Fluorinated PDMS membrane with anti-biofouling property for in-situ biobutanol recovery from fermentation-pervaporation coupled process

Hydrophobic pervaporation membranes such as polydimethylsiloxane (PDMS) have shown great potential for biofuels recovery from fermentation process, which however face the challenge of biofouling issue. In this work, a new kind of anti-biofouling PDMS membrane was developed by creating an ultra-low energy surface via a facile crosslinking reaction between fluorosilane and PDMS. The chemical properties and wettability of the membrane surface were characterized by IR, XPS and contact angle measurements, in which the effect of chemical groups on the surface free energy was studied. The performance of PDMS membranes were evaluated in a typical acetone-butanol-ethanol (ABE) fermentation-pervaporation coupled process. The results demonstrated that the introduction of fluoroalkyl groups highly reduced the surface energy of PDMS membrane, thereby achieving excellent hydrophobicity and lipophobicity at the same time, and successfully alleviating microbial adhesion onto the membrane. As a result, the fluorinated PDMS membrane exhibited excellent anti-biofouling property, as well as much higher stabilized total flux (0.74 vs 0.36 kg/m²h) and ABE separation factor (21.8 vs 7.1) than the pristine PDMS membrane as coupling fed-batch fermentation for 140 h. In addition, a significant enhancement in ABE productivity (e.g., 51% higher than batch fermentation) was obtained in the fluorinated PDMS membrane coupled fed-batch fermentation process.