Spatial discriminated aluminum sites in high-silica ERI zeolite for selective O2/N2 separation

The small pore aluminosilicate zeolites are always accompanied by the abundant framework aluminum content and the consequential extra-framework counterparts severely restrained its application in the gas separation process. In this work, the high-silica zeolite ERI (Si/Al = 7.3) was successfully fabricated using a OSDA in the potassium cation medium. It is found that the spatial distribution of aluminum sites in the ERI zeolite can be effectively tailored in the synthetic system with varying aluminum content. Furthermore, the ERI frameworks with spatially biased aluminum sites were also clarified. By combining multiple spectroscopy techniques and powder X-ray diffraction crystallography, the framework of aluminum sites related to host-guest interactions confined in high-silica ERI was clarified. In the gas separation of a binary mixture of O 2 /N 2 (21:79  v /v), the Sr 2+ cation-exchanged high-silica zeolite ERI exhibited efficient O 2 adsorption capacity: 0.74 mmol·g −1 and IAST selectivity: 2.89. These findings not only provide a structural foundation but also offer a model for the efficient separation of O 2 from multi-component gas mixtures.