Distillation membrane constructed by TiO2 nanofiber followed by fluorination for excellent water desalination performance

The hydrophobicity and module characteristic of membrane are key factors affecting the performance of the direct contact membrane distillation. In this paper, the superhydrophobic membrane, constrained by high porosity and large pore size, was prepared. Titania is regarded as a promising candidate material for environmental application, due to its high photocatalytic ability, relatively low cost, remarkable photostability, and toxicity. The membrane, consisted of titania nanofibers, was designed and fabricated by vacuum filtration and fluorination modification. Compared with ceramic particle aggregated membrane distillation (MD) membrane, an interconnected pore structure was constructed by entangled nanofibers to endow the prepared membrane with porosity higher than 80%. During direct contact membrane distillation process, the prepared membrane displayed an excellent desalination performance with flux of 12 LMH and salt rejection of 99.92%. Importantly, the flux was much higher than those of ceramic membranes with particle aggregation structure. Moreover, the prepared membrane possesses a good stability for long-term MD operation in pure water and even desalinating high saline water. The superhydrophobic titania nanofibrous ceramic membrane modified by fluorinated holds promise for practical applications due to its excellent performance for water desalination.