Subject Membrane filtration

Tests should also be carried out for sediment if the naphtha has been subjected to events (such as oxidation) that could lead to sediment formation and instability of the naphtha and resulting products. Test methods are available for the determination of sediment by extraction (ASTM D473, IP 285) or by membrane filtration (ASTM D4807 IP 286) and the determination of simultaneously sediment with water by centrifugation (ASTM D96, D1796, D2709, D4007 IP 373, 374). 

A simple centrifugation or MF step in the primary clarification may directly be succeeded by a secondary clarification or an enrichment step, such as extraction, precipitation, or adsorption. The concentrated product may then be subjected to membrane filtration processes. Ultrafiltration might be done earlier and then followed by extraction or precipitation with salts. Diafiltration units can subsequently be used to remove the... 

Microbiological checks are usually centred on the bright beer tank, the filler and seamer units, and particularly on the canned beer emerging from the pasteurizer. The latter is membrane-filtered and the membranes are incubated on nutrient medium there should be no colonies after 3-4 days at 25-30°C (77-86 F). Some cans are held for 14 days at 30°C (86°F) before being subjected to the membrane-filtration and incubation tests. Again there should be no development of colonies. 

The undissolved portion is separated from the water sample by means of membrane filtration, washed out and if applicable subjected separately to activity measurement in the test laboratory. 

Subjects LCSH Water—Purification— Membrane filtration. ... 

When we talk about this subject, the term foulant or foulant layer comes to the forefront. Foulant, or fouling layer, are general terms for deposits on or in the membrane that adversely affect filtration. The term "fouling" is often used indiscriminately in reference to any phenomenon that results in reduced product rates. "Fouling" in this casual sense can involve several distinct phenomena. These phenomena can be desirable or undesirable, reversible or irreversible. Different technical terms apply to each of these possibilities. 

NMR analysis, the PHA was extracted from freeze-dried cells. For this purpose, 1.0 g freeze-dried cells were stirred in 200 mL of chloroform for 24 hours at 30°C. The extract was filtered to remove cells debris, and the chloroform was concentrated to a volume of about 15 ruL using rotary evaporator. The concentrated solution was then added drop-wise to 150 luL of rapidly stirred methanol to precipitate the dissolved PHA.The precipitated PHA was then recovered by filtration using a 0.45 pm PTFE membrane and dried overnight at room temperature. The purified PHA was dissolved in deuterated chlorofonn (CDCl ) and subjected to H and NMR analyses. 

The mechanism of particle filtration by screen filters has been the subject of many studies because it is relatively easily described mathematically Bungay has published a review of this work [49], Ferry [50] was the first to model membrane retention by a screen filter in his model pores were assumed to be equal circular capillaries with a large radius, r, compared to the solvent molecule radius. Therefore, the total area of the pore is available for transport of solvent. A solute molecule whose radius, a, is an appreciable fraction of the pore radius cannot approach nearer than one molecular radius of the pore overall. The model is illustrated in Figure 2.32. 

---