Electrically Enhanced Extraction

Weatherley L. R., Electrically enhanced Extraction. Science and Practice of Liquid-Liquid Extraction (Ed. I. D. Thornton), Oxford University Press, 1968, Vol. 2, p. 407-419. 

Electrically-enhanced extractions - charged droplets, electrostatic spraying, etc. 

Figure 8.16 Electrically-enhanced extraction of penicillin-G into methylene chloride.

T0728 Solox, Hybrid Solar/Electric Ultraviolet Oxidation System T0747 SteamTech Environmental Services and Integrated Water Resources, Inc., Steam-Enhanced Extraction (SEE)... 

Improved mass transfer leads to smaller extraction equipment with shorter residence times. Weatherley et al.52 studied ethanol extraction with decanol under a range of electrically enhanced experimental conditions. 

Membrane technology may become essential if zero-discharge mills become a requirement or legislation on water use becomes very restrictive. The type of membrane fractionation required varies according to the use that is to be made of the treated water. This issue is addressed in Chapter 35, which describes the apphcation of membrane processes in the pulp and paper industry for treatment of the effluent generated. Chapter 36 focuses on the apphcation of membrane bioreactors in wastewater treatment. Chapter 37 describes the apphcations of hollow fiber contactors in membrane-assisted solvent extraction for the recovery of metallic pollutants. The apphcations of membrane contactors in the treatment of gaseous waste streams are presented in Chapter 38. Chapter 39 deals with an important development in the strip dispersion technique for actinide recovery/metal separation. Chapter 40 focuses on electrically enhanced membrane separation and catalysis. Chapter 41 contains important case studies on the treatment of effluent in the leather industry. The case studies cover the work carried out at pilot plant level with membrane bioreactors and reverse osmosis. Development in nanofiltration and a case study on the recovery of impurity-free sodium thiocyanate in the acrylic industry are described in Chapter 42. 

Similarly, electrophoretic methods are also finding increasing applications in other areas. For instance, electrophoretic processes are established techniques for the dewatering of fine clays and latexes. Electrically enhanced liquid-liquid extraction was reported by Thornton [166]. Adaptation of this method for the extraction of biochemicals was reported [167]. Greater clarification and faster floe formation were claimed using electrocoagulation in comparison with conventional chemical methods [4]. 

Pulsed electric field is another alternative to conventional methods of extraction. PEF enhances mass transfer rates using an external electrical field, which results in an electric potential across the membranes of matrix cells that minimizes thermal degradation and changes textural properties. PEF has been considered as a nonthermal pretreatment stage used to increase the extraction efficiency, increasing also permeability throughout the cell membranes. 

For a single band gap system, two basic approaches for the conversion of hot carriers into electricity or chemical energy have been proposed to enhance the efficiency of photon conversion (a) extraction of the hot carries before they cool, with the production of an enhanced photovoltage [35] (b) production of two or more electron-hole pairs per photon absorbed, with photocurrent enhancement [36, 37]. 

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