Hybrid ionic liquid–silica xerogels for CO2 capture at different pressures

https://doi.org/10.3390/app9132614

“CO₂ adsorption tests were performed immediately after the synthesis of the materials. The tested materials were the Xerogel, SILTF2NX20, SILCLX20, and SILCLX40. It is worth noting that for the calculation of the adsorption in excess and absolute from the PTGA data, the density value for the sample SILTF2NX20 obtained through helium pycnometry (see Table 2) was used. As the experimental CO₂ adsorption curves, absolute and in excess, were very similar due to employing the low working pressure, only the absolute adsorption data is presented Figure 3 as a function of CO₂ pressure.”

“Figure 3. CO₂ adsorption at 298 K.”

“It is evident that the sample SILCLX20 exhibits the greater capacity to CO₂ adsorption, reaching a value of 0.35 g CO₂ / g adsorbent at 1.0 MPa. The sample with the same IL, but with greater immobilized concentration SILCLX40 has a very low performance, only 0.07 g CO₂ / g adsorbent at the same pressure, which indicates that increasing the amount of IL immobilized in the xerogel hinders the adsorption capacity. This effect can be caused by both a block of the solid’s pores by the IL and IL trapped without accessibility or free volume to adsorb CO₂.