Facile co-precursor sol-gel synthesis of a novel amine-modified silica aerogel for high efficiency carbon dioxide capture.

Massive amount of CO emission, which could cause climate change, has been recognized as a serious environmental issue. Chemical adsorption is generally considered as a promising technology for CO capture in low CO partial pressure. Physical properties and chemical components of the adsorbent are important to CO adsorption performance. To address structure limitation and complicated preparation process of the conventional adsorbent, herein, we reported a rapid and simple route to synthesis amine-modified silica aerogel monolith by co-precursor sol-gel method. Microstructure and the surface functional groups of the amine-modified silica aerogel could be easily manipulated. The products were characterized by SEM, XPS, NMR, in situ DRIFT and CNS elemental analyzer. The amine-modified silica aerogel exhibited good physical properties and demonstrated excellent CO adsorption performance. The density, porosity and BJH pore volume of the amine-modified silica aerogel were 0.12 g/cm, 94.5% and 2.39 cm/g, respectively. The maximum static and dynamic adsorption capacities of CO on the amine-modified silica aerogel were 2.2 mmol/g and 5.59 mmol/g under anhydrous and humid mixed gas conditions, respectively. The as-prepared aerogel also showed good cyclic ability for CO adsorption and desorption. The CO adsorption on the amine-modified silica aerogel is by the formation of carbamate through a two-step zwitterion mechanism. This easily prepared amine-modified silica aerogel could be a promising adsorbent for CO capture.