| Poly(vinylidene fluoride)(PVDF) is one of the widely used membrane materials, dueto its good mechanical strength, thermal and chemical stability, radiation resistance. ForPVDF ultrafiltration membrane preparation, the solution phase inversion method has anadvantage that technical conditions are simple. Due to its hydrophobicity, the applicationof PVDF membrane was limited.In this paper, organoclay was introduced to prepare PVDF/organoclay nanocompositemembrane by the way of blend. Effect of casting solution compositions and preparationconditions on membrane structure and performance was discussed. Modern instrumentalanalysis was used to investigate membrane surface, cross-section and inner section.It was found that the addition of organoclay can enhance the water permeation fluxand rejection of nanocomposite membrane, the water permeation can be enhanced 2 times.At the same time, the effect of the polymer concentration on membrane performance wasstudied. The suitable concentration of PVDF should fall into the range of 16% to 20%from abundant experiments. With the increasing of PVDF concentration in castingsolution, the pore density and size on the surface of the membrane decreased, and thewater flux of membrane also decreased gradually.The nano-dispersion of organoclay was realized. The nano-dispersion of organoclay isthe key problem in the preparation of nanocomposite membrane. The nano-dispersedorganoclay can lead to the pore diameter of membrane more uniform, increase theporosity and increase the water permeation flux. During the application,the waterpermeation flux of PVDF membrane and nanocomposite membrane attenuate to someextent, which can recover to some extent after cleaning. Nanocomposite membrane whichorganoclay was introduced can recover to a high extent. This is because that organoclaywas introduced to hydrophilize PVDF nanocomposite membrane. Hydrophilic polargroups can decrease then speed of attenuation and enhance anti-fouling capability ofmembrane.
|
PDF Full Text Request