Characterization, Performance, and Toxicological Assessment of Polysulfone-Sulfonated Polyether Ether Ketone Membranes for Water Separation

Authors

• Muhammad Usman Yousaf, University of KentuckyFollow
• Lucca Madeo Cortarelli, University of KentuckyFollow
• Nerissa I. Jebet, University of KentuckyFollow
• Jason M. Unrine, University of KentuckyFollow
• Nirupam Aich, University of Nebraska-LincolnFollow
• Olga V. Tsyusko, University of KentuckyFollow
• Isabel C. Escobar, University of KentuckyFollow

ORCID IDs

Yousaf https://orcid.org/0009-0001-1574-6679

Cortarelli https://orcid.org/0009-0006-8022-5315

Unrine https://orcid.org/0000-0003-3012-5261

Tsyusko https://orcid.org/0000-0001-8196-1062

Escober https://orcid.org/0000-0001-9269-5927

Document Type

Article

Date of this Version

2025

Citation

Membranes (2025) 15: 87

doi: 10.3390/membranes15030087

Comments

Open access

License: CC BY 4.0

Abstract

The removal of small molecular weight charged compounds from aqueous solutions using membrane remains a challenge. In this study, polysulfone (PSf)- and sulfonated polyether ether ketone (SPEEK)-based membranes were fabricated via non-solvent induced phase separation process (NIPS) using N-Methyl-2-Pyrrolidone (NMP) as solvent and water as non-solvent. Membranes were characterized structurally and morphologically, followed by toxicity assessment conducted before and after filtration, both with and without annealing at various pH values to evaluate potential leaching of trapped solvent from the membrane pores. Additionally, membrane performance was characterized using binary mixtures of cationic and anionic dyes. The results demonstrated selective filtration behavior, with cationic dyes being preferentially rejected due to size exclusion and electrostatic interactions. Additionally, a key focus of this work was the investigation of solvent leaching, framed within a Safe(r)-by-Design (SbD) approach aimed at enhancing functional performance while minimizing environmental toxicity. Toxicity assessments using a model organism, a nematode Caenorhabditis elegans, revealed that annealing reduced solvent leaching and thus permeate toxicity, particularly at neutral pH values, by facilitating trapped solvent release prior to membrane use. These findings provide insights for the importance of including an SbD approach during membrane casting to fabricate membranes with desirable properties while minimizing toxicity.