Green and facile production of UTSA-16 (Zn) in aqueous media with improved CO2 adsorption performance

UTSA-16 (Zn) is the most promising adsorbent for CO2 capture because of its excellent CO2 capture performance and low material cost. An eco-friendly synthesis method for UTSA-16 (Zn) was investigated by changing the ratio of water to ethanol in solution (60:40 to 100:0) under microwave irradiation with different washing conditions: 1. diethyl ether and methanol washing (DEMW), 2. diethyl ether and water washing (DEWW), and 3. water washing (WW). Synthesis at an optimal ratio of water to ethanol (100:0) presented the best CO2 adsorption capacity of 5.08 mmol/g and CO2/N2 selectivity of 120. The integrity of the samples was investigated in terms of the particle morphology, crystallinity, porosity, and thermal stability using scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller analysis, and thermogravimetric analysis. The stability of pelletized UTSA-16 (Zn) synthesized in a water-only solution was examined by exposing samples to humid air and acidic gases (NO2 and SO2); the pellets exhibited excellent stability to humid air and NO2 exposure. Additionally, the pellets exhibited excellent recyclability during the temperature swing adsorption–desorption process.