ENVIRONMENTAL OXIDATIONS

Oxidation is defined as a loss of electrons. Oxidizing agents gain electrons and are by definition electrophiles. In organic chemistry, oxidation can either be associated with the introduction of oxygen into a molecule or the conversion of a molecule to a higher oxidation state. For example, in Equation 4.1 

Almost all oxidations are kinetically second-order reactions in which the rate is proportional to the concentrations of both the oxidizing agent. Ox, and the substrate, A (Equation 4.2)  

For reactions in water, there are few values for the rate constant, k, and also few data on the concentrations of potential oxidants. 

In environmental chemistry, there are many sources of oxidants w hose importance is highly variable due to changes in concentration or reactivity as one moves from one compartment or region of the environment to another. A potent oxidant such as the hydroxyl radical, -OH, that is of critical importance for organic transformations in the gas phase or during combustion, may not be important at all in 

At lower elevations O atoms take part in less important reactions with water, ammonia, oxides of sulfur and nitrogen, and organic compounds. 

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Calabrese, E.J., J.A. Garreffi, and E.J. Stanek. 1992. The effects of joint exposures to environmental oxidants on methemoglobin formation copper/nitrate and copper/chlorite. Jour. Environ. Sci. Health 27A 629-642. 

Shaaltiel, Y., A. Glazer, P.F. Bocion, and J. Gressel. 1988. Cross tolerance to herbicidal and environmental oxidants of plant biotypes tolerant to paraquat, sulfur dioxide, and ozone. Pestic. Biochem. Physiol. 31 13-23. 

The technology has been used during bench-scale experiments and field-scale demonstrations. The technology is available for licensing through SUNY, Oswego, and is commercially available through Environmental Oxidation Systems, L.L.C. 

Environmental Oxidation Systems, L.L.C., prepared cost estimates for a theoretical ECP system. The system was designed to treat water contaminated with 5000 parts per billion (ppb)... 

After the pilot-scale demonstration at a former petroleum storage site in Saratoga Springs, New York. Environmental Oxidation Systems, L.L.C., estimated the cost of consumables used during an ECP application. Pretreatment with 93% sulfuric acid would cost approximately 0.40 per 1000 gal of water treated. The hydrogen peroxide could be applied at a cost of 0.37 per 1000 gal of water treated. The electricity required by the electrodes would cost approximately 0.06 per 1000 gal of water treated (D22708H, p. 12). 

J. O. Nriagu and M. S. Simmons (eds.), Environmental Oxidants. Wiley, New York, 1994 A. M. Thompson, The oxidizing capacity of the Earth s atmosphere probable past and future changes. Science 256, 1157-1165 (1992). 

Trifluoroacetic acid has two characteristics that are cause for environmental concern exceptional stability and phytotoxicity. Its stability arises from its effective immunity to environmental oxidation and reductive dehalogena-tion [235,236]. As a result of its stability, it has been demonstrated that trifluoroacetic acid accumulates in terminal water bodies [233,237,238]. 

Estimation of rates for redox reactions in environmental systems requires that the problem be formulated in terms of specific oxidation and reduction half-reactions. In addition, we assume that the rate-limiting step of the transformation mechanism is bimolecular—that is, the slow step requires an encounter (collision) between the electron donor and electron acceptor. Under most conditions found in environmental systems, such reactions exhibit rate laws for the disappearance of a pollutant, P, that are first-order in concentration of P and first-order in the concentration of environmental oxidant or reductant, E,... 

In many cases, the concentration of the environmental oxidant or reductant is effectively constant over the time frame of interest, so Equation (21) can be simplified to a pseudo-first-order rate law... 

Larson, R.A. and E.J. Weber. 1994. Chapter 4. Environmental Oxidations. In Reaction Mechanisms in Environmental Organic Chemistry, pp. 217-273. Lewis, Chelsea, MI. 

The liquid phase reaction kinetics and mechanisms of oxidation of biogenic sulfur compounds (H2S, RSH, C 2, OC, CH3SCH3, CH3SSCH3) by various environmental oxidants (02,... 

Tratnyek PG, Reilkoff TE, Lemon A, Scherer MM, Balko BA, Feik LM, Henegar B. Visualizing redox chemistry probing environmental oxidation-reduction reactions with indicator dyes. Chem Educ 2001 6 172-179. 

Tratnyek, P. G. Reilkoff, T. E. Lemon, A. W. Scherer, M. M. Balko, B. A. Feik, L. M. Hene-gar, B. D. Visualizing Redox Chemistry Probing Environmental Oxidation-Reduction Reactions with Indicator Dyes, Chem. Educ. 2001, 6(3) 172-179. 

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