Study On Polypiperazing-Amide/Polysulfone Composite Nanofiltration Membrane

Because of its special pore size and special process during preparation, nanofiltration membrane has special separation performance. Nanofiltration exactly fills the gap between ultrafiltration and reverse osmosis. The research and application about nanofiltration membrane is paid widely attention among membrane research persons. Using polysulfone membrane as substrate, piperazine and isophthaloyl chloride (IPC) or trimesyol chloride (TMC) as monomers, composite nanofiltration membrane was prepared through interfacial polymerization.Appropriate substrate membrane was prepared through changing proportion of polysulfone solution. Using different concentration piperazine and IPC or TMC, through changing immersion time, heat treatment time and temperature, composite nanofiltration membrane with good performance was prepared. Appropriate conditions about IPC system are as following: concentration of piperazine is about 0.5wt%, concentration of IPC is about 0.45wt%, immersion time is about 4min and 6min respectively. Time and temperature about heat treatment are about 20min and 70 ℃ respectively. Appropriate conditions about TMC system are as following: concentration of piperazine is about 0.45wt%, concentration of TMC is about 0.15wt%, immersion time is about 4min and 3min respectively. Time and temperature about heat treatment are about 20min and 70 癈 respectively. Microstructure of composite layer was analysed by Fourier Transform Infrared Adsorption Spectrum(FTIR), Scanning Electron Microscopy(SEM) and Environment Scanning Electron Microscopy(ESEM).Using polysulfone hollow fiber membrane as subatrate, appropriate condition of preparation of composite hollow fiber nanofiltration membrane was studied on the bases of sheet membrane. Appropriate conditions about IPC system are as following: concentration of piperazine is about 0.5wt%, concentration of IPC is about 0.45wt%, immersion time is about 2min and 4~6min respectively. Time and temperature about heat treatment are about 20~25min and 70 癈 respectively. Appropriate conditions about TMC system are as following: concentration of piperazine is about 0.45wt%,concentration of TMC is about 0.15wt%, immersion time is about 2min and 3min respectively. Time and temperature about heat treatment are about 20~25min and 70 癈 respectively. Microstructure of composite layer is analysed by the means same as sheet membrane.Under the appropriate condition, composite nanofiltration membrane with good performance was prepared. At 25℃, 0.8MPa, the rejection ratio of 1g/L MgSO4 solution can over 95%, the rejection ratio of 2g/L NaCl solution is about 50% , the flux of sheet membrane can over 50L/m h and the flux of hollow fiber membrane is about 15L/m2h.