Composition and temperature effects on air separation through liquid crystalline alkyl cellulose membranes

The air separation through triheptyl cellulose (THC)/ethyl cellulose (EC) blend membranes containing no more than 20 wt % THC at the temperature range from 298 to 358 K was investigated using a variable volume method. The air‐separation ability for the THC/EC membranes were greater than that for the THC‐free pure EC membrane. P for the THC/EC membranes was between 1.06–8.89 × 10−9 cm3 (STP) cm/cm2 s cmHg and P /P 3.04–3.66. The THC/EC membrane showed a unique trend in its P /P − P relationship, i.e., the magnitude of P /P increased simultaneously with that of P . The THC/EC membrane yielded a maximum oxygen concentration in the oxygen‐enriched air (OEA) of 39.5% at an OEA flux of 6.99 × 10−4 cm3 (STP)/s cm2 for a pressure difference of 0.43 MPa at 358 K. After 300 h of measurement at 0.40 MPa and 313 K, the efficiency of the concentrating oxygen was almost constant.