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Polymeric ionic liquid modified silica for CO 2 adsorption and diffusivity
Author(s) -
Sun Yachai,
Zhu Jiamei,
Huang Junhua,
Xin Feng,
Liu Jingxia
Publication year - 2017
Publication title -
polymer composites
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.577
H-Index - 82
eISSN - 1548-0569
pISSN - 0272-8397
DOI - 10.1002/pc.23635
Subject(s) - ionic liquid , sorption , adsorption , materials science , diffusion , gravimetric analysis , desorption , thermal diffusivity , polymerization , tetrafluoroborate , chemical engineering , chemistry , polymer , organic chemistry , catalysis , composite material , thermodynamics , physics , engineering
Two types of polymeric ionic liquids (PILs) modified porous silica for CO 2 sorption were synthesized by the polymerization of dialkylphosphate di‐butyl phosphate [VYIM][Bu 2 PO 4 ] and 1‐allyl‐3‐methylimidazolium tetrafluoroborate [AMIM][BF 4 ] with alkoxyl‐modified silica. The PILs‐modified silica (SiO 2 ‐P[VYIM][Bu 2 PO 4 ] and SiO 2 ‐P[AMIM][BF 4 ]) were evaluated by CO 2 adsorption isotherms at 273 K for investigating the porous structures. The adsorption and desorption behaviors of CO 2 (at 298, 313, and 333 K) and N 2 (at 313 K) up to 0.2 MPa were also investigated using a gravimetric method. In comparison with bare silica, the grafting of PILs on the support surface leads to a loss of microporosity, resulting in a slight decrease in CO 2 sorption capacity. The difference of CO 2 sorption capacity between SiO 2 ‐P[VYIM][Bu 2 PO 4 ] and SiO 2 ‐P[AMIM][BF 4 ] is little, especially under 0.1 MPa. CO 2 /N 2 selectivity is however notably improved, and especially [AMIM][BF 4 ] modified silica shows the best performance. The homogeneous surface diffusion model (HSDM) was used to estimate the diffusivities and good agreement between experimental values and fitting curves was obtained. The diffusion coefficients of CO 2 in the PILs‐modified silica are level with that of bare silica at level of 10 −7 −10 −8 m 2 /s, about two to three orders of magnitude faster than that of reported [BMIM][BF 4 ]. POLYM. COMPOS., 38:759–766, 2017. © 2015 Society of Plastics Engineers