Carbonization of periodic mesoporous phenylene- and biphenylene-silicas for CO2/CH4 separation
authors Lourenco, MAO; Pinto, ML; Pires, J; Gomes, JRB; Ferreira, P
nationality International
journal CARBON
author keywords CO2 adsorption; Periodic mesoporous organosilica; Gas separation; Pyrolysis
keywords MOLECULAR-SCALE PERIODICITY; CARBON-DIOXIDE; ACTIVATED CARBON; POROUS MATERIALS; CO2 ADSORPTION; LANDFILL GAS; DFT CALCULATIONS; METHANE STORAGE; ORGANIC GROUPS; SICO GLASSES
abstract Periodic mesoporous organosilicas (PMO), with phenylene or biphenylene organic linkers, were thermally treated in flowing nitrogen atmosphere upon different conditions aiming the enhancement of their CO2 adsorption/separation properties. As-synthesized and template-extracted phenylene-and biphenylene-PMO were pyrolysed at 800 and 1200 degrees C. The effects of: i) the type of organic bridge; ii) the presence of nitrogen atoms; iii) the use of an acid catalyst prior to carbonization; and iv) pore size were investigated. It was found that pyrolysis promotes modifications in the physical-chemical and the textural properties of the PMO materials, being the formation of micropores one of the most notable differences. Furthermore, with the exception of biphenylene-PMO, the molecular-scale periodicity of the materials was strongly affected by the pyrolysis treatment probably as a result of Si-C bond cleavage. The CO2 adsorption capacity and the selectivity for CO2/CH4 separation of all pyrolysed materials were enhanced. In general, the increase of the microporosity in the pyrolysed PMO is accompanied by an improvement of the CO2 adsorption properties with concomitant reduction of the CH4 adsorption behavior. The most interesting material for CO2/CH4 separation is the biphenylene-PMO pyrolysed at 1200 degrees C, with a selectivity of 9.5 at 25 degrees C and 500 kPa. (C) 2017 Elsevier Ltd. All rights reserved.
publisher PERGAMON-ELSEVIER SCIENCE LTD
issn Aug-23
isbn 1873-3891
year published 2017
volume 119
beginning page 267
ending page 277
digital object identifier (doi) 10.1016/j.carbon.2017.04.029
web of science category Chemistry, Physical; Materials Science, Multidisciplinary
subject category Chemistry; Materials Science
unique article identifier WOS:000402713300032

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