Dissertation
Mechanisms of base, mineral, and soil activation of persulfate for groundwater treatment
Washington State University
Doctor of Philosophy (PhD), Washington State University
05/2008
DOI:
https://doi.org/10.7273/000005756
Abstract
The purpose of this study was to examine mechanisms of base, mineral, and soil persulfate activation when used for ground water treatment by in situ chemical oxidation. Four base-activated persulfate systems (adjusting the pH to 12 and using molar ratios of 1:1, 2:1, or 3:1 base to persulfate) were studied using three reaction-specific probe compounds and two radical scavengers. Rapid degradation of oxidative probes occurred at pH 12, but minimal degradation of the reductive probe, carbon tetrachloride, was observed at pH 12. Degradation of all probe compounds occurred in molar ratios systems. The results of this research demonstrate that the reactivity of persulfate formulations increases with increasing base:persulfate ratios. The potential for 13 minerals to mediate the decomposition of persulfate and generate a reactive oxygen species was investigated. Reactions were conducted at 25?C using 2 g of minerals and 5 ml of 0.5 M sodium persulfate with the addition of oxidative, reductive, and nucleophilic probes. The decomposition of persulfate and the probes by minerals varied extensively. Most of the minerals mediated the decomposition of persulfate, but did not promote the generation of reactive oxygen species, although cobaltite, ilmenite, and pyrite did. The results demonstrate that most of the minerals evaluated do not activate persulfate. The decomposition of persulfate by 11 soils was investigated in order to observe the impact of these soils on pH and persulfate concentration. Reactions were conducted at 25?C using 10 g of soil and 20 mL of either 0.5 M or 0.1 M persulfate. Reactions were conducted using base:persulfate molar ratios of 1:1, 2:1, or 3:1 over 120 d. Decomposition of persulfate and pH varied greatly between soils, although not between 0.1 M and 0.5 M persulfate. A second set of experiments were conducted in which anisole was used a probe for the overall reactivity of the system. These experiments used 0.5 M persulfate in a 2:1 base:persulfate molar ratio and two soils. The results demonstrated a reduction in anisole destruction when the pH declined. This research demonstrated the importance of pH and soil properties in the use of persulfate treatments.
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Details
- Title
- Mechanisms of base, mineral, and soil activation of persulfate for groundwater treatment
- Creators
- Joseph Franklin Corbin
- Contributors
- Richard J. Watts (Chair)
- Awarding Institution
- Washington State University
- Academic Unit
- College of Agricultural, Human, and Natural Resource Sciences
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 177
- Identifiers
- 99901054764101842
- Language
- English
- Resource Type
- Dissertation