Halloysite nanotubes capturing isotope selective atmospheric CO ₂

With the aim to capture and subsequent selective trapping of CO 2, a nanocomposite has been developed through selective modification of the outer surface of the halloysite nanotubes (HNTs) with an organosilane to make the nanocomposite a novel solid-phase adsorbent to adsorb CO 2 from the atmosphere at standard ambient temperature and pressure. The preferential adsorption of three major abundant isotopes of CO 2 (12 C 16 O 2, 13 C 16 O 2, and 12 C 16 O 18 O) from the ambient air by amine functionalized HNTs has been explored using an optical cavity-enhanced integrated cavity output spectroscopy. CO 2 adsorption/desorption cycling measurements demonstrate that the adsorbent can be regenerated at relatively low temperature and thus, recycled repeatedly to capture atmospheric CO 2. The amine grafted halloysite shows excellent stability even in oxidative environments and has high efficacy of CO 2 capture, introducing a new route to the adsorption of isotope selective atmospheric CO 2.