Extraction of {UO2}2+ in Intensified Separators of Different Sizes Using Ionic Liquids

2016 ◽  
Author(s):  
Dimitrios Tsaoulidis ◽  
Eduardo Garciadiego Ortega ◽  
Panagiota Angeli
Keyword(s):  
Mass Transfer ◽  
High Speed ◽  
Extraction Efficiency ◽  
Liquid Mixtures ◽  
Small Scale ◽  
Acid Solutions ◽  
Transfer Coefficients ◽  
High Speed Imaging ◽  
Channel Size ◽  
Aqueous Nitric Acid

In this work the extraction of dioxouranium(VI) from aqueous nitric acid solutions (3M) into TBP/ionic liquid mixtures (30% v/v), is studied in intensified small scale separator channels of different sizes. High speed imaging is used to obtain the important hydrodynamic features of the flow (i.e. plug velocity and plug length) which are related to mass transfer and extraction efficiency. It was found that the overall mass transfer coefficients varied between 0.07 and 0.24 s−1 and increase by decreasing the channel size. The extraction efficiency was also affected by the channel size. A decrease in channel size leads to higher extraction efficiencies, while for a certain channel size the extraction efficiency decreases by increasing the mixture velocity.

scholarly journals Microfluidics Used as a Tool to Understand and Optimize Membrane Filtration Processes

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 316
Author(s):  
Izabella Bouhid de Aguiar ◽  
Karin Schroën
Keyword(s):  
High Speed ◽  
Particle Deposition ◽  
Membrane Filtration ◽  
Oil And Gas ◽  
Membrane Separation ◽  
Microfluidic Devices ◽  
Small Scale ◽  
High Speed Imaging ◽  
Time Observation ◽  
Real Time Observation

Membrane filtration processes are best known for their application in the water, oil, and gas sectors, but also in food production they play an eminent role. Filtration processes are known to suffer from a decrease in efficiency in time due to e.g., particle deposition, also known as fouling and pore blocking. Although these processes are not very well understood at a small scale, smart engineering approaches have been used to keep membrane processes running. Microfluidic devices have been increasingly applied to study membrane filtration processes and accommodate observation and understanding of the filtration process at different scales, from nanometer to millimeter and more. In combination with microscopes and high-speed imaging, microfluidic devices allow real time observation of filtration processes. In this review we will give a general introduction on microfluidic devices used to study membrane filtration behavior, followed by a discussion of how microfluidic devices can be used to understand current challenges. We will then discuss how increased knowledge on fundamental aspects of membrane filtration can help optimize existing processes, before wrapping up with an outlook on future prospects on the use of microfluidics within the field of membrane separation.

scholarly journals Mass transfer effects in 2-D dual-permeability modeling of field preferential bromide leaching with drain effluent

2011 ◽  
Vol 8 (3) ◽  
pp. 5917-5967
Author(s):  
H. H. Gerke ◽  
J. Dusek ◽  
T. Vogel
Keyword(s):  
Mass Transfer ◽  
Preferential Flow ◽  
Mass Transfer Rate ◽  
Variable Mass ◽  
Chemical Properties ◽  
Small Scale ◽  
Transfer Coefficients ◽  
Permeability Model ◽  
Soil Matrix ◽  
Mass Transfer Coefficients

Abstract. Subsurface drained experimental fields are frequently used for studying preferential flow (PF) in structured soils. Considering two-dimensional (2-D) transport towards the drain, however, the relevance of mass transfer coefficients, apparently reflecting small-scale soil structural properties, for the water and solute balances of the entire drained field is largely unknown. This paper reviews and analyzes effects of mass transfer reductions on Br− leaching for a subsurface drained experimental field using a numerical 2-D dual-permeability model (2D-DPERM). The sensitivity of the "diffusive" mass transfer component on bromide (Br−) leaching patterns is discussed. Flow and transport is simulated in a 2-D vertical cross-section using parameters, boundary conditions (BC), and data of a Br− tracer irrigation experiment on a subsurface drained field (5000 m2 area) at Bokhorst (Germany), where soils have developed from glacial till sediments. The 2D-DPERM simulation scenarios assume realistic irrigation and rainfall rates, and Br-application in the soil matrix (SM) domain. The mass transfer reduction controls preferential tracer movement and can be related to physical and chemical properties at the interface between flow path and soil matrix in structured soil. A reduced solute mass transfer rate coefficient allows a better match of the Br− mass flow observed in the tile drain discharge. The results suggest that coefficients of water and solute transfer between PF and SM domains have a clear impact on Br− effluent from the drain. Amount and composition of the drain effluent is analyzed as a highly complex interrelation between temporally and spatially variable mass transfer in the 2-D vertical flow domain that depends on varying "advective" and "diffusive" transfer components, the spatial distribution of residual tracer concentrations, and the lateral flow fields in both domains from plots of the whole subsurface drained field. The local-scale soil structural effects (e.g., such as macropore wall coatings), here conceptualized as changes in mass transfer coefficients, can have a clear effect on leaching at the plot and field-scales.

