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Thesis
UV induced photolysis of fructose: generation of reactive oxygen species and their application in photo-degradation of pesticides
Master of Science (M.S.), Drexel University
01 Jun 2015
DOI:
https://doi.org/10.17918/etd-6529
Abstract
Exposure to UV-light at 254 nm has shown to induce photolysis of fructose present in the open chain form, generating reactive oxygen species (ROS). The objective of this study was to identify these ROS and evaluate whether fructose can be used as a photosensitizer for accelerated photodegradation of recalcitrant organic compounds such as the pesticides chlorpyrifos and diuron and the organic contaminant pentachlorophenol found in flowback water resulting from the hydraulic fracturing process. Using fluorescein as reactive oxygen species probe, I demonstrated that ROS such as hydrogen peroxide and acidic photolysis products were generated during UV exposure of fructose. Hydrogen peroxide generation from UV exposed fructose solution was investigated using ferrous sulfate- xylenol orange (FOX) assay. After 7 minutes of UV exposure, 63.7±1.11, 52.91±1.07 and 67.08±1.08 [mu]M hydrogen peroxide was generated in 500 mM fructose solution prepared in distilled water and buffer solutions of pH 4.5 and 6.7, respectively. Generation of singlet oxygen was identified using Singlet Oxygen Sensor Green (SOSG) probe which forms fluorescent endoperoxides (EP) upon reaction with singlet oxygen. Approximately 20-fold increase in fluorescence from SOSG-EP was observed in 500 mM fructose solution after 1 minute of UV exposure, indicating generation of singlet oxygen. The degradation rate of chlorpyrifos and diuron was accelerated by approximately two-fold when comparing 500 mM fructose as a photosensitizer to UV-alone. Likewise, the presence of 500 mM fructose in water and 10% saline solution increased the rate of PCP degradation by 2.3 and 6.3 times respectively compared to the control (UV exposure alone). These results highlight the use of fructose as a photosensitizer for photo-catalytic degradation may be particularly attractive to food and beverage processing industry where the effluents typically contain high amount of fructose and possibly high amounts of pesticide residues. In addition, the results demonstrate the potential of fructose as a photosensitizer to treat organic contaminants in highly saline solutions, such as flowback water produced during hydraulic fracturing.
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Details
- Title
- UV induced photolysis of fructose
- Creators
- Shaila R. Nayak - DU
- Contributors
- Rohan Tikekar (Advisor) - Drexel University (1970-)Christopher Sales (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Center for Hospitality and Sport Management (2013-2017); Drexel University
- Other Identifier
- 6529; 991014632072404721