Preparation And Technology Of Polyamide Composite Reverse Osmosis Membrane

During the last half century of development, reverse osmosis technology is widely employed in the fields of industry, food, medicine, and so forth. Because it has the advantages of being low energy consumption, easy to operate, and sustainable development, reverse osmosis technology is honored as "purification technique in 21 century". Nowadays, the certain reverse osmosis technology that driven by pressure is one of the most promising technologies all over the world. But the start time of the study in composite reverse osmosis membrane was late in our country, although the current domestic reverse osmosis technology has developed rapidly. From the point of the whole field of reverse osmosis, obviously there are still large gaps between our country and the international advanced level. So it is very necessary to explore and optimize the current composite reverse osmosis membrane preparation technology.Firstly, with polysulfone (PSF) as basal material, polyethylene glycol (PEG) as additive, N,N-dimethyl acetamide (DMAc) as solvent, the supported membrane prepared by phase transformation and optimized the preparation condition. Through the membrane performance test such as water flux, rejection rate, water contact angle, pressure resistance and analyses the structure of the cross section by Scanning Electron Microscope (SEM). Found that the supported membrane with the preparation condition of PSF-24wt%/PEG2000-22wt% had a higher rejection rate (98.67%) and a appropriate water flux (443L·m-2·h-1,0.2MPa).Secondly, on the basis of optimized the basement membrane, using in industrial production were relatively common aqueous monomer m-phenylene diamine (MPD) and organic phase monomers 1,3,5-trihydroxybenzene (TMC), explored and optimized the preparation technology of polyamide separation layer. Investigated in the water phase monomer concentration, organic solvent type, interfacial polymerization time, curing temperature and time on the effect of properties and morphology of composite reverse osmosis membrane, achieving a set of optimization of experimental data, the preparation of composite membrane in 1.6 MPa,2000 ppm (mg/L) NaCl test conditions, the rejection rate is> 96%, the water flux is>45 L·m-2·h-1.Finally experiments used common anionic surfactant sodium dodecyl sulfonate (SDS) as the modified materials on PSF membrane surface. Found that after using SDS treated the surface, the hydrophilicity and water flux raised, but SDS absorption ability was bad, easy to fall off from the membrane. Preparation of composite membrane with SDS modified substrate membrane, the rejection rate slightly raised but the flux had some decreased.