Programming Ion Transport in Layered 2D Hybrid Membranes via Coordination-Occupation Coupling

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Separating chemically similar metal ions is difficult, posing challenges for nuclear waste management and resource recovery.
• Existing two-dimensional (2D) membranes have limited selectivity due to fixed transport pathways.
• Developing energy-efficient and highly selective separation methods is essential.

Purpose of the Study:

• To develop a novel coordination-occupation-coupled strategy for programming ion transport in 2D hybrid membranes.
• To enhance the selectivity of membranes for separating challenging metal ions, particularly in nuclear waste remediation and resource recovery.
• To investigate the mechanism of targeted pathway occupation for selective ion permeation.

Main Methods:

• Fabrication of layered 2D hybrid membranes using vermiculite and a confined polyacrylate network.
• Utilizing Al³⁺ ions for irreversible crosslinking to create unexchangeable coordination sites within the polyacrylate network.
• Investigating the transport behavior of various metal ions (Cs⁺, Sr²⁺, La³⁺, Zr⁴⁺) through the engineered membranes.

Main Results:

• The developed membranes demonstrated highly selective transport, efficiently separating Cs⁺ from Sr²⁺, La³⁺, and Zr⁴⁺.
• Achieved Cs⁺/Sr²⁺ separation factors approaching 10³, indicating superior performance.
• The coordination-occupation-coupled strategy effectively suppressed the transport of multivalent ions while allowing efficient Cs⁺ permeation.

Conclusions:

• Coordination-occupation coupling is an effective principle for designing high-selectivity ion separation membranes.
• This strategy offers a scalable and material-efficient approach for critical metal recovery and sustainable radionuclide remediation.
• The engineered membranes show significant promise for advanced separation applications in nuclear and environmental fields.