Stability of cross linked polymer for CO2 capture

https://doi.org/10.1039/D1MA01072G

“For its economical industrial application, it is essential that an adsorbent be regenerable and capable of multiple adsorption–desorption cycles.² To test its repetitive CO₂ uptake, 10 : 1 (R) was subjected to multiple adsorption events at 30 °C, with each adsorption event lasting for one hour. The uptake of each cycle is presented in Fig. 12, with full data shown in Fig. S15 (ESI†). Over the initial cycle, the adsorption is 1.899 mmol g⁻¹ CO₂, and this drops by 10% to 1.706 mmol g⁻¹ for the second cycle. Uptake then becomes stable, with the 25th cycle adsorbing 1.594 mmol g⁻¹. Between the 2nd and 25th cycles, uptake deviates by a maximum of 0.154 mmol g⁻¹. A slight drop in adsorption between the initial and subsequent adsorption cycles is also apparent in the cyclic adsorption of diethylenetriamine (DETA) modified porous organic polymers synthesised by Yang et al. for which adsorption was carried out under breakthrough conditions using a CO₂/N₂ mixture (20 : 80 v/v) at 25 °C, with desorption at 100 °C.⁶³ It may be that for 10 : 1 (R), on the first cycle, the most strongly CO₂-adsorbing amine sites, likely the primary amines on the most exposed, external surface, are saturated and the condition of desorption (120 °C for 30 minutes) is insufficient to regenerate them thereafter.”

“Fig. 12 CO₂ uptake of 10 : 1 (R) under temperature swing adsorption–desorption cycles. Uptake and desorption were carried out at 30 °C and 120 °C, respectively, in 1 atm pure, dry CO₂.”