Pervaporation Recovery of Acetone-Butanol from Aqueous Solution and Fermentation Broth Using HTPB-Based Polyurethaneurea Membranes

Abstract

In this paper, hydroxyterminated polybutadiene-based polyurethaneurea (HTPB-PU) pervaporation membranes were prepared by phase inversion and used for recovering acetone and n-butanol from dilute aqueous solutions. The effects of the operation temperature and feed composition on the pervaporation performance were investigated. The differences of the separation performance between the ternary mixture and binary mixture were also studied through evaluating the permeability coefficient, the swelling degree of the membrane, and the activity coefficient. The results indicated that a complex “coupling effect” occurred in the ternary mixture. The pervaporation performance for the ternary mixture was superior to that for the binary mixture because of the permeant-permeant and permeant-membrane interactions. A high selectivity towards acetone and n-butanol was obtained. Acetone and butanol were condensed from 1.5 to 11.9 wt% and 3.0 to 43.5 wt% at 40°C for the ternary mixtures, respectively. Furthermore, potential of the membrane for separation of organics from fermentation was also studied by testing the pervaporaton performance, and acetone and butanol were condensed from 0.5 to 8.7 wt% and 1.1 to 16.4 wt% at 45°C, respectively.

Keywords:

• acetone
• butanol
• fermentation
• pervaporation membrane
• polyurethaneurea

ACKNOWLEDGEMENT

The authors greatly appreciate the financial support of the national Hi-Tech research and development program of China (Grant numbers 2006AA02Z237, 2006AA020103, 2006AA020101), and the National Science Foundation for Post-doctoral Scientists of China (No. 20070421173).

Notes

^a Derived from Handbook of solubility parameters and other cohension parameters.

^b The calculated value.

M: molecular weight; V_m : molar volume; T _b : boiling point; P _v : vapour pressure; δ: total solubility parameter. ∗: average molecular weight.

P _i,b for the binary aqueous solution; P _i,t for the ternary aqueous solution.

P _i,b for the binary aqueous solution; P _i,t for the ternary aqueous solution.