Study On Modified Carbon Nanotube Composite Nanofiltration Membrane

Membrane separation processes is a new technology of separation,concentration and purification.In seawater softening process,the modified composite membrane was applied more and more widely.In recent years,the rapid development of nanotechnology,the carbon nanotube can improve the performance of the composite film by interaction with the polymer.Therefore,this article is intended to modify the carbon nanotube and add it to the preparation of modified method utilizing polyelectrolyte layer self-assembled carbon nanotube composite film to improve the performance of the composite membrane.The biggest problem of the application of the carbon nanotubes is that is difficult to dissolve and disperse.In this study,sulfonated and amino modification was used to prepare the carbon nanotubes.Their structures were characterized by FTIR,XRD,TGA,Raman,etc.It can be determine the presence of a modified group by FTIR;XRD pattern analysis confirms that the special structure of the modified carbon nanotubes did not be damaged;TGA further evidenced the presence of carbon nanotubes which introduced groups.Add the modified carbon nanotube to the preparation of composite film by layer self-assembly method.Determining optimal conditions by examining the effects of different content on the modified carbon nanotube composite membrane performance.The results show that carbon nanotubes may be added to improve the composite membrane water flux.When the carbon nanotube dosage 0.08 g / L,the water flux of the composite membrane improve by 93%.The retention rate of 0.01 M magnesium chloride solution improve by 12%.Commercially,sulfonation,amination nanotubes were added to the modified material which are polyethyleneimine(PEI)and polyacrylic acid(PAA)as a cation-modified and anionic polyelectrolytein the preparation of carbon nanotube composite membrane.Experiments show that: amino carbon nanotubes in PEI polycation electrolyte was dispersed easily.And the composite membrane performance improvement effect is obvious;sulfonated carbon nanotubes polyanion electrolyte PAA was dispersed easily.And the composite membrane performance significantly enhanced obviously.