Membrane columns

Methods for DNA extraction Silica-membrane column-t)rpe kit Qiagen DNeasy Plant Mini kit Anion-exchange column-type kit Qiagen Genomic-tip kit CTAB method... 

Liposome partition Immobilized artificial membrane column Liposome electrokinetic chromatograph Solid-supported lipid membrane etc... 

By maximizing the contact area between extraction solvent and surfactant-solubilized hydrophobic oil contaminant through the use of state-of-the-art hollow fiber membrane columns, we hypothesize that hydrophobic oil contaminants can be separated from surfactant solutions without macroemulsification. For this research we were interested in the partitioning of the hydrophobic oil from the hydrophobic environment of the micelle via its aqueous concentration into a more preferred extracting solvent. 

Research on separation processes demonstrated that hydrophobic oilladen surfactant was efficiently regenerated through the use of state-of-the-art hollow fiber membrane columns. Specifically, the hydrophobic oil dodecane was effectively separated from the surfactant system SDBS/IPA/NaCl (Table VI). This separation was accomplished by counterflowing the oil/surfactant solution, comprised of 10.3 ml. dodecane per 100ml. of SDBS/IPA/NaCl solution, with the extraction solvent squalane. These results demonstrate the ability to effectively regenerate and reuse these surfactant systems. 

Determination of the Retention Time on Artificial Membrane Columns... 

Figure 19.13. Continuous membrane column with reflux from both product streams.

Kaliszan, R., Nasal, A. and Bucinski, A. (1994). Chromatographic Hydrophobicity Parameter Determined on an Immobilized Artificial Membrane Column Relationships to Standard Measures of Hydrophobicity and Bioactivity. Eur.J.Med.Chem.,29,163-170. 

Earlier papers on the continuous membrane column (28,29) have discussed the separation of CO2-N2, CO2-O2 and O2-N2 (air) mixtures in stripper, enricher and total column units composed of 35 silicone rubber capillaries. A characterization of the membrane column using a membrane unit concept (analogous to transfer unit concept — HTU, NTU) has also been presented. The purpose of this paper is to present some new data and discussions on the extended study of continuous membrane column. Specifically, the topics of multicomponent separations, Inherent simulation difficulties, composition minima in the enriching section, variation of experimental parameters, and local HMU variation along the column will be covered. 

Thus far, only binary mixtures have been separated in the total membrane column. Results of this work have been discussed elsewhere (28,29). A sample shell-side composition profile from a total column experiment with a CO2-O2 mixture is shown in Figure 2. Table I summarizes the total column data obtained to date. 

One of the next steps in developing the continuous membrane column will be to obtain extensive data on multicomponent systems. Some preliminary experiments with a C02 CH -N2 mixture using a stripper have already been conducted. The results of two such experiments are presented in Figures 3 and 4. The agreement between experiment and model is excellent. 

In modeling multicomponent systems It Is necessary to modify the axial-pressure loss, gas permeation and concentration gradients previously described (28). The governing equations, required to execute the numerical simulation over Infinitesimal segments along the membrane column as shown In Figure 5 are ... 

The curves shown in Figures 3 and 4 are simulated composition profiles based on experimental data. The calculated trends fit the experimental compositions quite well, and in each case the experimental methane peak is well described. This demonstrates that the basic model for the membrane column can be applied to multicomponent systems as well as to binary mixtures. 

The performance of the continuous membrane column was characterized earlier (28) in a manner analogous to the transfer unit concept for packed columns. The expressions developed for NMU (difficulty of separation) and HMU (efficiency) were... 

Usually in an enricher or the enriching section of the membrane column, the more permeable component is steadily concentrated from the feed inlet to the compressor. However, some of the results show that the shell-side and even the tube-side composition profiles can pass through a minimum. Note the experimental data in Figures 7 and 8. In these cases the feed flow is relatively slow and reflux action, rather than bulk flow, is predominant. Figure 8 Illustrates that a composition minimum can also occur dinring operation of the total column when the residue flow rate from the enriching section is too slow. 

The numerical simulation of the total membrane column works well, but does contain some inherent problems. These problems relate to restrictions in the direction that integrations are executed, and to the Influence of propagated errors in the final results. 

Inherent difficulties accompany some simulations of the continuous membrane column. Perturbation of boundary conditions within the range of experimental error may be necessary in certain Instances to achieve a proper fit of experimental data. 

Thorman, J.M. "Engineering Aspects of Capillary Gas Perme-ators and the Continuous Membrane Column," Ph.D. Thesis, University of Iowa, Iowa City, Iowa, 1979. 

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