Pervaporation Membrane Preparation And Separation Property Study

As a high efficient, energy saving, environment friendly membrane separation process, pervaporation was widely studied and has potential applications in industry. In this paper, several copolymers were synthesized and used as pervaporation membrane materials for the separation of benzene from its dilute aqueous solution and benzene/cyclohexane mixture.Novel double functionalized calix[4]arene derivative has been synthesized and used for the preparation of calix[4]arene containing PBT-PDMS copolyester by polycondensation. The copolyester was characterized by 1H NMR, FT-IR and SEC to specify its composition and molecular weight. The membrane was prepared by casting method using this copolyester solution and the crossing structure of membrane was observed by SEM. The pervaporative removal of benzene from its dilute aqueous solution was performed using this composite membrane under different temperatures and original benzene concentrations. The membrane showed a good separation factor of 491 and permeate flux of 58 g/m2h using 100 ppm concentration at 40℃.P(AA-r-MA) random copolymers with similar composition but different molecular weight were synthesized. Meanwhile, P(AA-r-MA) random copolymer and P(AA-b-MA) block copolymer with similar composition and molecular weight were also prepared. The membranes for prevaporation separation were prepared by casting method using these copolymers. The effects of molecular weight and sequence structure of the P(AA-MA) copolymer on separation of benzene/cyclohexane solution through pervaporation process were studied in detail. For P(AA-r-MA) random copolymers, the permeate flux decreased with the increasing of molecular weight. However, the separate factor was not influenced by molecular weight significantly. On the other hand, the sequence structure of copolymer essentially changed the separation property of membrane. P(AA-r-MA) random copolymer membrane shows no selectivity or cyclohexane selectivity to benzene/cyclohexane solution, while P(AA-b-MA) block copolymer membrane shows good benzene selectivity with separate factor of 4.3 and permeate flux of 157 g/m2h to 50 wt.% benzene/cyclohexane solution at 50℃.