Membrane wetting is a crucial issue
in the desalination process
by vacuum membrane distillation (VMD). However, the micromechanism
of the wetting behavior is far from clear. Here, electrospun nanofiber
membranes (ENMs) had been utilized to clarify the pore variations
inside the membrane for desalination from NaCl aqueous solution, where
the distinct open pore structure of ENMs could address the characterizing
limitations for the change occurring in the membrane pores. A wetting
formation model had been depicted on the basis of characterized results,
illustrating that the basic reason for wetting was the initial NaCl
crystallization caused by supersaturation, which was different from
the membrane pores blocking or the structure damage caused by scaling.
Moreover, membrane regeneration experiments also showed that the wetting
caused by the crystallization of NaCl was reversible. By a reasonable
regeneration strategy, VMD used for desalination was expected to achieve
continuous operation with rejection over 99.9%.