2023 Fiscal Year Research-status Report
Optimizing Nanofiltration Membranes for Unprecedented Ultra-Fast Lithium Extraction
| Project/Area Number |
23K19183
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| Research Institution | Kobe University |
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Principal Investigator |
Xu Ping 神戸大学, 先端膜工学研究センター, 特命助教 (40978706)
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| Project Period (FY) |
2023-08-31 – 2025-03-31
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| Keywords | Lithium extraction / Nanofiltration membrane / Salt lake brines / Mg2+/Li+ separation |
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| Outline of Annual Research Achievements |
The project mainly focuses on improving the Mg2+/Li+ separation efficiency of nanofiltration (NF) membranes by adjusting the base layer. We designed a polyphenol-metal-assisted method to regulate the structure of polyethylenimine (PEI)-based polyamide NF membranes. Tannic acid (TA) was first deposited onto the substrate, followed by the impregnation of the Cu2+ ions-incorporated aqueous PEI monomer solution to establish ternary interactions among PEI, TA, and Cu2+ ions. Based on the synergetic effect of Donnan exclusion and size sieving, the resultant PA-TA-Cu membrane has a large rejection difference between MgCl2 and LiCl. Furthermore, the NF membrane also exhibited excellent long-term stability. This study provides an efficient strategy for lithium extraction from salt-lake brines.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
This year, we designed a polyphenol-metal-assisted method to regulate the structure of PEI-based polyamide NF membranes. It was found that the coordination interactions between TA, PEI, and Cu2+ ions efficiently improved the distribution and loading of PEI monomers on the substrate. In addition, the Cu2+ ions severely reduced the activity of the amino groups and served as positive charge centers. The prepared membrane exhibits competitive Li+/Mg2+ separation performance and has significant potential for lithium recovery from salt lake brines. The basic knowledge of the formation and modification of membrane and membrane separation mechanisms has been mastered. Therefore, it is judged that the current progress of the project is generally smooth.
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| Strategy for Future Research Activity |
Based on these previous results, this project will be further continued by controlling the formation conditions of the polyamide layer：
（1）To investigate the influence of monomer concentration on the morphology and properties of the polyamide layer.
（2）To examine the effect of reaction time on the formation and characteristics of the polyamide layer.
（3）To optimize the membrane formation conditions to achieve superior performance in terms of permeability, selectivity, and mechanical strength.
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| Causes of Carryover |
The initial procurement of test modular and materials was essential to conduct the corresponding experiment. However, due to unforeseen delays in delivery from the manufacturer, the execution of this part of the experiment has been postponed until the next fiscal year. Therefore, in order to finish the experiment and achieve the project target, additional funds are still needed in the new fiscal year to purchase the necessary equipment, consumables, and experimental drugs.
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