Reverse osmosis performance of layered-hybrid membranes consisting of an organosilica separation layer on polymer supports

A novel layered-hybrid membrane consisting of a thin and defect-free organosilica separation layer deposited onto a flexible polymeric nanofiltration membrane was successfully developed via a simple sol-gel, spin-coating, low-temperature, heat-treatment process. This marked the first application of this type of a layered-hybrid membrane to the reverse osmosis (RO) desalination of a 2000 ppm NaCl solution. The optimal heat-treatment temperature for the membrane preparation was also investigated. These layered-hybrid membranes displayed good stability and reproducibility in the RO process, and showed a stable and high degree of water permeability (approximately 1.2×10−12 m3 m−2 s−1 Pa−1) with salt rejection that was competitive (96%) with conventional processing. Moreover, this layered-hybrid membrane also showed good hydrothermal stability at operating temperatures ranging from 25 to 60 °C and stable RO performance during a continuous RO desalination process that lasted for more than 160 h.