Interlayer-free P123 carbonised template silica membranes for desalination with reduced salt concentration polarisation

• Published in: Journal of membrane science 2015-02, Vol.475, p.376-383
• Main Authors: Elma, Muthia, Wang, David K, Yacou, Christelle, Diniz da Costa, Joao C
• Format: Article
• Language: English
• Subjects: Brackish; Brackish water; Chemical engineering; Chemical Sciences; Desalination; Fluxes; Material chemistry; Membranes; Precursors; Salt water; Silicon dioxide; Tetraethyl orthosilicate
• ISSN: 0376-7388
• DOI: 10.1016/j.memsci.2014.10.026

Carbonised template silica membranes were synthesised and investigated for water desalination for brackish (0.3 wt%), sea water (3.5 wt%) and brine (7.5 wt%) NaCl solutions at temperatures range from 22 to 60 degree C. The membranes were prepared by a two-step base catalysed sol-gel method using tetraethyl orthosilicate TEOS as the silica precursor and triblock copolymer of Pluronic super( registered ) P123 as the templating agent. The P123 silica membranes calcined under vacuum only produced high quality membranes by the interlayer-free method. The membranes were stable during testing of up to 250 h under different thermal and salt concentration solutions, always delivering very high salt rejections >99.5%. It was found that by increasing the template concentration in the silica matrix from 5 to 50 wt%, salt concentration polarisation was greatly reduced. As such, high water fluxes were measured up to 8.5 kg m super(-2) h super(-1) for brackish water and 6.6 kg m super(-2) h super(-1) for brine water.