Study on the Vacuum Membrane Distillation Performances of PVDF Hollow Fiber Membranes for Aqueous NaCl Solution

Membrane distillation (MD) is a novel membrane seperation thechonology which can be applied in seawater or brine desalination process. In this work, hydrophobic microporous PVDF Hollow Fiber membranes vacuum membrane distillation (VMD) performance were investigated for aqueous NaCl solution. The effect of concentration of aqueous NaCl soluton, feed flow rate and temperature were studied. The lab scale and pilot scale experiments were carried out with membrane module effective area 0.0386m(2) and 3.7397m(2), respectively. The VMD performance of 6wt.% aqueous NaCl solution(which is the same concentration as the brine of seawater desalination) showed that the permeation flux reached 25.171 kg/(m(2).h) and the salt rejection was as high as 99.8%, the pressure on the vacuum side was 3kPa, the feed temperature was 343.15K and the feed linear flow rate was 0.461 m/s.