- Title
- Development of diffusive gradient in thin film technology for emerging organic contaminants
- Creator
- Duan, Qiushi
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2022
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Currently, the distribution and longevity of emerging organic contaminants in the environment are attracting much concern. These new compounds can be transported across different environmental mediums, causing contamination and posing potential dangers to ecosystems and people’s health. The current study seeks to understand the environmental distribution and state of monitoring them. The conventional method for sampling organics in water is direct grabbing, which presents some limitations and backwards in terms of time required, sample transportation and future sample process. The novel passive water sampler DGT, diffusive gradient in thin films technique, was based on Fick’s law to describe a steady gradient diffusion process, successfully overcame the traditional methods’ drawbacks, and provided reliable and quantitative sampling results. In this study, we would like to expand the knowledge for the application in the organic and find the most appropriate environment conditions for DGT’s application. DGT with appropriate materials of filters, diffusive gels and binding gels were devised to sample pesticides, pharmaceuticals and perfluorinated alkylated substances In this study, the different materials used in advanced sampling technique had been chosen and tested to determine the optimal combination. Environmental factors and internal capacity have been verified, including pH, ionic strength, and dissolved organic matter and internal factors, such as the diffusion coefficient which is the most important element to the diffusion process and DGT’s sampling performance. In order to know the effects of these critical factors, considerable experiments in lab conditions and filed environment had been organized. The lab experiment was mostly designed to be similar real nature status and the extreme one. The time dependence was always considered in the experiment to ensure the basic deployment capacity. The results showed the DGT was suitable for application of emerging organic contaminants, including diuron, ibuprofen, ketoprofen, diclofenac, perfluoroocatanoic acid and perfluoroocatanesulfonic acid, in the pH of 4-9, ionic strength of 0.001 -0.5M, and dissolved organic matter of 0- 20 mg L-1. Sampler can be deployed in the water environment for up to half year based on the predicted concentrations. The results also showed DGT can be applied in the various environment conditions based on the above value. Although DGT is a potential technique to sample emerging organic contaminants in various water conditions, there are still some concerns about the field application. Competitive effects may occur in the complexed contaminations environment and cause the inaccuracy in the sampling results. This issue was tested, and the results showed the little effects based on the hypothesis conditions. While, for another drawback, the biofouling effects which are more common in the water samplers, showed the negative impacts on the DGT’s performance. The accumulated amount of compounds were disturbed by the increased thickness of diffusion phase and the poor DGT’s performance. The increase of thickness of diffusion phase would increase the diffusion time and the time of the accumulation of the compound. This also provide the reference for the DGT’s application in the real environment and the importance of role of filters. As the filters not only can allow the certain size compounds to pass through layer but it can slow process of the biofouling and provide the protection for the diffusion process. These data can be helpful to the different objectives for DGT’s application in the industry or environment monitoring, which can be considered as the reference in the sampling process and results discuss. This study made the DGT more practical. This research had demonstrated that DGT is a promising tool for sampling emerging organic compounds in the water environment. It gives the potential of monitoring and ecological risk assessment of the environment through understanding the fate and behavior of compounds.
- Subject
- emerging contaminants; water supply; passive water sampler; diffusive gradient
- Identifier
- http://hdl.handle.net/1959.13/1512488
- Identifier
- uon:56623
- Rights
- Copyright 2022 Qiushi Duan
- Language
- eng
- Full Text
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| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | ATTACHMENT01 | Thesis | 3 MB | Adobe Acrobat PDF | View Details Download | ||
| View Details Download | ATTACHMENT02 | Abstract | 1 MB | Adobe Acrobat PDF | View Details Download |