Commercial polyethylene supported thin-film composite membranes within 10 µm thickness for organic solvent forward osmosis

Abstract

Organic solvent forward osmosis (OSFO) as a promising separation process for the pharmaceutical industry. The practicality and suitability of OSFO membrane are significant for the OSFO process. In this study, we developed and characterized an ultrathin (<10 µm) and solvent-resistant thin-film composite (TFC) membrane for use in the OSFO process. The commercialized polyethylene (PE) membrane with thicknesses of 5 and 9 μm were selected as a novel substrate, and hydrophilic polyvinyl alcohol was introduced on its surface to enhance hydrophilicity and structural attributes. After interfacial polymerization reaction, the utilization of the 5 μm PE substrate elevates water and alcohol fluxes, while the 9 μm PE substrate possesses the higher rejection for salts and APIs. Notably, following a 2-hour DMF activation process, the resulting TFC5-0.05 membrane attains a noteworthy ethanol flux of 2.6 L m–2h−1, along with a robust oxytetracycline rejection of > 95 % during 10-hour continuous operation. These findings underscore the favorable permselectivity of the ethanol and oxytetracycline and solvent stability of the ultrathin PE-PA TFC membrane on the commercial substrates for OSFO process.