Flux enhancement in membrane distillation by incorporating AC particles into PVDF polymer matrix

Abstract

In this paper, a novel method of preparing porous hydrophobic membrane was proposed and further experiments had been carried out for verification. A kind of hydrophobic porous inorganic particles, macroporous structure activated carbon (AC), was introduced into polyvinylidene fluoride (PVDF) polymer matrix to fabricate porous membrane for vacuum membrane distillation (VMD) application. The incorporation of AC particles in the polymer matrix can efficiently enhance the membrane permeability because of the intrinsic porous structure of AC particles could directly provide water vapor mass transfer channels in the VMD process. Results showed that: the VMD flux of PVDF hydrophobic membranes was obviously improved by the addition of AC particles. When 0.09wt% AC particles were added in membrane casting dope, a VMD flux of 54.9kg/m2h was obtained. The flux is 30% higher than that of pure PVDF membrane (42.0kg/m2h). Furthermore, the conductivity of the M-3 membrane was kept lower than that of pure PVDF membrane in the 16h continuous desalination experiments. All of the results demonstrated that the prepared PVDF/AC hollow fiber membrane not only has higher permeability but also exhibited satisfying performance stability. It performed well in the VMD program and is expected to be applied in the field of MD to improve the MD membrane performance.