Electrochemical concentration

Chlorine, when contaminated with C02 or other relatively inert gases, can, in principle, be purified by electrochemical concentration. At a graphite cathode, Cl2 is reduced to chloride ions ... 

ECOC (Electro-Chemical Ozone Cell) is the Electrochemical ozonometer based on the electrochemical concentration cell (ECC) ozonesonde. The air sample is pumped through the ECC where ozone molecules are completely absorbed by the potassium iodide solution which causes an electric current to flow through the external circuit connected to the cell electrodes. Each ozone molecule produces a two electron flow in the outer circuit. Thus measurement of the electric current allows to determine a number of ozone molecules pumped into the ECC in one second. This number can be converted to ozone pressure using a pump productivity and air temperature at the pump output. 

Electrochemical analytical methods, particularly polarography and voltammetry rise in the 1960s was caused by the demand in trace analysis and new technique of preliminary electrochemical concentration of the determined substance on the electrode surface [1,2]. The reason for the new renaissance is the use of screen-printed technologies, which resulted in creation of new electrodes so cheap that they can be easily disposed and there is no need of regenerating the solid electrode surface [3]. 

The membrane-bound Na, K-ATPase pump transports potassium ions into the cell, whilst simultaneously extruding sodium ions, and is driven by the simultaneous breakdown of ATP. Both ions are transported against their electrochemical concentration gradients. The energy in ATP is transformed into ion gradients for potassium and sodium, which subsequently provides the energy for the operation of secondary active potassium- and sodium-dependent cotransporters, and potassium-and sodium-selective conductance channels (Peterson 1997). 

Engelsma M., Kok W.Th. and Smit H.C. (1990) Selective determination of trace levels of phenol in river water using electrochemical concentration modulation correlation chromatography. J. Chromatogr., 506, 201-210. 

Identical metals in contact with different concentrations In this case, the metal immersed in a dilute solution is dissolved from the electrode and deposited on the electrode immersed in a more concentrated solution. The other type of electrochemical concentration ceU is known as a differential aeration cell. In this case, the electrode potential difference occurs when the electrode is immersed in the same electrolyte with different oxygen partial pressures. Differential aeration initiates crevice corrosion in aluminum or stainless steel when exposed to a chloride environment. 

The electrochemical concentration and isolation of iodine and other substances from dilute aqua solutions. Phthalocyanines of REM [123,124]... 

Intensive investigations of REM phthalocyanines have led to the foundation of several useful properties of them. These complexes are offered for utilazation as electrodes for electrochemical concentration and isolation of iodine from dilute water solutions [123, 124]. Changing of color of REM phthalocyanines in electric field became the basis for elaboration and preparation of rare earth electrochromic indicators [145, 146] and light filters [122]. 

PRINCIPLES AND APPLICATIONS OF ELECTROCHEMISTRY 5.5 Electrochemical concentration cells... 

Ozone measurements were performed from balloons with Electrochemical Concentration Cell sondes cou-pled to Vaisala radiosondes, on KCO as described by W.D. Komhyr et al. [Journal of Geophysical Research, 100 9231 (1995)], and on the RPJ Brown as described by D. Kley et al. [Quarterly Journal of the Royal Meteorological Society, 123 2009 (1997)]. 

---