Facile Surface Engineering of Commercial Polyamide Membranes With <scp>PVA</scp> / <scp>PEI</scp> Facilitated Transport Barriers for Durable <scp>CO</scp> ₂ Separation

ABSTRACT Facilitated transport membranes (FTMs) offer a low‐energy route for CO 2 separation but face challenges in industrial application due to complex fabrication and poor long‐term hydration stability. In this study, a scalable surface engineering strategy was proposed to construct high‐performance CO 2 ‐FTMs by co‐depositing poly(vinyl alcohol) (PVA) and polyethyleneimine (PEI) onto commercial polyamide (PA) membrane surfaces. As a critical improvement, the incorporation of PVA serves dual functions. First, it significantly increases the PEI carrier loading on the PA surface by nearly six times through molecular affinity with both PEI and the PA matrix. Surface characterizations (SEM, XPS, FTIR) confirm uniform and stable deposition of the PVA/PEI facilitated transport barrier. Secondly, PVA introduction improves membrane hydrophilicity to enable a sustained hydration state and subsequently durable CO 2 transport over 70 h, outperforming PEI‐only membranes with only 10‐h stable operation. The resulting membrane achieves a CO 2 permeance of 102 GPU and a CO 2 /N 2 selectivity of 92.7 under optimal modification conditions. These findings demonstrate a facile and effective pathway toward industrially scalable FTMs with enhanced durability, offering mechanistic insights and practical value for advanced membrane design in CO 2 capture technologies.