title: Chemical vapor deposition on chabazite (CHA) zeolite membranes for effective post-combustion CO2 capture.
abstract: Chabazite (CHA) zeolites with a pore size of 0.37 × 0.42 nm(2) are expected to separate CO2 (0.33 nm) from larger N2 (0.364 nm) in postcombustion flue gases by recognizing their minute size differences. Furthermore, the hydrophobic siliceous constituent in CHA membranes can allow for maintaining the CO2/N2 separation performance in the presence of H2O in contrast with the CO2 affinity-based membranes. In an attempt to increase the molecular sieving ability, the pore mouth size of all silica CHA (Si-CHA) particles was reduced via the chemical vapor deposition (CVD) of a silica precursor (tetraethyl orthosilicate). Accordingly, an increase of the CVD treatment duration decreased the penetration rate of CO2 into the CVD-treated Si-CHA particles. Furthermore, the CVD process was applied to siliceous CHA membranes in order to improve their CO2/N2 separation performance. Compared to the intact CHA membranes, the CO2/N2 maximum separation factor (max SF) for CVD-treated CHA membranes was increased by ∼ 2 fold under dry conditions. More desirably, the CO2/N2 max SF was increased by ∼ 3 fold under wet conditions at ∼ 50 °C, a representative temperature of the flue gas stream. In fact, the presence of H2O in the feed disfavored the permeation of N2 more than that of CO2 through CVD-modified CHA membranes and thus, contributed to the increased CO2/N2 separation factor.
authors.affiliation: Department of Chemical & Biological Engineering, College of Engineering, Korea University , Anam-dong, Seongbuk-gu, Seoul 136-713, Republic of Korea.
authors.forename: Eunjoo
authors.initials: E
authors.lastname: Kim
authors.forename: Taehee
authors.initials: T
authors.lastname: Lee
authors.forename: Hyungmin
authors.initials: H
authors.lastname: Kim
authors.forename: Won-Jin
authors.initials: WJ
authors.lastname: Jung
authors.forename: Doug-Young
authors.initials: DY
authors.lastname: Han
authors.forename: Hionsuck
authors.initials: H
authors.lastname: Baik
authors.forename: Nakwon
authors.initials: N
authors.lastname: Choi
authors.forename: Jungkyu
authors.initials: J
authors.lastname: Choi
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D057965:Carbon Sequestration; D008567:Membranes, Artificial; D009584:Nitrogen / Q000737:chemistry; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D017641:Zeolites / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D008567:Membranes, Artificial; C554923:chabazite; D017641:Zeolites; D002245:Carbon Dioxide; D012822:Silicon Dioxide; D009584:Nitrogen