Fabrication and characterization of superhydrophobic polypropylene hollow fiber membranes for carbon dioxide absorption

The membrane wetting by amine absorbents results in performance deterioration of membrane gas absorption system for CO2 post-combustion capture. To solve this problem, in this study, the polypropylene membrane fiber was modified by depositing a rough layer on the surface to improve its hydrophobicity. Weighing the coating homogeneity, hydrophobicity and modification process efficiency, the mixture of cyclohexanone and MEK system was considered as the best non-solvent. The contact angle increased dramatically from 122° to 158° by the modification, thereby obtaining superhydrophobic membrane surface. The membrane–absorbent interaction results demonstrated that the modification treatment effectively enhanced the stability and maintained the superhydrophobicity of fibers contacting with the absorbent. In addition, continuous CO2 absorption experiments for up to 20 days were carried out in untreated and modified polypropylene hollow fiber membrane contactors, using 1 mol L−1 MEA solution as the absorbent. The long-term system operation results indicated that, even though additional mass transfer resistance was introduced by the surface coating, the modified polypropylene hollow fiber membrane contactor was still technically feasible for CO2 capture from the power stations.