Carbon dioxide capture with amino-functionalised zeolite-beta: A temperature programmed desorption study under dry and humid conditions

摘要

Novel functionalised adsorbents have been synthesised by the immobilization of aminopropyltriethoxysilane (APTES) on zeolite beta. APTES modified beta-25 zeolite was shown to have excellent CO2 adsorption/desorption properties, with a CO2 adsorption capacity of up to 207 mg CO2 g(-1) and desorption occurring from 60 degrees C. The APTES modified zeolite-beta most likely adsorbs CO2 via both carbamate and bicarbonate mechanisms with desorption of CO2 from the bicarbonate species occurring at a lower regeneration temperature compared to CO2 release from anhydrous carbamates. The silicon anchoring group in APTES was found to be an important characteristic in support modification with APTES molecules forming stable covalent bonds on the surface of the support which was not always observed in non-silane molecules such as tetraethylenepentamine (TEPA) particularly regarding stable bond formation on the external surface. The use of zeolite beta was found to be a good support for functional amines as well as being an inexpensive starting material for the synthesis of CO2 adsorbents. The APTES modified zeolite beta was found to be highly adsorbent compared with amine modified zeolites reported in literature. The adsorption capacity was maintained over a wide range of adsorption conditions and was found to be stable with repeated CO2 adsorption/desorption cycles for the APTES modified beta-25 zeolite materials. The addition of moisture to the gas adsorption stream was found to further improve the CO2 adsorption capacity of the APTES modified zeolite beta. (C) 2016 Elsevier Inc. All rights reserved.