Preparation of low-pressure hollow fiber nanofiltration composite membranes via interfacial polymerization
In recent years,hollow fiber nanofiltration membranes have received continuous attention due to high packing density.However,the energy consumption of existing hollow fiber nanofiltration membranes is relatively high in practical applications.In this paper,firstly,polysulfone(PSf)hollow fiber ultrafiltration membrane was prepared via dry-wet spinning technology as the substrate membrane.Piperazine(PIP)and trimesoyl chloride(TMC)were selected as aqueous monomer and organic monomer,respectively.Through the optimization of interfacial polymerization conditions,low-pressure hollow fiber nanofiltration membranes were successfully prepared.The surface morphology of the membrane was characterized by scanning electron microscope and atomic force microscope.The chemical structure and element composition of the membrane surface were analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy.Water contact angle and Zeta potential of the membrane surface,molecular weight cut off and pore size distribution of the composite membrane were investigated.The effect of interfacial polymerization monomer concentration,reaction time and testing pressure on the performance of composite membranes were studied and the optimal process conditions were determined.The results show that the optimized low-pressure hollow fiber nanofiltration membrane has a low cross-linking degree polyamide functional layer.Under a test pressure of 0.2 MPa,the pure water flux reaches(16.0±0.4)L/(m2·h),and the rejection rates for salt solutions with a concentration of 1 g/L are Na2SO4(94.2％±0.9％)＞MgSO4(92.2％±0.9％)＞MgCl2(51.0％±0.5％)＞NaCl(9.5％±0.3％),exhibiting excellent Na2SO4/NaCl selectivity.
interfacial polymerizationnanofiltrationhollow fiber membranelow-pressurethin film composite membrane
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