A developed asymmetric PVDF hollow fiber membrane structure for CO2 absorption

Abstract

Carbon dioxide (CO2), the main greenhouse gas, has been associated with global climate change. Therefore, it is important to develop technologies to mitigate this issue. In present study, porous hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes with developed structure for CO2 absorption were prepared via a wet spinning process. The prepared membranes were characterized in terms of morphology examination, gas permeability, critical water entry pressure (CEPw) and mass transfer resistance. From the morphology examination, the membrane showed an almost sponge-like structure with inner skinless layer and ultra-thin outer skin layer. Results of gas permeation test indicated that the membrane possess very small mean pore size (3.96 nm) with high surface porosity. The CO2 absorption experiment demonstrated a significant improvement in the CO2 flux of the prepared PVDF membrane compared to the commercial porous polytetrafluoroethylene (PTFE) hollow fiber membrane. At the absorbent flow rate of 200 ml/min, CO2 flux of the PVDF membrane (4.10 × 10-4 mol/m2 s) was approximately 68% higher than the CO2 flux of the PTFE membrane. In addition, the results indicated that an approximate 25% CO2 flux reduction was gradually occurred at initial 26 h, then the CO2 flux maintained constant over 140 h of the operation.