In situ synthesis of copper-based mordenite for nitrogen/methane sieving

Area of Science:

• Materials Science
• Chemical Engineering
• Adsorption Science

Background:

• Efficient nitrogen rejection from methane is crucial for natural gas purification.
• Existing methods face challenges in achieving precise pore size control for effective sieving.
• A pore size resolution of 0.1-0.2 Å is required for optimal nitrogen/methane separation.

Purpose of the Study:

• To develop a novel adsorbent for low-energy, high-efficiency sieving of nitrogen from methane.
• To investigate the effect of copper incorporation and crystallization temperature on adsorbent performance.
• To achieve enhanced nitrogen adsorption capacity and selectivity for natural gas purification.

Main Methods:

• Synthesis of mordenite with in-situ copper incorporation via high-temperature crystallization (MOR-Cu).
• Structural analysis to understand the influence of crystallization temperature on copper location, pore volume, and geometry.
• Gas adsorption and desorption experiments at 298 K and 1 bar to evaluate nitrogen and methane uptake.
• Cyclic adsorption tests and column breakthrough experiments to assess separation performance and recyclability.

Main Results:

• MOR-Cu adsorbent exhibits precise sieving of nitrogen and methane due to optimized pore size and geometry.
• Higher crystallization temperatures enhance pore volume and nitrogen adsorption capacity and kinetics.
• MOR-Cu-210 demonstrates a record nitrogen adsorption capacity (0.74 mmol g⁻¹) and N₂/CH₄ uptake ratio (62.1) at 298 K and 1 bar.
• The adsorbent shows high separation performance and stable recyclability in cyclic tests and breakthrough experiments.

Conclusions:

• The novel MOR-Cu adsorbent effectively addresses the challenge of precise nitrogen/methane sieving.
• Optimized in-situ copper incorporation and crystallization conditions lead to superior adsorption capacity and selectivity.
• This material offers a promising solution for energy-efficient natural gas purification with stable performance.