Rice husk derived Aminated Silica for the efficient adsorption of different gases
Rashed S. Bakdash, Isam H. Aljundi, Chanbasha Basheer, Ismail Abdulazeez
Abstract
Abstract In this present work, we successfully prepared aminated silica (ASiO 2 ) from rice husk ash (RHA) and functionalized with 3-aminopropyltriethoxysilane (APTES). Physical and chemical properties of the synthesized material were investigated by various techniques SEM–EDX, XPS, FTIR, TGA. The surface area of RHA was 223 m 2 /g, while for ASiO 2 was 101 m 2 /g. Molecular level DFT calculations revealed that the functionalization of ASiO 2 resulted in a significant decrease in the HOMO–LUMO energy gap, a reduction in hardness, and a consequent increase in charge transfer characteristics. The adsorption behavior at low pressure (1 atm.) of aminated silica on different gases CO 2 , CH 4 , H 2 , and N 2 at temperatures 77, 273, 298 K was studied. The adsorption of hydrogen was reported for the first time on aminated silica with an excellent adsorption capacity of 1.2 mmol/g. The ASiO 2 exhibited excellent performance in terms of gas separation in binary mixtures of CO 2 /CH 4 , CO 2 /N 2 and CO 2 /H 2 at 273, and 298 K, respectively. The catalyst further exhibits high stability during three cycles with less than 10% variation in the separation capacity.