POS9-1143
Quaternary ammonium tetrachloroferrate ionic liquids as thermo-responsive, magnetically recoverable, and antibacterial multifunctional draw solutes for forward osmosis
Topic
S9. Polymer Technology for Sustainability
When and Where
Sep 30, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Heesuk KIM
Jinhye BAE
Presenter(s)
Aida Zhamanshalova (BK-21 Four Graduate Program, Department of Chemical Engineering, Dong-A University, 37 Nakdong-Daero 550 Beon-Gil, Saha-Gu, Busan 49315, Republic of Korea)
Co-Author(s)
Abstract
The development of efficient, recyclable, and multifunctional draw solutes remains a critical bottleneck in advancing forward osmosis (FO) technology toward practical water treatment applications. In this study, three novel tetrachloroferrate(III)-based thermomagnetic ionic liquids (TMILs) — butyltrimethylammonium tetrachloroferrate ([N1114][FeCl4]), octyltrimethylammonium tetrachloroferrate ([N1118][FeCl4]), and dodecyltrimethylammonium tetrachloroferrate ([N11112][FeCl4]) — were synthesized via anion-exchange and characterized by 1H NMR, FT-IR, HRMS, and UV–Vis spectroscopy. TGA confirmed excellent thermal stability with decomposition temperatures exceeding 300 °C. Osmotic pressure and electrical conductivity increased with concentration and decreased with alkyl chain elongation, following the order [N1114][FeCl4] > [N1118][FeCl4] > [N11112][FeCl4]. LCST behavior was observed for [N1118][FeCl4] and [N11112][FeCl4], reaching ~54 °C and ~66 °C at 20 wt%, enabling thermally triggered phase separation and draw solute recovery. All TMILs exhibited paramagnetic behavior attributed to the high-spin Fe(III) center in [FeCl4]-, with susceptibility decreasing with chain length. Notably, all TMILs demonstrated complete antibacterial activity against Escherichia coli and Staphylococcus aureus, providing intrinsic biofouling mitigation absent from previously reported draw solutes. The concurrent integration of osmotic activity, thermo-responsive phase separation, magnetic responsiveness, and contact-killing antibacterial performance establishes these TMILs as a promising multifunctional platform for energy-efficient FO desalination.
