Tailoring a wetting- and scaling-resistant superhydrophobic membrane for high-efficiency membrane distillation of 99TcO4−/ReO4− radioactive wastewater

The sustainable and efficient treatment of high-salinity radioactive wastewater containing 99 TcO 4 − represents a critical challenge, driven by the severe environmental risks of 99 TcO 4 − and the inadequacy of existing treatment technologies. Here, we introduced membrane distillation (MD) as a novel approach for such wastewater and developed a robust superhydrophobic membrane (# PVDF-PN ) that simultaneously resisted wetting and scaling while overcoming the conventional selectivity-permeability trade-off. The # PVDF-PN was fabricated through in situ hydrolysis and polymerization of trichloromethylsilane (TCMS) on hydroxylated polyvinylidene fluoride (PVDF), yielding a surface densely covered with low-surface-energy polysiloxane nanofilaments. This unique nanofilament architecture significantly enhanced the gas-liquid interfacial area for vapor evaporation, without compromising pore integrity or permeability due to surface modification. When tested with challenging feeds containing surfactants or supersaturated gypsum, # PVDF-PN maintained a stable flux of ∼33.0 kg·m −2 ·h −1 and near-complete salt rejection (>99.99%), outperforming both unmodified # PVDF and fluorinated silica-coated # PVDF-FS . Its exceptional performance was attributed to a high liquid entry pressure, an elevated energy barrier for crystal nucleation, and reduced liquid-solid contact area and interaction time. Importantly, in long-term MD treatment of simulated 99 TcO 4 − /ReO 4 − -laden high-salinity wastewater, # PVDF-PN achieved non-detectable effluent concentrations of target oxyanions, demonstrating its potential as a reliable and efficient solution for radioactive wastewater management and emergency response.