Details zur Publikation |
| Kategorie | Textpublikation |
| Referenztyp | Zeitschriften |
| DOI | 10.1016/j.chemosphere.2007.12.001 |
| Titel (primär) | Influence of sorption to dissolved humic substances on transformation reactions of hydrophobic organic compounds in water, Part II. Hydrolysis reactions |
| Autor | Georgi, A.; Trommler, U.; Reichl, A.; Kopinke, F.-D. |
| Quelle | Chemosphere |
| Erscheinungsjahr | 2008 |
| Department | TUCHEM |
| Band/Volume | 71 |
| Heft | 8 |
| Seite von | 1452 |
| Seite bis | 1460 |
| Sprache | englisch |
| Keywords | Dissolved organic matter; Sorption; Hydrolysis; Catalysis; Dechlorination |
| Abstract | The effect of dissolved humic acid (HA) on two types of hydrolysis reactions was investigated: (I) dehydrochlorination of ?-hexachlorocyclohexane (HCH) and 1,1,2,2-tetrachloroethane (TeCA) as a reaction involving hydroxide ions (OH-) and (II) hydrolysis of 1-octyl acetate (OA) which is catalyzed by H+ at the applied pH value (pH 4.5). The rate of TeCA hydrolysis was not affected by addition of 2 g l-1 of HA at pH 10 (k' = 0.33 h-1) but HCH hydrolysis was significantly inhibited (k' = 4.6 × 10-3 h-1 without HA and 2.8 × 10-3 h-1 at 2 g l-1 HA). HCH is sorbed by 51% whereas TeCA sorption is insignificant at this HA concentration. Sorbed HCH molecules are effectively protected due to electrostatic repulsion of OH- by the net negative charge of the HA molecules. In contrast, OA hydrolysis at pH 4.5 (k' = 1.6 × 10-5 h-1) was drastically accelerated after addition of 2 g l-1 HA (k' = 1.1 × 10-3 h-1). The ratio of the pseudo-first-order rate constants of the sorbed and the freely dissolved ester fraction is about 70. H+ accumulation in the microenvironment of the negatively charged HA molecules was suggested to contribute to the higher reaction rate for the sorbed fraction in case of this H+-catalyzed reaction. Analogous effects from anionic surfactants are known as micellar catalysis. |
| dauerhafte UFZ-Verlinkung | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=935 |
| Georgi, A., Trommler, U., Reichl, A., Kopinke, F.-D. (2008): Influence of sorption to dissolved humic substances on transformation reactions of hydrophobic organic compounds in water, Part II. Hydrolysis reactions Chemosphere 71 (8), 1452 - 1460 10.1016/j.chemosphere.2007.12.001 |
|