Abstract
Overcoming barriers to the remediation of CCl4 through manipulation of competing reaction mechanisms were studied. The product-branching ratio depended on the nature of the reducing surface as well as the composition of the aqueous phase. The presence in solution of readily available H donors could affect the product-distribution ratio. Isopropanol increased the amount of CCl4 degraded by the one-electron pathway under photochemical stimulation. Manipulation of solution pH also affected product distribution. With sorbed Fe(II) systems, increasing the pH above 6 enhanced the amount and density of Fe(II) sorbed and this, in turn, increased both the overall rate and the proportion of reactant following the two-electron pathway. Similar enhancement at high pH was observed for photochemical degradation of CCl4 at TiO2 surfaces and attributed to the base-catalyzed hydrolysis of the dichlorocarbene. At pH of ≥ 8.5, however, hydrolysis of Fe(II) led increasingly to its oxidation by water and precipitation of mixed-valence green-rust phases in which the Fe(II) density was less and the dichlorocarbene pathway was less favored.
Original language | English (US) |
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Journal | ACS Division of Environmental Chemistry, Preprints |
Volume | 44 |
Issue number | 1 |
State | Published - 2004 |
Event | ACS Division of Environmental Chemistry, Preprints of Extended Abstracts - Anaheim, CA., United States Duration: Mar 28 2004 → Apr 1 2004 |
ASJC Scopus subject areas
- General Chemical Engineering