CO₂ stripping from amine solutions using PES hollow fiber membrane contactors

Amine-based post-combustion CO 2 capture is a mature carbon capture and storage (CCS) technology, its large-scale deployment is limited by the high energy demand of solvent regeneration. Advanced hollow fiber membrane contactors (HFMCs) offer a promising alternative by providing large interfacial areas and efficient mass transfer. In this study, polyethersulfone (PES) hollow fiber membranes were fabricated using the non-solvent induced phase separation (NIPS) method and modified with lithium chloride (LiCl), titanium dioxide (TiO 2 ), and polyvinylidene fluoride (PVDF) to improve CO 2 stripping performance. LiCl tailored pore size and porosity, TiO 2 nanoparticles strengthened the structure and promoted carbamate breakdown, and PVDF increased hydrophobicity and wetting resistance. The modified membranes were tested under different operating conditions, including temperature, liquid flow rate, and gas flow rate. Compared to pristine PES, the modified PES membranes delivered significantly higher flux and regeneration efficiency, with efficiency rising from 47% to 69% at 80°C. Although flux increased strongly with flow rate, efficiency gains were more modest, and both flux and efficiency showed an optimum with gas flow near 700 mL/min. Fitted correlations developed from the experimental data confirmed these trends and provide predictive tools for estimating performance under untested conditions. These correlations also highlight practical operating windows, moderate liquid flow provided flow near 700 mL/min, and regeneration temperatures around 70°C, where energy demand and CO 2 recovery are balanced. The results demonstrate that tailoring PES membranes with LiCl and TiO 2 is an effective strategy for improving amine regeneration and advancing energy-efficient CO 2 capture systems.