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Keywords
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membranes, nanocrystals, nanoparticles, nanowires, porous materials
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Abstract
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The membrane distillation process is one of the most important membrane
technologies being developed for water desalination, which has the ability to
compete with expensive processes such as reverse osmosis. In this study, the
performance of polycarbonate (PC) hollow fiber membranes modified with silica
aerogel nanoparticles (SIA-NPs) and polydimethylsiloxane (PDMS) coating
solution for direct contact membrane distillation was investigated. The membranes
were fabricated by dry jet-wet spinning method. In this respect, 0.25,
0.5, and 1 wt% of SIA nanoparticles were coated over the hollow fiber surface
in order to improve the performance of the membranes. The results indicated
that the optimum loading of SIA was 0.5 wt% at which the contact angle of the
surface shifted from 77.5 to 100 relative to the unmodified PC membrane.
Although the addition of SIA nanoparticles to the membrane matrix did not
alter the membrane conductivity, it increased the membrane thickness,
thereby reduced the heat loss of the membrane. Accordingly, the results of performance
tests for the membrane distillation (MD) showed that by adding
0.5% SIA nanoparticles to the membrane bulk and coating the surface with
0.5% SIA nanoparticles in 1.0% PDMS solution and 96% increase in energy efficiency,
33% increase in water flux, as well as higher stability of salt rejection
were obtained. This study proved that the application of SIA nanoparticles
have a great potential to modify and improve MD performance.
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