The Preparation And Application Of Polyamide Composite Nanofiltration Membrane

NF membranes have come a long way since it was first introduced during the late 80’s. NF membranes have been used in many interesting applications especially in water and wastewater treatment and desalination. Other applications include in pharmaceutical and biotechnology, food and non-aqueous types of application. Generally, commercial NF membranes usually prepared by the interfacial polymerization. This review Used commercial PSF membrane as a support structure, will comprehensively look at a NF membrane was synthesized by the interfacial polymerization, the specific work is as follows:With piperazine (PIP) as water phase reaction monomers, and trimesoyl chloride (TMC) as oil phase reaction monomers, respectively, on the surface of the base membranes interfacial polymerization reaction.Optimize the interfacial polymerization of main preparation conditions, using the single factor method for concentration of PIP, the concentration of Na3PO4, TMC concentration, reaction time were analyzed respectively. By investigating the pure water flux and rejection of NF membrane, combining with the contact Angle, SEM and FTIR spectra of composite NF membrane surface morphology and physical and chemical properties were characterized, and analyze the influence of different operating conditions on performance of NF membrane, the study of reaction mechanism. Through the single factor experiment, the composite NF membrane optimized preparation conditions are:PIP1.6 (wt%), reaction time is 20 s, Na3PO40.35 (wt%), TMC0.3 (w/v)%, under the pressure of 0.5 MPa, NF membrane water flux of 51.62 L/(h · m2), NaCl rejection is 61.56%, MgSO4 rejection was 95.74%. With ultra-thin composite layer thickness increases, reduces the diffusion coefficient about PIP migrate to organic phase. So PIP concentration, reaction time, concentration of TMC, pH very important influence to the growth of the dense layer thickness and the increase of crosslinking degree, but because of TMC and PIP form high crosslinking degree proportion of dense layer has a certain reaction, and completely dependent on PIP to the spread of oil phase volume to the choice of forming dense layer, so too much PIP concentration, reaction time and concentration of TMC can’t form the good performance of NF membrane. Na3PO4 for acid-binding agent, and also as phosphonium salt, with the PIP complexation, transport PIP from water phase to the organic phase, have the effect of part of the phase transfer catalyst. Polyamide composite NF membrane surface with burden, has good effect on dye rejection, especially high molecular weight, the negatively charged dyes. Polyamide NF membrane is rejection performance is good, strong ability to resist pollution, the advantages of stable performance, has practical application value for dye wastewater treatment.