Antibacterial effect of ethyl-methylimidazolium-based ionic liquids anions on forward osmosis membranes

Abstract

Ionic liquids (ILs) have emerged as promising materials in various sectors, particularly for enhancing membrane separation and antibacterial performance in water and wastewater treatment applications. This study investigates the antibacterial effects of ethyl methylimidazolium ([EMIM]⁺)-based IL anions on forward osmosis (FO) membranes. Imidazolium-based IL cations were synthesized using a microwave method and grafted onto a thin-film composite (TFC) membrane to improve bacterial inhibition and separation performance. A novel approach utilizing ultrasound methods was employed to integrate polyamide (PA) and ILs onto the polysulfone (Psf) membrane surface. Among the tested ILs, [EMIM][NTf₂] demonstrated the highest antibacterial activity against Escherichia coli, as evidenced by agar disk diffusion and total plate count (TPC) measurements. The Psf-PA-[EMIM][NTf₂] membrane significantly outperformed other membranes in antibacterial activity and exhibited excellent FO membrane performance. The results indicate that incorporating ILs into FO membranes enhances hydrophilicity and antibacterial properties, making them highly suitable for water and wastewater treatment. This study provides valuable insights into developing dual-functional membranes with improved antibacterial and separation performance, contributing to more effective and sustainable treatment technologies.