Chemical oxidation/reduction

White AF, Dubrovsky NM (1994) Chemical oxidation-reduction controls on selenium mobility in groundwater systems. In Environmental Chemistry of Selenium. Frankenberger Jr. WT, Engberg RA (eds), Marcel Dekker, New York, p 185-221... 

Most of the abiotic chemical transformation products reported in this book are limited to only three processes hydrolysis, photooxidation, and chemical oxidation-reduction. These processes are the most widely studied and reported in the literature. Detailed information describing the above technologies, their availability/limitation and company sources is available (U.S. EPA, 1987). 

The next example of molecular tunneling near absolute zero was the rebinding of ligands to heme proteins that I have already mentioned. The typical distances of electron tunneling in various (e.g., radiation-chemical) oxidation reduction processes in solid state at 100 to 140°K are of the order of tens of angstroms. Distances of molecular tunneling at about 4°K are equal to 0.3 to 0.5 A. 

Several studies of chemical oxidation-reduction reactions in nonaqueous solvents have been made.8 12 Not all dipolar aprotic solvents exhibit good stability toward oxidation or reduction. While some solvents extend the range... 

Actually, this situation may be further generalized as shown later. In particular reversible processes that involve any infinitesimal departures from the quiescent condition of the open-circuit conditions, chemical oxidation-reduction processes occur, which keep in step with the electron flow through a closed external circuit. 

Table 10.1. Redox potentials of some chemical oxidants, reductants, and radical species of interest in waste treatment and/or disinfection processes.

In addition to those chemicals released directly, chemical reactions in the environment generate still more pollutants. After being discharged into the soil and groundwater, some pollutants degrade into chemicals that are sometimes more toxic than the parent compounds. Such degradation occurs via chemical oxidation, reduction, hydration, and bacterial action. 

The above sections of this chapter have shown the high variability of iron-inpnt modes, flnxes and reactivity towards oxidized and reduced species in marine sediments. Within this section the importance of iron and manganese reactivity with respect to the mineralization of organic matter as well as to the chemical oxidation (reduction) of reduced (oxidized) species within different depositional enviromnents will be discussed and hopefully inspire further considerations. 

The production of an electric current from a chemical (oxidation-reduction) reaction... 

Many chemical oxidation-reduction reactions can be performed in an electrochemical cell in which electrons liberated by oxidation of a species at one electrode (anode) flow through an external conductor to a second electrode (cathode) where they are consumed by a reduction reaction. A corresponding ionic current flows through the electrolyte that separates the electrodes in the electrochemical cell. In such a device. 

FIGURE 1 5.18 Permanent waving, a chemical oxidation-reduction process. 

It is also feasible to use enzymatic assays as an alternative to chemical oxidation/reduction. Many of these enzymatic assays are based on the fluorescence of the reduced form or the oxidized form of the... 

A further development of the Mopac process led to the KWU Cord process (Chemical—Oxidation—Reduction-Decontamination), a multi-cycle, low-concentration process which proved to be especially suitable for the decontamination of subsystems and full reactor systems (Wille and Sato, 1994). The principles of this process are shown in Fig. 4.52. A CoRD decontamination cycle starts with an oxidation step, using a dilute solution of permanganic acid the excess Mn04 is then reduced by addition of a dicarboxylic acid, thereby generating CO2. By further addition of the dicarboxylic acid up to a concentration of about 0.2%, dissolution of the oxides starts and the metal ions are retained in the solution as complex compounds. The whole process is conducted at about 95 C it does not require a fixed number of cycles, but can be repeated according to the final radiation dose... 

Yang GCC (2009) Electrokinetic-chemical oxidation/ reduction. In Reddy KR, Cameselle C (eds) Electrochemical remediation technologies for polluted soils, sediments and groundwater. Wiley, Hoboken, pp 439-471... 

Fig. 1.39. Chemical oxidation-reduction processes ofdirheniun complexes [Cotton FA, Walton RA (1985) Struct. Bonding 62 1]...

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