Cake membrane technology

Blatt, W. F., Dravid, A., Michaels, A. S. and Nelson, L. In Membrane Science and Technology, Flinn, J. E. (ed.) (Plenum, New York, 1970). Solute polarisation and cake formation in membrane ultrafiltration Causes, consequences and control techniques. 

In filtration unit operation, especially in microfiltration, one usually differentiates between dead-end filtration (with cake formation) and cross-flow filtration [25] (Fig. 5). The cross-flow filter can have different geometries (Fig. 6) phase membranes, tubular membranes, or pleated membranes, of which the tubular and pleated ones are already accepted as cross-flow geometries in reactor technology, as mentioned above. In filtration engineering the cross-flow term means that the filtrate flows perpendicularly to the suspension stream. Cross-flow may not be considered a sufficiently illustrative term here [25]. A better term would be parallel filtration, but the term cross-flow filtration has been accepted generally and may be difficult to change at present. 

Blatt, W.F. et al.. Solute polarizahon and cake formation in membrane ultrafiltration. Causes, consequences, and control techniques, in Membrane Science and Technology, J.E. Flinn (Ed.), pp. 47-97. Plenum Press, New York, 1970. 

Blatt, W.F. et al. "Solute Polarization and Cake Formation in Membran Ultrafiltration Causes Consequences and Control Techniques," Ultrafiltration Membranes and Applications, Polymer Science and Technology, Volume 13. 

The primary technology for citric acid recovery from fermentation broths is through precipitation with CaCOs, although other technologies include ion exchange, carbon adsorption, membrane filtration, chromatography, and liquid extraction [29]. Unlike other TCA cycle carboxylic acids, citric acid is excreted in the acid form rather than precipitated as citrate salt [30], which has the implication that the cell mass can first be filtered, followed by crystallization with iime with subsequent separation by filtration. The filter cake is next acidified with sulfuric acid, which precipitates the calcium as gypsum and the aqueous citric acid can next be decolourized and recrystallized by evaporation [29]. 

---