Effect of the Characteristic Properties of Membrane on Long-Term Stability in the Vacuum Membrane Distillation Process.

Membranes (Basel)

Research Center for Membrane and Film Technology, Department of Chemical Science and Engineering, Kobe University, Nada, Kobe 657-8501, Japan.

Published: March 2021

Membrane distillation (MD) is a technology that can treat feed solutions with higher osmotic pressure, as well as produce high-purity water. However, the water production cost of the MD process is expensive. In this study, to decrease the water production cost, we attempted to evaluate the effect of membrane characteristics on the long-term stability of a vacuum MD (VMD) system. We fabricated four different types of polyvinylidene difluoride hollow fiber membranes, and operated a VMD system with 3.5 wt% NaCl aqueous solution at 65 °C as a feed under 11 kPa of air gap pressure. Consequently, in the proposed VMD system, it is found that the liquid entry pressure (LEP) is the most important factor. When LEP was higher than 0.37 MPa, the pilot-scale module was very stable for long-term operations, and the vapor flux was approximately 19.3 kg/m·h with a total salt retention factor of over 99.9% during the 300-h operation.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8066549PMC
http://dx.doi.org/10.3390/membranes11040252DOI Listing

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