scholarly journals Dynamics of Bubble Motion and Gas-Liquid Interfacial Phenomena

2003 ◽  
Author(s):  
Katsumi Tsuchiya
Keyword(s):  
Mass Transfer ◽  
Surface Wave ◽  
High Speed ◽  
Bubble Surface ◽  
Liquid Interface ◽  
Oscillatory Motion ◽  
Wave Formation ◽  
High Speed Imaging ◽  
Vertical Projection ◽  
Near Surface

Two aspects of the dynamics associated with oscillating bubbles are discussed in this paper: oscillatory motion of bubble itself and bubble-surface wave. The primary issue here is whether it is the case that the surface wave occurs in sychronization with the bubble’s oscillatory motion. The dynamic process of wave formation and propagation along the surface of an oscillating bubble is studied based on high-speed imaging, through which the wave characteristics such as wavelength and phase/propagation speed are evaluated as mostly the vertical projection of rather regularly generated bubble-surface ripples. The bubble oscillating motion is characterized quantitatively by the bubble-gyration (or edge-rotation) frequency, diameter and velocity. In addition, dynamics of mass transfer across gas–liquid interface in a gas-dispersed (continuous liquid) system are examined via high-sensitivity, high-speed imaging. The dispersive dynamics of the dissolved component from the gas into the liquid phase are visualized using laser-induced fluorescence (LIF) with pH-sensitive pyrene (HPTS) for both a single and multi-bubble systems. The coupling between these dynamics of surface/interfacial flow and mass transfer is attempted towards better understanding of such complex phenomena prevailing in the vicinity of the fluctuating gas–liquid interface. Enhancement of the mass transfer is found to be associated with the (nonlinear) wave formation, influence of which could be included in modeling the mass-transfer coefficient, apart from an physical account of the near-surface concentration gradient. Due to significant bubble–bubble interactions in a multi-bubble system, the dispersive pattern of low-pH region arising from gas dissolution becomes extremely complex; the visual estimate of time variation in fluorescence level is then mainly made over a fixed space in the gas–liquid flow system.

scholarly journals Liquid-phase Adsorption of Bulk Ethanol–Water Mixtures by Alumina

1993 ◽  
Vol 10 (1-4) ◽  
pp. 93-104 ◽  
Author(s):  
M.B. Rao ◽  
S. Sircar
Keyword(s):  
Mass Transfer ◽  
Liquid Phase ◽  
Selective Adsorption ◽  
Adsorbed Water ◽  
Liquid Mixtures ◽  
Bulk Water ◽  
Activated Alumina ◽  
Transfer Coefficients ◽  
Liquid Phase Adsorption ◽  
Adsorption Of Water

Separation of ethanol–water liquid mixtures can be carried out by selective adsorption of water on activated alumina. The moderate selectivity and heat of adsorption of water on the alumina permits easier and less energy intensive desorption of the adsorbed water. Experimental binary surface excess isotherms, liquid-phase adsorption kinetics and column dynamics for the adsorption of bulk water–ethanol mixtures on Alcoa H152 alumina are reported. Model analyses of the data are carried out to quantify the selectivity of adsorption, adsorptive mass-transfer coefficients and the properties of the mass-transfer zones in adsorption columns.

scholarly journals Scale-Up Studies for Co/Ni Separations in Intensified Reactors

Micromachines ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1106
Author(s):  
Dimitrios Tsaoulidis ◽  
Milan Mamtora ◽  
Marta Mayals Gañet ◽  
Eduardo Garciadiego-Ortega ◽  
Panagiota Angeli
Keyword(s):  
Mass Transfer ◽  
Scale Up ◽  
Plug Flow ◽  
Impinging Jets ◽  
Small Scale ◽  
Residence Times ◽  
Transfer Coefficients ◽  
Channel Diameter ◽  
Mass Transfer Coefficients ◽  
Cyanex 272

In this paper, the effect of the scalability of small-scale devices on the separation of Co(II) from a binary Co(II)/Ni(II) mixture in a nitric acid solution by an organic Cyanex 272/TBP/kerosene (Exxsol D80) phase is studied. In particular, circular channels with diameters of 1, 2, and 3.2 mm are considered. The results were compared against those from a confined impinging-jets (CIJ) cell with a main channel diameter of 3.2 mm. The effects of total flowrate, residence time, Cyanex 272 concentration, and flowrate ratio on the mass transfer performance were investigated. It was found that at increased channel size, the throughputs were also increased but the extraction percentages remained the same. Higher extraction percentages were obtained by using the CIJ configuration at short residence times. However, for longer residence times, the mass transfer coefficients were similar and capillary channels should be preferred over the CIJ because of the ease of separation of the two phases at the end of the unit. The overall mass transfer coefficients ranged between 0.02 and 0.14 s−1 for the capillary channels during plug flow and between 0.05 and 0.45 s−1 for the CIJ cells during dispersed flow.

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