Synthesis pure ETS-10 by optimization synthesis parameters using One Factor At a Time (OFAT) approach: CO 2 adsorption study

In this work, ETS-10 was synthesized by hydrothermal method. The effect of synthesis parameters of ETS-10 on purity and characterization was studied by One At a Time (OFAT) approach. According to this approach, in each test, one synthesis parameter was changed while the other parameters were kept constant. All samples were identified by PXRD and the purest sample was characterized by SEM, EDX, BET, and TGA/DTA. To evaluate the CO2 capture abilities of the synthesized purest sample, CO2 adsorption isotherm at 298 K was obtained by the constant-volume adsorption method. The isotherm models Dual-site Langmuir, Toth, and UNILAN were used to fit the obtained isotherm data. The results showed that with gel pH = 11.3, crystallization temperature 230°C, and crystallization time 72 h, the ETS-10 with the highest purity was achieved. Also, it was observed that there is an important interaction between the potassium source with other synthesis parameters. The adsorption results showed that the CO2 adsorption capacity of the pure ETS-10 was 3.37 mmol/g. It was observed that the Dual-site Langmuir model was fitted better the CO2 adsorption data at 298 K compared to Toth and UNILAN models. The adsorption kinetics showed that about 90% of the equilibrium adsorption was reached within 25s which demonstrates a remarkable fast kinetics.