A solid sorbent for carbon dioxide capture was developed on the basis of montmorillonite nanoclay, which is a low-cost and easily available bulk material. This high specific surface area, platelet-like nanoclay with hydroxyl groups on edges was treated with aminopropyltrimethoxysilane and polyethylenimine to provide sites for CO2 capture. CO2 sorption tests showed fast kinetics and capture capacities as high as 7.5 wt % at atmospheric pressure and about 17 wt % at 2.07 MPa pressure in the temperature range of 75-85 degrees C. the regeneration of these nanoclays can be achieved using nitrogen at 100 degrees C or CO2 (dry or humid) at 155 degrees C as the sweep gases. Furthermore, pressure swing operation, employing vacuum at 85 degrees C, is also effective in regenerating the sorbent. This work shows that amine-modified montmorillonite nanoclay has the potential to provide a high-performing solid sorbent for CO2 capture.