This study presented a novel method for the surface modification of a hydrophilic polyethersulfone (PES) membrane via dip-coating. The performance of the new membrane was investigated in a membrane distillation process. The surface free energy (SFE) of the modified PES was studied by the Owens–Wendt method. A significant decrease of surface free energy from 36.1 mN/m to 16.4 mN/m was observed after modifying the membrane surface with fluoro-organothiol (1H, 1H, 2H, 2H-perfluorodecanethiol). The water contact angle of the membrane increased from 66° for PES to 115° for surface-modified membrane. This remarkable increase suggests a successful switch from hydrophilicity to hydrophobicity owing to the creation of hierarchical submicro/nanostructures on the surface of PES. This structure was achieved by depositing polydopamine and silver nanoparticles, followed by lowering the surface free energy by fluoro-organothiol treatment. The performance of the modified membranes was evaluated through a direct contact membrane (DCMD) process in the presence of anionic and non-ionic surfactants and high salt concentrations (4.5 wt%). The membranes reached a high and stable flux of approximately 39.37 kg/m²h after surface modification. Besides, the newly engineered membranes had excellent stability during long-term operation, showing a salt rejection rate of 99.80% after 36-h.

本研究提出了一种通过浸涂对亲水性聚醚砜 (PES) 膜进行表面改性的新方法。在膜蒸馏过程中研究了新膜的性能。通过 Owens-Wendt 方法研究了改性 PES 的表面自由能 (SFE)。在用氟有机硫醇（1H、1H、2H、2H-全氟癸硫醇）改性膜表面后，观察到表面自由能从 36.1 mN/m 显着降低到 16.4 mN/m。膜的水接触角从 PES 的 66° 增加到表面改性膜的 115°。这种显着的增加表明，由于在 PES 表面上产生了分级亚微/纳米结构，成功地从亲水性转变为疏水性。这种结构是通过沉积聚多巴胺和银纳米颗粒来实现的，然后通过氟代有机硫醇处理降低表面自由能。在阴离子和非离子表面活性剂和高盐浓度 (4.5 wt%) 存在下，通过直接接触膜 (DCMD) 工艺评估改性膜的性能。膜达到了大约 39.37 kg/m 的高且稳定的通量表面改性后²小时。此外，新设计的膜在长期运行过程中具有出色的稳定性，36 小时后脱盐率为 99.80%。