Fabrication And Performance Study Of PAN/PEI/GO Liquid Separation Membrane By Layer-by-layer Assembly

With the rapid development of world economy and population growing, global freshwater resources and the energy crisis are getting more and more serious. In order to solve the global shortage of water resources, a lot of research has been committed to exploring the desalination and waste water recycling technology within acceptable cost.Liquid separation membrane such as filtration membrane and forward osmosis membrane is one of the effective means to solve the problem.This work optimizes the method to synthesize graphene oxide firstly. And GO used as anionic polyelectrolytes, poly(ethyleneimine) used as cationic polyelectrolytes. A kind of nanofiltration membrane with excellent properties can be prepared by layer-by-layer self-assembly technology, which based on the combination of the electrostatic bonding. After ten layers alternated assembled base on PAN ultrafiltration membrane which has porous, the PAN/PEI/GO composite nanofiltration membrane exhibited a water permeance of 6.97L/m2 barh and an RB rejection of approximately 99.99%, an MB rejection of approximately 94.21%, an CV rejection of approximately 76.08%. However, in ethanol system, the rejection of RB is only about 81.26%,and the rejection of MB and CV is about 71.26% and 80.06%. And in water system, the rejection of cephalexin is 76.04%, and rejection of tobramycin and clindamycin phosphate is 89.04% and 96.02% respectively. After 40 hours, the PAN/PEI/GO composite nanotiltration membrane exhibited a constant water permeance of 6.50L/m2 barh and an RB rejection of approximately 99.99% respectively.In FO desalination, LBL assembly seems to have more suitability compared with other methods. Similarly, LBL assembly method can be used to fabricate novel kinds of FO membranes by directly depositing polyelectrolytes on various substrates. On the basis of nanofiltration membrane research, after the membrane was immersed in PEI, it can be immersed in glutaraldehyde, and the PEI crosslinked by the GA. After ten layers alternated assembled base on PAN ultrafiltration membrane which has porous, the PAN/PEI/GO composite forward osmosis membrane has permeance of 8.3L/m2 h, and the reverse salt flux is about 3.5g/m2 h.Transport of water and selected solutes in the PAN/PEI/GO membrane was investigated in a pressure retarded osmosis(PRO) system. In PRO mode, water flux was higher and the reverse salt flux is lower. This is because GO is hydrophilic. Besides, the anti-fouling of the FO membrane performance has been enhanced.