Effect of different PVDF and additives on the properties of hollow fiber membranes contactors for CO 2 separation

In the present work, different poly(vinil fluoride) (PVDF) were selected for preparing membranes, based on the fact that they are able to form polymer solutions with different viscosities. This characteristic can affect spinning, as well as, mass transfer between the polymer solution and precipitation bath; therefore, each PVDF solution can differently affect membrane formation. The effect of different additives in the polymer solutions was also investigated. Flat sheet and hollow fiber membranes were characterized by Scanning Electron Microscopy analysis, contact angle, gas permeation, porosity, and membrane gas–liquid contactor tests, aiming carbon dioxide removal. The hollow fibers prepared by the polymer which formed a less viscous solution (named PVDF‐I) had a faster light transmittance decay, which started around 150 s before the more viscous solution (PVDF‐II). Hollow fibers obtained using PVDF‐I and propionic acid, in the polymer solution, presented the best gas–liquid contactor performance. CO 2 removal increased from 21 to 35.1%, for PVDF‐II and PVDF‐I, respectively, using aqueous diethanolamine solution, as absorbent liquid. In conclusion, even though PVDF‐I and PVDF‐II membranes were obtained by using the same spinning conditions and experimental methodology, the difference between the polymers properties certainly affected the final membrane morphology and transport properties.