Low-pressure high-flux chlorine-containing polymer nanofiltration membrane with stable separation layer and preparation method thereof

The invention discloses a low-pressure high-flux chlorine-containing polymer nanofiltration membrane with a stable separation layer and a preparation method thereof. The nanofiltration membrane comprises a macroporous support layer and a dense function layer, wherein the macroporous support layer and the dense function layer are connected with each other by virtue of a C-N bond; the dense function layer is made of a positive, charged or amphoteric ionic cross-linking polyamine compound; the macroporous support layer is made of a chlorine-containing polymer. The preparation method of the filtration membrane comprises the following steps: firstly coating the surface of a chlorine-containing polymer ultrafiltration membrane with the polyamine compound, carrying out heat treatment, washing the ultrafiltration membrane, then dipping the ultrafiltration membrane in a mixed solution of a cross-linking agent and a charge reagent and carrying out heat treatment again. The membrane flux of the prepared polymer nanofiltration membrane can reach 60L/m .h under the pressure of 0.3MPa; the retention rate on micromolecule dye and high-valence inorganic salt can reach 90%; the chlorine-containing polymer nanofiltration membrane can be in a flat fiber ultrafiltration membrane form or a hollow fiber ultrafiltration membrane form, and has good practical prospect.