A high capacity, water tolerant adsorbent for CO2:: diethanolamine supported on pore-expanded MCM-41

A high capacity, water tolerant adsorbent for CO2 based on diethanolamine-containing pore-expanded MCM-41 silica has been developed. Various supports including activated carbon, silica gel, and standard MCM-41 silica were also tested. Due to its large pore volume, the pore-expanded MCM-41 was capable of accommodating a greater quantity of amine resulting in higher CO2 adsorption capacity compared to the other supports. Adsorption capacity studies were conducted by gravimetry using dry CO2 to obtain uptake curves and apparent rate data. The capacity and uptake rate with respect to amine content reached a maximum due to deposition of the excess amine on the particle external surface and in inter-particle voids. Comparison with zeolite 13X showed that the current impregnated material had superior adsorption capacity below a CO2 partial pressure of 0.15 atm. Adsorption studies with humid CO2 revealed that the adsorption capacity of the impregnated material was insensitive to the presence of moisture, which represents a major advantage over zeolite 13X.