Synthesis and Characterization of PVDF Hollow Fiber Using Adipic Acid as an Additive for Gas–Liquid Membrane Contactor Application

In the present work, poly(vinylidene fluoride) (PVDF) hollow fiber membranes were obtained using adipic acid as an additive in dope solution. The PVDF hollow fibers produced were used in the gas-liquid membrane contactor process, aiming at CO₂ capture. The morphology of PVDF hollow fibers was also characterized by scanning electron microscopy and helium ion microscopy (HIM). These techniques, mainly HIM, allowed us to clearly observe the presence of nanopores at the outer membrane surface, which may favor the process efficiency by preventing membrane wetting. The hollow fiber membranes were also characterized by helium picnometry, gas permeation, and the contactor membrane process. In the performance tests for CO₂ removal, the number of fibers and length of the PVDF hollow fibers were taken into account, since in-house modules were also compared to commercial ones. From these experiments, it could be seen that PVDF hollow fibers exhibited better performance of the CO₂ flux than commercial polypropylene hollow fibers.