| Author: | Liang, Chaofu |
| Title: | Mitigation of copper phytotoxicity to maize and cucumber by TiO₂ nanoparticles |
| Advisors: | Li, X. D. (CEE) |
| Degree: | M.Sc. |
| Year: | 2018 |
| Subject: | Hong Kong Polytechnic University -- Dissertations Phytoremediation Nanoparticles -- Environmental aspects Plants -- Effect of heavy metals on Heavy metals -- Environmental aspects |
| Department: | Faculty of Construction and Environment |
| Pages: | 57 pages : color illustrations |
| Language: | English |
| Abstract: | Severe heavy metal pollutants are widely present in soil around the world, and may pose risk on food safety and consequently human health. Simultaneously, continuous high production of engineered nanoparticles (NPs) has contributed to their large accumulation in agricultural soils. Therefore, it is important to reveal how nanoparticles may influence the geochemical fate and food chain of heavy metals in contaminated site, and may bring deep understanding on heavy metal remediation technologies. In this study, we selected copper, an essential micronutrient for plant, to investigate its interaction with TiO₂ nanoparticles during maize and cucumber vegetation in hydroponic system. After 10-day hydroponic culture, plant seedlings were transferred into 50 ml plastic centrifuge tubes for different treatments with free copper with or without TiO₂ nanoparticles for two days. In the study, the seeding growth, TOC content, chlorophyll content, and copper and titanium content in plant tissues were measured. Furthermore, the copper species in shoot and root were analyzed using XANES technique. The results showed that TiO₂ NPs can mitigate the poisoning effect of copper on plant seedling significantly evidenced by the plant mass content. In addition, copper stress induced sharp increase in TOC content of hydroponic solution. Titanium was only detected in root, with no detection in shoot tissue, which indicated no or very less TiO₂ nanoparticles assimilated into plant seedlings in such a short term. TiO₂ nanoparticles significantly decreased the content of copper in both root and shoot, e.g., 60% and 20% decline of copper content in maize shoot and cucumber shoot, respectively, coexisting with 250NPs + 16 mg/L Cu. Copper XANES analysis indicated a large amount of adsorbed copper species on TiO₂ nanoparticle in plant root samples, which consequently decreased the mobility of copper and alleviated its toxicity to plant. This results provide better proof for the mitigation mechanism of copper under NPs coexistence. Further study in a longer culture period of plants should be conducted. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| 991022244146003411.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.92 MB | Adobe PDF | View/Open |
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