Pervaporation Separation Of Methanol/MTBE Mixture Using Filled Cellulose Acetate Membranes

Pervaporation, as a novel liquid mixture separation technology, has outstanding technical advantages and favorable promising application prospects in the separation of organic- organic mixture especially azeotropic mixture. Separation performance of pervaporation process mainly depends on the property of the target membranes, therefore selecting the appropriative material with excellent separation performance constitutes an important issue in pervaporation research. In our work, methanol and MTBE mixture was the separation object, cellulose acetate(CA)was chosen out as the membrane material considering the solution parameters, chemical structures, properties difference of methanol and methyl-tertiary-butyl ether(MTBE). Cellulose acetate filled membranes were prepared with acetone(AC) and dimethylformamide (DMF) as solvents and HZSM5 zeolite and 4A zeolite as filler. The filled pervaporation membrane had better separation performance. The directions for prepare membranes and pervaporation separation technics were investigated.The structure morphology, the physical and chemical properties of the membranes were characterized and analysed by FT-IR, XRD, SEM, TGA and universal testing machine.The pervaporation performance of CA-AC-HZSM5, CA-AC-4A and CA-DMF-HZSM5 membranes for separation of methanol and MTBE mixture was investigated. The effects of zeolite content and methanol content in feed on the pervaporation performance and swelling behaviour were discussed. Moreover, effects of operating conditions (methanol concentration in feed, feed temperature, feed flow rate) on pervaporation performance were also studied. From the results, for the CA-AC-HZSM5 membrane, containing 0.2wt% HZSM5 exhibited the separation performance with a permeation flux of 226g/(m~2h) and a separation factor of 346 at 30oC for 20wt% in the feed, keeping feed flow rate 60L/h. for the CA-AC-4A membrane, containing 1wt% 4A exhibited the separation performance with a permeation flux of 202g/(m~2h) and a separation factor of 421 at 30oC for 20wt% in the feed, keeping feed flow rate 50L/h. for the CA-DMF-HZSM5 membrane, containing 1.5wt% HZSM5 exhibited the separation performance with a permeation flux of 227g/(m~2h) and a separation factor of 806 at 30oC for 20wt% in the feed, keeping feed flow rate 50L/h.