TY - JOUR
T1 - Permeation of xylene isomers through supported liquid membranes containing cyclodextrins
AU - Shingjiang, Jessie Lue
AU - Huei, Jun Juang
AU - Shian, Yin Hou
PY - 2002
Y1 - 2002
N2 - The permeation of p- and m-xylenes through supported liquid membranes (SLM) containing cyclodextrins (CDs) was investigated in this study. Three CDs were used in the experiments, α-CD, β-CD, and hydroxypropyl-β-CD (HP-β-CD). The mass transfer mechanisms with and without facilitating carriers (CDs) were studied individually by applying the solution-diffusion model. The facilitated mass transfer mechanism was elucidated as partitioning of xylenes from the organic phase into an aqueous phase, formation of an inclusion complex with CDs, diffusion of the complex, and extraction into the receiving phase. The formation constants in aqueous solutions for CDs and p-xylene were 1.6-2.4 times higher than that of CDs and m-xylene. The diffusivity coefficient of the xylene-CD complex (Dm) and the equilibrium extraction constant (Kex) associated with each CD were determined. Meanwhile, Kex, the parameter used to describe the ability of CD to extract xylene and to form a complex, of p-xylene and CDs was almost twice as much as that for m-xylene and CDs. Thus, the addition of CD into the membrane phase for xylene separation yields a two-fold benefit in favor of p-xylene: an increase in selectivity and an enhancement of the mass transfer flux.
AB - The permeation of p- and m-xylenes through supported liquid membranes (SLM) containing cyclodextrins (CDs) was investigated in this study. Three CDs were used in the experiments, α-CD, β-CD, and hydroxypropyl-β-CD (HP-β-CD). The mass transfer mechanisms with and without facilitating carriers (CDs) were studied individually by applying the solution-diffusion model. The facilitated mass transfer mechanism was elucidated as partitioning of xylenes from the organic phase into an aqueous phase, formation of an inclusion complex with CDs, diffusion of the complex, and extraction into the receiving phase. The formation constants in aqueous solutions for CDs and p-xylene were 1.6-2.4 times higher than that of CDs and m-xylene. The diffusivity coefficient of the xylene-CD complex (Dm) and the equilibrium extraction constant (Kex) associated with each CD were determined. Meanwhile, Kex, the parameter used to describe the ability of CD to extract xylene and to form a complex, of p-xylene and CDs was almost twice as much as that for m-xylene and CDs. Thus, the addition of CD into the membrane phase for xylene separation yields a two-fold benefit in favor of p-xylene: an increase in selectivity and an enhancement of the mass transfer flux.
KW - Cyclodextrins
KW - Facilitated transport
KW - Separation
KW - Supported liquid membranes
KW - Xylene isomers
UR - http://www.scopus.com/inward/record.url?scp=0036165717&partnerID=8YFLogxK
U2 - 10.1081/SS-120000799
DO - 10.1081/SS-120000799
M3 - 文章
AN - SCOPUS:0036165717
SN - 0149-6395
VL - 37
SP - 463
EP - 480
JO - Separation Science and Technology
JF - Separation Science and Technology
IS - 2
ER -