2020 Fiscal Year Research-status Report
Adsorption and separation behaviors of Cs-137 from high level liquid waste by a novel porous covalent organic frameworks (COFs) based adsorbent
| Project/Area Number |
20K22320
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
呉 昊 東北大学, 工学研究科, 助教 (70881796)
|
|---|
| Project Period (FY) |
2020-09-11 – 2022-03-31
|
| Keywords | COFs |
|---|
| Outline of Annual Research Achievements |
An acid-stable covalent organic frameworks was synthesized by a combination of reversible and irreversible reactions. The first reversible Schiff base reaction facilitate to the formation of a crystalline framework. Exceptional resistance towards acid treatment could be realized through enhancing its chemical stability by the following irreversible enol-to-keto tautomerization. This kind of covalent organic frameworks was composed of light HCNO elements through covalent bonding, and could be utilized in an acidic nitric acid solution. Its adsorption performances towards many metal ions in simulated high-level liquid waste was evaluated and the possible adsorption mechanism was considered to be the role of N, O donors in its structure.
|
| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The prepared acid-stable covalent organic frameworks (COFs) was found to have a nano-porous structure from the results of nitrogen adsorption and desorption. The pristine COFs also exhibited good adsorption performances towards Pd in simulated high-level liquid waste (sHLLW) without the interference of co-existing other tested 14 types of metal ions. And its crystalline structure was well-kept even in highly acidic solution which made it feasible to be used as a novel support for many other organic materials.
|
| Strategy for Future Research Activity |
In order to make the prepared COFs possesses the selective adsorption ability towards other nuclides such as Cs etc. Organic material such as Calix[4]arene-R14 will be loaded onto its pores using wet-impregnating method. And its adsorption performance towards Cs in nitric acid solution will be systematically investigated from the aspects of contact time, adsorption capacity and so on. Next, the distribution of Cs onto adsorbent after adsorption experiments will be characterized by PIXE analysis. In addition, the dynamic chromatography separation of Cs will be conducted using the adsorbent packed column (H 170 mm × Φ 10 mm).
|
