Scalable nanoconfined GO/SWCNT-OH membranes for efficient high-salinity organic wastewater treatment

Recovering valuable organic compounds from high-salinity organic wastewater is essential for sustainable chemical manufacturing. However, conventional polymeric membranes suffer from insufficient organic/inorganic selectivity, poor solvent resistance, and severe membrane fouling during practical applications. Herein, we developed a hydroxylated carbon nanotube (CNT-OH)-modulated graphene oxide (GO) membrane to address these challenges. By precisely regulating the inner diameter and hydroxyl content of CNT-OH, rapid transport channels for water molecules and hydrated ions were constructed, which simultaneously suppressed interlayer swelling and enhanced the rejection of organic compounds. The optimized GO/single-walled hydroxylated carbon nanotubes (SWCNT-OH) membrane achieved water permeability of 28.7 l m⁻² h⁻¹ bar⁻¹ and separation factor above 15 for negatively charged dyes, antibiotics, and per- and polyfluoroalkyl substances (PFASs) relative to inorganic salts (NaCl), outperforming commercial nanofiltration (NF) membranes by one order of magnitude. During one-month continuous treatment of real erythromycin (ERY) fermentation broth, the membrane showed only a 7.1% flux decline and maintained 99.9% ERY rejection. Compared with conventional ultrafiltration-nanofiltration (UF-NF) processes, the system reduced operating costs by 66.4% and CO₂ emissions by 76.8%, demonstrating pronounced economic and environmental advantages. Overall, the system demonstrates outstanding application potential, strong scalability and engineering feasibility.