Commercial anion exchange resin modified with azolates for remarkable separation of SO2 from CO2

Abstract

It is still challenging to prepare solid materials with improved SO2 capture performance from readily available chemicals through facile routes. In this work, we proposed to modify Amberlite® IRA-900 − a commercial anion exchange resin with azolates (i.e., imidazolate, triazolate and tetrazolate), to prepare a new kind of solid materials for reversible SO2 capture. The major purpose is to utilize the multiple-site strong interaction of azolates with SO2, and special attention was paid to the performance of SO2 separation from CO2. The modified IRA-900 samples were characterized by FTIR spectra, elemental analysis, Mohr titration and low-temperature N2 adsorption. The SO2 separation performance of modified IRA-900 samples was examined systematically by both single gas and mixed gas adsorption experiments. It is found that the tetrazolate-modified IRA-900 sample displays remarkable performance for the separation of SO2 from CO2, with high SO2 capacities (3.15 mmol/g at 25 °C and 11.1 kPa) and large SO2/CO2 selectivities (907 for at 0.1/0.9 v/v and 25 °C). The SO2 separation mechanism of tetrazolate-modified IRA-900 sample was also examined in details with the help of spectroscopic and theoretical methods.