Electrically assisted separation

Chemical composition Chemical composition of the liquid phase affects separability of the particles. Electrical conductivity may determine suitability of electrically assisted separation processes. Paramagnetism may prevent use of high intensity magnetic separation methods. 

In many cases, membrane processes seem to be the most energy efficient separation processes available for industry. However, the costs related to cleaning or replacement of membranes, the need for skilled personnel, and the associated turn down costs determine their economical feasibility. Table 40.1 lists the various electrically assisted membrane processes with the type of effluents that could be treated most efficiently by each process. For most of the electrically assisted membrane processes (1 ), it is expected that the treatment of effluents would be most feasible when ion or particle concentration is high. These are also the effluents where alternative purification processes require a significant part of the process cost to be spent upon membrane... 

Adam, T. and Unger, K.K., Comparative study of capillary electroendosmotic chromatography and electrically assisted gradient nano-Hquid chromatography for the separation of peptides, J. Chromatogr. A, 894, 241, 2000. 

Sung, M., Huang, C.P., Weng, Y.H., Lin, YT. Li, K.C. (2007) Enhancing the separation of nano-sized particles in low-salt suspensions by electrically assisted cross-flow filtration. Separation and Purification Technology, 54 (2), 170-177. 

Electrofining A process for purifying petroleum fractions by extracting them with various liquid reagents and then assisting their separation by means of an electric field. Developed by the Petreco Division of Petrolite Corporation, and first operated in California in 1951. 

Marsh RA, Hodgkiss JM, Friend RH (2010) Direct measmement of electric field-assisted charge separation in polymer fullerene photovoltaic diodes. Adv Mater 22 3672... 

Both photon-assisted collisions and collision-induced absorption deal with transitions which occur because a dipole moment is induced in a collisional pair. The induction proceeds, for example, via the polarization of B in the electric multipole field of A. A variety of photon-assisted collisions exist for example, the above mentioned LICET or pair absorption process, or the induction of a transition which is forbidden in the isolated atom [427], All of these photon-assisted collision processes are characterized by long-range transition dipoles which vary with separation, R, as R n with n — 3 or 4, depending on the symmetry of the states involved. Collision-induced spectra, on the other hand, frequently arise from quadrupole (n = 4), octopole (n = 5) and hexadecapole (n = 6) induction, as we have seen. At near range, a modification of the inverse power law due to electron exchange is often quite noticeable. The importance of such overlap terms has been demonstrated for the forbidden oxygen —> lD emission induced by collision with rare gases [206] and... 

Figure 183. Drums with coalescers for assisting in the separation of small amounts of entrained liquid, (a) A liquid-liquid separating drum equipped with a coalescer for the removal of small amounts of dispersed phase. In water-hydrocarbon systems, the pot may be designed for 0.5 ft/sec (Facet Enterprises, Industrial Division), (b) An oil-water separator with corrugated plate coalescers (General Electric Co.).

As a rough guide the amount of adsorbent used should normally be 25-50 times the weight of the material to be separated. A slurry of the adsorbent in the solvent (approximately 1 10) is poured through a funnel into a clean dry column clamped vertically, in a position away from draughts or warm air currents from a radiator or electric oven, etc. The adsorbent will settle evenly and free of air bubbles if assisted by gentle tapping of the tube with a wooden rod. For... 

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