will drop. The advantage of this technique is that the equilibrium between the adsorbed molecules and the free gas (or liquid) is not disturbed. The actual amount of radioactive material added is so minute that there is no effective change in the concentration of the free gas (or liquid).</p>

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Pressure Drop and Mass Transfer Studies in Liquid Fluidized Beds

Fluids Engineering ◽

10.1115/imece2006-13455 ◽

2006 ◽

Author(s):

Bhagavatula Venkata Ramana Murthy

Keyword(s):

Mass Transfer ◽

Pressure Drop ◽

Liquid Velocity ◽

Water System ◽

Solid Particles ◽

Sugar Water ◽

Minimum Fluidization Velocity ◽

Liquid Systems ◽

Mass Transfer Studies ◽

Solid Liquid

Fluidized beds are widely used in industries for mixing solid particles with liquids as the solid is vigorously agitated by the liquid passing through the bed and the mixing of the solid ensures that there are practically no temperature gradients in the bed even with exothermic or endothermic reactions (Mixing and the segregation in a liquid fluidized of particles with different sizes and densities", The Canadian Journal of Chemical Engineering, 1988). The violent motion of the solid particles also gives high heat transfer rates to the wall or to cooling tubes immersed in the bed. Because of the fluidity of the solid particles, it is easy to pass solid from one vessel to another. In the present experimental work, the relative density between solid and liquid phases on pressure drop under fluidized condition has been studied using the solid-liquid systems namely, glass beads-water, glass beads-kerosene, plastic beads-kerosene and diamond sugar-kerosene. Pressure drop - liquid velocity and void fraction - liquid velocity relationships have been found for all the mentioned solid-liquid systems under fluidized condition and results have been noted. The effect of the nature of the fluid on the minimum fluidization velocity and the pressure drop has been studied. In addition to the pressure drop studies, mass transfer studies have also been conducted with diamond sugar-water system with and without fluidization and results have been obtained. In addition to these, comparison of bed voidage, pressure drop and minimum fluidization velocity between denser and lighter liquids have been studied and the results have been obtained. Also, the value of rate of mass transfer with fluidization is compared that without fluidization for diamond sugar-water system and the results have been obtained.

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Density, viscosity, refractive index and electrical conductivity of saturated solutions of the lithium hydroxide+ethanol+water system at 298.15K, and thermodynamic description of the solid–liquid equilibrium

Fluid Phase Equilibria ◽

10.1016/j.fluid.2005.05.022 ◽

2005 ◽

Vol 235 (1) ◽

pp. 104-111 ◽

Cited By ~ 7

Author(s):

Maria Elisa Taboada ◽

Héctor R. Galleguillos ◽

Teófilo A. Graber ◽

Javier Álvarez-Benedí

Keyword(s):

Electrical Conductivity ◽

Refractive Index ◽

Thermodynamic Description ◽

Water System ◽

Lithium Hydroxide ◽

Liquid Equilibrium ◽

Solid Liquid ◽

Saturated Solutions

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Moving into Nanotechnology Roles to Mimic and Boost Enzyme Activity

Research Advancements in Pharmaceutical, Nutritional, and Industrial Enzymology - Advances in Medical Technologies and Clinical Practice ◽

10.4018/978-1-5225-5237-6.ch019 ◽

2018 ◽

pp. 421-440

Author(s):

Maria Laura Soriano

Keyword(s):

Enzyme Activity ◽

Catalytic Activity ◽

Enzyme Immobilization ◽

Mesoporous Materials ◽

Specific Activity ◽

Artificial Enzymes ◽

Catalytic Nanoparticles ◽

Solid Liquid ◽

By Products ◽

Insight Into

A new tendency toward the design of artificial enzymes based on nanostructures (nanodots, nanofibers, mesoporous materials) has emerged. On one hand, nanotechnology bestows self-catalytic nanoparticles with a specific activity to achieve efficient reactions with low number of by-products. On other hand, the nanoparticles may behave as nanometric scaffolds for hosting enzymes, promoting their catalytic activity and stability. In this case, enzyme immobilization requires the preservation of the catalytic activity by preventing enzyme unfolding and avoiding its aggregation. These approaches render many other advantages like hosting/storing enzymes in nanotechnological solid, liquid, and gel-like media. This chapter focuses on the most up-to-date approaches to manipulate or mimic enzyme activity based on nanotechnology, and offers examples of their applications in the most promising fields. It also gives new insight into the creation of reusable nanotechnological tools for enzyme storage.

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β-Cyclodextrin Modified Poly(Acrylonitrule-co-Acrylic Acid) Hydrogel for Thorium(IV) Adsorption

Polymers ◽

10.3390/polym9060201 ◽

2017 ◽

Vol 9 (6) ◽

pp. 201 ◽

Cited By ~ 19

Author(s):

Guojian Duan ◽

Qiangqiang Zhong ◽

Lei Bi ◽

Liu Yang ◽

Tonghuan Liu ◽

...

Keyword(s):

Adsorption Capacity ◽

Contact Time ◽

Ph Value ◽

Water System ◽

Maximum Adsorption Capacity ◽

Practical Application ◽

X Ray Diffraction ◽

Liquid Ratio ◽

X Ray ◽

Solid Liquid

In this report, the β-CD(AN-co-AA) hydrogel was used to remove the thorium(IV) [Th(IV)] from the water system, and the new adsorbent was characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The influences of contact time, pH value, ionic strength, solid-liquid ratio, initial Th(IV) concentration, and temperature on Th(IV) adsorption onto the functional hydrogel were researched. The results showed that the experimental data followed the Langmuir isotherm and the maximum adsorption capacity (qmax) for Th(IV) was 692 mg/g at pH 2.95, which approached the calculated (qe) 682 mg/g. The desorption capacity of Th(IV) in different HNO3 concentrations ranging from 0.005 to 0.5 M was also studied, and the percentage of the maximum desorption was 86.85% in the condition of 0.09 M HNO3. The selectivity of β-CD(AN-co-AA) hydrogel was also be studied, the results indicated that this material retained the good adsorption capacity to Th(IV) even when the Ca2+, Mg2+, or Pb2+ existed in the system. The findings indicate that β-CD(AN-co-AA) can be used as a new candidate for the enrichment and separation of Th(IV), or its analogue actinides, from large-volume solution in practical application.

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