1. High-temperature reverse osmosis and molecular separation with robust polyamide-ceramic membranes.
- Author
-
Chong, Jeng Yi, Zhao, Yali, and Wang, Rong
- Subjects
- *
MOLECULAR weights , *SURFACE charges , *SUBSTRATES (Materials science) , *THERMAL stability , *HIGH temperatures , *REVERSE osmosis , *COMPOSITE membranes (Chemistry) - Abstract
[Display omitted] • RO-type polyamide (PA) thin-film was synthesized on ceramic tubular substrates. • The PA-ceramic membranes showed excellent performance and stability in HT-RO. • The MWCO increased at HT and surface charge was critical for salt rejection. • PA thin-films are stable at < 75 °C but thermal hydrolysis was observed at 80 °C. • The robustness of the substrates could enhance the membrane stability in HT-RO. Polyamide thin-film composite (TFC) membranes are widely used for reverse osmosis (RO), but most commercial RO membranes have a limited operating temperature of <45 °C. This has constrained the broader applications of RO in industries, where process and water feeds with high temperature >50 °C are common. In this study, robust polyamide-ceramic TFC membranes were developed for high-temperature RO (HT-RO). RO-type polyamide thin-film was successfully synthesized on the inner surface of ceramic tubular membranes via interfacial polymerization. The polyamide-ceramic membranes exhibited excellent thermal stability, maintaining high NaCl rejection (>98 %) and steady water permeability (∼5 LMH/bar) during HT-RO at 70 °C. The molecular weight cut-off (MWCO) of the membranes increased slightly from 90 to 140 Da at 70 °C, and the surface charge played an important role in maintaining the high salt rejection. Long-term stability tests showed that polyamide thin-films may undergo thermal hydrolysis at 80 °C. It was also found that polymeric substrates of flat-sheet RO membranes may experience serious compaction at high temperature, which could subsequently affect the performance and stability of the polyamide layer. The ceramic substrates provide strong support at high temperature, and the highly stable polyamide-ceramic membranes demonstrated huge potential for RO applications under more challenging conditions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF