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Date: 18-11-2020
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Diafiltration
Ultrafiltration and microfiltration are able to prepare reasonably concentrated samples of macromolecules, but they permit only a limited separation of the retained solutes from the smaller or more permeable components present in the solution needing to be filtered. In order to remove such smaller components more efficiently from the retained species, the feed solution can be washed in a process known as diafiltration. In this process, water or an appropriate buffer solution is added to the retentate during filtration, with the membrane-permeating species being removed as the excess fluid or buffer is filtered. Such a process may be undertaken in two different modes: continuous, in which the wash fluid is added throughout filtration, or discontinuous, in which the feed solution is first concentrated by a predetermined amount using standard ultrafiltration techniques, the wash fluid is then added, and the process repeated any number of times until the final solute concentration is achieved. When using continuous diafiltration, the amount of solute remaining in the retentate may be determined from a mass balance and expressed as
Where CR is the concentration of the retentate, C0 the initial concentration, ND is the number of diavolumes, defined as the total volume of the wash fluid divided by the initial volume of the solution, and S is the solute sieving coefficient.
For discontinuous diafiltration, it is given by
Where n corresponds to the number of discontinuous diafiltration procedures.
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اكتشاف تأثير صحي مزدوج لتلوث الهواء على البالغين في منتصف العمر
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زهور برية شائعة لتر ميم الأعصاب التالفة
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موكب أهالي كربلاء يستذكر شهادة الإمام الصادق (عليه السلام)
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العتبة العباسية تستذكر شهادة الإمام الصادق (عليه السلام) بإقامة مجلس عزاء
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أهالي كربلاء يحيون ذكرى شهادة الإمام الصادق (عليه السلام) في مدينة الكاظمية
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شعبة مدارس الكفيل النسوية تعقد اجتماعًا تحضيريًّا لوضع الأسئلة الامتحانية
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