CO₂ capture from gas streams with low CO₂ concentrations using solid molecular basket sorbent

In addition to larger CO₂ emission sources, CO₂ capture from dispersed sources including transportation vehicles is an option to reduce CO₂ emissions. In the past years, we have developed a novel sorbent concept, named as molecular basket sorbent (MBS) which shows some potential advantages including higher sorption capacity, high selectivity, easy regeneration and positive effect of moisture. In this paper, we report the application of MBS for CO₂ removal from gas streams with low CO₂ concentrations at ambient conditions. The study has shown that the nano-composite molecular basket sorbent, 50 wt% PEI/SBA-15 could effectively capture CO₂ from a gas stream containing 1 vol% CO₂ at ambient conditions and atmospheric pressure. A sorption breakthrough capacity and saturation capacity of 63.1 and 66.7 mg/g, respectively and a separation selectivity of ca. 14 for CO₂/CO and ca. 185 for CO₂/Ar was achieved at 75 °C. The study on CO₂-TPD using a simulated air containing 400 ppm CO₂ in N₂ clearly showed that the sorbent can effectively capture CO₂ directly from air at room temperature with a sorption capacity of ca. 22.5 mg/g. The current work indicates that the molecular basket sorbent is promising for practical applications including air-decarbonization and other-related industrial applications in CO₂ removal.