Long-term filtration

Jeon, H.Y., Kim, S.H., Chung, Y.I., Yoo, H.K., Mlynarek, J., 2003. Assessments of long-term filtration performance of degradable prefabricated geotextile drains. Pol3Tner Testing 22 (7), 779-784. 

Figure 10.14 Images of fiber surface after long-term filtration of yeast suspension. Fiber 2.7 mm OD, Ug = 0.34 m/s, = 0.19 m/s. Fluxes (a) = 30, (b) = 15, and (c) = 10 L/m h (Chang and Fane, 2000).

To purify the SATA-modified (strept)avidin use gel filtration on a desalting column or dialyze against 0.1M sodium phosphate, 0.15M NaCl, pH 7.2, containing lOmM EDTA. At this point, the derivative is stable and may be stored under conditions which favor long-term (strept)avidin activity. 

Long-Term Cross-flow Filtration Test with Fischer-... 

The objective of the present study is to develop a cross-flow filtration module operated under low transmembrane pressure drop that can result in high permeate flux, and also to demonstrate the efficient use of such a module to continuously separate wax from ultrafine iron catalyst particles from simulated FTS catalyst/ wax slurry products from an SBCR pilot plant unit. An important goal of this research was to monitor and record cross-flow flux measurements over a longterm time-on-stream (TOS) period (500+ h). Two types (active and passive) of permeate flux maintenance procedures were developed and tested during this study. Depending on the efficiency of different flux maintenance or filter media cleaning procedures employed over the long-term test to stabilize the flux over time, the most efficient procedure can be selected for further development and cost optimization. The effect of mono-olefins and aliphatic alcohols on permeate flux and on the efficiency of the filter membrane for catalyst/wax separation was also studied. 

A similar problem occurs with beer stabilization. A serious problem in the brewing industry is the tendency of some beers to develop hazes during long-term storage due to protein precipitation that is usually stimulated by small quantities of naturally occurring proanthocyanidin polyphenols. In the same way as observed for wine, the excess polyphenols are traditionally removed by treatment with insoluble PVPP, with the same resulting problems. To resolve the problems, several authors have proposed the use of laccase, which forms polyphenol complexes that may be removed by filtration or other separation means. 

The first aim of this work was to study the influence of an unwashed membrane filter on the cadmium, lead, and copper concentrations of filtered seawater samples. It was also desirable to ascertain whether, after passage of a reasonable quantity of water, the filter itself could be assumed to be clean so that subsequent portions of filtrate would be uncontaminated. If this were the case, it should be possible to eliminate the cleaning procedure and its contamination risks. The second purpose of the work was to test the possibility of long-term storage of samples at their natural pH (about 8) at 4 °C, kept in low-density polyethylene containers which have been cleaned with acid and conditioned with seawater. 

In systems where the liquid phase interaction between the solute and solvent is close to ideal, then Eq. 2 can be used successfully on it s own to fit and extrapolate solubility data with respect to temperature. The technique is valuable in an industrial setting, where time pressures are always present. Solubility data points are often available without any additional effort, from initial work on the process chemistiy. The relative volume of solvent that is required to dissolve a solute at the highest process temperature in the ciystallization is often known, together with the low temperature solubility by analysis of the filtrates. If these data points fit reasonably well to the ideal solubility equation then it can be used to extrapolate the data and predict the available crystallization yield and productivity. This quickly identifies if the process will be acceptable for long term manufacture, and if further solvent selection is necessary. 

An important aspect of a-methyldopa s hemodynamic effects is that renal blood flow and glomerular filtration rate are not reduced. As occurs with most sympathetic depressant drugs and vasodilators, long-term therapy with a-methyldopa leads to fluid retention, edema formation, and plasma volume expansion. While data conflict somewhat, it is generally thought that a-methyldopa suppresses plasma renin activity. 

Extensive literature has accumulated concerning other forms of renal dysfunction during long-term lithium therapy, including chronic interstitial nephritis and minimal-change glomerulopathy with nephrotic syndrome. Some instances of decreased glomerular filtration rate have been encountered but no instances of marked azotemia or renal failure. 

Pinal UF/DP and Sterile Filtration concentration and buffer exchange for long-term product storage or preparation for drug product formulation... 

The AQUATECH technology, used in conjunction with conventional separation techniques such as filtration and electrodialysis is able to overcome the disposal problem in a cost effective manner while recycling valuable resources back to the processing plant. The net result is a cleaner environment and the avoidance of long term liabilities to the processor. 

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