resumo
Nonfunctionalized and functionalized periodic mesoporous phenylene-silicas (Ph-PMOs) with different kinds of amine groups were prepared and their capacity to uptake CO2 and CH4 molecules were experimentally evaluated considering biogas upgrading. It was found that aminopropyl groups grafted to the free silanols of the Ph-PMO displayed the highest selectivity for CO2 gas, adsorbing 26.1 times more CO2 than CH4 at 25 degrees C. The interaction effect of the surface of these materials with the CO2 or CH4 molecules was obtained through the calculation of the Henry constants, and the adsorption mechanisms involved were elucidated from density functional theory calculations. The good synergy between experimental gas adsorption and computational studies suggests that the latter can be used to guide the experimental synthesis of more effective materials. Thus, our computational studies were extended to PMOs with other functional groups having different polarity for predicting interaction energies with CO2 and thus identifying the most promising candidates for experimental synthesis.
palavras-chave
TOTAL-ENERGY CALCULATIONS; WAVE BASIS-SET; CHEMICAL-MODIFICATION; POROUS MATERIALS; ORGANIC GROUPS; LANDFILL GAS; WALLS; ADSORBENTS; SURFACE; METALS
categoria
Chemistry; Science & Technology - Other Topics; Materials Science
autores
Lourenco, MAO; Siquet, C; Sardo, M; Mafra, L; Pires, J; Jorge, M; Pinto, ML; Ferreira, P; Gomes, JRB
nossos autores
José R. B. Gomes
Investigador Principal
Luís Mafra
Investigador Principal
Mariana Coutinho Sardo
Investigador Auxiliar
Mirtha A. O. Lourenço
Investigador
Paula Celeste da Silva Ferreira
Investigador CoordenadorGrupos
G1 - Materiais Porosos e Nanossistemas
G2 - Materiais Fotónicos, Eletrónicos e Magnéticos
G6 - Materiais Virtuais e Inteligência Artificial
Projectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
RMNE-UA-National Network of Electron Microscopy (REDE/1509/RME/2005 )
agradecimentos
This work was developed in the scope of the Projects POCI-01-0145-FEDER-007679 vertical bar UID/CTM/50011/2013 (CICECO), UID/MULTI/00612/2013 (CQB), UID/ECI/04028/2013 (CERENA), NORTE-07-0124-FEDER-000011 vertical bar UID/EQU/500230/2013 (LSRE-LCM), PTDC/EQU-EQU/099423/2008 (FCOMP-01-0124-FEDER-010345), financed by national funds through the FCT/MEC and cofinanced by FEDER under the PT2020 Partnership Agreement. The authors are also grateful to FCT Programmes Ciencia 2007 and Investigador FCT, to the Portuguese NMR Network (RNRMN), and to the National Network of Electron Microscopy and University of Aveiro: Project REDE/1509/RME/2005. The Ph.D. Grant SFRH/BD/80883/2011 (to M.A.O.L.) and Postdoc Grant SFRH/BPD/65978/2009 (to M.S.) are also acknowledged. Umberto Martinez and Gianfranco Pacchioni are acknowledged for kindly providing the structure of p-phenylenesilica corresponding to a sequence of six and four member rings with T3 to T2 ratio 2:1. The authors are also indebted to Joao Santos for fruitful discussions.