Facile and fast determination of Si/Al ratio of zeolites using FTIR spectroscopy technique

A facile quantitative determination of the Si/Al ratio (SAR) in zeolite frameworks using IR spectroscopy is reported. From the linear regression analysis, the SAR for the medium-to-high Al content zeolites (1 < SAR < 5) correlates linearly to the corresponding intensity of the IR band at wavenumbers (950-1090 cm−1). This model has been validated with 19 zeolites with different SAR and different framework topologies (EDI, ABW, EMT, MER, LTL, LTJ, MOR, FAU, SOD, HEU, BRE, OFF, GIS, *BEA, MFI). The quantitative determination of the SAR of zeolites by IR spectroscopy is shown to be an alternative technique to the conventional ICP-OES and XRF spectroscopy techniques.