Interlocked PTFE/Ceramic Membrane with Pine-Needle-Like Interlayer for Efficient Water-NMP Separation

N-Methyl-2-pyrrolidone (NMP) is a water-miscible, polar aprotic solvent extensively used in various industrial processes. However, its widespread use has led to the generation of large volumes of NMP-containing wastewater, which poses significant environmental and health concerns. In this study, a robust PTFE/ceramic composite membrane was developed for effective separation of water and N-methyl-2-pyrrolidone (NMP) using a solvent resistant membrane distillation (SR-MD) process. To address the challenge of PTFE infiltration into macroporous ceramic supports, a pine-needle-like TiO 2 interlayer was constructed via in-situ hydrothermal synthesis. This interlayer not only reduced surface macroporosity but also strengthened the interfacial bonding between the ceramic support and the PTFE layer by mechanical interlocking, while simultaneously preventing PTFE penetration into large pores of the support. Additionally, carbon nanotubes (CNTs) were incorporated into the PTFE matrix to alleviate sintering-induced cracking and improve membrane mechanical properties. The resulting composite membrane exhibited a well-defined three-layer structure, low friction coefficient, excellent scratch resistance, and high interfacial integrity. The optimized membrane achieved high water flux (30 kg·m –2 ·h –1 ) and excellent NMP rejection (>96%) at 70 °C over prolonged operation. Vapor–liquid equilibrium analysis confirmed the selective permeability based on volatility differences between water and NMP. This study provides a practical and scalable strategy for constructing high-performance PTFE/ceramic composite membranes suitable for organic wastewater treatment under harsh conditions.