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

Achieving low-energy and high-efficiency sieving of nitrogen rejection from methane in natural gas purification processes requires precise control of material pore size with a resolution of 0.1–0.2 Å, which is highly challenging. Here, we report a novel adsorbent (MOR-Cu), a mordenite with copper introduced in situ via high-temperature crystallization, enabling precise sieving of nitrogen and methane by the appropriate pore size and pore geometry. Refinement of the crystal structure shows that the higher crystallization temperature changes the position of the copper component, increasing pore volume and enhancing nitrogen adsorption capacity and kinetics. MOR-Cu-210 obtained by crystallization at 210 °C exhibits a record nitrogen adsorption capacity (0.74 mmol g–1) and nitrogen/methane uptake ratio (62.1) at 298 K and 1 bar, breaking the bottleneck of adsorption capacity and selectivity. Cyclic gas adsorption tests and column breakthrough experiments confirm high separation performance and stable recyclability. Copper component is introduced into MOR zeolites via in situ high-temperature crystallization to tune pores for N2/CH4 sieving. MOR-Cu-210 exhibits high N2 adsorption capacity and N2/CH4 uptake ratio, alleviating the capacity-selectivity trade-off.