A solid molecular basket sorbent for CO₂ capture from gas streams with low CO₂ concentration under ambient conditions

In this paper, a solid molecular basket sorbent, 50 wt% PEI/SBA-15, was studied for CO₂ capture from gas streams with low CO₂ concentration under ambient conditions. The sorbent was able to effectively and selectively capture CO₂ from a gas stream containing 1% CO ₂ at 75°C, with a breakthrough and saturation capacity of 63.1 and 66.7 mg g^-1, respectively, and a selectivity of 14 for CO ₂/CO and 185 for CO₂/Ar. The sorption performance of the sorbent was influenced greatly by the operating temperature. The CO ₂-TPD study showed that the sorbent could be regenerated under mild conditions (50-110°C) and was stable in the cyclic operations for at least 20 cycles. Furthermore, the possibility for CO₂ capture from air using the PEI/SBA-15 sorbent was studied by FTIR and proved by TPD. A capacity of 22.5 mg g^-1 was attained at 75°C via a TPD method using a simulated air with 400 ppmv CO₂ in N₂.