HF Resistant Porous Aromatic Frameworks for Electronic Special Gases Separation

Area of Science:

• Materials Science
• Chemical Engineering
• Environmental Science

Background:

• Electronic special gases (e.g., SF₆, NF₃, CF₄, Xe, Kr) are crucial in semiconductor manufacturing but pose environmental challenges.
• Efficient separation and recovery of these gases are vital for economic and environmental reasons.
• Existing adsorbent materials often lack the required stability and selectivity for harsh industrial conditions.

Purpose of the Study:

• To develop novel porous aromatic frameworks (PAFs) for selective adsorption and separation of high-value electronic special gases.
• To evaluate the physicochemical stability, reusability, and adsorption performance of the synthesized PAFs.
• To elucidate the molecular-level adsorption mechanisms using theoretical calculations.

Main Methods:

• Synthesis of two novel HF acid-resistant porous aromatic frameworks: New-PAF-1 and N-SO₃H.
• Single-component gas adsorption experiments to assess selectivity and capacity.
• Time-dependent adsorption rate and dynamic breakthrough experiments to evaluate performance under realistic conditions.
• Regeneration tests to confirm reusability.
• Density Functional Theory (DFT) and Mulliken atomic charge analyses for mechanism elucidation.

Main Results:

• New-PAF-1 and N-SO₃H exhibited exceptional adsorption selectivity for Xe and F-gases (e.g., SF₆, NF₃, CF₄) from simulated semiconductor exhaust gas mixtures.
• The synthesized PAFs demonstrated high physicochemical stability, even in the presence of HF acid.
• Excellent reusability was confirmed through multiple adsorption-desorption cycles.
• Theoretical calculations provided insights into adsorption sites, binding energies, and electrostatic interactions governing gas selectivity.

Conclusions:

• The developed PAFs, New-PAF-1 and N-SO₃H, are highly effective and stable adsorbents for separating valuable electronic special gases.
• These materials show significant potential for application in semiconductor exhaust gas treatment and resource recovery.
• The findings highlight the promise of PAFs as robust adsorbents for challenging separation processes under harsh conditions.