This paper reports an attempt to synthesize a CuCl-modified gamma-alumina m
embrane for separation. of ethylene from ethane. Cucl was effectively coate
d in the 4 nn pore gamma-alumina top layers of disk-shaped and tubular alum
ina membranes by the reservoir method. Permeation of a single gas and binar
y mixture of ethylene and ethane was measured to characterize separation pr
operties of the modified membranes. Pure ethylene permeance of the CuCl-mod
ified membrane is 10-40% lower than that predicted from the pure ethane per
meance by the Knudsen theory, This result is explained by a model based on
the adsorbed layer of ethylene via pi-complexation. Such an adsorbed layer
hinders the diffusion of ethylene in the nanopores of CuCl-modified gamma-a
lumina. Multiple gas permeation measurements on the CuCl-modified membranes
show a separation factor for ethylene over ethane larger than the Knudsen
value. This confirms a positive contribution of the surface flow of ethylen
e ts the permeance of ethylene in the multiple gas permeation system. A max
imum separation factor for ethylene over ethane of 1.4 is obtained for the
CuCl-modified membrane at 60 degrees C.