Preparation And Characterization Of Nanofiltration Membrane Based On The Macrocyclic Polyamine

Nanofiltration (NF) has been widely used in biological chemical, pharmaceutical, food and water treatment. Given its huge economic benefits, the negatively charged NF membrane has been paid more attention. How to improve the perforamance of the NF membrane has become one of the hottest topics. In this paper, composite nanofiltration membranes were prepared by interfacial polymerization selecting macrocyclic polyamine as water phase monomer. In the preparation process of the composite nanofiltration membranes, the performance of NF membranes had been optimization by added silica sol or organic salt in the polymerizable monmer solution. The results of the study are as follows:1、A novel nanofiltration (NF) membrane was prepared with cyclen and trimesoyl chloride (TMC) by interfacial polymerization on polyethersulfone (PES) ultrafiltration membrane with molecular weight cut-off (MWCO) of 50,000 Da. The effects of reaction time, monomer concentration, and heat treatment temperature were discussed. The physicochemical properties and morphology of the prepared NF membrane were characterized by FTIR-ATR, SEM, EDS, and AFM. The NF performances were evaluated with the solutions of Na2SCO4, MgSO4, Mg(NO3)2, and NaCl respectively. The salt rejection order of the prepared NF membrane was as follows:Na2SO4>MgSO4>Mg (NO3)2>NaCl. The resulting rejection of Na2SO4 and PEG600 were more than 90%, whereas that of NaCl was approximately 10%. After the addition of silica sol in the aqueous phase [silica sol concentration:0.1%(w/v)], the salt rejection of the membrane changed slightly; however, the water flux was from 24.2 L·m-2·h-1(25℃,0.6 MPa) up to 38.9 L·m-2·h-1(25℃,0.6 MPa) and the resulting membrane exhibited excellent hydrophilicity.2> Studying the preparation and nanofiltration properties of a novel thin-film composite polyamide membrane formed by the interfacial polymerization of 1,4-Diaminocyclohexane (DCH) and trimesoyl chloride(TMC) on a porous polysulfone supporting membrane. At the same time, we find that the introduction of Sodium N-cyclohexylsulfamate (SCHS) can improve a degree of the water flux and salt rejection. The active surface of the membrane was characterized by employing ATR-IR、SEM and AFM. The performance of nanofiltration membrane was optimized by discussing the preparation condition, including monomer concentration, reaction time, curing condition and SCHS concentration. The result NF membrane prepared under the optimum condition exhibited Na2SO4 rejection of 98.1% and the water flux of 44.6L·m-2·h-1 under 0.6MPa. The pore size of the NF membrane is about 0.33-0.42nm which was calculated from the rejection of PEG and carbohydrates, respectively.