Tailoring the Morphological and Transport Properties of PES–Activated Carbon Composites Through PEG Molecular Weight Modulation

The rising prevalence of chronic kidney disease (CKD) has intensified the demand for innovative blood filtration therapies. Hemoperfusion, which integrates membrane filtration with adsorbent technologies to sequester circulating uremic toxins, represents a promising therapeutic alternative. In this study, polyethersulfone (PES)-powdered activated carbon (PAC) composite membranes were fabricated via nonsolvent-induced phase separation (NIPS), and the molecular weight of polyethylene glycol (PEG) was optimized as a hydrophilic pore-forming agent. Dope solutions were formulated with 15 wt.% PES, 1 wt.% PAC, and 10 wt.% PEG at varying molecular weights (200, 400, 600, and 1000 Da). Comprehensive characterization revealed that PEG molecular weight significantly dictates the structural and functional performance of the resulting composites. The PEG 600 Da variant achieved an optimal balance of properties, characterized by homogeneous PAC dispersion, a peak water flux of 420.88 LMH/Bar, a water contact angle of 37.11°, and a porosity of 74.74%, while maintaining a high Bovine Serum Albumin (BSA) rejection of 90.87%. While increasing PEG molecular weight generally enhanced permeability through the formation of an open pore architecture, a performance trade-off was observed beyond the 600 Da threshold due to increased dope viscosity and altered phase inversion kinetics. These findings suggest that PEG 600-optimized PES-PAC membranes offer a high-performance, affordable platform for advanced hemoperfusion applications.