Mineralization trichloroethene

Trichloroethene 20 Polysulfone fibers Acetate, minerals Yes Sludge 74... 

Teppen et al. [89] have used a flexible model for clay minerals that allows full movement of the M-O-M bonds in the clay structure, where M represents Si, Al, or other cations in the octahedral sheet. This model was used in MD simulations of interactions of hydrated clay minerals with trichloroethene [90, 91]. The simulations suggest that at least three distinct mechanisms coexist for trichloroethene sorption on clay minerals [90], The most stable interactions of trichloroethene with clay surfaces are by full molecular contact, coplanar with the basal surface. The second type more reversible, less stable is adsorption through single-atom contact between one chlorine atom and the surface. In a third mechanism, trichloroethene interacts with the first water layer and does not interact with clay surface directly. Using MC and MD simulation the structure and dynamics of methane in hydrated Na-smectite were studied [92], Methane particles are solvated by approximately 12-13 water molecules, with six oxygen atoms from the clay surface completing the coordination shell. 

Vinylidene chloride is a human-made chemical and is not naturally found in the environment. It can be found from the breakdown of polyvinylidene (PVDC) products, and from the biotic and abiotic breakdown of 1,1,1-trichloroethane, tetrachloroe-thene, 1,1,2-trichloroethene, and 1,2-dichloroethane. Biotransformation of the chemical in groundwater can form vinyl chloride through reductive dechlorination, which is subsequently mineralized to carbon dioxide. The major transport process from water, soil and sediment is volatilization. Half-lives of... 

In this section we shall briefly review three different cases taken from our recent work the adsorption of trichloroethene by clay minerals, the adsorption of methylene blue by clay minerals, and studies dealing with the alkyl ammonium ion method for layer charge determination. 

Some Computational Aspects of the Trichloroethene Simulations. To model the properties of TCE on clay surfaces, in one series of calculations the 1 1 clay mineral knolinile was constructed using experimental coordinates (Bish,... 

Dependence of degradation rates on flow velocity indicates rate limitation by transport processes, e.g. reported by Sivavec and Homey (1995) or Burris et al. (1995) for the degradation of trichloroethene (TCE) by zerovalent iron in batch reactors. Even if there has been no real explanation for the different degradation behaviour at the two column experiments, it must be dependent on the characteristics of the granular iron, because of the similar experimental conditions. The diverse granulate shape or the distribution of reactive surface as well as mineral precipitations usually present in iron... 

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