Membrane advantages/disadvantages

Comparison between Flat Sheet and Hollow Fiber Membrane BOs Membrane Module Advantages Disadvantages... 

Vapor permeation is often a preferred technique to pervaporation, and liquid feeds are often evaporated, especially, to run the vapor permeation process. The evaporator is typically operated under pressure, giving a vapor feed at the maximum temperature and flux rate consistent with membrane stability. The advantages are a simpler plant and more reliable operation, because both dissolved and suspended solids are removed in the evaporator and cannot damage the membranes. The disadvantage is the extra energy required to evaporate the complete feed (Fig. 5). 

Nondiffusible ionic species of the poly electrolyte present in the carrier membrane solution of the BAHLM should affect the anomalous osmosis in both sides in the feed-side and strip-side membranes. The disadvantage of conventional osmosis, dilution ot the product, may be obviated if not turned out to the advantage of enrichment of the product. 

Material Absorbent Membrane Contactor Categories/Applications Advantages Disadvantages O O... 

Dense ceramic membranes allow oxygen or hydrogen permeation in a dissociated or ionized form other than the conventional molecular diffusion, and thus exhibit extremely high selectivity (up to 100%). They can be incorporated into membrane reactors for a variety of oxidation and dehydrogenation reactions where the membrane functions as either a product extractor or a reactant distributor. Three configurations, that is, disc/flat-sheet, tubular and hollow fibre membranes have been applied in membrane reactors. They exhibit respective advantages/disadvantages in terms of the ease and cost of fabrication, the effective membrane area/volume ratio, and... 

Electrodialysis. In reverse osmosis pressure achieves the mass transfer. In electro dialysis (qv), dc is appHed to a series of alternating cationic and anionic membranes. Anions pass through the anion-permeable membranes but are prevented from migrating by the cationic permeable membranes. Only ionic species are separated by this method, whereas reverse osmosis can deal with nonionic species. The advantages and disadvantages of reverse osmosis are shared by electro dialysis. 

The advantage of sol-gel technology is the ability to produce a highly pure y-alumina and zirconia membrane at medium temperatures, about 700 °C, with a uniform pore size distribution in a thin film. However, the membrane is sensitive to heat treatment, resulting in cracking on the film layer. A successful crack-free product was produced, but it needed special care and time for suitable heat curing. Only y-alumina membrane have the disadvantage of poor chemical and thermal stability. 

Wang Y, Li L, Hu L, Zhuang L, Lu J, Xu B. 2003. A feasibility analysis for alkaline membrane direct methanol fuel cell Thermodynamic disadvantages versus kinetic advantages. Electrochem Commun 5 662. 

A comparison of the advantages and the disadvantages of membrane cells and of mercury cells is given in Table 6.21. A similar comparison between membrane cells and diaphragm cells is given in Table 6.22. 

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