Porous CaCO3 fabricated by Ca-containing solid wastes for effective CO2 adsorption

Daily discarded egg residues such as eggshells reach an astronomical figure around the world, causing severe environmental pollution and waste of Ca-based sources. CaCO 3 , especially these porous CaCO 3 nanoparticles, could role as an effective plastic stuffing, filler, ink filler, and adsorbent, having a great prospect for industrial application. Herein, based on a solid-state reaction between strong and weak acids, we successfully prepared a porous CaCO 3 -es with the BET specific surface area (SSA) up to 97.4 m 2 /g, and meanwhile with abundant mesopores and tiny small CaCO 3 primary nanoparticles about 7.4 nm. Notably, the prepared CaCO 3 -es showed significantly improved CO 2 adsorption capacity than the contrast CaCO 3 samples in both static and breakthrough tests. According to the characterization such as FTIR, Raman, XPS, TEM, and DFT calculations, the high CO 2 adsorption of CaCO 3 -es originated from its high porous structure, small nanoparticle size, and rich defective sites.