Synthesis, characterization, and CO2 adsorption properties of pure ETS-10

Abstract

Synthesis of titanosilicate ETS-10 with high purity and crystallinity is a big challenge due to its limited crystallization region. ETS-10 was synthesized and characterized by SEM, EDX, BET, and TGA/DTA methods. The effect of synthesis parameters including pH of the gel, crystallization temperature and time, and the potassium source, were studied using the one-at-a-time (OFAT) approach. The results showed that the ETS-10 with the highest purity was achieved considering the gel pH of 11.3, and the crystallization time and temperature of 72 h and 230 °C. It was also revealed that there was considerable interaction between the potassium source with other synthesis parameters. Afterward, CO2 adsorption of the pure synthesized sample was obtained at 298 K using a volumetric setup. The Dual-site Langmuir, Toth, and UNILAN isotherms were applied to model the obtained equilibrium adsorption data. The CO2 adsorption capacity of the synthesized pure ETS-10 was obtained equal to 3.37 mmol/g. Finally, the adsorption kinetics data were modeled using the PNO model with n = 3.5. The results showed that about 90% of the equilibrium absorption was achieved in only 25 s, which indicates the remarkable capability of using pure ETS-10 for CO2 capture by the PSA method.